10x Your Memory Power
Chronic difficulties with memory appear to be a core problem in ADD syndrome, but the impairments are not generally with long-term storage memory instead they involve working memory, a term that has been used in many different ways, most of which are unrelated to the older term short-term memory. Working memory has several functions. An important one is to hold one bit of information active while working with another. One patient described his impairment of this essential function as lacking a hold button in his memory. Working memory, then, is not short-term memory. It does not function as the queue on a computer's printer, simply holding information briefly while it awaits further processing. Working memory, instead, is like a very active computational unit that not only holds information, but also actively processes this current information in connection with the vast files of longer-term memory. In other words, working memory might be compared to the RAM of a computer combined...
Among the many specialized aspects of the prefrontal cortex are circuits managing central working memory functions. Many people think of memory as a self-contained function that, somewhat like a video recorder, captures pictures and sounds of each moment of personal experience, then files all of them in some cerebral vault for playback on demand. If that were the case, the brain would quickly be flooded with so much information that effective action would be impossible. Research suggests that the systems of memory are more efficient. The brain has networks of neurons that very briefly hold in an active state the perceptions and thoughts of each moment, linking them with stored memories that allow the individual to string together experiences moment by moment to make sense of what is being perceived or thought and to act accordingly. This is working memory. Without it, an individual is perpetually locked into the present moment, unable to link what was seen, heard, or thought a moment...
The processes of working memory are complicated. They involve not only briefly holding onto current information needed for current tasks, and transiently holding information to be encoded into longer-term memory, but also calling up those memories in longer-term storage needed for immediate tasks and experiences. Neuroscientists Stephen Kosslyn and Olivier Koenig (1995) described these complex functions Working memory . corresponds to the activated information in long-term memories, the information in short-term memories, and the decision processes that manage which information is activated in the long-term memories and retained in short-term memories . . . an interplay between information that is stored temporarily and a larger body of stored knowledge. (p. 388) This interplay between a current focus of attention, some task or idea that an individual is attending to, and that person's store of long-term memories is essential to countless functions in daily life where one must pull...
Many of the cognitive abnormalities in schizophrenia are similar to those resulting from damage to the prefrontal cortex (PFC) including attentional abnormalities, problems in reasoning and judgment and working memory deficits 69 . Together with evidence of reduced prefrontal dopaminergic function in schizophrenia, these observations have lead to the view that positive symptoms are due to subcortical hyperdopaminergia, while cognitive deficits are the results of hypodopaminergia in the PFC 70 . There are in fact data indicating that reduced dopaminergic activity in the PFC may cause over activation of the subcortical dopamine system 71,72 . Clinical reports that PFC D1 receptors are upregulated in schizophrenia due to a localized decrease in dopaminergic activity and that D1 receptor antagonists aggravate psychotic symptoms, are consistent with this hypothesis 73,74 .
Evidence indicates that abnormal regulation of nicotine acetylcholine receptors (nAChRs) may contribute to the inattention and cognitive impairments associated with ADHD. Presynaptic nAChRs modulate the release of NE, DA, 5-HT, acetylcholine, glutamate and g-aminobutyric acid, neurotransmitters important to learning and memory 63 . nAChRs are comprised of a combination of 5a and b subunits which confer distinct pharmacologic properties. a4b2 and a7 antagonists were shown to disrupt working memory in rats 64 . In clinical trials, nicotine skin patches and the nicotine agoinist ABT-418 were shown to be effective in alleviating inattention in adults with ADHD 65,66 . The significantly higher occurrence of cigarette smoking (nearly twice the general population) in adolescents and adults with ADHD may represent a form of self-medication 67 .
Symptoms of ADD can be compared to impairments not in the individual musicians, but in the orchestra's conductor. As is clear in the cases of Larry and Monica, persons diagnosed with ADD usually are able to pay attention, to start and stop their actions, to keep up their alertness and effort, and to utilize their short-term memory effectively when engaged in certain favorite activities. This successful functioning of persons with ADD in preferred activities indicates that these people are not totally unable to exercise attention, alertness, or effort. They can play their instru
This paper received some 20,000 requests for reprints, but is seldom mentioned in current texts. It is clear, as suggested above, that Clements and Peters were writing about issues that later became translated into ADD or ADHD, namely problems of attention, impulsivity, hyperactivity, and working memory (incoming stimuli compared with stored information).
A system of this kind is capable of learning. Exposure to a given combination of stimuli activates17 some signalling pathways and inhibits others. As a result, responses appropriate to the cell's or organism's needs are evoked. After the response has begun, the cell still contains a specific pattern of activated and inactivated signalling components. This pattern might persist in the short term. If some of the stimuli are repeated while the pattern lasts, the same responses will be evoked. Therefore, signalling pathways confer a kind of short-term memory on the cell.
Figure 3 Primary brain structures involved in executive functions. Working memory circuits are located primarily in the prefrontal cortex the hippocampus converts working memories into longer-term memories. Risks and rewards are identified primarily via the amygdala and dopamine circuits, which originate in the ventral tegmental area. Alertness is supported by circuits from the locus coeruleus and reticular formation, and circuits from the cerebellum drive the fine-tuning of cognition. These circuits all interact with many others. Figure 3 Primary brain structures involved in executive functions. Working memory circuits are located primarily in the prefrontal cortex the hippocampus converts working memories into longer-term memories. Risks and rewards are identified primarily via the amygdala and dopamine circuits, which originate in the ventral tegmental area. Alertness is supported by circuits from the locus coeruleus and reticular formation, and circuits from the cerebellum drive...
It needs to be emphasized that the functional meaning of each of these circuits is defined in very broad terms, quite different from the segregated functional representation of different parts of the body, or the retina, in the classic sensory and motor pathways. Alexander et al. (1990) describe five such functional domains represented by basal ganglia-thalamocortical circuits motor and oculomotor circuits, two prefrontal circuits (defined mainly in terms of connections, but tentatively related respectively to functions of short-term memory and switching behavioral set), and a limbic circuit (tentatively related to emotions and motivational processes).
While much of the data captured in working memory simply passes through in mere seconds, so as not to clutter up the brain's limited atten-tional resources, other information is held longer to be worked on and or gradually shifted into longer-term memory storage. A chess player may hold in mind several moves made by an opponent, trying to discern the underlying strategy and plan countermoves. Or a listener may hold in mind several sentences of a funny story being told by a friend so he can grasp the punch line of his friend's joke. Sometimes the chess moves and the words of the joke may be retained in other instances they are totally transient. Working memory functions like RAM on a computer files are not saved after use unless they are converted to hard-drive data through a save function. The brain has a process for converting contents of working memory into longer-term memories. Contents of working memory that are saved into long-term memory are usually routed through the...
Chronic fatigue syndrome (CFS) A severely disabling fatigue with self-reported impairments in concentration and short-term memory, sleep disturbances and musculoskeletal pain. Occurs worldwide. A number of infectious agents have been proposed as etiologic agents of CFS, including Human herpesviruses 4 (EBV), 5 (CMV) and 6 (HHV6) enteroviruses retroviruses and Borrelia burgdorferi. None has proved to be a unique causative agent, but it remains possible that such infections act as a trigger for the syndrome. Synonyms post-viral fatigue syndrome myalgic encephalitis (ME).
These various brain circuits that support executive functions do not work in isolation. For most tasks, their operations are closely linked and interdependent. For example, Jan de Fockert and others (2001) used imaging studies to demonstrate linkage of working memory with tasks of selective attention. Imaging by the labs of Helen Mayberg (1999) and Jean-Baptiste Pochon (2002) have demonstrated circuits in the brain that gate emotions. Florence Levy (2004) has explained the crucial role of dopamine in this gating process that allows most people to attenuate emotional reactions, such as anxiety or discouragement, when they are trying to deal with important concerns. Posner (1994) and Raichle did a series of imaging studies that showed linkages within the prefrontal cortex and with other brain regions they found four different areas of the brain consistently lighting up when adults were asked to do simple verbal tasks.
By December I was taking large amounts of Antivert, Dramamine, and ginger ale to get through a 3-hour class. If I moved too fast or a student waved a hand or turned a page of a book without warning, I would fight the nausea that comes from vertigo. I memorized my lectures so that I did not have to look down at my notes. I would sometimes have to vomit during the breaks in class, wash my face, and then continue to teach. On the day I picked up the students' exams to grade, I went to see my general doctor. He immediately said that I did not have a virus and refused to let me drive myself to the emergency appointment he made with a neurologist.
In a similar manner, individuals differ in their inborn baseline levels of sensitivity to change and stress. Studies by Jerome Kagan and colleagues (1994, 2004) showed that in a sample of infants about 20 percent are born with a very low threshold for anxiety they tend from the earliest months of life to respond with obvious distress and excessive behavioral inhibition when confronted with novel or stressful situations. These individuals are likely to be seen by others as exceptionally sensitive or overly fearful well into childhood and beyond. Work by Louis Schmidt and others (1999) indicates that these more socially reticent and anxious children tend to be less successful than age-mates at tasks requiring use of working memory and are more often off task. This may be due to these children being flooded with anxious emotions in ways that interfere with their attending to other stimuli and tasks.
Once developed, executive functions do not remain static over the lifetime. They may be refined further during early and middle adult years, and in later adulthood, for many, they begin to decline. Monica Fabiani and Emily Wee (2001) have shown that impairment in frontal lobe functioning is characteristic of elderly adults on many cognitive tasks, especially those involving working memory but they emphasize that individual differences tend to increase with age. Lifestyle, general health, and other factors greatly contribute to the effects of age on executive functions. Although there is considerable variability among elderly persons in the quality of their cognitive functioning, many manifest impairments in working memory as they age, even without any disease processes or dementias. Some suggest that the increasing inefficiency of working memory in the elderly is due to specific impairments in memory other researchers, for example, Timothy Salthouse (1991), suggest that the apparent...
DO NOT REFER TO THE TEXT WHEN TAKING THIS TEST. A good score is at least 18 (out of 25 questions) correct. Answers are in the back of the book. It's best to have a friend check your score the first time, so you won't memorize the answers if you want to take the test again.
The first kind is oral reading fluency in which children not only become faster in recognizing words, but their oral reading begins to reflect the melody or intonation of the spoken language. The second kind is silent reading fluency in which children quickly and automatically access . . . word forms . . . thereby freeing up limited working memory resources for reading comprehension. (pp. 162-163) Children who suffer from chronic impairments in their ability to sustain attention and effort, to utilize working memory, and to employ other executive functions usually impaired by ADD syndrome, are likely to have continuing difficulty in these more advanced aspects of reading comprehension. Children with significant attention impairments during their early school years are likely to experience difficulties not only in reading, but also in learning mathematics. Elizabeth Benedetto-Nasho and Rosemary Tannock (1999) studied students aged seven to eleven years, half of them with an ADHD...
Some situations require only the simple exercise of very basic functions waiting a moment, heeding a warning to stop, saying a few words, or noticing the lighted color on a stoplight. Others are more complex and require more refined executive abilities. For example, in many situations behaving carefully requires attending to details that may signal risk it also requires working memory to keep in mind what one is doing, for example, avoiding distractions and attending to traffic while trying to cross a street. It also requires calling to mind information relevant to the present moment, such as remembering cautions one has been given to avoid certain potentially risky situations. And it requires monitoring and self-regulating actions so that one is not completely dependent on others to protect and control what one is doing. Even in the early years of preschool, some children demonstrate significant delays or impairments in development of certain capacities of working memory, planning,...
''Okay, so what's all this marrow cavity stuff, about '' the involved reader may ask at this point. The medullary cavity is alternately called the marrow cavity, because it is filled with yellow marrow. Named for its yellowish color, the yellow marrow chiefly consists of thousands of adipocytes. Your memory may serve to remind you (Chapter 6) that adipocytes are ''fat cells'' that make up adipose connective tissue. Therefore, the yellow marrow has an energy-storing physiology for the long bone.
This girl reported that despite her initial discomfort with drinking beer and smoking marijuana, she soon came to enjoy its relaxing properties as well as the concomitant social interaction. She said she also appreciated her boyfriend's gentle sexual attentions that gradually developed into an active sexual relationship enjoyed by both of them. Her failure to take regularly the contraceptive pills she had obtained from a clinic was probably due to the effects of her ADD-related working memory problems combined with her dimly sensed hope that if she were accidentally to be
Could abnormal cholinergic function during circuit formation be one possible scenario under which excessive activation occurs in immature higher cortical circuits We consider this likely since activation of muscarinic receptors typically enhances neuronal excitability. More importantly, muscarinic receptors seem to be directly involved in enabling sustained firing. Thus in frontal cortex in vitro, neurons switch to a sustained firing mode in response to muscarinic activation (Haj-Dahmane and Andrade, 1996, 1998). This type of firing is similar to that seen in single units in vivo during delayed matching tasks requiring working memory. Moreover, muscarinic blockade in the medial prefrontal cortex of rats interferes with the performance of a delayed matching task (Broersen et al., 1994, 1995), suggesting again an important role for muscarinic receptors in sustained firing. If present, what effect could excessive cholinergic activity have during development One possibility at the local...
This longer-term future planning challenges an aspect of working memory that has not been discussed much in the neuropsychological literature thus far. Paul Eslinger (1996) observes This type of prospective archival memory is not well-defined in current models. It qualifies as a type of working memory because it implies prospective memory-guided responding rather than sensory-guided responding. It is frequently changing yet enduring over a long period of time. Does the influence of future goals reside in some form of longer-term working memory that is kept alive by daily activities such as the behaviors that alter future consequences (p. 385) It is during adolescence that this ability to relate the choices of the moment and of the day to longer-term aims and goals becomes increasingly important. This aspect of working memory is often significantly impaired in adolescents with ADD syndrome. As the scaffolding of earlier years is
I need to get evaluated for ADD because I know I have it and it's really messing me up. Maybe if I get the right medication, things will get better. In this graduate course we just studied about ADD and every symptom on the list is something that has been a problem for me all my life. I'm terrible about planning and organizing. I can't stay focused when I read. I never remember what I've read. I've got a great memory for things from a long time ago, but my short-term memory has never been any good. I'm the world's biggest procrastinator, always late with everything. I got through my undergraduate degree, just barely, but now I'm really struggling with this graduate course. I can't keep up with the reading and the tests are really hard. I haven't even started yet on a big paper that is due in three days.
Another region where wave activation takes place in coronal slices is a strip of lateral cortex. At the level from which slices are obtained, this area is ventral to the somatosensory cortex and may correspond to the agranular insular cortex, believed to contain higher order (associational) cortical regions involved in working memory for food reward (Ragozzino and Kesner, 1999). With slices that have been obtained from regions closer to the anterior pole of the brain, or those that have been prepared in the horizontal or sagital planes, it has been possible to observe very extensive wave-like activation in the prefrontal cortex. In contrast, imaging in sagital slices that include the occipital pole (visual cortex) reveals that cholinergic stimulation does not induce a wave of activation in this sensory region.
Taken together, these results suggest that across wide age spans, these tests of story recall offer a brief and effective way to test impairments of verbal working memory in individuals being assessed for ADHD. These simple tests take only about ten minutes to administer. The task allows the clinician to check the effectiveness of a patient's working memory on a task similar to many situations in daily life where one is given information orally and is able to hear it only once. It should be noted, however, that in each age group some persons with ADHD were not impaired on the story-recall task, while some who did not have ADHD were impaired. For this reason, results of such a test cannot be used alone to determine the presence or absence of ADHD. Multiple measures are needed. index scores on the WISC-III. Two of the indexes the Verbal Comprehension Index (VCI) and the Perceptual Organization Index (POI) summarize subtests less sensitive to executive-function impairments instead these...
In some cases these questions can be answered, yes or no, with little hesitation or ambiguity. Other cases are much more complicated, making one or both questions considerably more difficult to answer. Sometimes there are striking contradictions in the information provided by various informants about the patient's symptoms. One parent may describe a child as having significant problems with organizing and completing homework, retaining learned information, and utilizing short-term memory. The other parent of the same child may emphatically deny that such problems exist. Either one could be correct, or each may be correct about only certain aspects of the child's functioning.
In addition to this anatomical data, functional considerations support the concept of volume transmission. The number of cholinergic neurons within the basal forebrain is relatively small, on the order of 105 in the rat (Mesulam et al., 1983a,b). These cholinergic neurons innervate cortical structures containing many orders of magnitude more pyramidal cells and interneurons. These structures mediate encoding of a large number of different patterns of activity in semantic memory. This large discrepancy in number of neurons raises serious doubts about the ability of the basal forebrain to selectively regulate activity associated with specific memory patterns in cortical structures. Even if each stored pattern were being regulated by only a single basal forebrain neuron, the number of stored patterns in semantic memory would far exceed the capacity of the basal forebrain for selective regulation. In contrast, this relatively small number of neurons could work in a more cohesive manner to...
At age twelve, George was in fifth grade. He was a well-behaved boy who wanted very much to do well in school. His grades in math were always high, but he generally did poorly in reading and in any other classwork that involved reading. He was bright. On IQ tests he scored in the high average range. He had a strong vocabulary for listening and for speaking, but his reading vocabulary was very small. He could not read many words that were familiar when spoken to him. He could memorize a short list of words for weekly spelling tests, but he could not remember to spell those words correctly after the test and he was generally a very poor speller.
Comparison of these comorbid disorders with the characteristics of ADD syndrome shows considerable overlap as well as differences. Management of arousal, ability to activate for tasks, ability to sustain effort for tasks, management of emotions, ability to effectively utilize working memory, ability to size up and regulate actions in social situations these interacting executive functions tend to be impaired in each of these comorbid disorders. Yet each of the comorbid disorders of arousal and motivation is also characterized by more extreme intensity or absence of arousal, and or by motivation that is more extreme in its variability or fixity, than is usually found in ADD syndrome itself. These extremes of arousal and motivation, combined with specific related impairments of these various disorders, occur among persons with ADHD more often than in most others without ADHD. The high rates of comorbidity between ADHD and these various disorders of motivation and arousal may be seen as...
Numerous human memory studies demonstrate that blockade of muscarinic acetylcholine receptors by systemic administration of the drug scopolamine interferes with the encoding of new verbal information, while having little effect on retrieval of previously stored information (Crow and Grove-White, 1973 Drachman and Leavitt, 1974 Ghonheim and Mewaldt, 1975 Peterson, 1977 Beatty et al., 1986 Sherman et al., 2003 see Hasselmo, 1995 Hasselmo and Wyble, 1997 for review). Scopolamine appears to primarily affect episodic memory, while sparing semantic and procedural memory (Caine et al., 1981 Broks et al., 1988) and short-term memory phenomena such as the recency component of a serial position curve (Crow and Grove-White, 1973) and digit span (Drachman and Leavitt, 1974 Beatty et al., 1986).
If cholinergic activation of INCM is important to provide intrinsic mechanisms for self-sustained spiking activity, then blockade of this cholinergic activation should prevent sustained spiking activity during the delay period and match enhancement. This effect of muscarinic antagonists could underlie the behavioral impairments in delayed matching tasks seen with systemic injections of muscarinic antagonists (Bartus and Johnson, 1976 Penetar and McDonough, 1983). In addition to this role in short-term memory function, sustained activity in entorh-inal cortex could also be very important for effective encoding of long-term representations through synaptic modification in the hippocampal formation. Thus, the blockade of sustained spiking activity in entorhinal cortex could contribute to the encoding impairment caused by injections of scopolamine (Aigner and Mishkin, 1986 Buresova et al., 1986 Aigner et al., 1991 Anagnostaras et al., 1995 Tang et al., 1997 Anagnostaras et al., 1999).
Schematic of cholinergic modulation of hippocampal dynamics during active waking and slow wave sleep. Left During active waking, high levels of acetylcholine set appropriate dynamics for encoding. Sensory information from neocortical structures flows through the entorhinal cortex and dentate gyrus (DG) into hippocampal region CA3, where cholinergic enhancement of synaptic modification helps in formation of an intermediate term representation binding together different elements of an episodic memory. Feedback connections to region CA1, entorhinal cortex and association cortex are strong enough to mediate immediate retrieval, but cholinergic suppression of these connections (ACh) prevents them from dominating over the feedforward connectivity. Right During quiet waking or slow wave sleep, much lower levels of acetylcholine release the suppression of excitatory feedback. This strong excitatory feedback mediates reactivation of memories stored in region CA3 during EEG phenomena...
Many middle-aged women report that during menopause, whether naturally occurring or surgically induced, they experience for the first time a constellation of persisting symptoms that closely resembles ADD syndrome. They note significant declines in short-term memory, in the ability to screen distractions and to sustain attention, in the organization and prioritizing of tasks, and so on. Some of these women are very competent, well-educated professionals and business executives who until menopause have never experienced significant impairments of ADD syndrome. In addition, women who have been diagnosed before menopause with ADD often report that their ADD symptoms tend to worsen for several days each month at about the time their estrogen level is probably lowest. As they enter menopause, many of these women also report significant exacerbation of their long-standing ADD symptoms. Barbara Sherwin (1998) has reported that administrating estrogen to postmenopausal women enhances verbal...
Many men and women complain of increasing problems with attention, working memory, and other executive functions as they reach late middle age and beyond. Denise Park and Trey Hedden (2001) evaluated men and women aged twenty-nine to ninety to determine how performance on tests of perceptual speed and working memory changes across age groups. They found that the rate of decline on measures of processing speed, working memory, and long-term memory was consistent across the lifespan. As this analogy illustrates, the absolute decline in working memory function may be equivalent across decades, but the proportion of processing resources lost is greater as one gets older. (p. 154)
Nicotinic transmission has been proposed to participate in many cognitive processes. Not only can nicotine improve performance in various tasks involving spatial and associative learning, working memory and attention, but mecamylamine, a general nicotinic antagonist, has been demonstrated to impair memory performance (Levin, 1992). Furthermore, lesions of the cholinergic forebrain system result in cognitive deficits reverted by nicotine (Tilson et al., 1988 Decker et al., 1992 but see Gallagher and Colombo, 1995 Chappell et al., 1998). These findings, together with the observation that choliner-gic function is impaired in the brains of Alzheimer's disease patients have contributed to the formulation of a cholinergic hypothesis to explain the cognitive impairments observed in Alzheimer's disease (Robbins et al., 1997). Prompted by epidemiological studies suggesting that the incidence of Alzheimer's and Parkinson's disease is significantly reduced in smokers (reviewed in Fratiglioni and...
Using ERP methodology, there is evidence that potentials signifying the early excitatory responses (P1 and P2 to a visual stimulus) are larger-than-normal in Parkinson's disease (Wright et al., 1993 see also Praamstra and Plat, 2001). Later potentials (such as the P300), which are indicative of inhibitory processes, are smaller than normal, especially when produced under conditions of high working-memory load, normally requiring stronger inhibition (Robertson and Empson, 1999). Pulvermiiller et al. (1996) reported that P300 potentials were attenuated in Parkinson's disease, most severely when they were produced by a stimulus indicating a NoGo response, again normally involving especially strong inhibition.
The interpretation of these data requires a clear distinction between the cognitive enhancing properties of nicotine, which seem to be dependent on b2* nAChR activation, and the physiological role of nicotinic transmission in normal cognitive function, which has been more difficult to demonstrate. Apart from functional compensations, which could explain these findings, it is striking to note that highly specific lesions of basal forebrain cholinergic neurons fail similarly to produce overt behavioral deficits (Gallagher and Colombo, 1995 Chappell et al., 1998). In both cases, it is likely that in the absence of any other lesion, redundant neurotransmitter systems are sufficient to maintain high levels of performance in simple behavioral tasks. Examining the performance of Ko animals during aging (see below) or in more difficult tasks might be necessary to reveal a deficit. In fact, the physiological involvement of nAChRs in cognitive function seems particularly prominent in cognitive...
Essary focus and effort, or to engage their working memory and monitor their actions enough to do what they know they need to do. But when appropriate medication is in place to correct the chronic chemical problems that have impaired their executive functions, they generally function well.
Dren, including many with ADHD, to refrain from being disruptive in classrooms and at home. But it is difficult to see how even the best behavioral treatment program can modify an individual's impairments of ADD syndrome as they affect working memory or hamper one's ability to sustain attention enough to understand what one is reading, to write an essay, or to drive a car. And it is very difficult to imagine how such approaches could be used effectively for adolescents or adults with ADD syndrome who struggle to function as students in high school or university, or as working adults, or parents situations where no one is available to monitor their complex behaviors or manage their reinforcements.
John Chelonis (2002) tested whether MPH significantly improves working memory in children with ADHD. In a series of trials, children with ADHD were significantly more accurate and efficient in remembering shapes correctly when on the MPH than when off it on medication, their performance became as efficient as that of normal children of the same age range. The medication normalized their impaired working memory. MPH may influence global cognitive processes, such as atten-tional capacity or working memory, that are deficient in children with ADHD and result in improvements in aspects of response inhibition, as well as response execution. (p. 325) Taken together, these various studies demonstrate that stimulant medications improve a variety of functions impaired in ADD syndrome. These include sustaining alertness, focus, motivation, and effort for tasks that are not intrinsically interesting shifting attention as needed utilizing working memory adjusting processing speed to the demands...
However, the best available evidence suggests that LTP is relevant only to long-term memory storage, which is established only an hour or two after the learning event has taken place. It is not relevant to immediate and short-term memory. As an explanation for associative learning, therefore, it is not entirely adequate.
For many years, physicians prescribed stimulant medications to children only for school days or for weekend days when homework needed to be done. In recent years, however, clinicians have come to recognize that non-academic tasks are also impaired with ADD syndrome. A child who has great difficulty in maintaining focus, sustaining effort, utilizing working memory, managing frustration, monitoring action, and so on in school is likely also to have similar difficulties when playing Little League baseball, attending religious services, or interacting with friends and family. Most adults with ADD syndrome who are excessively distracted and forgetful at work are likely to have similar difficulties while shopping, driving their car, managing their children, or interacting with colleagues and family.
Children and adolescents with disruptive behavioral problems are the ones who primarily benefit from behavioral treatments, which are of limited use for improving cognitive functions such as working memory, processing speed, and sustaining alertness. Behavioral strategies may also help to reduce the common tendency of parents, teachers, and others unwittingly to reinforce a child's disruptive behaviors. For an overview of the extensive body of research showing the effectiveness of these interventions for disruptive behavior orders, including ADHD, see William Pelham and Daniel Waschbusch (1999).
However, the pattern of abnormal movement-related activity in frontal motor areas has been variable across studies (9-12). Since these studies used motor tasks that differed in terms of movement parameters and cognitive load, the implication is that, in PD, functional impairment of the various basal ganglia-thalamocortical motor loops is highly dependent on the motor context. In addition to motor activation studies, BOLD-sensitive fMRI has also successfully been employed to assess nonmotor functions such as attention to action and working memory in PD (12,13). Repeated fMRI measurements have also been used to image the acute effects of a therapeutic intervention. For instance, pharmacological fMRI studies have consistently demonstrated a partial normalization of movement-related activation in frontal motor areas after oral administration of levodopa (9-11).
A recent decline in self-help, communication or vocational skills a striking change in mood, social skills or memory capacity the appearance of epilepsy, myoclonus or impaired motor performance in the absence of alternative neuropathological diagnoses were considered as possible clinical evidence for dementia of Alzheimer type (DAT).
The most commonly requested accommodation is extended time for taking tests and examinations. Because of their slow cognitive processing speed and impairments of working memory, many children, adolescents, and adults with ADD syndrome have great difficulty completing tests and examinations within standard time allotments. To compensate for their ADD impairments, they often need to reread directions and test items multiple times and need repeatedly to recheck their answers. This may slow their work so much that they are unable even to attempt many items on the test. Thus they may get a low grade, not because they did not know the material and gave wrong answers, but because they were unable to complete the exam.
Drugs enhancing central cholinergic function provide a rational approach to the treatment of cognitive dysfunction associated with the Parkinson plus disorders. In PSP, however, a controlled trial of physostigmine showed only borderline changes in long-term memory (41), although improved visual attention has been reported (92). An open study of donepezil did not appear to ameliorate cognitive dysfunction (38), whereas a controlled trial suggested modest benefit in some cognitive measures but worsened mobility scores (42). A controlled trial on the direct cholinergic agonist RS-86 revealed comparable unsatisfactory results (43).
Tients' presenting complaints about impaired short-term memory, inattention, disorganization, underachievement, and so on as signs of anxiety or depressive problems. They also are likely to provide treatments appropriate for those disorders without even considering the possibility that these may be symptoms of ADHD, with or without comorbid anxiety or depression.
Since Freud's time, much more has been learned about the unconscious workings of the mind. A new view of the unconscious, quite different from psychoanalytic formulations, is emerging in psychology and neuroscience (see Hassin, Uleman, and Bargh 2005). But still many persons are reluctant to believe that their conscious thought does not reign supreme over their cognition. Even though they do not expect to control by willpower the endocrine malfunctions of diabetes or the growth of a cancer, they want to believe that willpower can sustain control over malfunctioning cognitive processes that, among other important tasks, organize and prioritize, maintain working memory, activate effort, and regulate alertness.
Any discussions of hope usually emphasize that one should use willpower and determination to overcome adversity. This view often is used to challenge persons with ADD syndrome. Children, adolescents, and adults with ADD syndrome often are told that if only they will push themselves hard enough and long enough, if only they will put forth enough determined effort, then they will be able to overcome their problems with inconsistency, disorganization, working memory, emotional regulation, and so on. Such exhortations are not helpful and may be damaging. This advice is equivalent to urging a driver to step more forcefully on the accelerator to move a car with a nonfunctioning transmission.
Furey et al. (1997) studied the changes in cerebral blood flow in healthy subjects receiving an infusion of physostigmine during the performances of a working memory task. They observed an increase in cerebral blood flow in the right prefrontal cortex during the task, which was less pronounced during the infusion of physostigmine. Since physostigmine improved the working memory test performance, they concluded that this was related to reduced task-related activity in the prefrontal cortex, suggesting that enhanced cholinergic function in brain could ameliorate processing efficiency (Furey et al., 1997). Cholinergic enhancement with physostigmine has also been shown to cause selective increases in the perceptual processing processes during working memory test (Furey et al., 2000). In addition, Sperling et al. (2002), using functional MRI technique, recently observed that administration of scopolamine to healthy young subjects decreased the activation in hippocampus and inferior...
As mentioned above, the initial findings of vaso-pressin effects on explicit memory have triggered at the time a number of clinical studies, but with moderate success. One of the constraints with human behavioural studies is the targeting of neuropeptides to the brain, and it has been shown that oxytocin and vasopressin do not or hardly cross the blood-brain barrier (Ermisch et al., 1985). Obviously, local intracerebral injections cannot be performed in humans and need to be
Amide 39 is a potent and selective inhibitor of GlyT-1 both in vitro (K 1.79 nM) and in vivo (CSF-glycine ED200 3.9 mg kg, rat, p.o.) but with limited permeability across Madin-Darby canine kidney (MDCK) cell membranes 78 . Optimization led to fused 3.1.0 and 3.3.0 azabi-cyclic analogs 40 (PF-3463275) 78 and 41 79 , respectively. Analogs of both systems demonstrated excellent potency (Ki 1.7-95 nM), and improved permeability, PK, and in vivo efficacy. Spatial working memory
The origin is the least movable tendon or attachment of a muscle. Conversely, the insertion is the more movable tendon or attachment. You can tell which end of a particular muscle is the origin, and which the insertion, without always having to memorize this information for every single muscle if you learn this important Muscle Freedom-of-Movement Rule
SZ is a common psychiatric disorder affecting 1 of the population. Onset usually occurs in late adolescence or early adulthood, coinciding with a developmental reduction in brain synapse density, and symptoms include delusions, hallucinations, impaired motivation, and changes in cognitive responses such as attention span and working memory. Pathologically, the hippocampus, superior temporal gyrus, and thalamus are affected, with predominant pathology occurring in the prefrontal cortex, which is thought to underlie the cognitive impairment symptoms. Gene expression studies have identified the involvement of presynaptic secretion, mitochondrial dysfunction, and oligodendrocyte impairment in the molecular pathogeneis of SZ.
When considering the possibility of abnormal levels of activation, cortical areas such as the frontal regions, the premotor or supplementary motor areas, and the cingulate areas are of particular interest for two reasons First, functional abnormalities in these areas in mature brain are generally associated with a range of neuropsychiatric disorders (Cohen et al., 1987 Weinberger et al., 1992 Carter et al., 1997 Curtis et al., 1998 Bradshaw and Sheppard, 2000 Holcomb et al., 2000), and therefore the occurrence of developmental events that may derail the process of circuit formation in these areas is of great importance clinically. Second, these areas have the ability to exhibit sustained neuronal firing in the absence of sustained sensory input, a property thought to underlie the ability of neural circuits in these areas to hold information in 'working' (short-term) memory (Durstewitz et al., 2000). It follows that if this property is present in some form during early circuit...
Fact Add is a complex disorder that involves impairments in focus organization motivation emotional modulation memory
Attention is an incredibly complex, multifaceted function of the mind. It plays a crucial role in what we perceive, remember, think, feel, and do. And it is not just one isolated activity of the brain. The continuous process of attention involves organizing and setting priorities, focusing and shifting focus, regulating alertness, sustaining effort, and regulating the mind's processing speed and output. It also involves managing frustration and other emotions, recalling facts, using short-term memory, and monitoring and self-regulating action.
The World Federation of Neurological Surgeons (WFNS) scale (Table 4) eliminates the subjective aspects of the Hunt and Hess scale and incorporates the GCS score as the basis for grading SAH. It effectively uses the objective criteria of the GCS to yield a WFNS SAH scale. Although this scale is easier to memorize and use, its categories have not been validated clinically.
The current classifications of memory include both implicit, or unconscious memory, and explicit, or conscious memory. Explicit memory refers to the conscious recollection of specific intraoperative events that took place during general anesthesia, also called anesthetic awareness. Recall can only be determined after surgery. These memories can occur with or without pain and can range from vivid recollections to vague memories. It was reported in 2008 that subjective auditory perceptions represented 50 of intraoperative awareness experiences. By contrast, implicit memory reflects changes in behavior or performance secondary to an anesthetic experience without the ability to specifically recall the event. The 2006 American Society of Anesthesiologists' (ASA) practice advisory regarding intraoperative awareness excludes dreaming as anesthetic awareness.
Since memory complaints are among the most frequently reported signs of decreasing abilities in both normal aged and dementing subjects, an enormous amount of research has been directed at establishing the nature of memory disorders in aging and dementia. Generally, different kinds of memory and memory disorders have been characterized (see Russell, 1981). In the clinic the term 'remote memory' is used to describe retrieval of information which has been acquired many years ago. The term 'recent memory', on the other hand, is used to describe retrieval of information which has been acquired some months, weeks, or only days ago. Much research has been centered around the concepts of 'short-term memory' or 'long-term memory' in the sixties, whereas a more recent trend in memory research asks the question 'how information is processed and used'. that information from the environment is sensed by the sensory registers (visual, auditory, tactile, etc.) and passed on to a central processing...
What has been recognized only in the past decade is that portions of the cerebellum provide similar fine-tuning for a wide variety of cognitive activities. Michael Posner and Marcus Raichle (1994) have demonstrated that the cerebellum plays an important role in selecting appropriate verbs to go with specific nouns. Antonio Damasio (2003) has reviewed research suggesting that portions of the cerebellum may also be involved in adjusting social behaviors, for example, laughing and crying, to specific situations. And Birgit Gottwald, with others (2003), has demonstrated that damage to specific areas of the cerebellum significantly impairs specific aspects of an individual's ability to divide attention between tasks and to utilize working memory. Apparently the cerebellum contributes to management of complex cognitive activities in a wide variety of ways.
The results of studies on different GABAA receptor ligands in animal models relevant to learning and memory seem to support such GABAergic therapeutic approaches in AD. Thus, whereas administration of GABAA agonists impairs learning and memory in animals 25, 26 via modulation of cholinergic pathways, memory enhancement was observed after injection of the GABAA antagonist bicuculline methiodide. Similarly, agonists and inverse agonists at the benzodiazepine (BZD) site of the GABAA receptor complex impair and enhance, respectively, performance in learning and memory tasks 27 . Administration of THIP to Alzheimer patients failed to significantly improve cognitive performance 28 .
Neural networks are based on neurons (computational elements) connected to a framework. The two most important subtypes are Kohonen self-organizing maps and artificial neural networks. SOM are examples of unsupervised NNs, particularly useful for features extraction, data classification, clustering, and visualization. Artificial neural networks is a pattern recognition approach 91 , fitting nonlinear function relating a discrete or continuous output Y and a set of inputs for a training set of molecules. Once memorized, this network can then be used to make predictions for molecules for which Y is unknown (see Section 2.3).
The administrative burdens of her manager's job included setting up the work schedules for three shifts, finding coverage for nurses calling in sick, keeping track of supplies that needed to be ordered, filing required reports, representing the interests of her unit in administrative meetings, and arbitrating disputes among staff members. Unlike direct patient care, which was intensive and complex but limited to dealing with just a few patients within the limits of eight-hour shifts, this administrative position required much planning, thought, and discussion over both the short and longer terms. It required her to keep in mind countless requests, complaints, and tasks that carried over from one day to the next, sometimes over weeks and months. In short, these management tasks severely challenged this nurse's chronic executive-function impairments in organizing and prioritizing, in sustaining attention, and in utilizing working memory.
Irrespective of current human practice, in the future it is impossible not to envisage high-throughput machines analysing routine samples of biological specimens. Widespread use of automation will not be immune from the introduction of human biases into the results. Errors will be due in part to the inadequacies of the machines and software themselves, which, after all, are both human constructs, but a proportion will be due to incorrect expert-labelled training data. To improve the entire process, these errors must be minimized and also quantified. It is possible that error rates as high as 25 per cent will be the norm for large-scale analysis. These error rates may well be similar to current and historical human errors in field sample analysis. Some of these errors will be due to human factors, short-term memory, fatigue, monotony and biases. Some errors will be due to a lack of consensus on the label given to difficult taxonomic specimens and species.
Model of short-term memory in aged and adult rats and in a water maze model, demonstrating effects on different aspects of cognitive impairment 27 . ABT-239 was also active in the prepulse inhibition (PPI) startle model 26 , a model of sensory gating proposed to be related to schizophrenia. JNJ-5207852, another potent H3 compound, ameliorated learning and memory deficits in PTZ-kindled mice in a variety of cognitive models 28 . However, the compound was inactive when tested at 5mg kg s.c. in a water maze model in these mice 25 .
Whether the basic deficits in ADHD children are in the areas of attention, self-regulation, EF, or some other process continue to be hotly debated issues. The boundaries among inat-tention attention, working memory, arousal, EF, and effort are more than just somewhat obscure. One could, for example, substitute terms like the following for ADHD intention disorder (14,15), inhibition disorder (12,22,50,234), motivation disorder (53,62,75,88,235), short-term memory disorder (140,141), rule-based disorder (74,84,93), or even MBD if we remove LD from the definition. Almost any label would be acceptable, if truly descriptive or better explanatory of the symptoms of these children.
People infected with HIV may experience a flulike illness within a month or two of exposure to the virus many have no symptoms. This symptom-free period lasts from a few months to a decade, although the virus is actively multiplying, infecting, and killing immune system cells during this time. The only sign of this virulent activity may be a decline in blood levels of CD4 cells from a normal level of about 1,000. Once a person's CD4-cell count falls below 200, he or she is considered to have AIDS. By that time, other signs of the immune system's deterioration have appeared swollen glands, lack of energy, weight loss, frequent fevers and sweats, persistent or frequent yeast infections, skin rashes, short-term memory loss, frequent and severe herpes infections, or a painful nerve disease called shingles.
The first involves difficulties in representing arithmetic facts in, or retrieving facts from, long term memory . . . many MD mathematics disorder children have problems remembering basic arithmetic facts such as 5 + 9 14, even with extensive drilling. . . . The second involves difficulties in executing arithmetic procedures, such as carrying or trading in complex addition, or in executing counting procedures to solve simple addition problems. (pp. 155-156) In 2000 I argued that impairment of working memory plays a critical role both in ADD syndrome and in the cognitive functions that are disrupted in learning disorders related to reading, math, and written expression. Reading involves holding in mind and integrating initial portions of a word, phrase, sentence, paragraph, chapter, and so forth long enough to connect these with subsequent portions so that connections can be made and various levels of meaning can be comprehended. Connections must be made between letter shapes and...
Although acrylate agents have been routinely used in Europe for more than 20 years, PVA particles were the main embolic agent for preoperative embolization of AVMs in the United States prior to the approval of NBCA by the Food and Drug Administration. Because embolization with PVA particles does not penetrate the nidus of the AVM efficiently, the degree of devascularization of the lesion tends to be overestimated, and the chance of recanalization increases (46,47) . Ethanol represents another alternative agent for AVM embolization. One series found no evidence of recanalization in patients after a mean follow-up time of 13 months (48). Although complications occurred in 8 of 17 patients (47 ) (including short-term memory loss in one patient and subarachnoid hemorrhage and death in two patients), it was concluded that ethanol has a permanence not observed in most other embolic agents (48 ). A new biocompatible liquid ethylene vinyl alcohol copolymer preparation is the most recently...
The caudate nucleus is an integral component of the frontostriatal network involved in cognitive functions (Chow and Cummings, 1999 Voelbel et al., 2006), including learning (Poldrack et al., 1999), short- and long-term memory (Fuh and Wang, 1995), and planning and problem-solving (Mendez et al., 1989 Schmidtke et al., 2002). The increased volume of the caudate observed in autistic children may be indicative of impaired neuronal pruning, contributing to a decrease in executive function (Voelbel et al., 2006).
What features pertinent to ADHD does the SHR model, which may also be influenced by NE and 5-HT The SHR explores more (112), though activity can be context-dependent (113), reminiscent of situational rather than pervasive hyperkinetic children. SHRs may learn Hebb-mazes, active-avoidance tasks, and multiple reversals faster than controls (114,115), yet this sometimes reflects poor WKY performance (113). Sometimes the SHR has difficulty with passive avoidance, water-maze extinctions, longer-term working memory, and delayed response learning (e.g., temporarily withholding response for gratification 116,117). To a degree these difficulties, especially the last one, do mirror some of the features of ADHD. Recent reviews on the contribution of transmitter systems to ADHD give prominence to NE alongside DA, to the neglect of 5-HT and other candidates (135). These views are predicated on the undisputed role of impaired frontal activity in ADHD performance where delayed reinforcement (136),...
In all of those areas of life in which you have to learn things, develop techniques for more efficient learning. Develop your own personal techniques to improve your memory, having first sorted out the areas in which it is weakest. Also develop ways in which you can avoid being unduly influenced or conditioned by your circumstances at home or at work when you do not wish to be. Practise thinking both lineally and laterally. Devise situations in which you are creative and simply practise creativity. Think about the problems in your own life and the lives of those that you know and practise solving them with flexible and original thinking.
Transformation for small coefficients but progressively implies nonlinear transformation when the coefficient values increase. The units in the middle of the networks, computing the derived features Zm, are called hidden units because the values Zm are not directly observed. In general there can be more than one hidden layer. The result is a powerful learning method with widespread applications in many fields. It is often difficult to decode the final model to identify the changes to molecular structure needed to obtain a desired property. NNs also have a tendency to memorize rather than learn and are particularly susceptible to overfitting, especially if the training data are noisy.
DO NOT REFER TO THE TEXT WHEN TAKING THIS TEST. A good score is at least 18 (out of 25 questions) correct. Answers are in the back of the book. It's best to have a friend check your score the first time, so you won't memorize the answers if you want to take the test again. DO NOT REFER TO THE TEXT WHEN TAKING THIS EXAM. A good score is at least 75 correct. Answers are in the back of the book. It's best to have a friend check your score the first time, so you won't memorize the answers if you want to take the test again.
Short-term memory (STM) lasts from a few seconds to a few hours and is limited to a few bits of information such as the digits of a telephone number. Information stored in STM may be quickly forgotten if we stop mentally reciting it, we are distracted, or we have to remember something new. Working memory is a form of STM that allows us to hold an idea in mind long enough to carry out an action such as calling a telephone number we just looked up, working out the steps of a mathematics problem, or searching for a lost set of keys while remembering where we have already looked. These short-term memory tasks may be carried out by reverberating circuits of neurons. Memories lasting for a few hours, such as remembering what someone said to you earlier in the day or remembering an upcoming appointment, may involve postte-tanic potentiation. In this process, the Ca2+ level in the synaptic knob stays elevated for so long that another signal, coming along well after the tetanic stimulation has...
Long-term memory (LTM) lasts up to a lifetime and is less limited than STM in the amount of information it can store. LTM allows you to memorize the lines of a play, the words of a favorite song, or textbook information for an exam. On a still longer timescale, it enables you to remember your name, the route to your home, and your childhood experiences. There are two forms of long-term memory declarative and procedural. Declarative memory is the retention of events and facts that you can put into words numbers, names, dates, and so forth. Procedural memory is the retention of motor skills how to tie your shoes, play a musical instrument, or type on a keyboard. These forms of memory involve different regions of the brain but are probably similar at the cellular level.
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