Laminar cortical dynamics of cognitive and motor working memory, sequence learning and performance: toward a unified theory of how the cerebral cortex works

How does the brain carry out working memory storage, categorization, and voluntary performance of event sequences? The LIST PARSE neural model proposes an answer that unifies the explanation of cognitive, neurophysiological, and anatomical data. It quantitatively simulates human cognitive data about immediate serial recall and free recall, and monkey neurophysiological data from the prefrontal cortex obtained during sequential sensory-motor imitation and planned performance. The model clarifies why spatial and non-spatial working memories share the same type of circuit design. It proposes how laminar circuits of lateral prefrontal cortex carry out working memory storage of event sequences within layers 6 and 4, how these event sequences are unitized through learning into list chunks within layer 2/3, and how these stored sequences can be recalled at variable rates that are under volitional control by the basal ganglia. These laminar prefrontal circuits are variations of visual cortical circuits that explained data about how the brain sees. These examples from visual and prefrontal cortex illustrate how laminar neocortex can represent both spatial and temporal information, and open the way towards understanding how other behaviors derive from shared laminar neocortical designs.     

Exploring the utility of functional analysis methodology to assess and treat problematic verbal behavior in persons with acquired brain injury

Functional analyses were conducted on four adults with acquired brain injuries who regularly displayed instances of inappropriate verbal behavior including depressive, aggressive, suicidal, profane, and sexually inappropriate utterances. After the functional analysis yielded a maintaining variable for each participant, a function‐based intervention consisting of differential reinforcement of alternative verbal behavior was implemented. Results of the behavioral interventions show that instances of vocal behavior can be assessed and subsequently treated using the functional analysis methodology often reserved for nonverbal forms of behavior. The utility of functional analysis for assessing complex human behavior is discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Effects of various hippocampal lesions on monkey plasma cortisol levels in two experimental conditions

The plasma cortisol levels of Rhesus monkeys with anterior, posterior, or near-total hippocampal lesions were compared to controls during two separate stressful conditions. In the first condition, each monkey was placed for the first time in a primate restraint chair for 72 h. In the second condition each monkey performed a complex behavioral task (titrating shock avoidance) to control the intensity of frequent footshock for a 24-h period. Control subjects had either no surgical operation or else surgical exposure of the hippocampus with no hippocampal lesion. They manifested lower plasma cortisol levels during shock avoidance compared with during the chair condition. Subjects with posterior hippocampal lesions manifested the same pattern but near-totally hippocampectomized subjects showed an opposite pattern with cortisol levels higher in the shock avoidance condition compared with the chair condition. Subjects with anterior hippocampal lesions had similar cortisol levels in both conditions. Thus hippocampal modulation of corticosteroid levels may depend on the specific condition under which such levels are measured, and may be relatively more subserved by anterior compared with posterior hippocampus in the monkey.     

Review for Cognitive Systems Research of the book The Brain and AI,by authors Karl Schlagenhauf and Fanji Gu

The human brain is often considered the most complex system known. It has a fantastic capacity to learn and remember, to recognize patterns in space and time, solve problems of all kinds, innovate tools and machines, create beautiful art and science. Is it reasonable to believe that we, in a foreseeable future, will be able to understand all the wonders of our own brain, enough to be able to mimic it and build artificial brains and minds that correspond to or even surpass the capacity of the human origin? Can we seriously believe that we (soon, or ever) will be able to build robots that know of and can reflect upon their own existence?This review of the book, The Brain and AI, deals with such issues, but in a very special way. It is written as a fascinating dialogue between the two authors, Chinese scientist Fanji Gu and German engineer Karl Schlagenhauf, where they discuss the development of neuroscience and artificial intelligence (AI) with a critical examination of given “truths” in these fields. The Brain and AI is indeed worth reading for many reasons, regardless if you are a student or researcher in any of the many fields of science discussed here (e.g. physics, computer science, neuroscience, cognitive science psychology, social science), or if you are just interested in the current and future development of brain research and artificial intelligence. The book is both educating and entertaining and can be strongly recommended.     

Is the inversion effect in rhesus monkeys face-specific?

This study investigated the face inversion effect in rhesus monkeys (Macaca mulatta). Face stimuli consisted of ten black-and-white examples of unfamiliar rhesus monkey faces, brown capuchin faces, and human faces. Two non-face categories included ten examples of automobiles and abstract shapes. All stimuli were presented in a sequential matching-to-sample format using an automated joystick-testing paradigm. Subjects performed significantly better on upright than on inverted presentations of automobiles, rhesus monkey and capuchin faces, but not human faces or abstract shapes. These results are inconsistent with data from humans and chimpanzees that show the inversion effect only for categories of stimuli for which subjects have developed expertise. The inversion effect in rhesus monkeys does not appear to be face-specific, and should therefore not be used as a marker of specialized face processing in this species. Received: 18 November 1998 / Accepted after revision: 9 May 1999     

Evolutionary-derived anatomical characteristics and universal attractiveness

Hominid fossils illustrate how modern humans have evolved anatomically. Included in the fossils are traits no longer phenotypically prevalent in humans (primitive) and phenotypic traits that have become increasingly prevalent (derived). In this study, published paleontological information about the anatomical evolution of humans was used to create line drawings of human form. Survey data were accumulated by having 759 individuals evaluate more than 40 anatomical traits. Each anatomical trait was presented as a panel of three line drawings intended to express the trait in a primitive, intermediate, and derived form. For each panel of three drawings, subjects were instructed to select the drawing they considered most attractive and then select the drawing they considered least attractive. The survey data indicate that males and females of diverse ages, races, cultures, and from varied geographical regions show commonality in their judgements of beauty of human form. The individuals surveyed appeared to have a strong aversion to primitive traits, preferring proportions and characteristics that are intermediate or more derived. In many instances, the evaluators preferred drawings that were exaggeratedly derived. The data may have relevance to the ongoing debate of whether averageness or atypicality is the essence of human beauty. Also, there was high agreement in judging the attractiveness of shapes and proportions in line drawings that were not immediately recognized to be representations of human form. These data could indicate that our general aesthetic sense for art, architecture, and fashion may be based on a subliminal reference to derived anatomical shapes and proportions. Overall, the data support the hypothesis that derived traits that are universally shared by anatomically modern humans may be the standard for our innate sense of beauty of human form.     

It's Not a Story

This writing presents a firsthand account of living with the certain knowledge that you can't rely on your brain the way you used to. Epilepsy, multiple sclerosis, brain tumor—what do these words really mean day by day, moment by moment? The author blends poetry and prose in her account of forging a new relationship with her own brain. Activities that were once routine are now difficult and even dangerous. No longer is her brain a silent partner as she navigates the debilitating, embarrassing, and occasionally humiliating symptoms of her disease. Can I really get through this shower? How much help do we need today, Brain? Mindfulness practice helps the author become more aware of her moment-by-moment experience. Her therapist prods her to dig into her own story, but the author resists. She resists and yet she shares her story that may not be a story.     

Evidence for a Disturbance of the Body Schema in Neglect

Subjects with left neglect often fail to use and, in some instances, recognize the left side of the body. We performed a series of investigations to determine if this deficit is, at least in part, attributable to an impairment in the “body schema,” an internal three-dimensional, dynamic representation of the spatial and biomechanical properties of one's body. First, subjects were shown a series of pictures of a single hand and asked to determine if the stimulus was a right or left hand. Subjects with neglect but not other subjects with brain lesions identified pictures of left (contralesional) hands significantly less reliably than pictures of right hands. On the basis of evidence demonstrating that the identification of pictured hands involves the matching of the stimuli to an on-line mental representation of one's body, these data suggest that neglect may be associated with a disruption of, or failure to attend to, the body schema. Data from subsequent investigations contrasting patients with left neglect and Gerstmann's syndrome argue for a distinction between a body schema and a “body image,” or conceptual representation of the body which articulates with language.     

Strategy use in question-answering: Memory strength and task constraints on fan effects

The time taken to recognize a studied fact increases as a function of the number of other previously studied facts sharing concepts with the test fact. The phenomenon, known as the “fan effect,” has been shown to disappear and sometimes even reverse itself when the set of facts are thematically related. The shift from interference toward facilitation occurs only when subjects can use a plausibility-like strategy. In this experiment, subjects learned variously sized sets of rehted facts about fictitious people. Subjects were asked to make either recognition judgments (“Did you study this fact?”) or consistency judgments (“Is this fact consistent with what you studied7”). Subjects made these judgments both the day the material was acquired and 2 days later. The research reported here supports the hypothesis that, with delay, there is a shift in tendency toward more use of the plausibility strategy, away from the careful strategy of searching for an exact match that produces the fan effect. The plausibility strategy produced either a speedup with greater fan or an increase in error rates when the strategy was inappropriate. Plausibility effects were larger at a delay, in both reaction time and error patterns, regardless of whether subjects were asked to make consistency judgments or recognition judgments. Also as predicted, response times became faster as the tendency to adopt the plausibility strategy without first trying direct retrieval increased.     

Developmental dyslexia and animal studies: at the interface between cognition and neurology

Recent findings in autopsy studies, neuroimaging, and neurophysiology indicate that dyslexia is accompanied by fundamental changes in brain anatomy and physiology, involving several anatomical and physiological stages in the processing stream, which can be attributed to anomalous prenatal and immediately postnatal brain development. Epidemiological evidence in dyslexic families led to the discovery of animal models with immune disease, comparable anatomical changes and learning disorders, which have added needed detail about mechanisms of injury and plasticity to indicate that substantial changes in neural networks concerned with perception and cognition are present. It is suggested that the disorder of language, which is the cardinal finding in dyslexic subjects, results from early perceptual anomalies that interfere with the establishment of normal cognitive-linguistic structures, coupled with primarily disordered cognitive processing associated with developmental anomalies of cortical structure and brain asymmetry. This notion is supported by electrophysiological data and by findings of anatomical involvement in subcortical structures close to the input as well as cortical structures involved in language and other cognitive functions. It is not possible at present to determine where the initial insult lies, whether near the input or in high-order cortex, or at both sites simultaneously.     

Another psychobiological view of sexual differentiation

The major psychobiological theory of sex differences is based on the hypothesis that hormones induce sex differences in neural organization. Hormonally masculinized or feminized brains are thought to underlie subsequent behavioral sex differences. This theory and the constructs, arguments, and evidence used in its support are closely examined. Some conceptual problems with widely used arguments are identified and discussed. Behavioral, physiological, and anatomical evidence from studies of animal sexual behavior is reviewed. It is concluded that the evidence fails to support generally accepted views that early hormones affect behavior through direct effects on brain differentiation and that behavioral differences must be located in the brain. It is argued instead that hormones coact and interact with other factors throughout development, that brain differences may result from as well as cause functional differences, and that hormone-based sources of sex differences may be located throughout the body and in the social surround. Directions for new research are suggested and implications for interpretation of human sex differences are discussed.     

Functionalism and type-type identity theories

Conclusion Token-token identity theorists do not and need not deny that it may frequently be the same (kind of) brain state which on different occasions fills the functional rôle definitive of a given mental state. That is not at issue. What is at issue is whether functionally-oriented identity theorists should make two claims or three claims.The two claims they customarily make are, first, that each instance of a mental state is an instance of a brain state, and, secondly, that being in a mental state is having in one a state filling the relevant functional rôle. But to be in a mental state is to have that state in one. To be in pain is to have pain, to desire water is to have desire for water, and so on; just as to be poisoned is to have poison in you. (It is to have what is poison for you at the time, of course; and likewise for pain, desire and so on.)Our paper has been about a third sort of claim — relating particularly not to being in a mental state, nor to instances of that state, but to the mental state itself. We have argued that functionally-oriented identity theorists can and should make, in addition to the first two claims, the third type-type identity claim that mental states are brain states. Consequently a token brain state is a token of pain in a derivative sense. What makes it a token of pain is that it is a token of the type of brain state which realizes the pain-rôle for the organism at the time.     

Re‐framing systemic paradigms for the art of learning

Thoughtful people are increasingly concerned that the current paradigms for social, corporate, and educational activities are in disgraceful disarray. The “problem‐solving” or analytical model, the competitive or game model, the commercial or consumer model, the bureaucratic or institutional model, and the disease or illness model which prevail in public discourse are proving to be especially unwholesome. We cannot, however, educate ourselves without paradigms. A credible educational paradigm must be generally accessible without being simplistic, informative without being monothematic, and accommodating as well as discriminating. Given our disquiet with the current cognitive situation, a renewing paradigm must be somehow novel; given the character of human nature, a sustaining paradigm must be somehow familiar.

For a very long time now, professional Sciences have committed themselves to paradigms about “reality out there,” while professional Arts have devoted themselves to expressing “imagination from within here.” The more these two worldviews polarize in opposition to one another, the more room there is—and the more human heed there becomes—for mediation by an applied philosophy which accommodates the “real” as well as the “imaginary” in a complementary way. Such a philosophy would address not only “what do you know?” and “how do you do?” but also “how do you know?” and “why do you do?” In earlier times, people would have been considered neither educated nor wise unless they appreciated the Sciences and the Arts whole. In our time, we may not survive unless we can re‐integrate our fractured perceptions. How might we proceed to do so? There may be a systemological way.     

Hormonal state affects recovery from frontal cortex lesions in adult female rats

Pseudopregnant and normal cycling female Sprague-Dawley rats were trained on a delayed-spatial alternation task. After acquisition training, the subjects received frontal cortex lesions and were subsequently tested for retention. The pseudopregnant animals with lesions were less impaired than their normal cycling counterparts. Learning and retention testing were not affected by hormonal status in the noninjured controls. Histological examination showed that the normal cycling rats with frontal cortex lesions possessed enlarged ventricles, indicating the presence of edema in this surgical group. However, brain tissue of pseudopregnant subjects given the same lesion and sham operates of both hormonal states did not display this characteristic of edema. We speculate that the behavioral and anatomical impairment observed in the normal cycling females with brain injury is due to higher levels of vasopressin, a potent vasoconstrictor synchronized with brain injury in our manipulation.     

Synchronized neuronal oscillations and their role in motor processes

Recant data on the relationship of brain rhythms and the simultaneous oscillatory discharge of single units to motor preparation and performance have largely come from monkey and human studies and have failed to converge on a function. However, when these data are viewed in the context of older data from cats and rodents, some consistent patterns begin to emerge. Synchronous oscillatory activity, at any frequency, may be an integrative sensorimotor mechanism for gathering information that can be used to guide subsequent motor actions. There is also considerable evidence that brain rhythms can entrain motor unit activity. It is not clear yet whether the latter influence is a means of organizing muscle phase relationships within motor acts, or is simply a 'test pulse' strategy for checking current muscle conditions. Moreover, although the traditional association of faster brain rhythms with higher levels of arousal remains valid, arousal levels are correlated so tightly with the dynamics of sensorimotor control that it may not be possible to dissociate the two.     

How to deal with your most difficult client—You

Conclusion Therapists are human-and, believe it or not, fallible humans. Ideally, they are supremely well infored, highly confident, minimally disturbed, extremely ethical and rarely under- or overinvolved with their clients/Actually, they are hardly ideal. If you, as a therapist, find yourself seriously blocked in your work, look for the same kind of irrational beliefs, inappropriate feelings, and dysfunctional behaviors that you would investigate in your underachieving clints. When you ferret out the absolutistic philosophies and perfectionist demads that seem to underlie your difficulties, ask yoursell—yes,strongly ask yourself—these trenchant questions: (a) Why do Ihave to be an indubitably great and unconditionally lowed therapist?; (b) Where is it written that my clientsmust follow my teachings and absolutelyshould do what I advise?; (c) Where is the evidence that therapymust be easy and that Ihave to enjoy every minute of it?If you persist in asking important questions like these and insist on thinking them through to what are scientific and logical answers, you may still never become the most accomplished and sanest therapist in the world. But I wager that you will tend to be happier and more effective than many other therapists I could—but charitably will not—name. Try it and see!This article is adapted from an invited address presented at the 91 st Annual Convention of the American Psychological Association at Anaheim, Calif., August 1983.     

Gastric pathology and feeding deficits induced by hypothalamic damage in rats: effects of lesion type, size, and placement.

Three doses each of cathodal or anodal direct current were delivered to coagulate lateral hypothalamic tissue bilaterally in rats. Increases in hypothalamic tissue damage were associated with more instances of aphagia, greater amounts of glandular, but not rumenal, gastric pathology, and greater weight loss. Both anodal and cathodal lesions produced aphagia and similar amounts of gastric pathology, but anodal lesions also appeared to facilitate weight loss independently of the tissue damage. Extensive chromatolysis surrounding anodal lesion cavities may be importantly related to the postoperative effects. In additional experiments, anodal electrolytic lesions or cortical suction ablations were used to vary the location of neural damage. Fedding deficits and gastric pathology resulted from the destruction of several brain areas. In particular, eating of dry food in the presence of high gastric pathology was observed in rats with lesions ventral and medial to an area in the dorsolateral hypothalamus that was associated with aphagia. When aphagia was accompained by severe gastric pathology, the brain lesions typically encroached extensively on more ventromedial areas. Moreover, aphagia sometimes was observed with only negligible gastric pathology. It is suggested that gastric pathology is not primary to the expression of the aphagia that follows lateral hypothalamic damage.     

Mirror Neurons and the Evolution of Embodied Language

ABSTRACT— Mirror neurons are a class of neurons first discovered in the monkey premotor cortex that activate both when the monkey executes an action and when it observes the same action made by another individual. These neurons enable individuals to understand actions performed by others. Two subcategories of mirror neurons in monkeys activate when they listen to action sounds and when they observe communicative gestures made by others, respectively. The properties of mirror neurons could constitute a substrate from which more sophisticated forms of communication evolved; this would make sense, given the anatomical and functional homology between part of the monkey premotor cortex and Broca's area (the "speech" area of the brain) in humans. We hypothesize that several components of human language, including some aspects of phonology and syntax, could be embedded in the organizational properties of the motor system and that a deeper knowledge of this system could shed light on how language evolved.     

Basal ganglia output and cognition: evidence from anatomical, behavioral, and clinical studies

The traditional view that the basal ganglia are simply involved in the control of movement has been challenged in recent years. Three lines of evidence indicate that the basal ganglia also are involved in nonmotor operations. First, the results of anatomical studies clearly indicate that the basal ganglia participate in multiple circuits or 'loops' with cognitive areas of the cerebral cortex. Second, the activity of neurons within selected portions of the basal ganglia is more related to cognitive or sensory operations than to motor functions. Finally, in some instances basal ganglia lesions cause primarily cognitive or sensory disturbances without gross motor impairments. In this report, we briefly review some of these data and present a new anatomical framework for understanding the basal ganglia contributions to nonmotor function.     

Unilateral brain lesions in childhood: performance on the Revised Token Test

Comprehension of connected language as assessed by the Revised Token Test (RTT) was studied in 17 children with left hemisphere lesions (LL) and 11 with right hemisphere lesions (RL). LL children's significantly lower performance on several subtests than left controls (LC) matched by age, sex, race, and social class appeared to be related to the memory demands of these subtests rather than the limited syntactic elements assessed by the RTT. LL subjects requested significantly more command repetitions than control or RL subjects and when a repetition was not requested LL subjects often responded with immediacy. Although RL children tended to perform lower than right matched controls (RC), these differences were not significant nor readily related to either the memory or specific linguistic structures assessed. RL subjects required fewer command repetitions than LL subjects and exhibited a significantly greater frequency of immediate responses than controls or LL subjects. While based on few children, a trend for LL children with retrorolandic lesions to perform more poorly than those with left prerolandic lesions was suggested. No systematic difference in performance was apparent for children with left cortical vs. left subcortical lesions or among discrete sites of lesions within the right hemisphere. Children with left lesions prior to 1 year of age performed no better and, in several instances, significantly poorer than LL patients sustaining lesions after 1 year of age. Among RL subjects, those sustaining lesions after 1 year of age had greater difficulty than those with lesion onset before 1 year of age, especially on linguistic elements which seemed to be dependent upon visual spatial properties. Further studies are needed to evaluate the comprehension of more complex linguistic structures among children with unilateral brain lesions as well as to study the role of more basic factors such as memory and attention in explaining the present findings.