Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Bartlett viewed thinking as a high level skill exhibiting ballistic properties that he called its “point of no return”. This paper explores one aspect of cognition through the use of a simple model...

/pdf/orienting-of-attention-2bi7r8jak3.pdf

Orienting of attention

The two basic phenomena that define the problem of visual attention can be illustrated in a simple example. Consider the arrays shown in each panel of Figure 1. In a typical experiment, before the arrays were presented, subjects would be asked to report letters appearing in one color (targets, here black letters), and to disregard letters in the other color (nontargets, here white letters). The array would then be briefly flashed, and the subjects, without any opportunity for eye movements, would give their report. The display mimics our. usual cluttered visual environment: It contains one or more objects that are relevant to current behavior, along with others that are irrelevant. The first basic phenomenon is limited capacity for processing information. At any given time, only a small amount of the information available on the retina can be processed and used in the control of behavior. Subjectively, giving attention to any one target leaves less available for others. In Figure 1, the probability of reporting the target letter N is much lower with two accompa­ nying targets (Figure la) than with none (Figure Ib). The second basic phenomenon is selectivity-the ability to filter out un­ wanted information. Subjectively, one is aware of attended stimuli and largely unaware of unattended ones. Correspondingly, accuracy in identifying an attended stimulus may be independent of the number of nontargets in a display (Figure la vs Ie) (see Bundesen 1990, Duncan 1980).

Neural Mechanisms of Selective Visual Attention

: The concept of attention as central to human performance extends back to the start of experimental psychology, yet even a few years ago, it would not have been possible to outline in even a preliminary form a functional anatomy of the human attentional system. New developments in neuroscience have opened the study of higher cognition to physiological analysis, and have revealed a system of anatomical areas that appear to be basic to the selection of information for focal (conscious) processing. The importance of attention is its unique role in connecting the mental level of description of processes used in cognitive science with the anatomical level common in neuroscience. Sperry describes the central role that mental concepts play in understanding brain function. As is the case for sensory and motor systems of the brain, our knowledge of the anatomy of attention is incomplete. Nevertheless, we can now begin to identify some principles of organization that allow attention to function as a unified system for the control of mental processing. Although many of our points are still speculative and controversial, we believe they constitute a basis for more detailed studies of attention from a cognitive-neuroscience viewpoint. Perhaps even more important for furthering future studies, multiple methods of mental chronometry, brain lesions, electrophysiology, and several types of neuro-imaging have converged on common findings.

/pdf/the-attention-system-of-the-human-brain-w797wllpat.pdf

The Attention System of the Human Brain

Attention deficit hyperactivity disorder (ADHD) comprises a deficit in behavioral inhibition. A theoretical model is constructed that links inhibition to 4 executive neuropsychological functions that appear to depend on it for their effective execution: (a) working memory, (b) self-regulation of affect-motivation-arousal, (c) internalization of speech, and (d) reconstitution (behavioral analysis and synthesis). Extended to ADHD, the model predicts that ADHD should be associated with secondary impairments in these 4 executive abilities and the motor control they afford. The author reviews evidence for each of these domains of functioning and finds it to be strongest for deficits in behavioral inhibition, working memory, regulation of motivation, and motor control in those with ADHD. Although the model is promising as a potential theory of self-control and ADHD, far more research is required to evaluate its merits and the many predictions it makes about ADHD.

/pdf/behavioral-inhibition-sustained-attention-and-executive-3s4ta68l66.pdf

Behavioral inhibition, sustained attention, and executive functions: Constructing a unifying theory of ADHD.

Divergent thinking is a process or method used to generate creative ideas by exploring many possible solutions or responses, and is a critical element of creativity Lesion and imaging studies have shown that the frontal lobes are important in mediating divergent thinking, and frontal lobe function is highly dependent on white matter connections with subcortical and cortical networks Normal aging often results in deficits in functions controlled by the frontal lobes, as well as decrements in white-matter connectivity Objectives of this study included comparing non-time-constrained tasks of verbal divergent processing in young adults (YAs) and older adults (OAs) and correlating performance with tasks of working memory, language ability, and disengagement/inhibition Participants were 30 YAs and 30 OAs Contrary to the a priori hypothesis, OAs produced significantly more unique responses than YAs, although total fluency was not significantly different Correlational analyses examining the groups together 

Divergent Task Performance in Older Adults: Declarative Memory or Creative Potential?

Gesture Laterality in Aphasic and Apraxic Stroke Patients

Limb Praxis Assessment

Phantom limb after stroke: an underreported phenomenon.

Methods: Thirty eight patients with probable Alzheimer's disease were included in a retrospective analysis of neuropsychological functions. 

Results: The four Gerstmann's syndrome signs did not cluster together. Finger naming and calculations were not significantly correlated. Right-left knowledge and calculations also did not correlate. 

Conclusions: The four cognitive functions impaired in Gerstmann's syndrome do not share a common neuronal network, and their co-occurrence with dominant parietal lobe injuries may be related to the anatomical proximity of the different networks mediating these functions.

https://jnnp.bmj.com/content/jnnp/72/3/403.full.pdf

Kenneth M. Heilman

Papers

Divergent Task Performance in Older Adults: Declarative Memory or Creative Potential?

Gesture Laterality in Aphasic and Apraxic Stroke Patients

Limb Praxis Assessment

Phantom limb after stroke: an underreported phenomenon.

The Gerstmann syndrome in Alzheimer's disease