The unity and diversity of executive functions and their contributions to complex "Frontal Lobe" tasks: a latent variable analysis.

▪ Abstract The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed

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An integrative theory of prefrontal cortex function

Publisher Summary This chapter focuses on the modern notion of short-term memory, called working memory. Working memory refers to the temporary maintenance of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behavior. Working memory is a system that is critically important in cognition and seems necessary in the course of performing many other cognitive functions, such as reasoning, language comprehension, planning, and spatial processing. This chapter demonstrates the functional importance of dopamine to working memory function in several ways. Elucidation of the cognitive and neural mechanisms underlying human working memory is an important focus of cognitive neuroscience and neurology for much of the past decade. One conclusion that arises from research is that working memory, a faculty that enables temporary storage and manipulation of information in the service of behavioral goals, can be viewed as neither a unitary, nor a dedicated system. Data from numerous neuropsychological and neurophysiological studies in animals and humans demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.

Chapter 11 Working memory

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

Attention and Effort

Item-location binding in working memory: Is it hippocampus-dependent?

The present special issue is the result of a call for papers on human memory, preferably with a biological perspective, so as to make it an appropriate companion issue to the animal section issue on memory. When invited to write an editorial, I accepted, provided I was to be allowed the traditional prerogative of writers of editorials, namely licence to substitute opinion for evidence and speculation for expertise. The topic on which I want to offer my ill-formed speculation is the traditional question of the extent to which human memory is modular, on the one hand, and to what extent Lashley’s concept of mass-action can be applied to those parts of the brain responsible for memory. I speculate with some trepidation, as a cognitive psychologist dabbling in a classical area of physiological psychology. I would suggest, however, that this is an issue of direct current interest both to cognitive psychologists and to those interested in memory in animals, and as such is perhaps an appropriate editorial topic for this particular issue of the journal. Over the last decade or so, the combination of neuropsychological single case techniques with the development of cognitive approaches to human memory have produced a considerable advance in our functional understanding of human memory. Theoretical development has typically occurred by means of a series of dissociations established between different aspects of memory, allowing the previous unitary concept of memory to be fractionated into a number of interrelated subsystems. The first example of this was the distinction between short-term and long-term memory strongly supported by studies of the classical amnesic patient H M (Milner, 1966), followed by the demonstration that this neuropsychological dissociation could be tied in with the theoretical distinctions proposed by cognitive psychologists working with normal

Modularity, mass-action and memory.

Evidence on human performance in dangerous environments is reviewed and suggests that danger reduces efficiency, except in the case of experienced subjects. Perceptual narrowing is shown to be one source of decrement. It is suggested that danger increases the subject's arousal level which influences performance by producing a narrowing of attention. The nature of the performance decrement and of adaptation to danger are discussed in this context.

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Selective Attention and Performance in Dangerous Environments

Charting the acquisition of semantic knowledge in a case of developmental amnesia.

Two experiments attempted to improve face recognition by ac- companying the faces with elaborative contextual information regarding the personality and background of the person depicted. In neither experi- ment did elaboration lead to better subsequent recognition of the face pre- sented without context. A third study explored the role of context as a potential retrieval cue. Faces were accompanied by descriptive phrases which might or might not accompany the appropriate face during recogni- tion. A previously presented context had a substantial effect on response bias, but little effect on the discriminability of the memory trace. Compara- ble data from verbal memory are discussed, and a distinction drawn be- tween independent context in which the context and stimulus are pro- cessed separately, and interactive context in which the context modifies the encoding of the stimulus.

Alan D. Baddeley

Papers

Item-location binding in working memory: Is it hippocampus-dependent?

Modularity, mass-action and memory.

Selective Attention and Performance in Dangerous Environments

Charting the acquisition of semantic knowledge in a case of developmental amnesia.

Depth of processing, context, and face recognition.