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

Correlational studies have suggested that immediate phonological memory, as measured by the capacity to repeat back non-words varying in length, is associated with level of vocabulary in young children. The present study explores the possibility of a causal relationship between phonological memory and vocabulary acquisition by testing the abilities of children high and low in repetition performance to learn labels for unfamiliar toy animals. The low repetition children were found to be slower at learning phonologically unfamiliar names such as ‘Pimas’ for the toys, although there was no difference in learning speed for familiar names such as ‘Thomas’. The two groups also differed one day later in their retention of the labels that had initially been learned. These results suggest that immediate memory processes are directly involved in the learning of new vocabulary items in young children. The possible nature of the contribution of temporary phonological memory to vocabulary acquisition is discussed.

The role of phonological memory in vocabulary acquisition: A study of young children learning new names

Working memory may be defined as the system for the temporary maintenance and manipulation of information, necessary for the performance of such complex cognitive activities as comprehension, learning, and reasoning. Used in this sense, the term refers to an area of research that may or may not prove to be dependent on a single coherent system. Such a system is proposed within a broad and relatively speculative overview of human memory that emphasizes the putative role of working memory. This is followed by a brief account of a particular model of working memory, and a more detailed discussion of the way in which the various subcomponents of the model relate to other aspects of memory and cognition.

Working memory: The interface between memory and cognition

This paper describes the Rivermead Behavioural Memory Test (RMBT)-a short test of everyday memory problems with four parallel forms. It was administered to 118 control subjects aged between 16-69 years with a mean IQ of 106 (range 68-136). The limit of normal performance was established on this group and cut-off points were determined for individual components of the test. The test was also given to 176 brain-damaged people and its validity assessed both by correlating RMBT scores to performance on existing tests, to subjective ratings from patients and carers and to observation by therapists of memory lapses. Validity, parallel form and interrater reliability all proved to be high. It is concluded that the RBMT is a short, reliable, and valid test of everyday memory problems.

The development and validation of a test battery for detecting and monitoring everyday memory problems.

The working memory framework was used to investigate the factors determining the phenomenological vividness of images. Participants rated the vividness of visual or auditory images under control conditions or while performing tasks that differentially disrupted the visuospatial sketchpad and phonological loop subsystems of working memory. In Experiments 1, 2, and 6, participants imaged recently presented novel visual patterns and sequences of tones; ratings of vividness showed the predicted interaction between stimulus modality and concurrent task. The images in experiments 3, 4, 5, and 6 were based on long-term memory (LTM). They also showed an image modality by task interaction, with a clear effect of LTM variables (meaningfulness, activity, bizarreness, and stimulus familiarity), implicating both working memory and LTM in the experience of vividness.

Alan D. Baddeley

Papers

The role of phonological memory in vocabulary acquisition: A study of young children learning new names

Working memory: The interface between memory and cognition

The development and validation of a test battery for detecting and monitoring everyday memory problems.

Working memory and the vividness of imagery.

Attention and retrieval from long-term memory.