Short Term Memory and Selection Processes in a Frontal-Lobe Model

We present a neural model that addresses the capacity of a frontal lobe system to hold up information for short periods of time and to perform response selection. In the model, reverberation states are sustained after stimulus offset, due to loops of recurrent excitation in neural cell assemblies and lateral inhibition is necessary to block an uncontrolled spread of activation. At high levels of inhibition the system performs response selection, and at lower levels it retains a number of units in active states, after stimulus offset. It is shown formally that such a system has capacity limitations: only a limited number of cell assemblies can be retained. Sequential presentation of a list of items is simulated and serial position curves characterised by recency are obtained. The model explains recency, list-length and presentation rate effects in immediate cued recall, as well as semantic effects and patterns of forgetting in Brown-Peterson type of experiments. A reduction in the strength of recurrent excitations explains the absence of lexical effects in tests of immediate memory for frontal lobe patients [1] and more extreme reductions result in impairments of response selection in dynamic aphasia [2]

[1]  A. W. Melton.  Implications of short-term memory for a general theory of memory , 1963 .

[2]  Stephen A. Ritz,et al.  Distinctive features, categorical perception, and probability learning: some applications of a neural model , 1977 .

[3]  A. Baddeley,et al.  Recall of Semantic Clusters in Primary Memory , 1971 .

[4]  R. Atkinson,et al.  The control of short-term memory. , 1971, Scientific American.

[5]  Randi C. Martin,et al.  Language Processing and Working Memory: Neuropsychological Evidence for Separate Phonological and Semantic Capacities , 1994 .

[6]  E. Bizzi,et al.  The Cognitive Neurosciences , 1996 .

[7]  Edward E. Smith,et al.  Temporal dynamics of brain activation during a working memory task , 1997, Nature.

[8]  R. Desimone,et al.  Neural Mechanisms of Visual Working Memory in Prefrontal Cortex of the Macaque , 1996, The Journal of Neuroscience.

[9]  T Shallice,et al.  The selective impairment of auditory verbal short-term memory. , 1969, Brain : a journal of neurology.

[10]  N Brunel,et al.  Correlations of cortical Hebbian reverberations: theory versus experiment , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[11]  Alan D. Baddeley,et al.  Retrieval rules and semantic coding in short-term memory. , 1972 .

[12]  Nora S. Newcombe,et al.  Semantic effects on ordered recall , 1976 .

[13]  R. O’Reilly,et al.  A computational approach to prefrontal cortex, cognitive control and schizophrenia: recent developments and current challenges. , 1996, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[14]  James L. McClelland,et al.  Why there are complementary learning systems in the hippocampus and neocortex: insights from the successes and failures of connectionist models of learning and memory. , 1995, Psychological review.

[15]  Glen A. Raser.  Recoding of semantic and acoustic information in short-term memory , 1972 .

[16]  M. Botvinick,et al.  Anterior cingulate cortex, error detection, and the online monitoring of performance. , 1998, Science.

[17]  Arthur P. Shimamura,et al.  Memory and frontal lobe function. , 1995 .

[18]  Stephen Grossberg,et al.  A Theory of Human Memory: Self-Organization and Performance of Sensory-Motor Codes, Maps, and Plans , 1982 .

[19]  P. Goldman-Rakic.  Working memory and the mind. , 1992, Scientific American.

[20]  John R. Anderson.  The Architecture of Cognition , 1983 .

[21]  Gordon D. A. Brown,et al.  Memory for familiar and unfamiliar words: Evidence for a long-term memory contribution to short-term memory span , 1991 .

[22]  John J. Hopfield,et al.  Neural networks and physical systems with emergent collective computational abilities , 1999 .

[23]  M. P. Friedman,et al.  HANDBOOK OF PERCEPTION , 1977 .

[24]  Harvey G. Shulman,et al.  Encoding and retention of semantic and phonemic information in short-term memory , 1970 .

[25]  N. Cowan.  Activation, attention, and short-term memory , 1993, Memory & cognition.

[26]  D. O. Hebb,et al.  The organization of behavior , 1988 .

[27]  L. Cipolotti,et al.  Dynamic aphasia: an inability to select between competing verbal responses? , 1998, Brain : a journal of neurology.

[28]  Steven W. Keele,et al.  Mechanisms of Attention. , 1978 .

[29]  R. D. Patterson,et al.  Functional units and retrieval processes in free recall. , 1968, Journal of experimental psychology.

[30]  P. Carpenter,et al.  Individual differences in working memory and reading , 1980 .

[31]  B. Murdock,et al.  The retention of individual items. , 1961, Journal of experimental psychology.

[32]  D. Norris,et al.  The primacy model: a new model of immediate serial recall. , 1998, Psychological review.

[33]  M I Posner,et al.  Anatomy of word and sentence meaning. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[34]  F. Craik,et al.  Semantic and acoustic information in primary memory , 1970 .

[35]  J. Desmond,et al.  The role of left prefrontal cortex in language and memory. , 1998, Proceedings of the National Academy of Sciences of the United States of America.