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Cortical Dynamics of Working Memory

May 11, 2006 IBM Almaden Institute Cognitive Computing. Cortical Dynamics of Working Memory. Joaquín M. Fuster Semel Institute for Neuroscience and Human Behavior University of California Los Angeles. www. joaquinfuster. com.

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Cortical Dynamics of Working Memory

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  1. May 11, 2006 IBM Almaden Institute Cognitive Computing Cortical Dynamics of Working Memory Joaquín M. Fuster Semel Institute for Neuroscience and Human Behavior University of California Los Angeles www. joaquinfuster. com

  2. Working memory is the active (“online”) retention of information fora prospective action to solve a problem or to reach a goal (vs STM). • That information is unique for present context and for the immediate future, but inseparable from past context: It is long-term memory updated for prospective use. • Working memory and long-term memory share most of the same cortical structure.

  3. A corollary: A sensory stimulus to be retained in working memory activates a cortical network that encodes not only that stimulus, but also its past associative context in long-term memory.

  4. 1. Structure of cortical memory networks Cortical dynamics of working memory (WM) The Perception-Action Cycle (a) Cross-modal integration by WM (b) Neurovascular coupling in WM 3. Computational constraints 4. WM dynamics in the human cortex

  5. A NETWORK PARADIGM 1. Memory and knowledge are represented in widely distributed, interactive, and overlapping neuronal networks of the cerebral cortex (cognits). 2. Cognitive functions--perception, attention, memory, including working memory, language, and intelligence--are based on neural transactions within and between those cortical memory networks.

  6. Memories (cognits) consist of widely distributed networks made of neurons synaptically modulated by experience Executive memory in frontal cortex Perceptual memory in posterior cortex Networks intersect and overlap with one another profusely: A neuron can be part of many networks, thus many memories

  7. Hebb 1949 Carew et al 1984

  8. Scoville & Milner 1957 Corkin 1984 Squire 1987 Cohen & Eichenbaum 1993 Limbic structures essential for memory in neocortex

  9. Order of maturation of cortical areas Gibson 1991 Sowell et al 1999 Bartzokis 2003 Gillery 2005 Bonin, G. von, Essay on the Cerebral Cortex, C.C. Thomas, 1950

  10. Evolution of frontal association cortex (prefrontal)

  11. Maturation progresses from primary areas to progressively higher association areas. • “Upstream” connectivity also progresses from primary areas to progressively higher association areas. • Jones & Powell 1970 Cavada & Goldman-Rakic 1989 • Pandya & Yeterian 1985 Felleman & Van Essen 1991 • Thus, three structural gradients from primary to association cortex : a) Evolution b) Maturation c) Connectivity

  12. Along those gradients, memory networks (cognits) become layered hierarchically, from concrete sensory and motor memory at the bottom to abstract knowledge at the top. • Every new memory follows those gradients as it becomes associated with concurrent stimuli and, at higher levels, with pre-existent memories.

  13. Lorente de Nó 1938 Jones & Powell 1970 Pandya & Yeterian 1985 Cavada & Goldman-Rakic 1989 Felleman & Van Essen 1991 Memory formation in networks of the cerebral cortex, from sensory up to association cortex, through 11 cells or groups of cells (3 layers) linked by typical patterns of connectivity (feed-forward, feed-back, convergence, divergence, lateral)

  14. Executive memoryPerceptual memory

  15. Executive memoryPerceptual memory

  16. Executive memoryPerceptual memory

  17. Executive memoryPerceptual memory

  18. Executive memoryPerceptual memory

  19. At all hierarchical levels, executive and perceptual networks are associatively connected, thus executive memories contain perceptual elements or assemblies, and vice versa. This executive-perceptual connectivity becomes critical in the integrative dynamics of working memory.

  20. Essential to the dynamics of working memory, to ensure the orderly pursuit of a goal, is the mediation of cross-temporal contingencies between percepts and actions: IF NOW THIS, THEN LATER THAT; IF EARLIER THAT, THEN NOW THIS.

  21. J. von Uexküll, Theoretical Biology, Harcourt, 1926

  22. Working Memory Weizsäcker 1950 Neisser 1976 Arbib 1981 Cortical Perception-Action Cycle

  23. Inputs to frontal executive networks at the top of the Perception-Action Cycle

  24. Outputs from frontal executive networks at the top of the Perception-Action Cycle

  25. Working Memory Whereas the cycle operates in series and in parallel through the environment, integrative working memory at the top operates by reentrant cortical integration (RCI). Edelman, G.M. The Remembered Present. A Biological Theory of Consciousness. New-York: Basic Books, 1989.

  26. Fuster, J.M. and Alexander, G.E., Science 173:652-654. 1971 PREFRONTAL Niki 1974 Fuster et al. 1982 Quintana et al. 1988 Barone & Joseph 1989 Funahashi et al. 1989 Quintana & Fuster 1989 Requin et al. 1990 Fuster et al. 2000 TEMPORAL Fuster & Jervey 1982 Fuster et al. 1985 Miyashita 1988 Miyashita & Chang 1988 Miller et al. 1993 Tomita et al. 1999 PARIETAL Gnadt & Andersen 1988 Quintana et al. 1989 Andersen & al. 1990 Barash & Andersen 1991 Quintana & Fuster 1999 Zhou & Fuster 1996 Chafee & Goldman-Rakic 2000 Ardestani & al. 2005

  27. Cross-Modal Temporal Integration in Working Memory

  28. Fuster et al., Nature 405:347-351, 2000

  29. Fuster et al., Nature 405:347-351, 2000

  30. Zhou,Y. and Fuster, J.M., PNAS 93:10533-10537,1996

  31. Neurovascular Coupling in Working Memory Near-Infrared Spectroscopy (NIRS) Surface Field Potentials Local Field Potentials Unit Discharge

  32. PARIETAL FRONTAL 5 PS 9 7a IS 8 LS 10 mm AS STS

  33. The specialized WM “modules” of prefrontal cortex are nodes of heavy association in active executive-memory networks. Those nodes encode specific sensory-motor associations within widely distributed cortical networks, networks that encode the broad behavioral context in which those specific associations were formed and remain embedded.

  34. Cognit Modeling ConstraintsArchitecture (network) Relational code Hierarchical & heterarchical PlasticityDynamics Content-addressable Stochastic Reentry Hierarchical & heterarchical Parallel Serial Categorical (degeneracy) (a) in perception (b) in action

  35. Cortical Working Memory2006 Art work: Consultants: Amanda Hammond Joaquín Fuster Kim Hager Allen Ardestani UCLA Brain Mapping UCLA Semel Institute Cognitive Neuroscience

  36. Primate Units Fuster, J. Neurophysiol. 36: 61 (1973) Niki & Watanabe, Brain Res. 171: 213 (1979). Fuster & Jervey, J. Neurosci. 2: 361 (1982). Kojima & Goldman-Rakic, Brain Res. 248: 43 (1982). Fuster et al., Brain Res. 330: 299 (1985). Funahashi et al., J. Neurophysiol. 61: 331 (1989). Quintana et al., Brain Res. 503:100 (1989). Miller et al., J. Neurosci. 13: 1460 (1993). Quintana & Fuster, Cerebral Cortex 9: 213 (1999). Chafee & Goldman-Rakic, J. Neuro- physiol. 83: 1550 (2000). Fuster et al., Nature 405: 347 (2000). Schultz et al., Cerebral Cortex 10: 272 (2000). Human Imaging Courtney et al., Nature 386: 608 (1997). Petit et al., J. Neurosci. 18: 9429 (1998). D’Esposito et al., Exp. Brain Res. 133: 3 (2000). Pollmann & Von Cramon, Exp. Brain Res. 133: 12 (2000). *Duncan & Owen, TINS 23: 475 (2000). *Cabeza & Nyberg, J. Neurosci. 12: 1 (2000). Mecklinger et al., Hum. Brain Mapp. 11: 146 (2000). *Wager & Smith, Cog. Affect. Beh. Neurosci. 3: 255 (2003). Crottaz-Herbette et al., NeuroImage 21: 340 (2004). Buchsbaum et al., Neuron 48: 687 (2005). Goldstein et al., Neuropsychology 19: 509 (2005). *Rajah & D’Esposito, Brain 128: 1964 (2005).

  37. Superior parietal SMA Superior frontal Inferior parietal Anterior cingulate Motor Middle frontal Fusiform Visual Inferior frontal Superior temporal Inferior temporal Orbital Time Visual WM

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