A weekly feature (begun November 2004) connecting Center activities
to what's happening in the world at large.
The 11/12 Brown Bag discussion of "History,
Memory and the Brain" looked at the
troubles that historians get into, given the human "vice" for nostalgia...and
"Hegel was right when he said
that we learn from history that man can never learn anything
from history." ~ George Bernard Shaw
"History is the version of past events that
people have decided to agree upon." ~ Napoleon
A brain-wide distributed network orchestrates cognitive memorizing
and remembering of explicit memory (i.e., memory of facts and events).
The network was initially identified in humans and is being systematically
investigated in molecular/genetic, single-unit, lesion, and imaging
studies in animals. The types of memory identified in humans are extended
into animals as episodic-like (event) memory or semantic-like (fact)
memory. The unique configurational association between environmental
stimuli and behavioral context, which is likely the basis of episodic-like
memory, depends on neural circuits in the medial temporal lobe, whereas
memory traces representing repeated associations, which is likely
the basis of semantic-like memory, are consolidated in the domain-specific
regions in the temporal cortex. These regions are reactivated during
remembering and contribute to the contents of a memory. Two types
of retrieval signal reach the cortical representations. One runs from
the frontal cortex for active (or effortful) retrieval (top-down signal),
and the other spreads backward from the medial temporal lobe for automatic
retrieval. By sending the top-down signal to the temporal cortex,
frontal regions manipulate and organize to-be-remembered information,
devise strategies for retrieval, and also monitor the outcome, with
dissociated frontal regions making functionally separate contributions.
The challenge is to understand the hierarchical interactions between
these multiple cortical areas, not only with a correlational analysis
but also with an interventional study demonstrating the causal necessity
and the direction of the causality.
Department of Physiology, University of Tokyo School of Medicine,
Hongo, Tokyo 113-0033, Japan.
These pages have been created by
Selene Platt in consultation
with Paul Grobstein.
Please submit suggestions for other topics to explore in "Science Matters" to Selene Platt