Working memory localization in hippocampus

F. Frank LeFever flefever at ix.netcom.com
Thu Mar 12 22:53:38 EST 1998


One big problem in this area is the diversity of definitions of
"working" memory.

Using at least some (operational as well as explicit) definitions, I
believe oone can argue that the hippocampus is NOT very important for
Working Memory.  Part of the difference may lie in the organisms and
paradigms used (e.g. rats and rat tasks vs. humans and human tasks).

Patricia Godman-Rakic has elegantly demoonstrated temporary coding of
"things to be remembered temporarily for use in a task" in specific
neurons within the prefrontal cortex (monkeys).  Her initial paradigms
involved memory of visual spatial locations, but it appears this
frontal role is not limited to that modality.  She has gone on to look
in fine detail at the complex anatomy of neurotransmitters underlying
this activity.  (Check her out in Medline--numerous publications and
more yet "in press")

Soomeone (I think it may have been Joachim Fuster) said the better term
might be "working WITH memory".  Fuster's work (monkeys again) has
shown the importance of the prefontal cortex of selecting/activating
specific regions of posterior cortex so as to make not just transient
memory but long-term memory NEEDED FOR PERFORMANCE OF A TASK
temporarily available (and, I would argue, dominant in competition with
other memories and/or ambient stimuli).  Accordingly, "working with"
the relevant memories can be disrupted by local cooling of either the
relevant frontal region or the relevant posterior region (e.g. a
particular part of parietal cortex).  (Again, easy to locate via
Medline).

In human clinical neuropsychology, performance of tasks with relatively
little "intellectual" demands but strong "working memory" demands (e.g.
Trails B) is impaired with frontal dysfunction (cortical or
subcortical).

Frank LeFever
New York Neuropsychology Group










In <3508204b.1101985 at news.ntnu.no> stumol at stud.ntnu.no (Sturla Molden)
writes: 
>
>On Thu, 12 Mar 1998 11:21:45 -0600, Lab <lab at purdue.edu> wrote:
>
>>A few weeks ago I remember reading something on this newsgroup about
>>work with evoked potentials to localize the function (or role) of
>>hippocampus in working memory.  However, I have found little in the
>>literature about hippocampus and working memory, and even less about 
>>using EPs to explore that issue. Can someone point me the right
>>direction? 
>
>Olton, DS, JT Becker & GE Handelmann (1979). Hippocampus, space, and
>memory. Behav. Brain Sci., 2,  313-322.
>
>Rawlins, JNP (1985). Associations across time: the hippocampus as a
>temporary memory store. Behav. Brain Sci., 8, 479-528.
>
>
>Sturla Molden
>
>
> 
>
>




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