[Murg] Characterizing functional hippocampal pathways in a brain-based device (fwd from krichmar@nsi.edu)

[Eugen Leitl]

----- Forwarded message from Jeff Krichmar <krichmar at nsi.edu> -----

From: "Jeff Krichmar" <krichmar at nsi.edu>
Date: Mon, 21 Feb 2005 10:23:33 -0800 (PST)
To: connectionists at cs.cmu.edu, cneuro at bbb.caltech.edu
Subject: Characterizing functional hippocampal pathways in a brain-based 
     device
User-Agent: SquirrelMail/1.4.2
Reply-To: "Jeff Krichmar" <krichmar at nsi.edu>


Dear Colleagues,

The following paper is available through PNAS Open Access:

http://www.pnas.org/cgi/reprint/102/6/2111

J.L. Krichmar, D. A. Nitz, J.A. Gally, and G. M. Edelman (2005).
Characterizing functional hippocampal pathways in a brain-based device as
it solves a spatial memory task. Proc Natl Acad Sci USA, 102: 2111-2116.

Analyzing neural dynamics underlying complex behavior is a major challenge
in systems neurobiology. To meet this challenge through computational
neuroscience, we have constructed a brain-based device (Darwin X) that
interacts with a real environment, and whose behavior is guided by a
simulated nervous system incorporating detailed aspects of the anatomy and
physiology of the hippocampus and its surrounding regions. Darwin X
integrates cues from its environment to solve a spatial memory task.
Place-specific units, similar to place cells in the rodent, emerged by
integrating visual and self-movement cues during exploration without prior
assumptions in the model about environmental inputs. Because synthetic
neural modeling using brain-based devices allows recording from all
elements of the simulated nervous system during behavior, we were able to
identify different functional hippocampal pathways. We did this by tracing
back from reference neuronal units in the CA1 region of the simulated
hippocampus to all of the synaptically connected units that were coactive
during a particular exploratory behavior. Our analysis identified a number
of different functional pathways within the simulated hippocampus that
incorporate either the perforant path or the trisynaptic loop. Place
fields, which were activated by the trisynaptic circuit, tended to be more
selective and informative. However, place units that were activated by the
perforant path were prevalent in the model and were crucial for generating
appropriate exploratory behavior. Thus, in the model, different functional
pathways influence place field activity and, hence, behavior during
navigation.

KEYWORDS: network, entorhinal cortex, CA1, place cell, computational model

Best regards,

Jeff Krichmar
The Neurosciences Institute
10640 John J. Hopkins Drive
San Diego, CA 92121
krichmar at nsi.edu
http://www.nsi.edu/users/krichmar

----- End forwarded message -----
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a>
______________________________________________________________
ICBM: 48.07078, 11.61144            http://www.leitl.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE
http://moleculardevices.org         http://nanomachines.net
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: not available
Url : http://minduploading.org/pipermail/murg/attachments/20050223/ed3a3d51/attachment.pgp