|
This model addresses the potential role of the hippocampus in goal
directed spatial navigation, the role of theta rhythm oscillations in
reversal learning, and the role of entorhinal cortex as a buffer for
novel information. The model can encode a spatial environment and guide
movement of a virtual rat to find a food reward within this
environment. The structure of the model is constrained by the overall
anatomical connectivity of the hippocampus, and the spread of activity
is constrained by the relative size of place fields in entorhinal
cortex and regions CA3 and CA1 of the hippocampus. The model has a
simple form of theta phase precession. The model avoids interference
from prior retrieval during encoding by implementing separate phases of
encoding and retrieval on each cycle of the theta rhythm. The model
uses sustained spiking activity in entorhinal cortical neurons to allow
slow transitions in sensory input from the environment to cause
synaptic modification dependent upon a very brief temporal window of
spike timing dependent synaptic plasticity.
Prof. Michael E. Hasselmo
Department of Psychology
Center for Memory and Brain,
Program in Neuroscience and
Center for BioDynamics
64 Cummington St.
Boston, MA 02215
Tel: (617) 353-1397
E-mail: hasselmo@bu.edu
Overview of research projects:
laboratory web page.
Articles available as PDF files:
publications page.
|
|
Spatial navigation in a T-maze: This integrate-and-fire model
created with Catacomb relates hippocampal physiological data with the
possible functional role of the hippocampus for behavior in a spatial
navigation task.
To test this model:
(1) Download the Catacomb script newtmaze.ccm.
(Press the right hand mouse button on the link. A "Save As" window
will pop up. At the bottom of the window, make sure to save as "All
files", not as "HTML document".)
(2) Make sure you have Catacomb version 2.034, which the newtmaze model is designed to work with: catacomb-2.034.zip.
Some simple exercises with the newtmaze model are shown here.
Obtaining and running Catacomb: The most recent stable release of Catacomb may be obtained at: http://askja.bu.edu/catacomb/.
(The most recent version will not work with the newtmaze model. As
indicated above, that model is designed to work with version 2.034 of
Catacomb.)
To run the Catacomb environment, you need a suitable implementation of JAVA
for your computer and operating system. While Catacomb may run with the
Java provided as a standard installation on your platform, the best way
to insure that Catacomb will run correctly is to install Java from one
of these two sources:
(1) The official Java site at http://www.java.com.
A box displayed at this site offers automated and manual download of
java software. If you follow the link to the automated download, a page
will appear that immediately attempts an automated installation of the
correct Java for your platform.
If the automated install does not work, or if you wish to manually
select a different platform, such as Linux, Macintosh or Solaris, use
the "Manual Download" link at the front page of http://www.java.com.
(If your operating system is Windows95, the FAQ link at the official Java site indicates how to install Java properly.)
(2) The Java developers download page at http://java.sun.com/j2se/1.4/download.html.
Scroll down the page to the section labeled "Download J2SE v 1.4.2_03".
There, download from the column labeled "JRE". Software for all
operating systems is provided.
Project Guidelines for PS530 students: The following guidelines
may be useful for those who would like to learn about Catacomb and the
details of the hippocampal simulation.
(You will need a PDF reader, such as the free Acrobat Reader to open the PDF files above.)
|
