Dissn Research Summary - Primary Visual Cortex

[WEEVEY]

The following is the abstract from my dissertation which was completed 
back in May.  More information about this research may be found at the 
following URL:  http://www.cris.com/~Weevey.

Sincerely,
Eva S. Simmons

************************************************************************

   CIRCUITRY STUDIES OF A COMPUTATIONAL MODEL OF THE PRIMARY VISUAL CORTEX

   			  Eva Sabrina Simmons, Ph.D.
		     University of Texas at Austin, 1995

			  Supervisor:  Robert E. Wyatt

   The goals of this project include:  (1) proving a procedure for circuit 
determination of any cytoarchietectonic area of the brain, given certain 
kinds of data are known as in the computational model being used here, and 
(2) one circuit of activity will be proposed with three variations on it by 
changing the connection strength from the standard.  Applying the concept of 
the connection matrix and obtaining basic statistical data about the connec-
tions present with respect to presynaptic cells, basic connection data are 
obtained as the specified anatomy of the cells and random placement in appro-
priate layers has allowed.  Also, by allowing activity over a period of 20 ms, 
time propagation data are produced.  By keeping a record of activated and 
deactivated cells at each time step whose minor types have been read-in from 
a file and by figuring out exactly how each cell was activated, pieces of the 
circuits can be produced.  Later a circuit diagram can be produced from this 
data.  The sets used for this study are:  400 and 2000 cell sets for basic 
data, and 1000 and 2000 cell sets for variations of connection strength.  The 
following conclusions can be made:  (1) The data shows increase in cell type 
activity with an increase in cell count in the first two time intervals 
(0.00-5.00 ms).  (2) The pattern seen over the time intervals is:  The first 
time interval A (0.00-2.50 ms), is always a period of immense activity.  
During the second time interval, B (2.55-5.00 ms), the activity continues to 
be heavy, with no new cell types being activated.  The following time inter-
vals, C through H (5.05-20.00 ms), moderate activity occurs.   (3) The pattern 
of activity, as found in experiment, is also found here.  (4) A pattern of 
cell type activity is seen when comparing sets to some degree, with some 
changes depending on cell count and variations in connection strength.  
(5) The circuits that have been found were as expected in the literature. 


@}---------- THE SIMMONS FACTOR --------- EVA SABRINA SIMMONS, PH.D. -------{@
        WWW Personal Page:  http://www.cris.com/~Weevey/index.html
@}---- @}---- @}---- WATCH IT, OR IT MIGHT ATTACK!! ;) ---{@ ---{@ ---{@ ---{@