It has been hypothesized that some schizophrenic
phenomena are best understood in terms of abnormal
interactions between different brain
regions. Preliminary data suggest that during
associative learning task hippocampus is involved in
the encoding (learning) and the prefrontal cortex in
the retrieval of associative memories. Specific
changes in the fMRI activities have also been observed
based on comparative studies between stable
schizophrenia patients and healthy control
subjects. Disconnectivity, observed between brain
regions in schizophrenic patients could result from
abnormal modulation of N-methyl-D-aspartate
(NMDA)-dependent plasticity implicated in
schizophrenia.
Our initial modeling efforts were directed toward a
simple model to simulate the behavioral associative
learning task, with model output as learning curves
depicting performance over each iteration of recall.
As will be evident, the model incorporates the
separation between encoding/consolidation and cued
recall while also retaining biological plausible
relationships between model architecture and neural
systems, as well as known learning parameters in the
brain. In particular, the model accounts for (i) the
separation between "where" and "what" regions (ii)
reduced synaptic plasticity in schizophrenia and
reduced cognitive capacity in schizophrenia.
A model has been built order to compare the (i)
activities with the fMRI data; (ii) the performance
with the behavioral data.
Publications:
P. Érdi, B. Ujfalussy, L. Zalányi, VA. Diwadkar: Computational approach to
schizophrenia: Disconnection syndrome and dynamical pharmacology. In: A
selection of papers of The BIOCOMP 2007 International Conference L. M.
Ricciardi (ed.) Proceedings of the American Institute of Physics (accepted for publication)
bognor@kzoo.edu
Last update 23.04.2008.
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