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Krasnow Institute > Monday Seminars > Abstracts
Neuromodulation and Time-Dependent Plasticity Jeffrey L. Krichmar The Neurosciences Institute In foraging behavior, where an animal searches for food caches, it is imperative for the animal to remember the locations and routes to these caches. An important consideration is the means by which the organism takes the appropriate actions to lead it to a goal that satisfies a particular need. We present a neural model that shows how different neuromodulatory signals may work in concert to develop effective behavior in a foraging task where a simulated agent has to find caches of different rewards. The model contains simulated hippocampal areas that respond differentially to locations in space, and simulated frontal cortex areas that respond to different salient cues from the environment. A time-dependent plasticity rule, which is modulated by different reinforcers, leads to asymmetric neuronal receptive fields that bias movement in a particular direction. This learning rule presents a novel method for reinforcing actions that lead to rewards and circumvent noxious stimuli. We suggest that different areas of the frontal cortex, which may evaluate different rewards and costs, can modulate time-dependent plasticity and give rise to a directional bias that facilitates action selection.
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