MODEL SYNAPSES WITH FREQUENCY POTENTIATION CHARACTERISTICS CAN COOPERATIVELY ENHANCE HEBBIAN LEARNING

C. Andrew Chapman and Suzanna Becker


Frequency potentiation, a short-term form of plasticity, is an enhancement in the amplitude of neuronal responses to each pulse in a train of stimulation pulses which occurs when the pulses are delivered within a certain frequency range. In the model, theta-frequency input from the subiculum via synapses with frequency potentiation characteristics cooperatively enhances Hebbian learning in pyriform cortex efferents to the entorhinal cortex, particularly when the inputs are phase-locked. This effect is further enhanced when inhibitory interneurons are added within the entorhinal layer. These simulations demonstrate a mechansism for frequency-dependent heterosynaptic modulation of Hebbian learning, and may be relevant to theta rhythm-related enhancements of plasticity in the hippocampal formation.


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