Emergence of oscillatory activity via spike timing dependent plasticity

by Sarit Nagar

at Condensed Matter Theory Seminar

Wed, 21 Jun 2017, 13:30
Physics building (#54) room 207


Neuronal oscillatory activity has been reported in relation to a wide range of cognitive processes In certain cases changes in the oscillatory activity have been related to pathological states Although the specific role of these oscillations has yet to be determined it is clear that neuronal oscillations are abundant in the central nervous system These observations raise the question of the origin of these oscillations: are the mechanisms responsible for generation and stabilization of these oscillations genetically hard wired or can they be acquired via a learning process Here we focus on spike timing dependent plasticity STDP and ask: Can oscillatory activity emerge in a neuronal network via an unsupervised learning process of STDP dynamics If so how and what features of the STDP learning rule govern and stabilize the resultant oscillatory activity To this end we studied the STDP dynamics of the effective coupling between two competing neuronal populations with reciprocal inhibitory connections To analyze the system it is convenient to study the phase diagram that depicts the possible dynamical states of the network as a function of the effective inhibitory couplings We find that this phase diagram displays a rich repertoire of possible dynamical behaviors including regions of different fixed point solutions bi stability and a region in which the system exhibits oscillatory activity STDP introduces dynamics for the inhibitory couplings themselves hence induces a flow on the phase diagram We developed mean field Fokker Planck theory for the stochastic dynamics of the synaptic couplings in the limit of slow learning In this limit we studied the STDP induced flow on the phase diagram and investigated the conditions for the flow to converge to an oscillatory state of the neuronal network We characterized how the features of the STDP rule govern and stabilize these oscillations

Created on 10-06-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 10-06-2017 by Bar Lev, Yevgeny (ybarlev)