Banca de QUALIFICAÇÃO: JULIO NUNES MACHADO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JULIO NUNES MACHADO
DATE: 16/06/2023
TIME: 09:00
LOCAL: Instituto de Física UFAL
TITLE:

 

Cortical oscillations: phase relation diversity between neuronal populations

KEY WORDS:

computational neuroscience, dynamical systems, oscillations

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

The synchronization of nonlinear systems has been widely studied in
different physical and biological systems. In particular, an unusual type of synchronization, called anticipated synchronization (AS),
was discovered by Voss between unidirectionally coupled dynamical systems.
This AS regime can occur when a dynamic “transmitter” system is described by a set of differential equations is unidirectionally coupled to a “receiver” system described by the same set of equations but subjected to a delayed negative feedback. In these cases, AS can be characterized
by a negative phase difference between the transmitter and receiver. Recently, it has been reported that the electrical activity of cortical regions of the brain of monkeys can exhibit this type of synchronization while performing cognitive tasks. In this work, we study a neuronal population model of Izhikevich neuron that can present both AS and the usual synchronization regime with delay (DS, delayed synchronization), characterized by a positive phase difference. In this model, each neuron receives an external noise, simulating excitatory synapses from other brain regions, which obey a Poisson distribution. We also studied the bidirectional coupling effect by adding synapses from the receiver population to the transmitter one. We show that, for a set of biologically plausible parameters, this model presents a bistable regime between DS and AS. Furthermore, our model can present zero-lag synchronization and a phase-drift regime. The diversity in phase relationships between cortical regions with oscillatory activity has been verified in several electrophysiological experiments. We verified that in our model the phase diversity depends on the relationship between the synaptic conductances of the receiver population, the couplings between the populations, and the external noise.

BANKING MEMBERS:
Presidente - 2621034 - MARIA SOCORRO SEIXAS PEREIRA
Interno(a) - 1695829 - ANDRE DE LIMA MOURA
Externo(a) à Instituição - ARIADNE DE ANDRADE COSTA