Seminários em Neurociências 2011.1

Segunda-feira 02/05/2011 10:50h Sala 4 – Escola de Ciência e Tecnologia

 

Theta phase modulates high gamma and ripple-like oscillations in the hippocampus

Robson Scheffer Teixeira (Mestrando - PGNeuro/UFRN)

It was recently proposed that fast gamma oscillations (60 – 150 Hz) convey spatial information from the medial entorhinal cortex to the CA1 region of the hippocampus. However, here we describe two functionally distinct oscillations in this frequency range, both coupled to the theta rhythm during active exploration and REM sleep: an oscillation with peak activity at ~80 Hz, and a faster oscillation centered at ~140 Hz. The two oscillations do not overlap in time and are differentially modulated by theta phase depending on the CA1 layer, suggesting independent mechanisms of generation. While the ~80 Hz oscillation likely originates from entorhinal cortex inputs to deeper CA1 layers, the faster ripple-like oscillation (~140 Hz) probably reflects local CA1 activity in superficial layers. Altogether, our results demonstrate the existence of novel theta-associated ripples, and suggest a redefinition of fast gamma oscillations.

Notícia cadastrada em: 29/04/2011 15:11
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