Total sleep deprivation-induced electrophysiological activities changes in rat hippocampal CA1 detected by microelectrode arrays

Abstract Total sleep deprivation (TSD) produces impairments in cognitive on individuals. The measurement of rat hippocampal CA1 neural activity after TSD is of importance to understand the harmful effect induced by TSD on the cellular level. In this work, the deficit of spatial learning and memory maintenance caused by TSD was demonstrated in the Morris Water Maze test. And a novel 16-site micro-electrode array we designed and fabricated was successfully implanted into the target area of rat brain to measure the neuronal activities in rat hippocampal CA1 before and after TSD. The probe was successfully implanted into the target area of brain. The detection results showed that the neuronal firing of both Pyramidal neurons and interneurons in CA1 got elevated, and the fluctuation of local field potential (LFP) became more frequent after TSD, indicating that TSD exerted excitatory effects on CA1 neurons. Besides, the power of spike firing and LFP got significantly increased in low frequency band, especially theta band after TSD, accompanied by the increased occurrence of OFF period during spike firing. It is concluded that the disturbed theta activity induced by TSD in hippocampus was associated with the altered excitatory/inhibitory balance of neurons in the brain. And the increased occurrence of OFF period in neuronal firing after TSD disrupted the propagation of theta activity in the brain, which might partially explain the overall decline in spatial learning performance of rats.