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My contribution in this presentation will be focused, using recorded LFP signals, on the investigation of the dynamic interactions between auditory and visual neural networks of awake gerbils. These interactions have been studied before, during, and after bi-modal stimulation using appropriate analysis methods based on phase coherence metric.

The study is focused specifically on the effects of adaptation to paired-audiovisual stimulus presentation onto the evolution of inter-cortical coherence of mass-activity states.

Mongolian gerbils were adapted to pairs of tones and flashes presented at fixed stimulus-onset-asynchrony (SOA) (+200ms or -200ms). Stimulus pairs were presented in many trials per day during 10 days. Before and after adaptation, animals were exposed to streams of tones or flashes presented with random inter-stimulus-intervals (ISI) between 1s and 2s. Phase difference series ∆φ(t) were calculated during the stimulation period ∆t =50ms.

To investigate these dynamics of intercortical neural networks of both auditory and visual cortex I analyzed the phase coherence between oscillatory components of local field potential activity, LFP signals, in the frequency range 7-200 Hz, recorded simultaneously from both auditory and visual cortex. The repeated paired stimulus, tone-flash or flash-tone, can be considered as an associative learning process between two modes of sensory stimulations for two different cortical neural networks. Furthermore I investigated if only the first stimulus of the paired-stimulus is able to cause a prediction or modulation of inter-cortical neuronal activities. Thus, if a repeated association of audiovisual stimulus pairs (Flash/Tone or Tone/flash) after a sufficient number of trials can lead to a second perceptual event, even when the second stimulus is omitted?