Detection of fear memory signals in the rat amygdala for brain-computer interface

Abstract

A Brain-Computer Interface (BCI) is a system that A Brain-Computer Interface (BCI) is a system that serves direct communication between one’s brain and a computer.. From EEGs and neurophysiological recordings, brain signals are extracted to monitor, detect, and translate its significance. To some extent, we would understand that the current goals of BCI researches still focus on restoring the motor control and the artificial sensory feedback. We proposed an implementation of a BCI technique using cognitive neural activities for the direct Brain-Brain Interface (BBI) that interprets and exchanges specific brain states. The interpretation of the brain state appears to be crucial in this implementation, and is the main object of our investigation. The aim of this study is to detect the specific state of the brain in fear condition, which is one of the emotional states, resulted from higher brain cognitive function. We analyzed the local field potential (LFP) recording to sort out activities associated with fear memory, which are stable for long period of time and contain useful information. For reproducible results and quantification of the fear response, we employed a Pavlovian fear conditioning paradigm (i.e., coupling tone presentation and foot electro-shock) and scoring of freezing state. We particularly considered the effect on the lateral amygdala (LA) and the medial geniculate (MGN), two well-known neural substrates for fear conditioning and fear memory. We applied linear and non-linear techniques to decipher the recordings obtained. We found a theta power increase during fear retrieval sessions in the LA. The linear functional connectivity between LA and MGN also increased after fear conditioning test and showed a significant increase on recalling the fear memory. In addition the value of Approximate Entropy (ApEn), a measure of complexity and irregularity of a given signal, indicated that there were more information processions during the fear state...