Investigating neural substrates of stable auditory representation in cortical and subcortical areas using illusory stimuli

• Applicant: Dr. Irene Onorato
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551506093

The objective of the proposed project is to investigate the brain mechanisms underlying stable auditory perception, even in noisy environments, using illusory stimuli. While auditory induction has been extensively studied behaviorally, the precise neural mechanisms and areas involved remain unclear. Mice are ideal for this research because of their highly developed sense of hearing. In addition, the vast majority of previous work has focused on visual illusions, making this auditory focus novel. The project is divided into three main work packages (WPs). WP1: The objective of this work package is to develop a behavioral task to confirm that mice perceive the continuity illusion paradigm. This will lay the groundwork for subsequent neural investigation. The approach will be combined with electrophysiological recordings in the auditory cortex (AC), thalamus (medial geniculate body, MGB) and inferior colliculus (IC), which will reveal the neural activity associated with the representation of the illusory percept. WP2: This section involves the optogenetic manipulation of cortical feedback projection to subcortical regions. The selective suppression of corticofugal neurons, combined with recordings of activity in subcortical areas, will improve our understanding of their function in generating a stable perception in spite of noisy input and provide insights into the neural underpinnings of auditory illusion. WP3: The objective of this section is to investigate the impact of integrating visual information with auditory input on perception. This will be achieved by examining how coherent versus conflicting sensory cues are integrated in the recorded auditory areas (AC, MGB, IC). Finally, the use of an innovative behavioral task in combination with state-of-the-art electrophysiological methods will allow me to investigate the neural substrate of inference processes in the mouse auditory system. The large single-unit dataset that will be acquired using two Neuropixels probes in conjunction with the optogenetics technique will permit the investigation of the neural correlates of illusory perception in different auditory brain regions, cortical layers, and neuronal excitatory and inhibitory sub-types.

• DFG Programme: WBP Position