Exploring the influence of higher order brain regions on the piriform cortex neuronal activity

NOEL FEDERMAN; OLIVIA PEDRONCINI; ANTONIA MARIN BURGIN

Cordoba

Congreso; Congreso SAN; 2019

SAN

The Piriform cortex (PC), the main region of the olfactory cortex, receives afferent (bottom-up) sensory inputs from the olfactory bulb (OB) and extensive (top-down) inputs from higher-order areas such as the basolateral amygdala (BLA) and the lateral entorhinal cortex (LEC). To understand the contribution of the BLA and LEC to the processing of odors we study their functional connectivity to the posterior PC (pPC). We infected the BLA and the LEC with adeno-associated virus to express channelrhodopsin (ChR2-AAV) in either excitatory neurons (under CamKIIa promoter) or inhibitory Parvalbumin interneurons (using PV-Cre mice). We recorded then, in acute brain slices, postsynaptic currents and spiking in different principal neurons of the pPC in response to photostimulation. We found that both excitatory and inhibitory long range projections coming from the BLA synapse preferentially onto pyramidal neurons of the deep layers of pPC and do not contact semilunar neurons of the superficial layer. Moreover, we discover that inputs from both BLA and LEC can modulate the output of pPC neurons in response to stimulation of OB afferents. The LEC and BLA inputs could provide contextual and valence information associated to odors. To investigate the role of those regions in the processing of odors in vivo, we are conducting experiments to photoinactivate them alternatively during an associative odor-context-reward task and evaluate the effect of that manipulation on the behavior.