Differential inhibition of pyramidal cells and inhibitory interneurons along the rostrocaudal axis of anterior piriform cortex

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 115; no. 34; pp. E8067 - E8076
• Main Authors: Large, Adam M., Vogler, Nathan W., Canto-Bustos, Martha, Friason, F. Kathryn, Schick, Paul, Oswald, Anne-Marie M.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 21.08.2018
• Series: PNAS Plus
• Subjects: Acetyl-L-carnitine; Acetylation; Animals; Antidepressants; Behavioral plasticity; Biological Sciences; Biomarkers; Carnitine; Cells; Children; Cortex (piriform); Dendritic plasticity; Domains; Epigenetics; GABAergic Neurons - cytology; GABAergic Neurons - metabolism; Glutamatergic transmission; Hippocampal plasticity; Hippocampus; Inhibition (psychology); Interneurons; Interneurons - cytology; Interneurons - metabolism; Medicine; Mental depression; Mice; Mice, Transgenic; Neurons; Olfactory Perception - physiology; Patients; Piriform Cortex - cytology; Piriform Cortex - metabolism; PNAS Plus; Precision medicine; Pyramidal cells; Pyramidal Cells - cytology; Pyramidal Cells - metabolism; Rodents; Sensory perception; Spatial data; Supplements; Synapses - metabolism; Synaptic Transmission - physiology; Target recognition; Therapeutic applications; Trauma; cortex; olfactory; inhibitory circuits
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1802428115

The spatial representation of stimuli in sensory neocortices provides a scaffold for elucidating circuit mechanisms underlying sensory processing. However, the anterior piriform cortex (APC) lacks topology for odor identity as well as afferent and intracortical excitation. Consequently, olfactory processing is considered homogenous along the APC rostral–caudal (RC) axis. We recorded excitatory and inhibitory neurons in APC while optogenetically activating GABAergic interneurons along the RC axis. In contrast to excitation, we find opposing, spatially asymmetric inhibition onto pyramidal cells (PCs) and interneurons. PCs are strongly inhibited by caudal stimulation sites, whereas interneurons are strongly inhibited by rostral sites. At least two mechanisms underlie spatial asymmetries. Enhanced caudal inhibition of PCs is due to increased synaptic strength, whereas rostrally biased inhibition of interneurons is mediated by increased somatostatin–interneuron density. Altogether, we show differences in rostral and caudal inhibitory circuits in APC that may underlie spatial variation in odor processing along the RC axis.