Recurrent circuitry is required to stabilize piriform cortex odor representations across brain states

• Published in: eLife Vol. 9
• Main Authors: Bolding, Kevin A, Nagappan, Shivathmihai, Han, Bao-Xia, Wang, Fan, Franks, Kevin M
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 14.07.2020; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Activity patterns; Anesthesia; Animals; Cortex (piriform); cortical circuits; Experiments; Ketamine; Ketamine - pharmacology; Mice; Neural circuitry; Neural networks; Neuroscience; Odor; Odorants; Odors; olfaction; Olfactory bulb; Olfactory Bulb - drug effects; Olfactory Bulb - physiology; Olfactory pathways; Olfactory Pathways - drug effects; Olfactory Pathways - physiology; pattern completion; Piriform Cortex - drug effects; Piriform Cortex - physiology; Respiration; Sensory evaluation; Somatosensory cortex; Synapses - physiology; Xylazine; Xylazine - pharmacology; mouse; olfaction; pattern completion; cortical circuits; neuroscience
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.53125

Pattern completion, or the ability to retrieve stable neural activity patterns from noisy or partial cues, is a fundamental feature of memory. Theoretical studies indicate that recurrently connected auto-associative or discrete attractor networks can perform this process. Although pattern completion and attractor dynamics have been observed in various recurrent neural circuits, the role recurrent circuitry plays in implementing these processes remains unclear. In recordings from head-fixed mice, we found that odor responses in olfactory bulb degrade under ketamine/xylazine anesthesia while responses immediately downstream, in piriform cortex, remain robust. Recurrent connections are required to stabilize cortical odor representations across states. Moreover, piriform odor representations exhibit attractor dynamics, both within and across trials, and these are also abolished when recurrent circuitry is eliminated. Here, we present converging evidence that recurrently-connected piriform populations stabilize sensory representations in response to degraded inputs, consistent with an auto-associative function for piriform cortex supported by recurrent circuitry.