Gap encoding by parvalbumin-expressing interneurons in auditory cortex

• Published in: Journal of neurophysiology 2018-07, Vol.120 (1), p.105-114
• Main Authors: Keller, Clifford H, Kaylegian, Katherine, Wehr, Michael
• Format: Article
• Language: English
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00911.2017

Synaptic inhibition shapes the temporal processing of sounds in auditory cortex, but the contribution of specific inhibitory cell types to temporal processing remains unclear. We recorded from parvalbumin-expressing (PV+) interneurons in auditory cortex to determine how they encode gaps in noise, a model of temporal processing more generally. We found that PV+ cells had stronger and more prevalent on-responses, off-responses, and postresponse suppression compared with presumed pyramidal cells. We summarize this pattern of differences as "deeper modulation" of gap responses in PV+ cells. Response latencies were also markedly faster for PV+ cells. We found a similar pattern of deeper modulation and faster latencies for responses to white noise bursts, suggesting that these are general properties of on- and off-responses in PV+ cells rather than specific features of gap encoding. These findings are consistent with a role for PV+ cells in providing dynamic gain control by pooling local activity. NEW & NOTEWORTHY We found that parvalbumin-expressing (PV+) interneurons in auditory cortex showed more deeply modulated responses to both gaps in noise and bursts of noise, suggesting that they are optimized for the rapid detection of stimulus transients.