PV+ Cells Enhance Temporal Population Codes but not Stimulus-Related Timing in Auditory Cortex

Abstract

Spatio-temporal cortical activity patterns relative to both peripheral input and local network activity carry information about stimulus identity and context. GABAergic interneurons are reported to regulate spiking at millisecond precision in response to sensory stimulation and during gamma oscillations; their role in regulating spike timing during induced network bursts is unclear. We investigated this issue in murine auditory thalamo-cortical (TC) brain slices, in which TC afferents induced network bursts similar to previous reports in vivo. Spike timing relative to TC afferent stimulation during bursts was poor in pyramidal cells and SOM+ interneurons. It was more precise in PV+ interneurons, consistent with their reported contribution to spiking precision in pyramidal cells. Optogenetic suppression of PV+ cells unexpectedly improved afferent-locked spike timing in pyramidal cells. In contrast, our evidence suggests that PV+ cells do regulate the spatio-temporal spike pattern of pyramidal cells during network bursts, whose organization is suited to ensemble coding of stimulus information. Simulations showed that suppressing PV+ cells reduces the capacity of pyramidal cell networks to produce discriminable spike patterns. By dissociating temporal precision with respect to a stimulus versus internal cortical activity, we identified a novel role for GABAergic cells in regulating information processing in cortical networks.

Altered stimulus representation in rat auditory cortex is not causal for loss of consciousness under general anaesthesia

“…To measure precision and reliability of spike timing across trials, we applied the spike time tiling coefficient (STTC), 26 which is relatively insensitive to firing rate and can be used even on non-periodic stimuli, to single channel spiking responses as described. 27 Stimulus representation in spike trains was quantified using information theory analysis 24 applied to individual multiunit clusters.…”

Selective effects of isoflurane on cortico-cortical feedback afferent responses in murine non-primary neocortex

“…20 In a subset of slices, intracellular recordings were made from cortical pyramidal neurones using whole-cell patch clamp to compare excitatory postsynaptic potentials (EPSPs) with extracellular responses, as described. 21…”

A Spike Train Distance Robust to Firing Rate Changes Based on the Earth Mover’s Distance

“…Besides firing rates, the temporal pattern of spike timings also carries important information about brain functions. For instance, it has been shown that temporal patterns encode the information of auditory (Machens et al, 2001;Narayan et al, 2006;Wang et al, 2007;Fukushima et al, 2015;Krause et al, 2017), gustatory (Di Lorenzo and Victor, 2003), motor (Vargas-Irwin et al, 2015), olfactory (MacLeod et al, 1998), somatosensory (Harvey et al, 2013), vestibular (Jamali et al, 2016), and visual (Mechler et al, 1998;Victor and Purpura, 1998;Reich et al, 2001;Carrillo-Reid et al, 2015) systems, as well as behavioral adaptation (Logiaco et al, 2015) and sleep (Tabuchi et al, 2018).…”

“…Finally, by removing rate dependence from the SPIKEdistance, Satuvuori et al (2017) proposed the RI-SPIKE-distance as a distance purely sensitive to timing. The spike train distances developed so far have been used in a number of studies for the analysis of neural firing patterns (MacLeod et al, 1998;Mechler et al, 1998;Victor and Purpura, 1998;Machens et al, 2001;Reich et al, 2001; Di Lorenzo and Victor, 2003;Narayan et al, 2006;Wang et al, 2007;Harvey et al, 2013;Fukushima et al, 2015;Logiaco et al, 2015;Vargas-Irwin et al, 2015;Jamali et al, 2016;Krause et al, 2017).…”