Temporal response properties in auditory cortex are layer-dependent

Abstract

Event Abstract Back to Event Temporal response properties in auditory cortex are layer-dependent In the visual and somatosensory cortices, many neuronal response properties vary systematically across layers within a cortical column. These laminar differences have provided the foundation for theories about how cortical columns transform visual and somatosensory information. In the auditory cortex, however, few clear laminar differences in neuronal response properties have been found, complicating attempts to understand intracolumnar cortical processing of auditory information. It has been suggested that temporal processing is a major function of the auditory cortex. We hypothesised that layer-dependence might therefore be most obvious for temporal response properties. To test this hypothesis, we recorded neuronal responses to short trains of pulsed noise in the mouse primary auditory cortex and the anterior auditory field. Rates of noise pulse trains varied from 1 to 20 pulses per second (PPS). Responses of neuronal clusters were recorded simultaneously at different cortical depths, using a single-shank silicon multielectrode with 16 recording sites spaced 100 microns apart. Over 400 cluster recordings were obtained from a total of 60 penetrations in six mice. Characteristic frequencies were similar for different recording sites within the same penetration, confirming that the multielectrode array was placed approximately orthogonal to the cortical surface. Cortical depth estimates for recordings from different penetrations were aligned relative to the depth at which a reversal of polarity was observed in the early wave of local field potentials (LFPs) recorded during noise pulses. This reference depth likely corresponded to layer II (Kral et al., Cerebral Cortex 10:714, 2000). Temporal precision of the responses to individual noise bursts was depth-dependent (p<0.001, Kruskal-Wallis test). The peak precision across PPS conditions, as quantified by vector strength and related measures of time-locked firing, was highest at the most superficial depths and decreased with depth. The probability of a response to second and later noise pulses in the pulse trains was also depth-dependent (p<0.001). Peak response probability across PPS was maximal about 500 microns below the LFP reversal point, a depth presumed to correspond to layer V (Anderson et al., Brain Research, in press). The same depth dependencies in temporal precision and response probability were observed when these measures were computed for a fixed slow PPS, rather than for the preferred PPS for each recording and response measure. The PPS at which measures of temporal precision were maximised did not vary significantly with cortical depth, while the PPS at which response probability was largest showed weak depth-dependence. These results demonstrate that temporal precision of cluster responses is highest in superficial layers, while response reliability is maximal at a depth likely to correspond to layer V. Thus, there is systematic depth-dependence in the temporal response properties of neuronal clusters within auditory cortical columns. It remains to be seen whether this arises from layer-dependent temporal response properties in single units, or layer-dependent changes in the composition of neuronal clusters. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). Temporal response properties in auditory cortex are layer-dependent. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.137 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Feb 2009; Published Online: 02 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.