Abstract
BackgroundRadial intra- and interlaminar connections form a basic microcircuit in primary auditory cortex (AI) that extracts acoustic information and distributes it to cortical and subcortical networks. Though the structure of this microcircuit is known, we do not know how the functional connectivity between layers relates to laminar processing.Methodology/Principal FindingsWe studied the relationships between functional connectivity and receptive field properties in this columnar microcircuit by simultaneously recording from single neurons in cat AI in response to broadband dynamic moving ripple stimuli. We used spectrotemporal receptive fields (STRFs) to estimate the relationship between receptive field parameters and the functional connectivity between pairs of neurons. Interlaminar connectivity obtained through cross-covariance analysis reflected a consistent pattern of information flow from thalamic input layers to cortical output layers. Connection strength and STRF similarity were greatest for intralaminar neuron pairs and in supragranular layers and weaker for interlaminar projections. Interlaminar connection strength co-varied with several STRF parameters: feature selectivity, phase locking to the stimulus envelope, best temporal modulation frequency, and best spectral modulation frequency. Connectivity properties and receptive field relationships differed for vertical and horizontal connections.Conclusions/SignificanceThus, the mode of local processing in supragranular layers differs from that in infragranular layers. Therefore, specific connectivity patterns in the auditory cortex shape the flow of information and constrain how spectrotemporal processing transformations progress in the canonical columnar auditory microcircuit.
Highlights
The thalamocortical synapse sets the stage for the cortical delineation and integration of auditory information
We characterized the functional connectivity of auditory cortex (AI) neurons across multiple laminae, and related it to processing properties reflected in spectrotemporal receptive fields
We found a weak correlation between connection strength and halfwidth (r = 20.152, p,0.01), and we investigated the correlation between halfwidth and other spectrotemporal receptive fields (STRFs) parameters
Summary
The thalamocortical synapse sets the stage for the cortical delineation and integration of auditory information. Antidromic stimulation and focal tracer injection studies have delineated the general scheme of columnar laminar connectivity [7,8,13,14]. Both response latency and local field potentials have been used to map the laminar flow of information [1,2,3,15]. Response latency relates to initial timing, and electrical stimulation and tracer studies provide anatomical confirmation and frameworks These approaches do not, reveal the responses of neurons to complex stimuli or synchronization within cortical columns and, cannot disclose how functional connectivity relates to cortical processing principles and emerging receptive field properties. Though the structure of this microcircuit is known, we do not know how the functional connectivity between layers relates to laminar processing
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
