title: Dynamics of Population Activity in Rat Sensory Cortex: Network Correlations Predict Anatomical Arrangement and Information Content.
abstract: To study the spatiotemporal dynamics of neural activity in a cortical population, we implanted a 10 × 10 microelectrode array in the vibrissal cortex of urethane-anesthetized rats. We recorded spontaneous neuronal activity as well as activity evoked in response to sustained and brief sensory stimulation. To quantify the temporal dynamics of activity, we computed the probability distribution function (PDF) of spiking on one electrode given the observation of a spike on another. The spike-triggered PDFs quantified the strength, temporal delay, and temporal precision of correlated activity across electrodes. Nearby cells showed higher levels of correlation at short delays, whereas distant cells showed lower levels of correlation, which tended to occur at longer delays. We found that functional space built based on the strength of pairwise correlations predicted the anatomical arrangement of electrodes. Moreover, the correlation profile of electrode pairs during spontaneous activity predicted the "signal" and "noise" correlations during sensory stimulation. Finally, mutual information analyses revealed that neurons with stronger correlations to the network during spontaneous activity, conveyed higher information about the sensory stimuli in their evoked response. Given the 400-μm-distance between adjacent electrodes, our functional quantifications unravel the spatiotemporal dynamics of activity among nearby and distant cortical columns.
authors.affiliation: School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM)Tehran, Iran; Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia.
authors.forename: Mohammad Mahdi
authors.initials: MM
authors.lastname: Sabri
authors.affiliation: Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia; School of Psychology, University of New South WalesSydney, NSW, Australia.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Adibi
authors.affiliation: Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National UniversityCanberra, ACT, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University NodeCanberra, ACT, Australia.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Arabzadeh
mesh_terms: D000818:Animals; D004567:Electrodes, Implanted; D008297:Male; D008839:Microelectrodes; D009415:Nerve Net / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology*
keywords: barrel cortex; noise correlation; sensory coding; signal correlation; vibrissal