title: Neural spike-timing patterns vary with sound shape and periodicity in three auditory cortical fields.
abstract: Mammals perceive a wide range of temporal cues in natural sounds, and the auditory cortex is essential for their detection and discrimination. The rat primary (A1), ventral (VAF), and caudal suprarhinal (cSRAF) auditory cortical fields have separate thalamocortical pathways that may support unique temporal cue sensitivities. To explore this, we record responses of single neurons in the three fields to variations in envelope shape and modulation frequency of periodic noise sequences. Spike rate, relative synchrony, and first-spike latency metrics have previously been used to quantify neural sensitivities to temporal sound cues; however, such metrics do not measure absolute spike timing of sustained responses to sound shape. To address this, in this study we quantify two forms of spike-timing precision, jitter, and reliability. In all three fields, we find that jitter decreases logarithmically with increase in the basis spline (B-spline) cutoff frequency used to shape the sound envelope. In contrast, reliability decreases logarithmically with increase in sound envelope modulation frequency. In A1, jitter and reliability vary independently, whereas in ventral cortical fields, jitter and reliability covary. Jitter time scales increase (A1 < VAF < cSRAF) and modulation frequency upper cutoffs decrease (A1 > VAF > cSRAF) with ventral progression from A1. These results suggest a transition from independent encoding of shape and periodicity sound cues on short time scales in A1 to a joint encoding of these same cues on longer time scales in ventral nonprimary cortices.
authors: Department of Psychology, University of Connecticut, Storrs, Connecticut;
authors: Christopher M
authors: CM
authors: Lee
authors: Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and.
authors: Ahmad F
authors: AF
authors: Osman
authors: Department of Psychology, University of Connecticut, Storrs, Connecticut;
authors: Maxim
authors: M
authors: Volgushev
authors: Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and Department of Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut.
authors: Monty A
authors: MA
authors: Escabí
authors: Department of Psychology, University of Connecticut, Storrs, Connecticut; Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and heather.read@uconn.edu.
authors: Heather L
authors: HL
authors: Read
mesh_terms: D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology; D001307:Auditory Perception; D005072:Evoked Potentials, Auditory; D008297:Male; D009474:Neurons / Q000502:physiology*; D010507:Periodicity; D051381:Rats; D011930:Reaction Time; D013016:Sound
keywords: cortical coding; spike precision