title: Cortical speech-evoked response patterns in multiple auditory fields are correlated with behavioral discrimination ability.
abstract: Different speech sounds evoke unique patterns of activity in primary auditory cortex (A1). Behavioral discrimination by rats is well correlated with the distinctness of the A1 patterns evoked by individual consonants, but only when precise spike timing is preserved. In this study we recorded the speech-evoked responses in the primary, anterior, ventral, and posterior auditory fields of the rat and evaluated whether activity in these fields is better correlated with speech discrimination ability when spike timing information is included or eliminated. Spike timing information improved consonant discrimination in all four of the auditory fields examined. Behavioral discrimination was significantly correlated with neural discrimination in all four auditory fields. The diversity of speech responses across recordings sites was greater in posterior and ventral auditory fields compared with A1 and anterior auditor fields. These results suggest that, while the various auditory fields of the rat process speech sounds differently, neural activity in each field could be used to distinguish between consonant sounds with accuracy that closely parallels behavioral discrimination. Earlier observations in the visual and somatosensory systems that cortical neurons do not rely on spike timing should be reevaluated with more complex natural stimuli to determine whether spike timing contributes to sensory encoding.
authors.affiliation: School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas 75080, USA. tmcentanni@gmail.com
authors.forename: T M
authors.initials: TM
authors.lastname: Centanni
authors.forename: C T
authors.initials: CT
authors.lastname: Engineer
authors.forename: M P
authors.initials: MP
authors.lastname: Kilgard
mesh_terms: D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010700:Phonetics; D051381:Rats; D013067:Speech Perception
keywords: auditory cortex; diversity; parallel hierarchy; rat; spike timing