title: Detection and identification of speech sounds using cortical activity patterns.
abstract: We have developed a classifier capable of locating and identifying speech sounds using activity from rat auditory cortex with an accuracy equivalent to behavioral performance and without the need to specify the onset time of the speech sounds. This classifier can identify speech sounds from a large speech set within 40 ms of stimulus presentation. To compare the temporal limits of the classifier to behavior, we developed a novel task that requires rats to identify individual consonant sounds from a stream of distracter consonants. The classifier successfully predicted the ability of rats to accurately identify speech sounds for syllable presentation rates up to 10 syllables per second (up to 17.9 ± 1.5 bits/s), which is comparable to human performance. Our results demonstrate that the spatiotemporal patterns generated in primary auditory cortex can be used to quickly and accurately identify consonant sounds from a continuous speech stream without prior knowledge of the stimulus onset times. Improved understanding of the neural mechanisms that support robust speech processing in difficult listening conditions could improve the identification and treatment of a variety of speech-processing disorders.
authors.affiliation: University of Texas at Dallas, United States. Electronic address: tmcentanni@gmail.com.
authors.forename: T M
authors.initials: TM
authors.lastname: Centanni
authors.affiliation: University of Texas at Dallas, United States.
authors.forename: A M
authors.initials: AM
authors.lastname: Sloan
authors.affiliation: University of Texas at Dallas, United States.
authors.forename: A C
authors.initials: AC
authors.lastname: Reed
authors.affiliation: University of Texas at Dallas, United States.
authors.forename: C T
authors.initials: CT
authors.lastname: Engineer
authors.affiliation: University of Texas at Dallas, United States.
authors.forename: R L
authors.initials: RL
authors.lastname: Rennaker
authors.affiliation: University of Texas at Dallas, United States.
authors.forename: M P
authors.initials: MP
authors.lastname: Kilgard
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology; D003198:Computer Simulation; D004192:Discrimination, Psychological / Q000502:physiology*; D004567:Electrodes, Implanted; D005260:Female; D009474:Neurons / Q000502:physiology; D009483:Neuropsychological Tests; D016011:Normal Distribution; D010700:Phonetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013067:Speech Perception / Q000502:physiology*; D013647:Task Performance and Analysis; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology
keywords: A1; CF; CVC; FM; IR; ISI; NM; SPL; auditory cortex; characteristic frequency; classifier; coding; consonant–vowel–consonant; frequency modulated; infrared; inter-stimulus-interval; normalized metric; primary auditory cortex; rat; sound pressure level; sps; syllables per second; temporal patterns