Functional characterization of human Heschl's gyrus in response to natural speech

Abstract

Heschl’s gyrus (HG) is a brain area that includes the primary auditory cortex in humans. Due to the limitations in obtaining direct neural measurements from this region during naturalistic speech listening, the functional organization and the role of HG in speech perception remain uncertain. Here, we used intracranial EEG to directly record neural activity in HG in eight neurosurgical patients as they listened to continuous speech stories. We studied the spatial distribution of acoustic tuning and the organization of linguistic feature encoding. We found a main gradient of change from posteromedial to anterolateral parts of HG. We also observed a decrease in frequency and temporal modulation tuning and an increase in phonemic representation, speaker normalization, speech sensitivity, and response latency. We did not observe a difference between the two brain hemispheres. These findings reveal a functional role for HG in processing and transforming simple to complex acoustic features and inform neurophysiological models of speech processing in the human auditory cortex.

Intact speech perception after resection of dominant hemisphere primary auditory cortex for the treatment of medically refractory epilepsy: illustrative case

“… 14 From this, auditory processing parameters were derived and compared with known parameters for the primary auditory cortex. 15 , 16 The best frequency, response onset latency, and best temporal modulation estimates from the patient-derived STRFs matched the distributions of these parameters seen in the primary auditory cortex ( Fig. 3B ).…”

“…B: Speech processing along Heschl’s gyrus matches known processing for the primary auditory cortex. The response latency value for each electrode within Heschl’s gyrus is within the range of response latencies observed in primary auditory cortex 15 , 16 (latencies computed from the peak of the spectrotemporal receptive field calculated for each electrode). C: The best temporal modulation value for each electrode is within the range of best temporal modulation tuning observed in the human primary auditory cortex (best temporal modulation values derived from the modulation transfer function of the spectrotemporal receptive field at each site 14 , 15 ).…”

Improved Speech Hearing in Noise with Invasive Electrical Brain Stimulation

“…The subject listened to 20 min of 69 commonly heard natural sounds. Among these 69 sounds were 16 samples of English and foreign speech and 53 nonspeech sounds from 14 categories (coughing, crying, screaming, music [jazz, pop, classical], animal vocalizations, laughing, syllables, sneezing, breathing, singing, shooting, tones, drumming, and subway noise) ( Khalighinejad et al, 2021 ). The sounds were on an average 12.5-s-long with intersentence interval of 0.5 s. To find the neural representation of each sound, we averaged the high γ (70-150 Hz) activity in response to the sound over time.…”

A Platform for Cognitive Monitoring of Neurosurgical Patients During Hospitalization

“…Proof of principle results from one patient demonstrated significant auditory encoding of the acoustic envelope in high gamma activity. The relatively low correlations of the model are likely a result of the locations of the electrodes in this particular patient – higher performance would be expected for electrodes in the superior temporal gyrus and Heschl’s gyrus ( Hamilton et al, 2021 ; Khalighinejad et al, 2021 ). However, more lateral electrodes (higher numbers on each device) generally showed better envelope following, which is consistent with what we would expect based on functional neuroanatomy.…”