Statistical learning in rooms under transcranial magnetic stimulation

Research output: Chapter in Book/Report/Conference proceedingConference abstract

Abstract

In the auditory system, adaptation to sound intensity can operate over multiple time scales and contributes to statistical learning (Dean et al., 2005, 2008; Simpson et al., 2014). Moreover, efferent feedback from the cortex to the inferior colliculus has been directly linked to learning the longer-term statistical structure of sound environments so that this information can be used when a familiar environment is re-encountered (Robinson et al., 2016). Brandewie and Zahorik (2010) described a psychoacoustic task that demonstrated speech perception advantages of re-exposure to familiar environments. They found that prior exposure to room statistics (Reverberation Times; RTs) in the form of a “carrier phrase” spoken in a simulated room significantly improved participants’ masked speech understanding for speech spoken in the same room. Here, we aimed to understand: 1) how real room RTs contribute to the statistical learning of room acoustics and 2) how this learning may be affected when the inferior frontal gyrus (IFG), involved in the expression of auditory statistical learning (Karuza et al., 2013), is temporarily impaired using repetitive transcranial magnetic stimulation (rTMS). Following the methods of Bradewie & Zahorik (2010; 2013), phrases from the Coordinated Response Measurement (CRM) corpus were presented in noise to ten participants with normal hearing. The CRM phrases had different durations: 0, 0.2357, 0.5715 and 0.8485 s (e.g., “Green Five now”, “Go to Green Five Now”, “Baron Go to Green Five now” and “Ready Baron Go to Green Five now”, respectively). Carrier phrases were convolved with impulse responses from 3 real rooms (Room 1: RT60 = 0.46 s; Room 2: RT60 = 0.96 s; Room 3: RT60 = 2.42 s) and presented in free sound-field conditions in an anechoic chamber using a ring of 41 loudspeakers. Similar to Brandewie & Zahorik (2013) participants perceived target phrases e.g., ‘’Green Eight”, more accurately when the carrier phrases had longer duration (containing more statistical information from the rooms presented). It was also observed that rTMS disrupts this learning across all carrier phrases and rooms tested (p< 0.05). In addition, we found that the carrier length effect is only observed when Room 1 is presented in the mixture of rooms. Our results revealed that IFG is involved in learning room statistics, which may reflect adaptation through feedback mechanisms from IFG to the auditory pathway. Moreover, our data suggest that ecologically relevant RTs such as that of Room 1 enable a perceptual anchoring that allows learning room statistics in less commonly encountered environments.

Original languageEnglish
Title of host publicationConference Program of the 43rd Annual MidWinter Meeting
Place of PublicationNashville, Tennessee
PublisherAssociation for Research in Otolaryngology (ARO)
Pages479-480
Number of pages2
Publication statusPublished - 2020
EventAnnual ARO MidWinter Meeting (43rd : 2020) - San Diego, United States
Duration: 25 Jan 202029 Jan 2020

Publication series

NameThe Abstracts of the Association for Research in Otolaryngology
Volume43
ISSN (Electronic)0742-3152

Conference

ConferenceAnnual ARO MidWinter Meeting (43rd : 2020)
Country/TerritoryUnited States
CitySan Diego
Period25/01/2029/01/20

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