Single-trial neural dynamics influence auditory category learning

Abstract

Percepts are naturally grouped into meaningful categories to process continuous stimulus variations in the environment. Theories of category acquisition have existed for decades, but how they arise in the brain due to learning is not well understood. Here, advanced computational modeling techniques borrowed from educational data mining and cognitive psychology were used to trace the development of auditory categories within a short-term training session. Nonmusicians were rapidly trained for 20 min on musical interval identification (i.e., minor and major 3rd interval dyads) while their brain activity was recorded via EEG. Categorization performance and neural responses were then assessed for the trained (3rds) and novel untrained (major/minor 6ths) continua. Computational modeling was used to predict behavioral identification responses and whether the inclusion of single-trial features of the neural data could predict successful learning performance. Model results revealed meaningful brain-behavior relationships in auditory category learning detectible on the single-trial level; smaller P2 amplitudes were associated with a greater probability of correct interval categorization after learning. These findings highlight the nuanced dynamics of brain-behavior coupling that help explain the temporal emergence of auditory categorical learning in the brain.

Functional Plasticity Coupled With Structural Predispositions in Auditory Cortex Shape Successful Music Category Learning

“…We used a five-step musical interval continuum to assess category learning of non-speech sounds ( Bidelman and Walker, 2017 ; Mankel et al, 2020b ). Individual notes of each dyad were constructed of complex tones consisting of 10 equal amplitude harmonics added in cosine phase.…”

“…Classifying continuously varying sounds into meaningful categories like phonemes or musical intervals enables more efficient processing of an auditory scene ( Bidelman et al, 2020 ). Categorization of auditory stimuli is also a foundational skill for language development and is believed to arise from both learned and innate factors ( Rosen and Howell, 1987 ; Livingston et al, 1998 ; Pérez-Gay Juárez et al, 2019 ; Mankel et al, 2020a , b ). Auditory categories are further shaped by experiences such as speaking a second language ( Lively et al, 1993 ; Escudero et al, 2011 ; Perrachione et al, 2011 ) or musical training ( Bidelman et al, 2014 ; Wu et al, 2015 ; Bidelman and Walker, 2019 ), suggesting flexibility in categorical perception with learning.…”

“…There is also significant variability in the acquisition of auditory categories (e.g., Howard et al, 1992 ; Golestani and Zatorre, 2009 ; Mankel et al, 2020b ; Silva et al, 2020 ), especially for speech ( Wong et al, 2007 ; Díaz et al, 2008 ; Mankel et al, 2020a ; Fuhrmeister and Myers, 2021 ; Kajiura et al, 2021 ). More successful learners show greater neural activation, particularly in auditory cortex ( Wong et al, 2007 ; Díaz et al, 2008 ; Kajiura et al, 2021 ).…”