Cortical hemisphere preference and brainstem ear asymmetry reflect experience-dependent functional modulation of pitch.

Temporal attributes of pitch processing at cortical and subcortical levels are differentially weighted and well-coordinated. The question is whether language experience induces functional modulation of hemispheric preference complemented by brainstem ear symmetry for pitch processing. Brainstem frequency-following and cortical pitch responses were recorded concurrently from Mandarin and English participants.

Tone language experience-dependent advantage in pitch representation in brainstem and auditory cortex is maintained under reverberation.

Long-term language and music experience enhances neural representation of temporal attributes of pitch in the brainstem and auditory cortex in favorable listening conditions. Herein we examine whether brainstem and cortical pitch mechanisms-shaped by long-term language experience-maintain this advantage in the presence of reverberation-induced degradation in pitch representation. Brainstem frequency following responses (FFR) and cortical pitch responses (CPR) were recorded concurrently from Chinese and English-speaking natives, using a Mandarin word exhibiting a high rising pitch (/yi/).

Language experience-dependent advantage in pitch representation in the auditory cortex is limited to favorable signal-to-noise ratios.

Long-term experience enhances neural representation of temporal attributes of pitch in the brainstem and auditory cortex in favorable listening conditions. Herein we examine whether cortical pitch mechanisms shaped by language experience are more resilient to degradation in background noise, and exhibit greater binaural release from masking (BRM). Cortical pitch responses (CPR) were recorded from Mandarin- and English-speaking natives using a Mandarin word exhibiting a high rising pitch (/yi/).

Language-dependent changes in pitch-relevant neural activity in the auditory cortex reflect differential weighting of temporal attributes of pitch contours.

There remains a gap in our knowledge base about neural representation of pitch attributes that occur between onset and offset of dynamic, curvilinear pitch contours. The aim is to evaluate how language experience shapes processing of pitch contours as reflected in the amplitude of cortical pitch-specific response components. Responses were elicited from three nonspeech, bidirectional (falling-rising) pitch contours representative of Mandarin Tone 2 varying in location of the turning point with fixed onset and offset.

Differential sensitivity to changes in pitch acceleration in the auditory brainstem and cortex.

The cortical pitch-specific response (CPR) is differentially sensitive to pitch contours varying in rate of acceleration-time-variant Mandarin Tone2 (T2) versus constant, linear rising ramp (Linear)-as a function of language experience (Krishnan, Gandour, & Suresh, 2014). CPR and brainstem frequency following response (FFR) data were recorded concurrently from native Mandarin listeners using the same stimuli. Results showed that T2 elicited larger responses than Linear at both cortical and brainstem levels (CPR: Na-Pb, Pb-Nb; FFR).

Changes in pitch height elicit both language-universal and language-dependent changes in neural representation of pitch in the brainstem and auditory cortex.

Language experience shapes encoding of pitch-relevant information at both brainstem and cortical levels of processing. Pitch height is a salient dimension that orders pitch from low to high. Herein we investigate the effects of language experience (Chinese, English) in the brainstem and cortex on (i) neural responses to variations in pitch height, (ii) presence of asymmetry in cortical pitch representation, and (iii) patterns of relative changes in magnitude of pitch height between these two levels of brain structure.

Language-experience plasticity in neural representation of changes in pitch salience.

Neural representation of pitch-relevant information at the brainstem and cortical levels of processing is influenced by language experience. A well-known attribute of pitch is its salience. Brainstem frequency following responses and cortical pitch specific responses, recorded concurrently, were elicited by a pitch salience continuum spanning weak to strong pitch of a dynamic, iterated rippled noise pitch contour-homolog of a Mandarin tone.

Pitch processing of dynamic lexical tones in the auditory cortex is influenced by sensory and extrasensory processes.

The aim is to evaluate how language experience (Chinese, English) shapes processing of pitch contours as reflected in the amplitude of cortical pitch response components. Responses were elicited from three dynamic curvilinear nonspeech stimuli varying in pitch direction and location of peak acceleration: Mandarin lexical Tone 2 (rising) and Tone 4 (falling), and a flipped variant of Tone 2, Tone 2' (nonnative). At temporal sites (T7/T8), Chinese listeners' Na-Pb response amplitudes to Tones 2 and 4 were greater than those of English listeners in the right hemisphere only; a rightward asymmetry for Tones 2 and 4 was restricted to the Chinese group.

LANGUAGE EXPERIENCE SHAPES PROCESSING OF PITCH RELEVANT INFORMATION IN THE HUMAN BRAINSTEM AND AUDITORY CORTEX: ELECTROPHYSIOLOGICAL EVIDENCE.

Pitch is a robust perceptual attribute that plays an important role in speech, language, and music. As such, it provides an analytic window to evaluate how neural activity relevant to pitch undergo transformation from early sensory to later cognitive stages of processing in a well coordinated hierarchical network that is subject to experience-dependent plasticity. We review recent evidence of language experience-dependent effects in pitch processing based on comparisons of native vs.

Language experience enhances early cortical pitch-dependent responses.

Pitch processing at cortical and subcortical stages of processing is shaped by language experience. We recently demonstrated that specific components of the cortical pitch response (CPR) index the more rapidly-changing portions of the high rising Tone 2 of Mandarin Chinese, in addition to marking pitch onset and sound offset. In this study, we examine how language experience (Mandarin vs.

Cortical pitch response components show differential sensitivity to native and nonnative pitch contours.

The aim of this study is to evaluate how nonspeech pitch contours of varying shape influence latency and amplitude of cortical pitch-specific response (CPR) components differentially as a function of language experience. Stimuli included time-varying, high rising Mandarin Tone 2 (T2) and linear rising ramp (Linear), and steady-state (Flat). Both the latency and magnitude of CPR components were differentially modulated by (i) the overall trajectory of pitch contours (time-varying vs.

Cortical pitch response components index stimulus onset/offset and dynamic features of pitch contours.

Voice pitch is an important information-bearing component of language that is subject to experience dependent plasticity at both early cortical and subcortical stages of processing. We have already demonstrated that pitch onset component (Na) of the cortical pitch response (CPR) is sensitive to flat pitch and its salience … CPR responses from Chinese listeners were elicited by three citation forms varying in pitch acceleration and duration. Results showed that the pitch onset component (Na) was invariant to changes in acceleration.

A functional deficit in the sensorimotor interface component as revealed by oral reading in Thai conduction aphasia.

The contemporary view is that a disruption in phonological encoding underlies the speech production deficit in conduction aphasia. We therefore expect to observe a commonality in phonological errors regardless of task - speaking, reading, or writing. A case report is presented of an oral reading task performed by a Thai conduction aphasic with evidence of localized damage in the left temporoparietal zone.

Relationship between brainstem, cortical and behavioral measures relevant to pitch salience in humans.

Neural representation of pitch-relevant information at both the brainstem and cortical levels of processing is influenced by language or music experience. However, the functional roles of brainstem and cortical neural mechanisms in the hierarchical network for language processing, and how they drive and maintain experience-dependent reorganization are not known. In an effort to evaluate the possible interplay between these two levels of pitch processing, we introduce a novel electrophysiological approach to evaluate pitch-relevant neural activity at the brainstem and auditory cortex concurrently.

Distortion products and their influence on representation of pitch-relevant information in the human brainstem for unresolved harmonic complex tones.

Pitch experiments aimed at evaluating temporal pitch mechanism(s) often utilize complex sounds with only unresolved harmonic components, and a low-pass noise masker to eliminate the potential contribution of audible distortion products to the pitch percept. Herein we examine how: (i) masker induced reduction of neural distortion products (difference tone: DT; and cubic difference tone: CDT) alters the representation of pitch relevant information in the brainstem; and (ii) the pitch salience is altered when distortion products are reduced and/or eliminated. Scalp recorded brainstem frequency following responses (FFR) were recorded in normal hearing individuals using a complex tone with only unresolved harmonics presented in quiet, and in the presence of a low-pass masker at SNRs of +15, +5, and -5 dB.

Experience-dependent plasticity in pitch encoding: from brainstem to auditory cortex.

Linguistic and musical pitch provide an analytic window to evaluate how neural representations of important pitch attributes of a sound undergo transformation from early sensory to later cognitive stages of processing in the human brain, and how pitch-relevant experience shapes these representations. These pitch attributes are shaped differentially depending on their functional relevance to a listener. Neural encoding of pitch-relevant information is shaped by the perceptual salience of domain-specific features at subcortical (auditory brainstem) and cortical stages of processing.

Linguistic status of timbre influences pitch encoding in the brainstem.

The aim of this experiment is to assess the effects of the linguistic status of timbre on pitch processing in the brainstem. Brainstem frequency following responses were evoked by the Mandarin high-rising lexical tone superimposed on a native vowel quality ([i]), nonnative vowel quality ([œ]), and iterated rippled noise (nonspeech). Results revealed that voice fundamental frequency magnitudes were larger when concomitant with a native vowel quality compared with either nonnative vowel quality or nonspeech timbre.

Musicians demonstrate experience-dependent brainstem enhancement of musical scale features within continuously gliding pitch.

In contrast to language, where pitch patterns consist of continuous and curvilinear contours, musical pitch consists of relatively discrete, stair-stepped sequences of notes. Behavioral and neurophysiological studies suggest that both tone-language and music experience enhance the representation of pitch cues associated with a listener's domain of expertise, e.g.

Musicians and tone-language speakers share enhanced brainstem encoding but not perceptual benefits for musical pitch.

Behavioral and neurophysiological transfer effects from music experience to language processing are well-established but it is currently unclear whether or not linguistic expertise (e.g., speaking a tone language) benefits music-related processing and its perception.

Functional ear (a)symmetry in brainstem neural activity relevant to encoding of voice pitch: a precursor for hemispheric specialization?

Pitch processing is lateralized to the right hemisphere; linguistic pitch is further mediated by left cortical areas. This experiment investigates whether ear asymmetries vary in brainstem representation of pitch depending on linguistic status. Brainstem frequency-following responses (FFRs) were elicited by monaural stimulation of the left and right ear of 15 native speakers of Mandarin Chinese using two synthetic speech stimuli that differ in linguistic status of tone.

Enhanced brainstem encoding predicts musicians' perceptual advantages with pitch.

Important to Western tonal music is the relationship between pitches both within and between musical chords; melody and harmony are generated by combining pitches selected from the fixed hierarchical scales of music. It is of critical importance that musicians have the ability to detect and discriminate minute deviations in pitch in order to remain in tune with other members of their ensemble. Event-related potentials indicate that cortical mechanisms responsible for detecting mistuning and violations in pitch are more sensitive and accurate in musicians as compared with non-musicians.

Language-dependent pitch encoding advantage in the brainstem is not limited to acceleration rates that occur in natural speech.

Experience-dependent enhancement of neural encoding of pitch in the auditory brainstem has been observed for only specific portions of native pitch contours exhibiting high rates of pitch acceleration, irrespective of speech or nonspeech contexts. This experiment allows us to determine whether this language-dependent advantage transfers to acceleration rates that extend beyond the pitch range of natural speech. Brainstem frequency-following responses (FFRs) were recorded from Chinese and English participants in response to four, 250-ms dynamic click-train stimuli with different rates of pitch acceleration.

Hemispheric asymmetries in phonological processing of tones versus segmental units.

The aim of this functional magnetic resonance imaging study is to identify neuroanatomical substrates underlying phonological processing of segmental (consonant, rhyme) and suprasegmental (tone) units. An auditory verbal recognition paradigm was used in which native speakers of Mandarin Chinese were required to match a phonological unit that occurs in a list of three syllables to the corresponding unit of a following probe. The results show that hemispheric asymmetries arise depending on the type of phonological unit.

Neural representation of pitch salience in the human brainstem revealed by psychophysical and electrophysiological indices.

Acoustically, pitch is related to the temporal regularity or periodicity of a sound. Perceptual and electrophysiologic studies have revealed that pitch salience grows systematically with increasing stimulus periodicity. The aim of this study is to show that information relevant to pitch salience is already encoded in the phase-locked neural activity of brainstem neurons in order to demonstrate that the neural manifestation of pitch salience emerges well before cortical involvement.