Tone Discrimination Research Articles

Idiosyncratic neurolinguistic presentations of Chinese speaking primary progressive aphasia individuals

AbstractBackgroundPast research on Primary Progressive Aphasia(PPA) has been centered around English language, thus there is limited knowledge to the presentations of linguistic features that differ from the English language. Chinese language possesses numerous linguistic features that contrast significantly from the English language. Chinese language is a tonal and numeral classifier language; hence tones are lexically contrastive and numeral cannot quantify a noun without classifiers. As more than 40% and 20% of living languages worldwide are tonal and numeral classifier languages, investigating these idiosyncratic neurolinguistics features in non‐English speaking PPA individuals may refine the clinical practice paradigm to be more adaptable worldwide.MethodThe CLAP (Chinese Language Assessment for PPA) project aims to investigate the neurolinguistics features of Chinese speaking PPA individuals. The CLAP battery consists of fourteen speech and language tasks and this presentation focuses on the tonal and numeral classifier performances as they are idiosyncratic traits of the Chinese language. The tonal perception function is assessed via tonal identification, tonal discrimination, tone‐picture matching, and tone‐word matching tasks. The tonal production performance is evaluated through serial tone reading, repetition of tonal tongue‐twisters, and multi‐tone multi‐repetition tasks. To illustrate classifier function, participants are tasked with producing the accurate classifiers after visual and auditory stimuli of the nouns.ResultThe CLAP project recruited 13 healthy controls and 20 PPA individuals (5 nfvPPA, 6 svPPA, and 9 lvPPA) that are native Chinese speakers. Individuals with svPPA were noted to perform significantly lower in the tone‐picture matching task (p=0.024) and classifier task (p<0.0001). Volumes in left inferior temporal and bilateral temporal poles were significantly correlated with the performance in the tone‐picture matching and classifier task respectively. Conversely, individuals with nfvPPA scored substantially lower than healthy controls in all three tone production tasks (p<0.0001, p=0.024, p<0.0001) and lower than other PPA variants in tonal tongue‐twisters tasks. Performance in tonal tongue‐twister tasks was found to correlate with the degree of atrophy in left inferior and superior frontal regions.ConclusionTone and classifier tasks can potentially serve as diagnostic and classification tools for PPA individuals that speaks Chinese language and other tonal and numeral classifier languages.

Perceived skin tone discrimination and psychotic experiences among Black Americans: Findings from the National Survey of American Life

BackgroundBlack Americans face significant discrimination, which has been linked to risk for psychotic experiences. However, fewer studies have examined whether perceived skin tone discrimination is associated with psychotic experiences. MethodsDrawing data from the National Survey of American Life (NSAL), we used multivariable logistic regression to examine the associations between perceived skin tone discrimination (from Blacks and Whites) and psychotic experiences, adjusting for sociodemographic covariates, common mental disorders, and major discriminatory events. ResultsIn bivariate regression models, a one-unit increase in frequency of perceived skin tone discrimination from Blacks was associated with a 24% increase in odds of having any lifetime psychotic experience (AOR: 1.24; 95% CI: 1.11–1.38). A one-unit increase in frequency of perceived skin tone discrimination from Whites was associated with an 18% increase in odds of having any lifetime psychotic experience (AOR: 1.18; 95% CI: 1.03–1.34). When examining perceived skin tone discrimination from Blacks and Whites in the same models, only perceived skin tone discrimination from Blacks was significantly associated with lifetime psychotic experiences, adjusting for sociodemographic characteristics, common metal disorders, and major discriminatory events. Perceived skin tone discrimination was associated with lifetime hallucinatory experiences, but not lifetime delusional ideation. ConclusionA significant portion of the Black population reported skin tone discrimination from Blacks and Whites, which is related to lifetime psychotic experiences. Future longitudinal and qualitative studies can elaborate on these findings and further contextualize skin tone discrimination and its health effects.

Simultaneous bilinguals who do not speak a tone language show enhancement in pitch sensitivity but not in executive function

Abstract Previous studies have reported perceptual advantages, such as when discriminating non-native linguistic or musical pitch differences, among first-year infants growing up in bilingual over monolingual environments. It is unclear whether such effects should be attributed to bilinguals’ enhanced perceptual sensitivity and/or cognitive abilities, and whether such effects would extend to adulthood. Twenty-four Dutch, 24 Dutch simultaneous bilingual (DSB), and 24 Chinese Mandarin speakers were examined by three sets of tasks assessing their linguistic pitch and music perception, executive function, as well as interactions across these modalities. Results showed degrees of advantages for DSB and Chinese participants’ over their Dutch peers in lexical tone discrimination and pitch-related music tasks. In tasks related to executive function, no difference was observed between DSB and Dutch participants, while Chinese participants’ performances were modulated by cognitive interference of language processing. Findings suggest that listeners’ enhanced sensitivity to linguistic and musical pitch may stem from acoustic (DSB) and experience (Chinese) rather than cognitive factors. Moreover, Dutch participants showed robust correlations between their linguistic and musical pitch perception, followed by limited correlations in DSB, and virtually no correlation among Chinese participants, illustrating how distinct language experiences can lead to specific pitch perception patterns between language and music.

Investigating the Influences of Task Demand and Reward on Cardiac Pre-Ejection Period Reactivity During a Speech-in-Noise Task.

Objectives:Effort investment during listening varies as a function of task demand and motivation. Several studies have manipulated both these factors to elicit and measure changes in effort associated with listening. The cardiac pre-ejection period (PEP) is a relatively novel measure in the field of cognitive hearing science. This measure, which reflects sympathetic nervous system activity on the heart, has previously been implemented during a tone discrimination task but not during a speech-in-noise task. Therefore, the primary goal of this study was to explore the influences of signal to noise ratio (SNR) and monetary reward level on PEP reactivity during a speech-in-noise task.Design:Thirty-two participants with normal hearing (mean age = 22.22 years, SD = 3.03) were recruited at VU University Medical Center. Participants completed a Dutch speech-in-noise test with a single-interfering-talker masking noise. Six fixed SNRs, selected to span the entire psychometric performance curve, were presented in a block-wise fashion. Participants could earn a low (€0.20) or high (€5.00) reward by obtaining a score of ≥70% of words correct in each block. The authors analyzed PEP reactivity: the change in PEP measured during the task, relative to the baseline during rest. Two separate methods of PEP analysis were used, one including data from the whole task block and the other including data obtained during presentation of the target sentences only. After each block, participants rated their effort investment, performance, tendency to give up, and the perceived difficulty of the task. They also completed the need for recovery questionnaire and the reading span test, which are indices of additional factors (fatigue and working memory capacity, respectively) that are known to influence listening effort.Results:Average sentence perception scores ranged from 2.73 to 91.62%, revealing a significant effect of SNR. In addition, an improvement in performance was elicited by the high, compared to the low reward level. A linear relationship between SNR and PEP reactivity was demonstrated: at the lower SNRs PEP reactivity was the most negative, indicating greater effort investment compared to the higher SNRs. The target stimuli method of PEP analysis was more sensitive to this effect than the block-wise method. Contrary to expectations, no significant impact of reward on PEP reactivity was found in the present dataset. Also, there was no physiological evidence that participants were disengaged, even when performance was poor. A significant correlation between need for recovery scores and average PEP reactivity was demonstrated, indicating that a lower need for recovery was associated with less effort investment.Conclusions:This study successfully implemented the measurement of PEP during a standard speech-in-noise test and included two distinct methods of PEP analysis. The results revealed for the first time that PEP reactivity varies linearly with task demand during a speech-in-noise task, although the effect size was small. No effect of reward on PEP was demonstrated. Finally, participants with a higher need for recovery score invested more effort, as shown by average PEP reactivity, than those with a lower need for recovery score.

The role of attentional slippage in Stroop dilution.

The present study examined the cognitive locus of Stroop dilution using a psychological refractory period (PRP) paradigm. Participants were asked to perform a tone discrimination task via a bimanual keypress response and a modified Stroop task via a vocal response serially as Task 1 and Task 2, respectively. In Task 2, a neutral word was added on half of the trials and no neutral word on the other half of the trials to observe the Stroop dilution effect. The amount of Stroop dilution, as well as the Stroop effect, was relatively constant across different stimulus-onset asynchronies (SOAs), which implies that Stroop dilution occurs due to the competition between a neutral word and a color word after a target color bar is selected to be processed further. These results indicate that focused attention plays an important role in the modulation of Stroop interference by the presence of a neutral word.

The effect of phonotactic structure on novel lexical tone perception

Results from several studies suggest that the tonal status of the listener’s first language (L1) accurately predicts novel tone discrimination ability. However, other studies show that novel tone discrimination is more complex than a simple dichotomy between tonal and non-tonal L1s, and that L1 prosodic features and acoustic properties of the target tones interact in predicting accuracy. The current study furthers this literature by examining phonotactic factors affecting novel tone discrimination. We examine the interaction between L1 and syllable structure in predicting discrimination accuracy. Tone discrimination studies typically operate under the implicit or explicit hypothesis that consonant-vowel (CV) syllables with familiar segments are the best tokens to use for tone perception tests. We test this hypothesis by including syllable structure as a predictor. This permits the examination of the interaction between L1 and syllable structure, as well as the effect of unfamiliar phonotactic structures on novel tone discrimination via consonant-consonant-vowel (CCV) syllables for native Mandarin participants and CV syllables with /ŋ/ onsets for native English participants. The results of the current study shed light on the effect of L1 background on novel tone discrimination across syllable types, as well as the effects of unfamiliar phonotactic structures on discrimination sensitivity.

Dichotic Perception of Lexical Tones in Cantonese-Speaking Congenital Amusics.

Congenital amusia is an inborn neurogenetic disorder of musical pitch processing, which also induces impairment in lexical tone perception. However, it has not been examined before how the brain specialization of lexical tone perception is affected in amusics. The current study adopted the dichotic listening paradigm to examine this issue, testing 18 Cantonese-speaking amusics and 18 matched controls on pitch/lexical tone identification and discrimination in three conditions: non-speech tone, low syllable variation, and high syllable variation. For typical listeners, the discrimination accuracy was higher with shorter RT in the left ear regardless of the stimulus types, suggesting a left-ear advantage in discrimination. When the demand of phonological processing increased, as in the identification task, shorter RT was still obtained in the left ear, however, the identification accuracy revealed a bilateral pattern. Taken together, the results of the identification task revealed a reduced LEA or a shift from the right hemisphere to bilateral processing in identification. Amusics exhibited overall poorer performance in both identification and discrimination tasks, indicating that pitch/lexical tone processing in dichotic listening settings was impaired, but there was no evidence that amusics showed different ear preference from controls. These findings provided temporary evidence that although amusics demonstrate deficient neural mechanisms of pitch/lexical tone processing, their ear preference patterns might not be affected. These results broadened the understanding of the nature of pitch and lexical tone processing deficiencies in amusia.

The Jake Mandell Test as a measure of individual differences in pitch discrimination: validity and reliability properties.

The Jake Mandell Tone Deaf Test (JMT) is an online measure designed to evaluate pitch discrimination in the normal population. The test has been available online since 2006, but no psychometric data have been published. The present research was designed to provide validity and reliability data for this test. Study 1 was conducted in university students, and the performance on the JMT was compared to the AMUSIA online screening tests. Correlations were high with the subtests of the AMUSIA online screening tests, but especially with the Tone discrimination test. Study 2 was conducted in children, and the JMT was compared to different tests of musical abilities. The JMT showed a good relationship with the Tone Discrimination and Rhythm Imitation subtest, but especially with the global score of musical abilities. In addition, the test showed good one-year test-retest reliability. Finally, external validation of the JMT was obtained by noting that musicians obtained higher scores than non-musicians. Discussion is focused on the possibility of using the JMT as a rapid screening measure of individual differences in pitch discrimination in the normal population.

Everyday communication challenges in aphasia: descriptions of experiences and coping strategies

ABSTRACT Background: Everyday communication often occurs in situations that pose high attentional and social demands. People with aphasia have reported perceiving greater challenge communicating in these situations, but more specific information about these challenges could help clinicians and researchers work toward more meaningful intervention outcomes and increased life participation. Aims: To explore the everyday communication experiences of people with aphasia based on their own perspectives and to identify how they report coping with everyday communication challenges. Method: Twenty-one participants with mild or moderate aphasia completed semi-structured interviews that immediately followed the experimental arm of a larger project. Interview questions solicited descriptions and examples of communication experiences from participants’ everyday life that related to the situations they experienced during the experiment (retelling stories to responsive and unresponsive communication partners and while completing a concurrent tone discrimination task). Interviews were recorded, transcribed orthographically, then coded using thematic analysis. Results: Qualitative analysis revealed two themes related to participants’ communication experiences (i.e., relationships, environmental distractions) and one theme relating to their reactions to challenging everyday communication experiences (i.e., coping). They perceived that they were influenced by their communication partners and the physical environment in which communication took place. Two thirds of participants described implementing behavioral and/or cognitive strategies to cope with everyday communication challenges. Conclusions: Everyday communication is often challenging for people with aphasia when they feel unsupported by communication partners (even close family members and friends), are exposed to background noise, or are performing a concurrent task. One way that participants coped with challenging communication situations was to regulate their thoughts, attitudes, or beliefs. Future research is needed to understand how to appropriately focus on cognitive strategies in aphasia therapy to improve generalization and social participation.

Dynamics and Hierarchical Encoding of Non-compact Acoustic Categories in Auditory and Frontal Cortex.

Categorical perception is a fundamental cognitive function enabling animals to flexibly assign sounds into behaviorally relevant categories. This study investigates the nature of acoustic category representations, their emergence in an ascending series of ferret auditory and frontal cortical fields, and the dynamics of this representation during passive listening to task-relevant stimuli and during active retrieval from memory while engaging in learned categorization tasks. Ferrets were trained on two auditory Go-NoGo categorization tasks to discriminate two non-compact sound categories (composed of tones or amplitude-modulated noise). Neuronal responses became progressively more categorical in higher cortical fields, especially during task performance. The dynamics of the categorical responses exhibited a cascading top-down modulation pattern that began earliest in the frontal cortex and subsequently flowed downstream to the secondary auditory cortex, followed by the primary auditory cortex. In a subpopulation of neurons, categorical responses persisted even during the passive listening condition, demonstrating memory for task categories and their enhanced categorical boundaries.

Processing of time reference in agrammatic speakers of Akan: a language with grammatical tone

ABSTRACT Background: Languages of the world have several ways of expressing time reference. Many languages such as those in the Indo-European group express time reference through tense. Languages such as Chinese and Standard Indonesian express time reference through aspectual adverbs, while Akan does so through grammatical tone. Previous studies have found that time reference is selectively impaired, with reference to the past being more impaired than reference to the non-past. The PAst DIscourse LInking Hypothesis (PADILIH) posits that pastime reference is difficult because it requires discourse linking. Aims: The goal of this study was first to examine whether pastime reference is impaired also in languages that do not use grammatical affixes but rather tone, to make time reference. Second, this study aims to decouple the effect of tone from the effect of temporal reference on Akan verbs. Method and Procedures: Ten Akan agrammatic speakers and 10 non-brain-damaged speakers (NBDs) participated in this study. An Akan adapted version of the Test for Assessing Reference of Time (African TART), for both production and comprehension was used. The TART focuses on the future, present (habitual) and the pastime frames. Additionally, five of the agrammatic speakers performed two tonal discrimination tasks: a non-linguistic and a linguistic (lexical) one. Outcomes and Results: While the NBDs scored at ceiling, the agrammatic speakers made errors, and these affected past more than present and the future time references, in both comprehension and production tasks. However, the comprehension data showed a dissociation between the present habitual and the future. The substitution error analysis revealed a preference for the present. The five agrammatic speakers showed an intact performance on non-linguistic tonal discrimination task. Conclusion: The conclusion is that regardless of how time reference is expressed, whether through inflectional morphology or grammatical tone, reference to the past is problematic for individuals with agrammatic aphasia. The fact that the agrammatic speakers could perceive the non-linguistic tonal differences demonstrates that it is not tone in general that is disrupted, but rather time reference, particularly reference to the past, as predicted by the PADILIH.

The effect of overnight consolidation in the perceptual learning of non-native tonal contrasts.

Sleep-mediated overnight consolidation has been found to facilitate perceptual learning by promoting learners' generalization across talkers in their perception of novel segmental categories. Lexical tone is characterized by high variability across talkers, and displays dynamic change over time. For this reason, it remains unclear whether a similar effect of overnight consolidation would be found for perceptual learning of novel tonal contrasts. Thus, this study aims to examine whether overnight consolidation facilitates talker-independent learning of lexical tones in the identification and discrimination of novel Cantonese level tones by Mandarin listeners. Two groups of Mandarin listeners were perceptually trained either in the morning or in the evening. Listeners were trained in a tone identification (ID) task with feedback using stimuli produced by a trained talker. Their post-training changes and generalization to a novel talker were then tested in the ID and AX discrimination tasks using stimuli produced by trained and untrained talkers in three posttests following training: immediately after training, 12-hour delay, and 24-hour delay. While the evening group slept between the first and second posttests, the morning group did not. The accuracy rates in the ID task showed that the evening group showed an improved trend, predicted by their individual sleep time, in identifying the level tones produced by both the trained and untrained talkers; in contrast, the morning group showed a declining trend. The d-prime scores in the AX discrimination task did not show different patterns between the two groups. The finding of sleep-related identification changes over time suggests that overnight consolidation might have facilitated tone learning of stimuli produced by the novel talker and eventually facilitated the formation of a more talker-independent representation of novel tone categories in long-term memory. The results are discussed in light of the features of lexical tones to shed light on the mechanism of phonetic learning.

Resumption in the production of focused constructions in Akan speakers with agrammatism

ABSTRACT Background: The distribution of pronouns varies cross-linguistically. This distribution has led to conflicting results in studies that investigated pronoun resolution in agrammatic indviduals. In the investigation of pronominal resolution, the linguistic phenomenon of “resumption” is understudied in agrammatism. The construction of pronominal resolution in Akan presents the opportunity to thoroughly examine resumption. Aims: To start, the present study examines the production of (pronominal) resumption in Akan focus constructions (who-questions and focused declaratives). Second, we explore the effect of grammatical tone on the processing of pronominal (resumption) since Akan is a tonal language. Methods & Procedures: First, we tested the ability to distinguish linguistic and non-linguistic tone in Akan agrammatic speakers. Then, we administered an elicitation task to five Akan agrammatic individuals, controlling for the structural variations in the realization of resumption: focused who-questions and declaratives with (i) only a resumptive pronoun, (ii) only a clause determiner, (iii) a resumptive pronoun and a clause determiner co-occurring, and (iv) neither a resumptive pronoun nor a clause determiner. Outcomes & Results: Tone discrimination .both for pitch and for lexical tone was unimpaired. The production task demonstrated that the production of resumptive pronouns and clause determiners was intact. However, the production of declarative sentences in derived word order was impaired; wh-object questions were relatively well-preserved. Conclusions: We argue that the problems with sentence production are highly selective: linguistic tones and resumption are intact but word order is impaired in non-canonical declarative sentences.

White Noise Background Improves Tone Discrimination by Suppressing Cortical Tuning Curves

The brain faces the difficult task of maintaining a stable representation of key features of the outside world in noisy sensory surroundings. How does the sensory representation change with noise, and how does the brain make sense of it? We investigated the effect of background white noise (WN) on tuning properties of neurons in mouse A1 and its impact on discrimination performance in a go/no-go task. We find that WN suppresses the activity of A1 neurons, which surprisingly increases the discriminability of tones spectrally close to each other. To confirm the involvement of A1, we optogenetically excited parvalbumin-positive (PV+) neurons in A1, which have similar effects as WN on both tuning properties and frequency discrimination. A population model suggests that the suppression of A1 tuning curves increases frequency selectivity and thereby improves discrimination. Our findings demonstrate that the cortical representation of pure tones adapts during noise to improve sensory acuity.

Perceptual asymmetry in lexical tone perception

Directional asymmetries have been documented in both infant and adult perception of lexical tones. For example, Tsao (2008) found that a stimulus change from the background mandarin T1 (55) to the target Mandarin T3 (213) was easier than the reverse among one-year-old Mandarin learning infants. Yeung et al. (2013) reported that 4- and 9-month-old Mandaring learning infants are better at Cantonese tone discrimination after being familiarized with T2 (25) than with T3 (33). Francis and Ciocca (2003) found that native Cantonese speakers’ tone discrimination was better when the first syllable was higher in frequency (about 4 Hz) than the second syllable. Finally, in an ERP study, Politzer-Ahles et al. (2016) found that Mismatch Negativity (MMN) was attenuated among both native and non-native Mandarin listeners when Mandarin T3 was the standard and another deviant in comparison to the reverse. In this talk, we will report results from two studies examining the effects of memory load and first language on perceptual asymmetry patterns in adult lexical tone perception among native English, Mandarin, and Cantonese speakers. Application of theoretical models including the perceptual magnet effects and perceptual assimilation will be discussed.Directional asymmetries have been documented in both infant and adult perception of lexical tones. For example, Tsao (2008) found that a stimulus change from the background mandarin T1 (55) to the target Mandarin T3 (213) was easier than the reverse among one-year-old Mandarin learning infants. Yeung et al. (2013) reported that 4- and 9-month-old Mandaring learning infants are better at Cantonese tone discrimination after being familiarized with T2 (25) than with T3 (33). Francis and Ciocca (2003) found that native Cantonese speakers’ tone discrimination was better when the first syllable was higher in frequency (about 4 Hz) than the second syllable. Finally, in an ERP study, Politzer-Ahles et al. (2016) found that Mismatch Negativity (MMN) was attenuated among both native and non-native Mandarin listeners when Mandarin T3 was the standard and another deviant in comparison to the reverse. In this talk, we will report results from two studies examining the effects of memory load and first language on perce...

Discrimination and identification of lexical tones and consonants in Mandarin-speaking children using cochlear implants.

Mandarin-speaking adults using cochlear implants (CI) experience more difficulties in perceiving lexical tones than consonants. This problem may result from the fact that CIs provide relatively sufficient temporal envelope information for consonant perception in quiet environments, but do not convey the fine spectro-temporal information considered to be necessary for accurate pitch perception. Another possibility is that Mandarin speakers with post-lingual hearing loss have developed language-specific use of these acoustic cues, impeding lexical tone processing under CI conditions. To investigate this latter hypothesis, syllable discrimination and word identification abilities for Mandarin consonants (place and manner) and lexical-tone contrasts (tones 1 vs 3 and 1 vs 2) were measured in 15 Mandarin-speaking children using CIs and age-matched children with normal hearing (NH). In the discrimination task, only children using CIs exhibited significantly lower scores for consonant place contrasts compared to other contrasts, including lexical tones. In the word identification task, children using CIs showed lower performance for all contrasts compared to children with NH, but they both showed specific difficulties with tone 1 vs 2 contrasts. This study suggests that Mandarin-speaking children using CIs are able to discriminate and identify lexical tones and, perhaps more surprisingly, have more difficulties when discriminating consonants.

WHY ARE LEXICAL TONES DIFFICULT TO LEARN?

AbstractL2 sounds present different kinds of challenges to learners at the phonetic, phonological, and lexical levels, but previous studies on L2 tone learning mostly focused on the phonetic and lexical levels. The present study employs an innovative technique to examine the role of prior tonal experience and musical training on forming novel abstract syllable-level tone categories. Eighty Cantonese and English musicians and nonmusicians completed two tasks: (a) AX tone discrimination and (b) incidental learning of artificial tone-segment connections (e.g., words beginning with an aspirated stop always carry a rising tone) with synthesized stimuli modeled on Thai. Although the four participant groups distinguished the target tones similarly well, Cantonese speakers showed abstract and implicit knowledge of the target tone-segment mappings after training but English speakers did not, regardless of their musical experience. This suggests that tone language experience, but not musical experience, is crucial for forming novel abstract syllable-level tone categories.

Auditory Cortex Contributes to Discrimination of Pure Tones.

The auditory cortex is topographically organized for sound frequency and contains highly selective frequency-tuned neurons, yet the role of auditory cortex in the perception of sound frequency remains unclear. Lesion studies have shown that auditory cortex is not essential for frequency discrimination of pure tones. However, transient pharmacological inactivation has been reported to impair frequency discrimination. This suggests the possibility that successful tone discrimination after recovery from lesion surgery could arise from long-term reorganization or plasticity of compensatory pathways. Here, we compared the effects of lesions and optogenetic suppression of auditory cortex on frequency discrimination in mice. We found that transient bilateral optogenetic suppression partially but significantly impaired discrimination performance. In contrast, bilateral electrolytic lesions of auditory cortex had no effect on performance of the identical task, even when tested only 4 h after lesion. This suggests that when auditory cortex is destroyed, an alternative pathway is almost immediately adequate for mediating frequency discrimination. Yet this alternative pathway is insufficient for task performance when auditory cortex is intact but has its activity suppressed. These results indicate a fundamental difference between the effects of brain lesions and optogenetic suppression, and suggest the existence of a rapid compensatory process possibly induced by injury.

Mismatch negativity in children with cochlear implant

<p class="abstract"><strong>Background:</strong> Cochlear implant provides a great opportunity for children with severe to profound sensorineural hearing loss to restore normal hearing. Identifying mismatch negativity (MMN) in cochlear implant recipients helps to assess the role of central auditory structures in processing speech stimuli in those patients. The objective of the present study is to evaluate tone and speech discrimination in cochlear implanted children using mismatch negativity test.</p><p class="abstract"><strong>Methods:</strong> MMN was recorded in 35 children. They were divided into two groups. Control group consisted of 15 normal hearing children, their age ranged from 3-11 years. Study group consisted of 20 children fitted with unilateral CI, and their age matched the control group. Two oddball paradigms were used; the first was tone bursts (1000 Hz as standard stimulus and 1050 Hz as deviant stimulus). The second was synthesized speech stimuli (/da/ as standard stimulus and /ga/ as deviant one). Both paradigms were presented at 75dB SPL.</p><p class="abstract"><strong>Results:</strong> All cochlear implanted children included showed MMN on using both oddball paradigms. Comparing results of both groups revealed statistically significant differences in MMN latency and amplitude. There was a significant positive correlation between MMN latencies and the implantation age as well as the duration of hearing loss before implantation.</p><p><strong>Conclusions:</strong> MMN provides an objective tool to assess the auditory discrimination abilities in cochlear implanted children which may help in their rehabilitation and also in the optimum setting of their devices.</p>

The role of auditory context in action-effect-related motor adaptation

Previous research indicates that adding auditory effects to a (silent) action can lead to substantial efficiency gains in the performance of the action, while compromising the connection between the motor and the auditory event (e.g., by removing, or by delaying the auditory effects), leads the agent to compensate for the loss of auditory feedback by executing actions in a way which increases the probability of success or enhances feedback in other modalities, thus departing from the optimal action performance. The current study explored how this motor adaptation was affected when the quality of auditory feedback was reduced by contextual factors, while keeping the physical link between the action and auditory effect intact. In two experiments, participants elicited pure tones by pinching a force sensitive resistor (FSR). In some of the conditions action-effect contingency was reduced by intermixing externally initiated tones with the self-induced ones. Pinch-force measurements indicated that action optimization was affected by contextual factors. The influence of auditory context was the most pronounced when the discrimination of self-induced and external tones was made difficult by the similarity and temporal proximity of the self-induced and external tones. In these conditions, tone eliciting actions were more forceful in comparison to conditions in which no external tones were presented, and in comparison to conditions in which the external tones were easily distinguishable from self-induced ones. This suggests that contextual factors can induce similar motor adjustments as manipulating the physical connection between the action and its sensory consequences.