OSP parameters and the cognitive component of reaction time to a missing stimulus: Linking brain and behavior

This within-subjects experiment tested the relationship between the premotor (cognitive) component of reaction time (RT) to a missing stimulus and parameters of the omitted stimulus potential (OSP) brain wave. Healthy young men (N = 28) completed trials with an auditory stimulus that recurred at 2 s intervals and ceased unpredictably. Premotor RT and Motor RT were measured on active trials that required an immediate response to a missing stimulus. Passive trials required no response in order to measure the complete set of OSP parameters (i.e., onset, rate of rise, amplitude and peak latency). The results showed that faster Premotor RT was strongly associated with a faster rate of rise in the OSP wave. Motor RT was unrelated the OSP parameters. This new evidence is consistent with the occurrence of some common cognitive processes generating behavioral and brain reactions to a missing stimulus.     

The role of the auditory brainstem in processing linguistically-relevant pitch patterns

Historically, the brainstem has been neglected as a part of the brain involved in language processing. We review recent evidence of language-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem. We argue that there is enhancing of linguistically-relevant pitch dimensions or features well before the auditory signal reaches the cerebral cortex. We propose that long-term experience with a tone language sharpens the tuning characteristics of neurons along the pitch axis with enhanced sensitivity to linguistically-relevant, rapidly changing sections of pitch contours. Though not specific to a speech context, experience-dependent brainstem mechanisms for pitch representation are clearly sensitive to particular aspects of pitch contours that native speakers of a tone language have been exposed to. Such experience-dependent effects on lower-level sensory processing are compatible with more integrated, hierarchically organized pathways to language and the brain.     

The Role of Native-Language Phonology in the Auditory Word Identification and Visual Word Recognition of Russian–English Bilinguals

Does native language phonology influence visual word processing in a second language? This question was investigated in two experiments with two groups of Russian-English bilinguals, differing in their English experience, and a monolingual English control group. Experiment 1 tested visual word recognition following semantic categorization of words containing four phonological vowel contrasts (\({/{{\rm i}}/-/{{\rm u}}/, /{{\rm I}}/-/\wedge/, /{{\rm i}}/-/{{\rm I}}/, /{{\varepsilon}}/-/\ae/}\)). Experiment 2 assessed auditory identification accuracy of words containing these four contrasts. Both bilingual groups demonstrated reduced accuracy in auditory identification of two English vowel contrasts absent in their native phonology (\(/{{\rm i}}/-/{{\rm I}}/, /{\varepsilon}/-/\ae/\)). For late- bilinguals, auditory identification difficulty was accompanied by poor visual word recognition for one difficult contrast (/i/-/I/). Bilinguals’ visual word recognition moderately correlated with their auditory identification of difficult contrasts. These results indicate that native language phonology can play a role in visual processing of second language words. However, this effect may be considerably constrained by orthographic systems of specific languages.     

The chronometry of mental ability: An event-related potential analysis of an auditory oddball discrimination task

The relation between intelligence and speed of auditory discrimination was investigated during an auditory oddball task with backward masking. In target discrimination conditions that varied in the interval between the target and the masking stimuli and in the tonal frequency of the target and masking stimuli, higher ability participants (HA) displayed more accurate discriminations, faster response time, larger P300 amplitude, and shorter P300 and mismatch negativity (MMN) latency than lower ability participants (LA). Task difficulty effects demonstrated with variation in mask type indicate that the mask does not interfere with the detection of the deviant target stimulus, but rather that the target and mask are integrated as a single compound stimulus. The temporal effects suggest that the speed of accessing short-term memory is faster for HA than LA and, on the basis of the MMN latency, the effect is accomplished automatically, without focused attention. Moreover, the pattern of results obtained with these data support the view that the accuracy effects are determined by processing speed rather than discrimination ability. Comparator models that accommodate these effects are discussed.     

A comparison of metacognitions in patients with hallucinations,delusions, panic disorder,and non-patient controls

This study tested the hypothesis that metacognitions are a general vulnerability factor for psychological disorder. It was predicted that patients with psychosis (hallucinations or delusions), and patients with panic disorder would score higher than non-patients on measures of metacognition. Moreover, it was hypothesised that patients showing most dysregulation of thinking (voice-hearers) would endorse significantly higher metacognition scores than individuals in the other groups. The Meta-Cognitions Questionnaire (MCQ: ) was administered to patients who met DSM-IV criteria for schizophrenia spectrum disorders with auditory hallucinations, patients who met DSM-IV criteria for schizophrenia spectrum disorders with persecutory delusions, patients who met DSM-IV criteria for panic disorder and non-patients. The results showed that psychotic patients who experience auditory hallucinations tended to exhibit higher levels of dysfunctional metacognitive beliefs than other patient groups, scoring significantly higher than at least two of the three control groups on positive beliefs about worry, negative beliefs about uncontrollability and danger, cognitive confidence and negative beliefs including superstition, punishment and responsibility. It was also found that the metacognitive beliefs of patients with persecutory delusions and panic patients were often similar to each other, and elevated in comparison to non-patients, suggesting that such beliefs are generic vulnerability factors. The theoretical and clinical implications of these findings are discussed.     

ERP correlates of auditory negative priming

Negative priming refers to slowed down reactions when the distractor on one trial becomes the target on the next. Following two popular accounts, the effect might be due either to inhibitory processes associated with the frontal cortex, or to an ambiguity in the retrieval of episodic information. We used event-related brain potentials (ERPs) to identify the processing stage primarily associated with negative priming. In an auditory categorization task, reactions in negative priming trials were compared to reactions in a standard control (unrelated primes and probes) and a repetition control (attended prime=ignored probe) condition. Reactions were slower for negative priming than for standard control (Delta32 ms) and repetition control trials (Delta64 ms). The corresponding ERP effect was reflected in an attenuation of a sustained parietal positivity extending from 300 to 600 ms. Because corresponding ERP components were found to be sensitive to stimulus recognition and familiarity, the results may be interpreted to support an episodic retrieval account of negative priming.     

睡眠学习的ERP研究

夜间用脑电监测被试睡眠状态,并反复播放英语单词和中文对译词,第二天用词汇决定任务检查学习效果,并记录ERP,结果发现：（1）与未学过的英—中词对相比,被试对学过的词对中中文词的反应时明显缩短;（2）学过的词对中中文词引发的N600的波幅比未学过的明显降低。以上结果表明睡眠学习效果在内隐记忆测验中明显。另外发现被试几乎不能在播放学过的英语词时说出中文对译词,与未学过的词对相比没有显著差别,提示睡眠学习效果在外显记忆测验中不明显。以上结果表明,在本实验条件下,间接测验比直接测验更敏感。     

Does visual experience influence the spatial distribution of auditory attention?

Sighted individuals are less accurate and slower to localize sounds coming from the peripheral space than sounds coming from the frontal space. This specific bias in favour of the frontal auditory space seems reduced in early blind individuals, who are particularly better than sighted individuals at localizing sounds coming from the peripheral space. Currently, it is not clear to what extent this bias in the auditory space is a general phenomenon or if it applies only to spatial processing (i.e. sound localization). In our approach we compared the performance of early blind participants with that of sighted subjects during a frequency discrimination task with sounds originating either from frontal or peripheral locations. Results showed that early blind participants discriminated faster than sighted subjects both peripheral and frontal sounds. In addition, sighted subjects were faster at discriminating frontal sounds than peripheral ones, whereas early blind participants showed equal discrimination speed for frontal and peripheral sounds. We conclude that the spatial bias observed in sighted subjects reflects an unbalance in the spatial distribution of auditory attention resources that is induced by visual experience.     

Does knowing speaker sex facilitate vowel recognition at short durations?

A man, woman or child saying the same vowel do so with very different voices. The auditory system solves the complex problem of extracting what the man, woman or child has said despite substantial differences in the acoustic properties of their voices. Much of the acoustic variation between the voices of men and woman is due to changes in the underlying anatomical mechanisms for producing speech. If the auditory system knew the sex of the speaker then it could potentially correct for speaker sex related acoustic variation thus facilitating vowel recognition. This study measured the minimum stimulus duration necessary to accurately discriminate whether a brief vowel segment was spoken by a man or woman, and the minimum stimulus duration necessary to accuately recognise what vowel was spoken. Results showed that reliable vowel recognition precedesreliable speaker sex discrimination, thus questioning the use of speaker sex information in compensating for speaker sex related acoustic variation in the voice. Furthermore, the pattern of performance across experiments where the fundamental frequency and formant frequency information of speaker's voices were systematically varied, was markedly different depending on whether the task was speaker-sex discrimination or vowel recognition. This argues for there being little relationship between perception of speaker sex (indexical information) and perception of what has been said (linguistic information) at short durations.     

Challenging perceptual tasks require more attention: The influence of task difficulty on the N1 effect of temporal orienting

Both filter and resource models of attention suggest an influence of task difficulty on the size of early attention effects. As for temporal orienting, the idea that early effects are modulated by task difficulty has not been tested directly, so far. To fill this empirical gap, the present study used an auditory temporal-orienting task, in which two differently pitched pure tones served as targets. To manipulate perceptual difficulty, the pitch difference between the targets was either small or large. Temporal orienting enhanced the N1 component of the auditory event-related potential. This early, sensory effect tended to be larger in the more difficult condition, particularly over the frontal scalp. Notably, increasing task difficulty affected predominantly the processing of attended stimuli. Hence, temporal orienting may operate by increasing processing resources or gain settings for the attended time point – rather than by withdrawing resources from the unattended time point.