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This study examined automaticity of discrimination of a Japanese length contrast for consonants (miʃi vs. miʃʃi) in native (Japanese) and non-native (American-English) listeners using behavioral measures and the event-related potential (ERP) mismatch negativity (MMN). Attention to the auditory input was manipulated either away from the auditory input via a visual oddball task (Visual Attend), or to the input by asking the listeners to count auditory deviants (Auditory Attend). Results showed a larger MMN when attention was focused on the consonant contrast than away from it for both groups. The MMN was larger for consonant duration increments than decrements. No difference in MMN between the language groups was observed, but the Japanese listeners did show better behavioral discrimination than the American English listeners. In addition, behavioral responses showed a weak, but significant correlation with MMN amplitude. These findings suggest that both acoustic-phonetic properties and phonological experience affects automaticity of speech processing. This article is part of a Special Issue entitled SI: Prediction and Attention., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Primary Objective: To examine active inhibition of irrelevant stimuli and evaluate its neural basis using functional near infrared spectroscopy in patients with attention deficits after traumatic brain injury (TBI)., Research Design: Case control study., Methods and Procedures: Ten patients with TBI and 10 healthy control subjects participated in this study. The Paced Auditory Serial Addition Test (PASAT) was performed with (distracting PASAT) and without (PASAT) distracting Japanese kana phonetic characters presented between each number. A block design was used. Subjects alternately performed each task three times., Main Outcomes and Results: Healthy controls performed better than patients with TBI on both the tasks. When performing the PASAT, healthy controls showed significant activity in every region of interest except the right lateral prefrontal cortex (PFC), but patients with TBI showed significant activity only in the left anterior PFC and left lateral PFC. When performing the distracting PASAT, the right lateral PFC was active in healthy controls, but not in patients with TBI., Conclusion: These results confirm that patients with moderate-to-severe TBI were affected by distractors that influenced order processing. It is suggested that the working memory of patients with TBI was affected by distracting stimuli, whereas that of healthy individuals was not.

Behavioral and electrophysiological studies indicate that altered language experience has different effects on distinct subsystems within language. In this study, we recorded event-related potentials (ERPs) in native Japanese late-learners of English listening to English sentences. ERP indices of semantic processing, syntactic processing, and speech segmentation were compared and contrasted for native Japanese and previously tested native English speakers. Native and non-native speakers showed similar semantic processing effects including an N400 for words as opposed to nonwords. In contrast, native Japanese speakers showed none of the effects associated with syntactic processing in native English speakers including an anterior negativity to nonwords presented in a syntactic context. Furthermore, the ERP word-onset effect evident in native English speakers was not found for the native Japanese speakers in this study. These data contribute additional and specific evidence to the proposal that subsystems within language display varying degrees of plasticity.

The N2 and P3b components of event-related potentials (ERPs) were studied in students who were identified as being at high risk for psychosis on the basis of their scores on the Chapman Psychosis Proneness Scales (PPS). The Magical Ideation subscale (MIS), the Perceptual Aberration subscale (PABS), and the Social Anhedonia subscale (SAS) were administered to 2,022 undergraduate university students. To determine if there were any relationships between these psychometric instruments and electrophysiological measures, 40 high-risk students were compared with 40 age- and gender-matched control students using auditory ERPs obtained from three midline electrodes (Fz, Cz, Pz) in a standard oddball paradigm. N2 (rare stimuli) and N2b latencies were significantly longer in the high-risk than in the control subjects, and the high-risk group also evidenced significantly smaller amplitude of the P3b component. No significant correlations between scores on the PPS or its three subscales and the amplitudes or latencies of the P3b or N200 component were found. These findings suggest that the N2 and P3b ERP components might serve as trait markers for psychosis and that individuals psychometrically identified as being at high risk for psychosis have deficits in the maintenance of attention and in decision-making.

We studied auditory event-related potentials (ERPs) in correlation with Rey's auditory verbal learning test (AVLT) in an amnesic patient with a left temporal lobe lesion. On the AVLT, the number of words recalled was limited to immediate memory capacity (nine words) throughout five trials, and recall after interference was remarkably decreased. In the ERPs, the P300 component was elicited normally, but no N400 component was apparent. Present findings suggest that these two ERP components may be associated with independent processes and support the view that the N400 may index a neural process involved in transfer of information from immediate memory to long-term storage.

We examined event-related potentials in patients with senile depression and silent cerebral infarction (SCI) to clarify the features of the P300 component. P300 event-related potentials were recorded in drug-free depressed patients (N = 16) and normal controls (N = 17). All patients underwent magnetic resonance imaging and were classified as SCI-positive (N = 7) or SCI-negative (N = 9). In depressed patients, the P300 was reexamined after antidepressant treatment. Prior to treatment, P300 amplitudes in depressed patients were significantly smaller than those in normal controls (P < 0.01). P300 amplitudes increased significantly in SCI-negative patients following recovery (P < 0.05), but did not change in SCI-positive patients. SCI may interrupt the treatment-related P300 amplitude increase in depressed patients.

Thirteen consecutive Japanese patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) were studied by MRI, evoked potentials, and EEG. We found 3 of these patients exhibited symptoms of CNS disorders. Of these 3, 2 with abnormal MRI and visual evoked potentials, and one with abnormal brainstem auditory evoked potentials were detected. Another case without clinical CNS signs showed abnormal EEG findings. The subclinical CNS abnormalities found in the Japanese patients were considered to be less frequent than in cases from Western countries reported previously.