Résumé
The auditory steady state response (ASSR) may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates (≤40 Hz) emanate mostly from central structures of the brain, and responses from high rates (≥80 Hz) emanate mostly from the peripheral auditory nerve or brainstem structures. Besides, it was reported that the gamma band ASSR (30-90 Hz) played an important role in working memory, speech understanding and recognition. This paper investigated the 40 Hz ASSR evoked by modulated speech and reversed speech. The speech was Chinese phrase voice, and the noise-like reversed speech was obtained by temporally reversing the speech. Both auditory stimuli were modulated with a frequency of 40 Hz. Ten healthy subjects and 5 patients with hallucination symptom participated in the experiment. Results showed reduction in left auditory cortex response when healthy subjects listened to the reversed speech compared with the speech. In contrast, when the patients who experienced auditory hallucinations listened to the reversed speech, the auditory cortex of left hemispheric responded more actively. The ASSR results were consistent with the behavior results of patients. Therefore, the gamma band ASSR is expected to be helpful for rapid and objective diagnosis of hallucination in clinic.
Résumé
The auditory steady state response (ASSR) may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates (≤40 Hz) emanate mostly from central structures of the brain, and responses from high rates (≥80 Hz) emanate mostly from the peripheral auditory nerve or brainstem structures. Besides, it was reported that the gamma band ASSR (30-90 Hz) played an important role in working memory, speech understanding and recognition. This paper investigated the 40 Hz ASSR evoked by modulated speech and reversed speech. The speech was Chinese phrase voice, and the noise-like reversed speech was obtained by temporally reversing the speech. Both auditory stimuli were modulated with a frequency of 40 Hz. Ten healthy subjects and 5 patients with hallucination symptom participated in the experiment. Results showed reduction in left auditory cortex response when healthy subjects listened to the reversed speech compared with the speech. In contrast, when the patients who experienced auditory hallucinations listened to the reversed speech, the auditory cortex of left hemispheric responded more actively. The ASSR results were consistent with the behavior results of patients. Therefore, the gamma band ASSR is expected to be helpful for rapid and objective diagnosis of hallucination in clinic.
Sujets)
Adulte , Femelle , Humains , Mâle , Adulte d'âge moyen , Jeune adulte , Stimulation acoustique , Méthodes , Algorithmes , Cortex auditif , Perception auditive , Physiologie , Électroencéphalographie , Méthodes , Hallucinations , Diagnostic , Linguistique , Modèles neurologiques , ParoleRésumé
The motivation of the brain-computer interface (BCI) research and its potential applications are introduced in this paper. Some of the problems in BCI-based medical device developments are also discussed.
Sujets)
Humains , Intelligence artificielle , Encéphale , Physiologie , Aides à la communication pour personnes handicapées , Électroencéphalographie , Méthodes , Potentiels évoqués , Physiologie , Maladies neuromusculaires , Réadaptation , Réadaptation , Traitement du signal assisté par ordinateur , Interface utilisateurRésumé
A strain with relative higher phytase-producing ability, Aspergillus fumigatus WY-2 was screened from soil. The optimal pH and temperature for activity of the phytase from A.fumigatus WY-2 were 5.5 and 55 ℃, respectively. The gene encoding the phytase was amplified from genomic DNA of the strain by PCR, and a 1.5 kb DNA fragment was obtained and then was cloned into vector pMD18-T. The sequencing analysis revealed that the DNA fragment contained a whole open reading frame (ORF) of phytase gene. The phytase gene was 1459 bp in length included with a 61 bp intron and encoded 465 amino acids. A signal peptide encoding 26 amino acids was found at 5′end of the gene. There were 7 potential glycosylation sites in the phytase. The present phytase showed 91% identity in nucleotide sequence and 91% identity in deduced amino acids sequence to the previously reported A.fumigatus ATCC34625 phytase.