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Titolo:
RESPONSES OF NEURONS IN THE INFERIOR COLLICULUS TO BINAURAL MASKING LEVEL DIFFERENCE STIMULI MEASURED BY RATE-VERSUS-LEVEL FUNCTIONS
Autore:
JIANG D; MCALPINE D; PALMER AR;
Indirizzi:
UNIV NOTTINGHAM,MRC,INST HEARING RES,UNIV PK NOTTINGHAM NG7 2RD ENGLAND UNIV NOTTINGHAM,MRC,INST HEARING RES NOTTINGHAM NG7 2RD ENGLAND
Titolo Testata:
Journal of neurophysiology
fascicolo: 6, volume: 77, anno: 1997,
pagine: 3085 - 3106
SICI:
0022-3077(1997)77:6<3085:RONITI>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-FREQUENCY NEURONS; INTERAURAL TIME SENSITIVITY; AUDITORY-NERVE FIBERS; MEDIAL SUPERIOR OLIVE; GUINEA-PIG; SOUND LOCALIZATION; CHANGING FREQUENCY; TONAL STIMULATION; COCHLEAR NUCLEUS; NOISE STIMULI;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
81
Recensione:
Indirizzi per estratti:
Citazione:
D. Jiang et al., "RESPONSES OF NEURONS IN THE INFERIOR COLLICULUS TO BINAURAL MASKING LEVEL DIFFERENCE STIMULI MEASURED BY RATE-VERSUS-LEVEL FUNCTIONS", Journal of neurophysiology, 77(6), 1997, pp. 3085-3106

Abstract

The psychophysical detection threshold of a low-frequency tone maskedby broadband noise is reduced by less than or equal to 15 dB by inversion of the tone in one ear (called the binaural masking level difference: BMLD). The contribution of 120 low-frequency neurons (best frequencies 168-2,090 Hz) in the inferior colliculus (ICC) of the guinea pigto binaural unmasking of 500-Hz tones masked by broadband noise was examined. We measured rate-level functions of the responses to identical signals (So) and noise (No) at the two ears (NoSo) and to identical noise but with the signal inverted at one ear (NoS pi): the noise was 7-15 dB suprathreshold. The masked threshold was estimated by the standard separation, ''D''. The neural BMLD was estimated as the difference between the masked thresholds for NoSo and NoS pi. The presence of So and S pi tones was indicated by discharge rate increases in 55.3% ofneurons. In 36.4% of neurons, the presence of So tones was indicated by an increase in discharge rate and S pi tones by a decrease. In 6.8%of neurons, both So and S pi tones caused a decrease in discharge rate. In only 1.5% of neurons was So indicated by a decrease and S pi by an increase in discharge rate. Responses to the binaural configurations were consistent with the neuron's interaural delay sensitivities; 34.4% of neurons showing increases in discharge rate to both So and S pitones gave positive BMLDs greater than or equal to 3 dB (S pi tones were detected at lower levels than So), whereas 37.3% gave negative BMLDs greater than or equal to 3 dB. For neurons in which So signals caused an increase in the discharge rate and S pi a decrease, 72.7% gave positive BMLDs greater than or equal to 3 dB and only 4.5% gave negative BMLDs greater than or equal to 3 dB. The results suggest that the responses of single ICC neurons are consistent with the psychophysical BMLDs for NoSo versus NoS pi at 500 Hz, and with current binaural interaction models based on coincidence detection. The neurons likely to contribute to the psychophysical BMLD are those with BFs near 500 Hz, but detection of So and S pi tones may depend on different populations of neurons.

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Documento generato il 05/12/20 alle ore 01:23:48