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Titolo:
BINAURAL PROCESSING IN THE DORSAL NUCLEUS OF THE LATERAL LEMNISCUS
Autore:
MARKOVITZ NS; POLLAK GD;
Indirizzi:
UNIV TEXAS,DEPT ZOOL AUSTIN TX 78712 UNIV TEXAS,DEPT ZOOL AUSTIN TX 78712
Titolo Testata:
Hearing research
fascicolo: 1, volume: 73, anno: 1994,
pagine: 121 - 140
SICI:
0378-5955(1994)73:1<121:BPITDN>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUPERIOR OLIVARY COMPLEX; BAT INFERIOR COLLICULUS; SOUND LOCATION SELECTIVITY; UNIT EXCITATORY RESPONSES; AUDITORY-SYSTEM; MUSTACHE BAT; PTERONOTUS-PARNELLII; INTERAURAL TIME; BRAIN-STEM; TONOTOPIC ORGANIZATION;
Keywords:
DORSAL NUCLEUS OF THE LATERAL LEMNISCUS; BINAURAL PROCESSING; INTERAURAL INTENSITY DISPARITIES; TIME-INTENSITY TRADE; EXCITATORY-INHIBITORY NEURONS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
75
Recensione:
Indirizzi per estratti:
Citazione:
N.S. Markovitz e G.D. Pollak, "BINAURAL PROCESSING IN THE DORSAL NUCLEUS OF THE LATERAL LEMNISCUS", Hearing research, 73(1), 1994, pp. 121-140

Abstract

We studied the binaural properties of 72 neurons in the dorsal nucleus of the lateral lemniscus (DNLL) of the mustache bat. There are six main findings: 1) Conventional EI neurons that were excited by stimulation of the contralateral ear and inhibited by ipsilateral stimulation,comprise the majority (80%) of binaural DNLL cells. 2) For most EI neurons the quantitative features of their interaural intensity disparity (IID) functions, maximum inhibition, dynamic range and 50% point IIDs, were largely unaffected by the absolute intensity at the contralateral ear. 3) Although the net effect of the inhibition evoked by ipsilateral stimulation was to suppress discharges evoked by contralateral stimulation, our results indicate that the inhibitory inputs can act inthree different ways. The first was a time-intensity trade, where increasing the intensity at the ipsilateral ear evoked inhibitory effectswith progressively shorter latencies. The second way was that the latency of inhibition did not appear to decrease with ipsilateral intensity, but rather increasing ipsilateral intensity appeared only to increase the strength of the inhibition. The third way was that the lowest effective ipsilateral intensity suppressed the first spikes evoked by the contralateral stimulus and higher ipsilateral intensities then suppressed the later discharges of the train. Each of these inhibitory patterns was seen in about a third of the cells. 4) Neurons that had more complex binaural properties, such as the facilitated EI neurons (EI/F) and neurons that were driven by sound to either ear (EE neurons), represented about 20% of the binaural population. There were two types of EE neurons; those in which there was a simple summation of discharges evoked with certain IIDs, and those in which the spike-counts to binaural stimulation at certain IIDs were greater than a summation of the monaural counts and thus were facilitated. 5) Air binaural neurons were strongly inhibited with IIDs that favored the ipsilateral ear. Ourfindings indicate that the more complex binaural types, the facilitated EI neurons (EI/F) as well as the two types of EE neurons, may be constructed from conventional EI neurons by adding inputs from several sources that impart the more complex features to these neurons. We propose four circuits that could account for the different binaural response properties that we observed. The circuits' are based on the known connections of the DNLL and the neurochemistry of those connections. Finally, we compared the binaural properties of neurons in the mustache bat DNLL with those of neurons in the mustache bat inferior colliculusand lateral superior olive. The comparative features suggest that theprocessing of the interaural intensity disparities undergoes at leastfour types of response transformations along the ascending auditory system.

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Documento generato il 29/11/20 alle ore 16:18:48