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Article: Modulatory effect of cortical activation on the lemniscal auditory thalamus of the guinea pig

TitleModulatory effect of cortical activation on the lemniscal auditory thalamus of the guinea pig
Authors
Issue Date2002
PublisherAmerican Physiological Society.
Citation
Journal Of Neurophysiology, 2002, v. 88 n. 2, p. 1040-1050 How to Cite?
AbstractIn the present study, we investigated the point-to-point modulatory effects from the auditory cortex to the thalamus in the guinea pig. Corticofugal modulation on thalamic neurons was studied by electrical activation of the auditory cortex. The modulation effect was sampled along the frontal or sagittal planes of the auditory thalamus, focusing on the ventral division (MGv) of the medial geniculate body (MGB). Electrical activation was targeted at the anterior and dorsocaudal auditory fields, to which the MGv projects and from which it assumptively receives reciprocal projections. Of the 101 MGv neurons examined by activation of the auditory cortex through passing pulse trains of 100-200 μA current into one after another of the three implanted electrodes (101 neurons x 3 stimulation sites = 303 cases), 208 cases showed a facilitatory effect, 85 showed no effect, and only 10 cases (7 neurons) showed an inhibitory effect. Among the cases of facilitation, 63 cases showed a facilitatory effect >100%, and 145 cases showed a facilitatory effect from 20-100%. The corticofugal modulatory effect on the MGv of the guinea pig showed a widespread, strong facilitatory effect and very little inhibitory effect. The MGv neurons showed the greatest facilitations to stimulation by the cortical sites, with the closest correspondence in BF. Six of seven neurons showed an elevation of the rate-frequency functions when the auditory cortex was activated. The comparative results of the corticofugal modulatory effects on the MGv of the guinea pig and the cat, together with anatomical findings, hint that the strong facilitatory effect is generated through the strong corticothalamic direct connection and that the weak inhibitory effect might be mainly generated via the interneurons of the MGv. The temporal firing pattern of neuronal response to auditory stimulus was also modulated by cortical stimulation. The mean first-spike latency increased significantly from 15.7 ± 5.3 ms with only noise-burst stimulus to 18.3 ± 4.9 ms (n = 5, P < 0.01, paired t-test), while the auditory cortex was activated with a train of 10 pulses. Taking these results together with those of previous experiments conducted on the cat, we speculate that the relatively weaker inhibitory effect compared with that in the cat could be due to the smaller number of interneurons in the guinea pig MGB. The corticofugal modulation of the firing pattern of the thalamic neurons might enable single neurons to encode more auditory information using not only the firing rate but also the firing pattern.
Persistent Identifierhttp://hdl.handle.net/10722/81255
ISSN
2015 Impact Factor: 2.653
2015 SCImago Journal Rankings: 2.230
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorHe, Jen_HK
dc.contributor.authorYu, YQen_HK
dc.contributor.authorXiong, Yen_HK
dc.contributor.authorHashikawa, Ten_HK
dc.contributor.authorChan, YSen_HK
dc.date.accessioned2010-09-06T08:15:35Z-
dc.date.available2010-09-06T08:15:35Z-
dc.date.issued2002en_HK
dc.identifier.citationJournal Of Neurophysiology, 2002, v. 88 n. 2, p. 1040-1050en_HK
dc.identifier.issn0022-3077en_HK
dc.identifier.urihttp://hdl.handle.net/10722/81255-
dc.description.abstractIn the present study, we investigated the point-to-point modulatory effects from the auditory cortex to the thalamus in the guinea pig. Corticofugal modulation on thalamic neurons was studied by electrical activation of the auditory cortex. The modulation effect was sampled along the frontal or sagittal planes of the auditory thalamus, focusing on the ventral division (MGv) of the medial geniculate body (MGB). Electrical activation was targeted at the anterior and dorsocaudal auditory fields, to which the MGv projects and from which it assumptively receives reciprocal projections. Of the 101 MGv neurons examined by activation of the auditory cortex through passing pulse trains of 100-200 μA current into one after another of the three implanted electrodes (101 neurons x 3 stimulation sites = 303 cases), 208 cases showed a facilitatory effect, 85 showed no effect, and only 10 cases (7 neurons) showed an inhibitory effect. Among the cases of facilitation, 63 cases showed a facilitatory effect >100%, and 145 cases showed a facilitatory effect from 20-100%. The corticofugal modulatory effect on the MGv of the guinea pig showed a widespread, strong facilitatory effect and very little inhibitory effect. The MGv neurons showed the greatest facilitations to stimulation by the cortical sites, with the closest correspondence in BF. Six of seven neurons showed an elevation of the rate-frequency functions when the auditory cortex was activated. The comparative results of the corticofugal modulatory effects on the MGv of the guinea pig and the cat, together with anatomical findings, hint that the strong facilitatory effect is generated through the strong corticothalamic direct connection and that the weak inhibitory effect might be mainly generated via the interneurons of the MGv. The temporal firing pattern of neuronal response to auditory stimulus was also modulated by cortical stimulation. The mean first-spike latency increased significantly from 15.7 ± 5.3 ms with only noise-burst stimulus to 18.3 ± 4.9 ms (n = 5, P < 0.01, paired t-test), while the auditory cortex was activated with a train of 10 pulses. Taking these results together with those of previous experiments conducted on the cat, we speculate that the relatively weaker inhibitory effect compared with that in the cat could be due to the smaller number of interneurons in the guinea pig MGB. The corticofugal modulation of the firing pattern of the thalamic neurons might enable single neurons to encode more auditory information using not only the firing rate but also the firing pattern.en_HK
dc.languageengen_HK
dc.publisherAmerican Physiological Society.en_HK
dc.relation.ispartofJournal of Neurophysiologyen_HK
dc.titleModulatory effect of cortical activation on the lemniscal auditory thalamus of the guinea pigen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-3077&volume=88&spage=1040&epage=1050&date=2002&atitle=Modulatory+effect+of+cortical+activation+on+the+lemniscal+auditory+thalamus+of+the+guinea+pigen_HK
dc.identifier.emailChan, YS: yschan@hkucc.hku.hken_HK
dc.identifier.authorityChan, YS=rp00318en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.pmid12163552-
dc.identifier.scopuseid_2-s2.0-0036340562en_HK
dc.identifier.hkuros72014en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0036340562&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume88en_HK
dc.identifier.issue2en_HK
dc.identifier.spage1040en_HK
dc.identifier.epage1050en_HK
dc.identifier.isiWOS:000177276100044-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridHe, J=7404984971en_HK
dc.identifier.scopusauthoridYu, YQ=7406253532en_HK
dc.identifier.scopusauthoridXiong, Y=8706548900en_HK
dc.identifier.scopusauthoridHashikawa, T=7005824098en_HK
dc.identifier.scopusauthoridChan, YS=7403676627en_HK

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