Publication:
Expression of cardiovascular and behavioural components of conditioned fear to context in T4 spinally transected rats

dc.contributor.author Choi, Eun en_US
dc.contributor.author Leman, Samuel en_US
dc.contributor.author Vianna, Daniel en_US
dc.contributor.author Waite, Phil en_US
dc.contributor.author Carrive, Pascal en_US
dc.date.accessioned 2021-11-25T12:57:32Z
dc.date.available 2021-11-25T12:57:32Z
dc.date.issued 2005 en_US
dc.description.abstract A spinal cord transection at the fourth thoracic level (T4) results in paraplegia. It also removes supraspinal control of sympathetic outflow to most viscera and their blood vessels but spares the heart. We studied the effects of such a transection on the expression of the conditioned fear response to context, which includes freezing, 22 kHz ultrasonic vocalisations, a marked pressor response and a slowly rising tachycardia. Rats implanted with radiotelemetric probes were fear conditioned, tested, then transected at T4 and finally re-tested 4 weeks after transection. Baseline blood pressure in transected animals was the same as in intact animals but baseline heart rate was 127 bpm higher. There were clear signs of fear in the transected animals: although freezing occurred in the upper part of the body only, there was a 3 fold increase in the number of ultrasonic vocalisations, most probably due to paralysis of abdominal muscles that made expirations shorter and therefore more frequent. The pressor response of fear was initially the same as in intact animals but controls revealed that this was due to handling during transfer to the aversive context. The rest of the pressor response was markedly reduced (70%) confirming that it depends in large part on a sympathetically mediated increase in vascular resistance in the lower part of the body. The cardiac response was characterized by an initial bradycardia followed by a marked tachycardia, which is consistent with a baroreceptor-mediated reflex response to the altered pressor changes. Finally, none of these changes was observed when the same experiment was repeated in sham transected animals. Thus, the pressor response of fear is in large part mediated by the thoracic cord below T4 and the baroreflex is not inhibited but maintained during conditioned fear. en_US
dc.identifier.issn 1566-0702 en_US
dc.identifier.uri http://hdl.handle.net/1959.4/38777
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/3.0/au/ en_US
dc.source Legacy MARC en_US
dc.subject.other blood flow en_US
dc.subject.other stress en_US
dc.subject.other sympathetic en_US
dc.subject.other tail en_US
dc.subject.other thermoregulation en_US
dc.title Expression of cardiovascular and behavioural components of conditioned fear to context in T4 spinally transected rats en_US
dc.type Journal Article en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.accessRights.uri http://purl.org/coar/access_right/c_14cb
unsw.identifier.doiPublisher http://dx.doi.org/10.1016/j.autneu.2004.08.014 en_US
unsw.relation.faculty Medicine & Health
unsw.relation.ispartofissue 1-2 en_US
unsw.relation.ispartofjournal Autonomic Neuroscience-Basic & Clinical en_US
unsw.relation.ispartofpagefrompageto 26-34 en_US
unsw.relation.ispartofvolume 120 en_US
unsw.relation.originalPublicationAffiliation Choi, Eun, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Leman, Samuel, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Vianna, Daniel, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Waite, Phil, Faculty of Medicine, UNSW en_US
unsw.relation.originalPublicationAffiliation Carrive, Pascal, Faculty of Medicine, UNSW en_US
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