TY - JOUR
T1 - Possible routes of visceral information in the rat brain in formation of conditioned taste aversion
AU - Sakai, Nobuyuki
AU - Yamamoto, Takashi
N1 - Funding Information:
We thank Thomas R. Scott for his comments on a draft of the manuscript. This work was supported by Grant-in-Aid for scientific research (Nos. 09470401 and 11557135; T.Y.) from the Ministry of Education, Science, Sports and Culture of Japan and by Research Program (No. JSPS-RFTF97L00906; T.Y.) from the Japan Society for the Promotion of Science.
PY - 1999/10
Y1 - 1999/10
N2 - When ingestion of a taste stimulus is paired with internal malaise, the animal remembers the taste and rejects its ingestion thereafter. This learning is referred to as conditioned taste aversion (CTA). To establish CTA in adult male Wistar rats, 0.1% saccharin and an i.p. injection of 0.15 M LiCl were used as the conditioned and unconditioned stimuli, respectively. Neuroanatomical study using the tracer method was performed to examine the ascending routes from the lateral part of the parabrachial nucleus (PBlat) which receives general visceral information and suggested the three possible routes to the amygdala: (1) direct route to the central nucleus of the amygdala (CeA); (2) diencephalic route to the basolateral nucleus of the amygdala (BLA) involving the zona incerta (ZI) and the midline and intralaminar thalamic complex (MITC); and (3) cortical route to the BLA involving insular cortex (IC). Rats with excitotoxic lesions of each of the CeA, ZI, MITC or IC had only a small or negligible effect on the acquisition of CTA. However, single lesions of the BLA and combined lesions of the ZI and IC, but not CeA and IC, almost completely abolished the acquisition of CTA. These results together with previous findings suggest that visceral (or unconditioned stimulus) information in the PBlat is sent to the BLA which is essential for the acquisition of CTA via the functionally important two parallel routes, the diencephalic and cortical routes, with either being able to create the aversion.
AB - When ingestion of a taste stimulus is paired with internal malaise, the animal remembers the taste and rejects its ingestion thereafter. This learning is referred to as conditioned taste aversion (CTA). To establish CTA in adult male Wistar rats, 0.1% saccharin and an i.p. injection of 0.15 M LiCl were used as the conditioned and unconditioned stimuli, respectively. Neuroanatomical study using the tracer method was performed to examine the ascending routes from the lateral part of the parabrachial nucleus (PBlat) which receives general visceral information and suggested the three possible routes to the amygdala: (1) direct route to the central nucleus of the amygdala (CeA); (2) diencephalic route to the basolateral nucleus of the amygdala (BLA) involving the zona incerta (ZI) and the midline and intralaminar thalamic complex (MITC); and (3) cortical route to the BLA involving insular cortex (IC). Rats with excitotoxic lesions of each of the CeA, ZI, MITC or IC had only a small or negligible effect on the acquisition of CTA. However, single lesions of the BLA and combined lesions of the ZI and IC, but not CeA and IC, almost completely abolished the acquisition of CTA. These results together with previous findings suggest that visceral (or unconditioned stimulus) information in the PBlat is sent to the BLA which is essential for the acquisition of CTA via the functionally important two parallel routes, the diencephalic and cortical routes, with either being able to create the aversion.
KW - Amygdala
KW - Conditioned taste aversion
KW - Insular cortex
KW - Parabrachial nucleus
KW - Rat
KW - Zona incerta
UR - http://www.scopus.com/inward/record.url?scp=0032828619&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032828619&partnerID=8YFLogxK
U2 - 10.1016/S0168-0102(99)00067-X
DO - 10.1016/S0168-0102(99)00067-X
M3 - Article
C2 - 10555164
AN - SCOPUS:0032828619
VL - 35
SP - 53
EP - 61
JO - Neuroscience Research
JF - Neuroscience Research
SN - 0168-0102
IS - 1
ER -