TY - JOUR
T1 - Pontine and thalamic influences on fluid rewards
T2 - I. Operant responding for sucrose and corn oil
AU - Liang, Nu Chu
AU - Freet, Christopher S.
AU - Grigson, Patricia S.
AU - Norgren, Ralph
N1 - Funding Information:
We thank Han Li for making lesions, and Kathy Matayas and Nellie Horvath for histological assistance. Supported by grants DK079182 , DC00240 , and DA012473 from the National Institute of Health , as well as an award from the PA State Tobacco Settlement Fund .
PY - 2012/1/18
Y1 - 2012/1/18
N2 - The reward strength of orosensory sucrose and corn oil was measured using fixed and progressive ratio operant schedules. Because the orosensory effects of the stimuli were of interest, Experiment 1 compared operant responses for sucrose in sham and real feeding rats. The results demonstrated that rats would work for sucrose solutions without the accompanying postingestive effects. Furthermore, the break points for high concentrations of sucrose (1.0. M or 2.0. M) were significantly higher in sham feeding rats than in real feeding controls. Experiment 2 investigated the role of the parabrachial nucleus (PBN) and of the thalamic orosensory area (TOA) in sucrose and corn oil reward. During free access, rats with PBN lesions (PBNx) licked significantly less sucrose solution than their controls, but both groups ingested a similar volume of corn oil emulsion. When an operant was imposed, these same PBNx rats failed to respond for sucrose and continued only modestly for corn oil. In contrast, the TOA lesioned rats (TOAx) showed no impairment in responding for sucrose or corn oil during either the free access or operant sessions. Furthermore, rats with TOA lesions demonstrated significantly higher break points for sucrose than did their controls. Together, the data imply that the PBN but not the TOA is critical for the perception of, or responding to the reward value of sucrose and corn oil.
AB - The reward strength of orosensory sucrose and corn oil was measured using fixed and progressive ratio operant schedules. Because the orosensory effects of the stimuli were of interest, Experiment 1 compared operant responses for sucrose in sham and real feeding rats. The results demonstrated that rats would work for sucrose solutions without the accompanying postingestive effects. Furthermore, the break points for high concentrations of sucrose (1.0. M or 2.0. M) were significantly higher in sham feeding rats than in real feeding controls. Experiment 2 investigated the role of the parabrachial nucleus (PBN) and of the thalamic orosensory area (TOA) in sucrose and corn oil reward. During free access, rats with PBN lesions (PBNx) licked significantly less sucrose solution than their controls, but both groups ingested a similar volume of corn oil emulsion. When an operant was imposed, these same PBNx rats failed to respond for sucrose and continued only modestly for corn oil. In contrast, the TOA lesioned rats (TOAx) showed no impairment in responding for sucrose or corn oil during either the free access or operant sessions. Furthermore, rats with TOA lesions demonstrated significantly higher break points for sucrose than did their controls. Together, the data imply that the PBN but not the TOA is critical for the perception of, or responding to the reward value of sucrose and corn oil.
KW - Parabrachial nucleus
KW - Progressive ratio
KW - Reward
KW - Sham feeding
KW - Thalamic orosensory area
UR - http://www.scopus.com/inward/record.url?scp=82155167688&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=82155167688&partnerID=8YFLogxK
U2 - 10.1016/j.physbeh.2011.06.010
DO - 10.1016/j.physbeh.2011.06.010
M3 - Article
C2 - 21703290
AN - SCOPUS:82155167688
SN - 0031-9384
VL - 105
SP - 576
EP - 588
JO - Physiology and Behavior
JF - Physiology and Behavior
IS - 2
ER -