title: Electrolytic lesions of the cortical and adjacent nuclei in the amygdala differentially influence thresholds for rewarding medial forebrain bundle stimulation.
abstract: After electrolytic lesions to the cortical and adjacent amygdaloid subnuclei, thresholds for rewarding medial forebrain bundle (MFB) stimulation were tracked in 19 rats with bilateral implants and 8 with single implants. Results were categorized into 3 groups depending on the magnitude of the lesion effect on ipsilateral frequency thresholds: substantial (> 60%), small (> 26%), or none (< 26%), compared with baseline values. Five rats exhibited threshold increases up to 225%, among the largest reported to the authors' knowledge. Small shifts were observed in another 5 rats, and no change in the remaining 17 rats. Threshold changes in the contralateral electrode mirrored ipsilateral ones. Results suggest that specific amygdaloid subnuclei modulate MFB reward signals through a diffuse collateralized organization of fibers and lend support to the existence of interhemispheric links in MFB reward pathways.
authors.affiliation: School of Psychology, University of Ottawa, Ontario, Canada. catch@uottawa.ca
authors.forename: Catherine
authors.initials: C
authors.lastname: Bielajew
authors.forename: Maïa
authors.initials: M
authors.lastname: Miguelez
authors.forename: Renfu
authors.initials: R
authors.lastname: Shiao
mesh_terms: D000679:Amygdala / Q000473:pathology / Q000502:physiology*; D000818:Animals; D002540:Cerebral Cortex / Q000473:pathology / Q000502:physiology*; D004558:Electric Stimulation; D004566:Electrodes; D008297:Male; D016548:Prosencephalon / Q000502:physiology*; D051381:Rats; D012054:Reinforcement, Psychology