Temporary inactivation of the rostral perirhinal cortex induces an anxiolytic-like effect on the elevated plus-maze and on the yohimbine-enhanced startle response.
The present study investigated whether the rostral perirhinal cortex is involved in aversive information processing, particularly in unconditioned fear (anxiety). We temporarily inactivated the rostral perirhinal cortex by local injections of the GABA(A) agonist muscimol (0.0, 1.1, and 4.4 nmol/0.5 microl) and tested whether these injections affected the behavior of rats in the elevated plus-maze and in the yohimbine-enhanced startle test. Temporary inactivation of the rostral perirhinal cortex increased the number of open arm entries and the open arm ratio in the elevated plus-maze. In addition, startle response enhancement caused by the anxiogenic drug yohimbine was reduced by perirhinal cortex inactivation. Taken together, these data clearly show that the rostral perirhinal cortex is involved in the processing of emotional stimuli and is critical for the expression of unconditioned fear (anxiety).
Schulz-Klaus
Brigitte
B
Tierphysiologie, Zoologisches Institut, Universität Tübingen, Germany.
Fendt
Markus
M
Schnitzler
Hans-Ulrich
HU
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D001522:Behavior, Animal; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D005106:Exploratory Behavior / Q000187:drug effects; D018782:Maze Learning / Q000187:drug effects* / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects* / Q000502:physiology; D015016:Yohimbine / Q000494:pharmacology*
D000317:Adrenergic alpha-Antagonists; D014151:Anti-Anxiety Agents; D009118:Muscimol; D015016:Yohimbine