ABSTRACT
Cholinergic stimulation of the mesencephalic reticular formation with carbachol impairs the induction of tonic immobility (TI) by restreining maneuvers and reduces the duration of immobility episodes in guiena pigs TI which permits the animal to evaluate the best6 time for escape. It is possible that this monitoring inolves cirucits and neurotransmitters other than the ascending cholinergic system origination in the mesencephalic reticular formation
Subject(s)
Guinea Pigs , Animals , Male , Behavior, Animal/drug effects , Carbachol/pharmacology , Cortical Synchronization/drug effects , Reticular Formation/physiology , Immobilization/physiology , Carbachol/administration & dosage , MicroinjectionsABSTRACT
Electrical or chemical (carbachol) stimulation of the dorsal thalamus of anesthetized and conscious toads induced synchronization (increased number of spindles and increased amplitude of the waves) in the electric tracing (EEG) of the telencephalon. This alteration was accompanied by mydriasis and greater behavioral alert in conscious animals. No recruitment response was observed in anesthetized toads. The present findings were compared to those obtained by stimulating the nonspecific thalamus of mmmals and reptiles. Even though the data available at present do not demonstrate the existence of a system with the morphological characteristics of the reticulo-thalamo-cortical system of mammals in anurans, the functional data presented here suggest this possibility