Lateralized wall-facing versus turning as measures of behavioral asymmetries and recovery of function after injection of 6-hydroxydopamine into the substantia nigra.
The tendency of a rat to approach the wall of an open-field and to travel along the perimeter of the field (termed as "peritaxis" or "wall-facing") is affected by unilateral removal of the vibrissae. Peritaxis is lateralized by hemivibrissotomy. The finding that the dopamine agonist apomorphine reversed the direction of wall-facing asymmetry after 10 days of vibrissae removal suggested a link between this sensorimotor asymmetry and dopamine transmission. The present experiment examined the influence of a unilateral injection of 6-hydroxydopamine into the substantia nigra on peritaxis and compared this behavioral measure with turning behavior as an index of lesion-induced sensorimotor asymmetries and of recovery of function. The lesion of the substantia nigra reduced wall-facing with the side contralateral to the lesion to near-zero values. During the first week after the injection animals with incomplete dopamine depletion recovered from this asymmetry. The changes in wall-facing behavior were paralleled by turning asymmetries. Wall-facing was at least as sensitive to application of amphetamine and apomorphine as turning behavior. We concluded that lateralized wall-facing, or peritaxis, can serve as a useful index of dysfunction in the nigrostriatal dopamine system and the influence of catecholaminergic drugs. Wall-facing can also serve as a measure of recovery of function.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D004298:Dopamine / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000503:physiopathology; D014738:Vibrissae / Q000502:physiology
D006892:Hydroxydopamines; D016627:Oxidopamine; D004298:Dopamine