The role of the inferior collicular cortex in the neonatal rat: sensorimotor modulation.
A tail pinch in rats up to 10 days of age produces a spectrum of motor behaviors characterized by forelimb paddling, hindlimb treading and occasional curling and rolling of the torso, a behavioral pattern similar to the seizure behaviors electrically-elicited from the inferior collicular cortex of 5- or 10-day-old rats. In 5-day-old rats, these tail pinch-induced paddling and treading behaviors coincided with afterdischarge-like EEG activity recorded from the seizure-sensitive site in the inferior collicular cortex. In contrast, no change in the EEG activity occurred in an adjacent seizure-insensitive site during these tail pinch-induced behaviors. Similar electrographic-behavioral synchrony was found in 10-day-old rats, but by 16 days of age, as in the adult rat, a tail pinch stimulus did not induce post-stimulus behavioral changes or afterdischarge-like EEG activity. Since auditory function does not develop until 12-14 days of age in the rat, we propose that the inferior collicular cortex modulates sensorimotor integration in the neonatal rat, prior to assumption of this function by the cerebral cortex.
McCown
T J
TJ
Department of Psychiatry, University of North Carolina, Chapel Hill 27599-7250.
Breese
G R
GR
D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D004558:Electric Stimulation; D004569:Electroencephalography; D005552:Forelimb / Q000502:physiology; D006614:Hindlimb / Q000502:physiology; D007245:Inferior Colliculi / Q000502:physiology*; D009043:Motor Activity; D010812:Physical Stimulation; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000503:physiopathology; D012677:Sensation; D013623:Tail