Changes in handedness in the rat by local application of acetylcholine to the cerebral cortex.

Abstract

After extended observations to determine the handedness of individual rats, acetylcholine and cholinergic drugs were applied locally to cortex subserving motor function of the non-preferred front limb. The operation was performed under ether anesthesia and took about 5 min. The drug was applied by placing 1/8-inch cotton pellets, saturated with a soln. (varying concns.) of the drug, on the intact meninges through a trephine hole in the frontal bone at its suture with the parietal. The wound was closed with wound clips leaving the cotton in place. Eating behavior was observed as soon after recovery from anesthesia as possible[long dash]usually within an hour or two. One initially single-handed animal changed preferred hand after ACH treatment (dosage not stated) and one after carbamylcholine treatment. None of the remaining 106 single-handed rats changed preference. 16 of 42 ambi- dextrous animals, however, changed dominant hands as result of treatment. The changes were not permanent. The relations between these findings and neurochemical theories of learning are briefly discussed.