The modulation of play fighting in rats: role of the motor cortex

The cortex is not necessary for rats to engage in play fighting, but it is necessary for them to modify their pattern of play fighting in different contexts. Two experiments were conducted to determine the role of the motor cortex (MC). Rats with bilateral ablations of the MC performed on Postnatal Day 10 failed to show the normally present age-related modulation in defense but were able to modulate defense with different social partners. This latter finding was confirmed in rats given ablations as adults, in which responses to social status could be monitored before and after brain damage. It appears that different forms of cortical modulation of play fighting involve different cortical circuits.