Recovery time and sensorimotor cortex lesion effects.

Rats received one-stage, bilateral lesions of the individual sensorimotor cortex areas (Sm-1, Sm-2) and were compared to sham operated rats or rats with lesions of Sm1 + 2 in learning a series of 5 ridge-smooth tactile discriminations. Some rats began testing 1 or 2 weeks after surgery, while others remained in their home cages for 1 month, 6 months, 1 year or 2 years before beginning testing. The rats with combined Sm1 + 2 lesions performed very poorly regardless of recovery time, and those with sham operations performed extremely well even when tested late in life. The animals with either Sm-1 or Sm-2 lesions did not do well after the shorter recovery periods, but obtained scores within the sham operated group range when given 1 year. (Sm-2) or 2 years (Sm-1) for recovery. These data show that spared parts of the damaged system are important in mediating tactile discriminative behavior. However, the reasons for the long delays in recovery are not clear.