Failure to find spatial reversal deficits following medial frontal lesions

Abstract

Following training on four spatial reversals, rats were given lesions in the medial frontal (MF), frontopolar (FP), or parietal neocortex, or they received sham operations. None of the groups differed significantly postoperatively. This finding was contrary to an earlier report of deficits following MF lesions. The animals in that study received 64 or 104 (60 or 100 in a previous experiment) preoperative reversals. Their mean errors for four postoperative reversals were 6.3 and 5.2, respectively. The MF group here had a mean of 5.2 errors for four postoperative reversals. Statistical comparison of the combined MF groups' data from the earlier study with our MF group data revealed no significant difference. However, the control groups from that study made significantly fewer errors than our controls postoperatively. It is suggested that spatial reversal deficits following MF lesions are subtle and may depend upon the extent of preoperative training received by control groups for their statistical confirmation.

Temporal and parietal association cortex lesions and spatial and black-white reversal learning in the rat

“…However, Killackey et al (1971) reported that a single temporally operated tree shrew that was incapable of improving its performance on a black-white reversal learning-set task was capable of learning a spatial reversal task. Since Weir and Thomas (1975) had the complicating factor …”

Comparative analysis of prefrontal learning functions in rats, cats, and monkeys.

“…For rodents, the variance between studies has been even greater (Divac, 1971;Hannon & Bader, 1974;Kolb et al, 1974;Nonneman, Voigt, & Kolb, 1974;Weir & Thomas, 1975), depending perhaps more on delay duration and the technical details of training than on size of lesion.…”