The individual and group reactions, learning techniques and capacities, and neurotic and drug-influenced behavior patterns of 64 cats and 49 monkeys were studied from 30 to 75 months before and after the implantation of lesions in 10 neo-, paleo- and sub-cortical brain areas. The data suggest that:1. There are effects specific to each lesion despite inevitable variation in site, altered blood supply, etc.2. There are a number of general changes common to lesions in several different areas.3. The effects of any lesion are highly relatable to pre-operative characteristics and acquired patterns of behavior.4. The effects are further dependent on the nature of post-operative treatment and experience.Abstract Teaser