Dissociation of a visual discrimination task into incentive, location and response habits.

Rats previously trained to run from a start box, through a choice chamber, approach and displace a white card rather than a black card and enter a goal box in order to avoid footshock sustained damage to either the medial thalamus, occipital cortex or rostral caudoputamen. The retention test disclosed that the avoidance response was abolished by thalamic lesions, the visual discrimination response was abolished by occipital lesions and the card displacement response was abolished by caudatal lesions. These data demonstrate that this visual discrimination task can be fractionated into a least three discrete habits: One is related to the initiation of the response leading to the reward (incentive habit), the second is related to the location of the correct pathway to the reward (location habit) and the third is related to the response necessary to gain access to the reward (response habit).