Disconnection Procedure with Bilateral and Unilateral Lesions
Objective: To examine the role of medial prefrontal cortex (mPFC) and perirhinal cortex (PRH) in recognition memory processes using bilateral and unilateral disconnection lesions to test whether these regions form an integrated neural network
Protocol Steps
Surgical Group Assignment
Male DA rats were divided into five experimental groups: bilateral PRH lesions, bilateral mPFC lesions, unilateral lesions in both cortices in ipsilateral hemispheres (PRH-mPFC IPSI), unilateral lesions in both cortices in contralateral hemispheres (PRH-mPFC CONTRA), and sham surgery control group (SHAM)
Note: Five distinct surgical groups were created to test disconnection of neural networks
View evidence from paper
“Male DA rats received bilateral lesions in the PRH or mPFC or unilateral lesions placed in both cortices in either the same (PRH–mPFC IPSI) or contralateral (PRH–mPFC CONTRA) hemispheres. A fifth group underwent sham surgery (SHAM).”
Novel Object Preference Task
Rats were tested on a novel object preference task to assess discrimination of novel and familiar individual objects
Note: Performance was only impaired in the PRH group, not in mPFC or disconnection groups
View evidence from paper
“performance in the novel object preference task was only impaired in the PRH group”
Object-in-Place Task
Rats were tested on an object-in-place task to assess associational memory based on integrating information concerning objects and location
Note: PRH, mPFC, and PRH-mPFC CONTRA groups were significantly impaired
View evidence from paper
“In the object-in-place and temporal order memory tasks, the PRH, mPFC, and PRH–mPFC CONTRA groups were significantly impaired.”
Temporal Order Memory Task
Rats were tested on a temporal order memory task to assess recency discrimination using recency information
Note: PRH, mPFC, and PRH-mPFC CONTRA groups were significantly impaired; ipsilateral disconnection did not impair performance
View evidence from paper
“In the object-in-place and temporal order memory tasks, the PRH, mPFC, and PRH–mPFC CONTRA groups were significantly impaired.”
Object Location Task
Rats were tested on an object location task
Note: No group was impaired in this task
View evidence from paper
“No group was impaired in the object location task.”