Title:

Dissociable attentional effects of dopaminergic and cholinergic lesions to the anterior cingulate cortex

Prior work from our lab has shown that excitotoxic lesions to the anterior cingulate cortex (ACC) impairs the ability of rats to filter certain types of distracting stimuli (Newman and McGaughy 2011). Specifically, rats with lesions of the ACC cannot filter distractors that have been made salient through pairing with reinforcement. In contrast, these same subjects can filter distracting stimuli that have not been predictive of reward. The present study investigates the effects of neuromodulator specific lesions of the same region to determine how specific neuromodulators contribute to the attentional function of ACC. Cholinergic or dopaminergic deafferentation of the ACC was achieved using either 192 IgG saporin (n=10) or dopamine transporter saporin (n=10). Lesions were restricted to the rostral portion of the area and did not spread to nearby prefrontal sub-regions e.g prelimbic cortex. After lesioning, subjects were tested in an attentional set-shifting task (Birrell and Brown 2000). While both cholinergic and dopaminergic lesions increased distractibility, these deficits were not as severe as those produced after excitotoxic lesions (n= 8). In contrast to excitotoxic lesions, both cholinergic and dopaminergic lesions also impeded formation of an attentional set. Because dopaminergic lesions produced impairments in many stages of the tasks, we hypothesized that these subjects had a more general impairment in stimulus processing. In order to address these broader processing impairments, we analyzed the data to determine whether lesioned rats showed more sensitivity to novel stimuli. The implications of these data for understanding the unique contributions of acetylcholine and dopamine to attentional processing in the ACC will be discussed.

Name

Comment*

Comments are viewable only by submitter

Captcha*