Cholinergic Deafferentation of Prefrontal Cortex Increases Sensitivity to Cross-Modal Distractors during a Sustained Attention Task

Abstract

The effects of restricted cholinergic deafferentation of prefrontal cortex in rats on sustained attention were assessed. Attentional demands were increased by presentation of distractor stimuli in a different modality (auditory) or the same modality (visual) as target stimuli. Additionally, the effects of the regularity of the distractor on rats' ability to disregard this stimulus were assessed by testing different frequencies of stimuli for each modality. Cholinergically lesioned rats were more sensitive to the effects of auditory distractors than nonlesioned rats, whereas visual distractors of any frequency potently impaired the performance of all subjects. The effects of the auditory stimuli on attentional performance varied depending on the frequency of the tone. A tone with a predictable pattern enhanced signal detection in all rats. An irregular tone selectively impaired performance of rats with cholinergic lesions. Additional tests suggest that rats use the regular tone to time when to attend. Lesioned rats were impaired when the regular tone was presented with a more variable intertrial interval in a subsequent testing session, suggesting impairments in top-down control. In addition to changes in top-down control of attention, differential effects on performance based on the regularity of the tone suggest that stimulus properties encoded by bottom-up processes are also altered after lesioning. The current data suggest that cholinergic deafferentation of prefrontal cortex alters top-down and bottom-up processing of stimuli.

Method for testing sustained attention in touchscreen operant chambers in rats

“…To achieve a more graded level of performance on signal trials, the middle signal duration could be increased. In fact, Newman and McGaughy (2008) used a 100 ms, rather than 50 ms, middle signal duration and they found a greater distinction in performance between 100 ms and 25 ms than we did between 50 ms and ms. Future studies could confirm this using the touchscreen boxes.…”

Cognitive control and the anterior cingulate cortex: How conflicting stimuli affect attentional control in the rat

“…The results also suggest the role of the ACC is dissociable from the prelimbic cortex in rats. Previous work in our lab has shown that neurochemical and regionally specific damage to the prelimbic cortex does produce a general increase in distractibility that is not limited to previously reinforced stimuli as found after ACC damage (Newman & McGaughy, 2008). Several studies suggest the prelimbic cortex (dorsolateral prefrontal cortex in primates) has also been shown to play a substantial role in conflict monitoring (Banich et al, 2000; Chen et al, 2006; Erickson et al, 2004; Milham, Banich, Claus, & Cohen, 2003).…”

Prenatal Malnutrition Leads to Deficits in Attentional Set Shifting and Decreases Metabolic Activity in Prefrontal Subregions that Control Executive Function

“…Impairments in attentional set shifting result from damage to the PrL in the rat [15,28,29] or to the dorsolateral PFC in humans [11] and nonhuman primates [13,14]. Specifically, damage to the noradrenergic afferents to the PrL impairs ED performance but does not affect performance on any other stage of the attentional set-shifting task [28,38].…”

“…Methods are similar to those described in previous work [20,28,29]. First, the rats were trained to dig for reinforcement in weighted terracotta pots (height of 10 cm, internal diameter of 10.2 cm) that were affixed to the floor of the testing box with velcro (Manchester, N.H., USA).…”