The Journal of Neuroscience, March 5, 2008, 28(10):2642-2650; doi:10.1523/JNEUROSCI.5112-07.2008
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Behavioral/Systems/Cognitive
Cholinergic Deafferentation of Prefrontal Cortex Increases Sensitivity to Cross-Modal Distractors during a Sustained Attention Task
Lori A. Newman and
Jill McGaughy
Department of Psychology, University of New Hampshire, Durham, New Hampshire 03824
Correspondence should be addressed to Jill McGaughy, Department of Psychology, University of New Hampshire, Conant Hall, 10 Library Way, Durham, NH 03824. Email: j.mcgaughy{at}unh.edu
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.
Key words: infralimbic cortex; prelimbic cortex; 192 IgG saporin; executive control; top-down control; selective attention
Received June 29, 2007;
revised Dec. 22, 2007;
accepted Jan. 16, 2008.
Correspondence should be addressed to Jill McGaughy, Department of Psychology, University of New Hampshire, Conant Hall, 10 Library Way, Durham, NH 03824. Email: j.mcgaughy{at}unh.edu