Kristin N Zajo1, Jim R Fadel2, Joshua A Burk3. 1. Department of Psychology, College of William & Mary, Williamsburg, VA, 23187, USA. 2. Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, USA. 3. Department of Psychology, College of William & Mary, Williamsburg, VA, 23187, USA. jabur2@wm.edu.
Abstract
RATIONALE: Orexins are neuropeptides released in multiple brain regions from neurons that originate within the lateral hypothalamus and contiguous perfornical area. The basal forebrain, a structure implicated in attentional processing, receives orexinergic inputs. Our previous work demonstrated that administration of an orexin-1 receptor antagonist, SB-334867, systemically or via infusion directly into the basal forebrain, can disrupt performance in a task that places explicit demands on attentional processing. OBJECTIVES: Given that the orexin-1 receptor binds orexin A with high affinity, we tested whether orexin A could enhance attention in rats. METHODS: Attentional performance was assessed using a task that required discrimination of variable duration visual signals from trials when no signal was presented. We also tested whether infusions of orexin A into the lateral ventricle could attenuate deficits following lesions of medial prefrontal cortical cholinergic projections that arise from the basal forebrain. RESULTS: Infusions of orexin A into the basal forebrain attenuated distracter-induced decreases in attentional performance. Orexin A attenuated deficits in lesioned animals when a visual distracter was presented. CONCLUSION: The present results support the view that orexin A can enhance attentional performance via actions in the basal forebrain and may be beneficial for some conditions characterized by attentional dysfunction due to disruption of cortical cholinergic inputs.
RATIONALE: Orexins are neuropeptides released in multiple brain regions from neurons that originate within the lateral hypothalamus and contiguous perfornical area. The basal forebrain, a structure implicated in attentional processing, receives orexinergic inputs. Our previous work demonstrated that administration of an orexin-1 receptor antagonist, SB-334867, systemically or via infusion directly into the basal forebrain, can disrupt performance in a task that places explicit demands on attentional processing. OBJECTIVES: Given that the orexin-1 receptor binds orexin A with high affinity, we tested whether orexin A could enhance attention in rats. METHODS: Attentional performance was assessed using a task that required discrimination of variable duration visual signals from trials when no signal was presented. We also tested whether infusions of orexin A into the lateral ventricle could attenuate deficits following lesions of medial prefrontal cortical cholinergic projections that arise from the basal forebrain. RESULTS: Infusions of orexin A into the basal forebrain attenuated distracter-induced decreases in attentional performance. Orexin Aattenuated deficits in lesioned animals when a visual distracter was presented. CONCLUSION: The present results support the view that orexin A can enhance attentional performance via actions in the basal forebrain and may be beneficial for some conditions characterized by attentional dysfunction due to disruption of cortical cholinergic inputs.
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