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Role of cholinergic NBM neurons in timing and divided attention.

Mcauley J, Stewart AL, Pang KCH (2009) Role of cholinergic NBM neurons in timing and divided attention. Neuroscience 2009 Abstracts 95.12/EE81. Society for Neuroscience, Chicago, IL.

Summary: The nucleus basalis magnocellularis (NBM) provides cholinergic and GABAergic innervation to the neocortex. In previous studies, non-selective lesions of the NBM using ibotenic acid impaired interval timing and divided attention. Rats with NBM damage produced rightward shifts in peak times, demonstrating overproduction (underestimation) of time. Additionally, NBM damage impaired the ability to divide attention when timing two intervals simultaneously. Damage of the frontal cortex produced similar impairments in timing and divided attention as NBM damage, suggesting the NBM projections to frontal cortex were critical. Currently, the NBM neurons responsible for modulating timing and attention are unknown. The present study will determine the importance of cholinergic NBM neurons in timing and attention using the selective immunotoxin 192-IgG saporin (192-SAP). Sixteen Sprague Dawley rats were first trained on a peak-interval (PI) procedure using fixed-intervals of 12 s and 24 s paired with light and tone stimuli, respectively. During this phase, only one stimulus was presented during a trial (focused attention). Following the initial phase of training, rats were trained on a divided attention version of the peak-interval procedure, in which 2 stimuli were presented simultaneously in a trial and rats timed both intervals in parallel. Rats were administered 192-SAP into the NBM (n = 10) or given SHAM surgeries (n = 6). Following surgery, 192-SAP rats produced a leftward shift in timing with increased variability compared to SHAM rats. These changes in timing were observed in both focused and divided attention conditions, but the effects were larger in divided attention conditions than in focused attention conditions. Results implicate the cholinergic NBM neurons in the modulation of interval timing and divided attention. Current work is verifying the selectivity and efficacy of the 192-SAP administration. Additional studies will examine the role of GABAergic NBM neurons in interval timing and divided attention.

Related Products: 192-IgG-SAP (Cat. #IT-01)