Taylor CL, Rostron PR, Latimer MP, Winn P (2004) Behavioral characteristics of pedunculopontine tegmental nucleus lesioned and nucleus basalis magnocellularis lesioned rats in a test of vigilance. Neuroscience 2004 Abstracts 780.4. Society for Neuroscience, San Diego, CA.
Summary: Previous work has shown pedunculopontine tegmental nucleus (PPTg) lesioned rats make more omissions on a vigilance task but improve if the target is longer. We compared vigilance performance of PPTg rats with rats bearing 192 IgG Saporin lesions of the nucleus basalis magnocellularis (NbM). The task involved a period of darkness before a dim light of variable duration, followed by a bright light target. A lever press was required during the target to receive food reward, while failure to press during the target constituted an omission. Rats were pre-trained to a criterion of >70% correct and <20% omissions at 1500ms target duration. Post-lesion, rats were assessed for 10 days at 1500ms, 5 days at 4000ms, and 5 further days at 1500ms target durations. Results showed both groups increased omissions relative to controls but this effect was transient in NbM rats. The percentage of omissions in all groups was sensitive to manipulation of target duration. Because increasing target duration also increased the time allowed to make a correct response we re-coded omissions in the 1500ms task to include only those occurring a further 2500ms following target offset (making the response time frame comparable with the 4000ms task). Again, comparison with omissions from the 4000ms task continued to show target duration sensitivity. This finding lends support to PPTg as well as NbM involvement in attention. In order to address why lesioned rats made more omissions in the task we analyzed video data of behaviour at the time of the dim and bright light. Results suggest increased distraction in PPTg lesioned rats while NbM lesioned rats additionally showed failed attempts to lever press in response to the bright signal. This finding has implications for studies using short response time frames where NbM rats may not have time to recover from a failed lever press attempt.
Related Products: 192-IgG-SAP (Cat. #IT-01)