Cerebral Hemodynamics and Brain Functional Activity During Lower Body Negative Pressure
Han W-Q, Hu W-D, Dong M-Q, Fu Z-J, Wen Z-H, Cheng H-W, Ma J, Ma R-S. Cerebral hemodynamics and brain functional activity during lower body negative pressure. Aviat Space Environ Med 2009; 80:698–702.
Introduction: Exposure to high +Gz acceleration forces on a centrifuge or in an aircraft can severely decrease cerebral blood perfusion and cause rapid G-induced loss of consciousness. However, milder acceleration may gradually reduce cerebral blood flow and affect cognitive function in subtler ways. This study used lower body negative pressure (LBNP) to mimic +Gz circulatory effects in order to study cerebral hemodynamics and brain function. Methods: Subjects were 15 healthy men, 19-21 yr of age. They were exposed to LBNP at two levels for 5 min each separated by a 10-min recovery period. The conditions were low (LO), −4.00 kPa (−30 mmHg) and high (HI), −6.67 kPa (−50 mmHg). Variables measured before, during, and after LBNP included cerebral blood flow velocity (CBFV) in the middle cerebral artery, blood oxygen saturation (Sao2), heart rate (HR), blood pressure, P300 of event-related EEG potentials, reaction time, and tracking error. Results: LO significantly reduced CBFV at 4 and 5 min, increased HR, and decreased the amplitude of P300, but none of the other variables changed from baseline. In contrast, HI produced significant changes in most variables: CBFV decreased at 2 min and then fell further at 4 and 5 min, HR increased, and Sao2 decreased. Significant neurocognitive changes included increased latency and reduced amplitude of P300, slower reaction time, and greater tracking error. Conclusion: The higher level of LBNP used here reduced cerebral perfusion sufficiently to impair neurocognitive function. This model may be useful for further studies of these and other variables under closely controlled conditions.
Introduction: Exposure to high +Gz acceleration forces on a centrifuge or in an aircraft can severely decrease cerebral blood perfusion and cause rapid G-induced loss of consciousness. However, milder acceleration may gradually reduce cerebral blood flow and affect cognitive function in subtler ways. This study used lower body negative pressure (LBNP) to mimic +Gz circulatory effects in order to study cerebral hemodynamics and brain function. Methods: Subjects were 15 healthy men, 19-21 yr of age. They were exposed to LBNP at two levels for 5 min each separated by a 10-min recovery period. The conditions were low (LO), −4.00 kPa (−30 mmHg) and high (HI), −6.67 kPa (−50 mmHg). Variables measured before, during, and after LBNP included cerebral blood flow velocity (CBFV) in the middle cerebral artery, blood oxygen saturation (Sao2), heart rate (HR), blood pressure, P300 of event-related EEG potentials, reaction time, and tracking error. Results: LO significantly reduced CBFV at 4 and 5 min, increased HR, and decreased the amplitude of P300, but none of the other variables changed from baseline. In contrast, HI produced significant changes in most variables: CBFV decreased at 2 min and then fell further at 4 and 5 min, HR increased, and Sao2 decreased. Significant neurocognitive changes included increased latency and reduced amplitude of P300, slower reaction time, and greater tracking error. Conclusion: The higher level of LBNP used here reduced cerebral perfusion sufficiently to impair neurocognitive function. This model may be useful for further studies of these and other variables under closely controlled conditions.
Keywords: LBNP; P300; brain function; cerebral blood flow; event related potentials; reaction time; tracking error
Document Type: Research Article
Publication date: 01 August 2009
- The peer-reviewed monthly journal, Aviation, Space, and Environmental Medicine (ASEM) provides contact with physicians, life scientists, bioengineers, and medical specialists working in both basic medical research and in its clinical applications. It is the most used and cited journal in its field. ASEM is distributed to more than 80 nations.
To access volumes 86 to present, please click here. - Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- Submit Articles
- Ingenta Connect is not responsible for the content or availability of external websites
- Access Key
- Free content
- Partial Free content
- New content
- Open access content
- Partial Open access content
- Subscribed content
- Partial Subscribed content
- Free trial content