title: Kinetics of exercise-induced neural activation; interpretive dilemma of altered cerebral perfusion.
abstract: Neural activation decreases cerebral deoxyhaemoglobin (HHb(C)) and increases oxyhaemoglobin concentration (O(2)Hb(C)). In contrast, patients who present with restricted cerebral blood flow, such as those suffering from cerebral ischaemia or Alzheimer's disease, and during the course of ageing the converse occurs, in that HHb(C) increases and O(2)Hb(C) decreases during neural activation. In the present study, we examined the interpretive implications of altered exercise-induced cerebral blood flow for cortical oxygenation in healthy subjects. Both O(2)Hb(C) and HHb(C) (prefrontal cortex) were determined in 11 healthy men using near-infrared spectroscopy (NIRS). Middle cerebral artery mean blood velocity (MCA V(mean)) was determined via transcranial Doppler ultrasonography. Measurements were performed during contralateral hand-grip exercise during suprasystolic bilateral thigh-cuff occlusion (Cuff+) and within 2 s of cuff release (Cuff-) for the acute manipulation of cerebral perfusion. During Cuff+, both MCA V(mean) and O(2)Hb(C) increased during exercise, whereas HHb(C) decreased. In contrast, the opposite occurred during the Cuff- manipulation. These findings highlight the inverse relationship between cerebral blood flow and cerebral oxygenation as determined by NIRS, which has interpretive implications for the kinetics underlying exercise-induced neural activation.
authors: Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama 350-8585, Japan.
authors: Taiki
authors: T
authors: Miyazawa
authors: Masahiro
authors: M
authors: Horiuchi
authors: Daisuke
authors: D
authors: Ichikawa
authors: Kohei
authors: K
authors: Sato
authors: Naoki
authors: N
authors: Tanaka
authors: Damian M
authors: DM
authors: Bailey
authors: Shigehiko
authors: S
authors: Ogoh
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D020768:Middle Cerebral Artery / Q000378:metabolism / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D010108:Oxyhemoglobins / Q000378:metabolism; D010477:Perfusion / Q000379:methods; D017397:Prefrontal Cortex / Q000378:metabolism / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology; D012119:Respiration; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen