Exercise increases blood flow to locomotor, vestibular, cardiorespiratory and visual regions of the brain in miniature swine

1. The purpose of these experiments was to use radiolabelled microspheres t o measure blood flow distribution within the brain, and in particular to ar eas associated with motor function, maintenance of equilibrium, cardiorespi ratory control, vision, hearing and smell, at rest and during exercise in m iniature swine. Exercise consisted of steady-state treadmill running at int ensities eliciting 70 and 100% maximal oxygen consumption ((V) over dot (O2 ,max)). 2. Mean arterial pressure was elevated by 17 and 26% above that at rest dur ing exercise at 70 and 100% (V) over dot (O2),max, respectively. 3. Mean brain blood flow increased 24 and 25% at 70 and 100 % (V) over dot (O2,max), respectively. Blood flow was not locally elevated to cortical reg ions associated with motor and somatosensory functions during exercise, but was increased to several subcortical areas that are involved in the contro l of locomotion. 4. Exercise elevated perfusion and diminished vascular resistance in severa l regions of the brain related to the maintenance of equilibrium (vestibula r nuclear area, cerebellar ventral vermis and floccular lobe), cardiorespir atory control (medulla and pens), and vision (dorsal occipital cortex, supe rior colliculi and lateral geniculate body). Conversely, blood flow to regi ons related to hearing (cochlear nuclei, inferior colliculi and temporal co rtex) and smell (olfactory bulbs and rhinencephalon) were unaltered by exer cise and associated with increases in vascular resistance. 5. The data indicate that blood flow increases as a function of exercise in tensity to several areas of the brain associated with integrating sensory i nput and motor output (anterior and dorsal cerebellar vermis) and the maint enance of equilibrium (vestibular nuclei). Additionally, there was an inten sity-dependent decrease of vascular resistance in the dorsal cerebellar ver mis.