Patterns of Brain Activity Associated With Variation in Voluntary Wheel-Running Behavior.

Abstract

Rodents spontaneously run on wheels, but what underlies variation within and between species is unknown. This study used Fos immunoreactivity to compare brain activity in mice selectively bred for high wheel running (S) versus control (C) mice. Mice ran for 6 days, but on Day 7, half the mice were prevented from running. A strong positive correlation was found between running distance and Fos in the dentate gyrus of C runners that was lost in S runners. In mice prevented from running, Fos was higher in S than in C in the lateral hypothalamus, medial frontal cortex, and striatum. Results implicate specific brain regions in motivation to run and others in control of the intensity of the locomotor behavior itself.Voluntary wheel running is one of the most widely studied behaviors in laboratory rodents, yet the underlying cause of variation in this behavior is not known (Sherwin, 1998). Recently, it has been proposed that wheel running is naturally rewarding and addictive

Mapping of functional brain activity in freely behaving rats during voluntary running using manganese-enhanced MRI: Implication for longitudinal studies

“…The pattern of activated brain regions was highly selective and in accordance with existing studies employing other brain imaging techniques like cerebral blood flow-related autoradiography, PET, or immunohistochemistry (Holschneider et al, 2003;Jordan, 1998;Nguyen et al, 2004;Rhodes et al, 2003). Yet, a possibility of some "false alarms" cannot be completely excluded and should be interpreted with caution, particularly in cases of significant activation detected in small brain nuclei.…”

“…The corresponding secondary cortices (M2 and S2) were also activated, however, to a lesser extent (6-7% ROI). The activation of these cortical regions was predictable and in agreement with other functional mapping studies using different brain imaging methods (Holschneider et al, 2003;Rhodes et al, 2003). Strikingly, activation was also observed in a number of brain stem structures including serotonergic nucleus dorsal raphe (36% ROI), periaqueductal grey (24% ROI) and pontine nuclei (20% ROI), which constitute a "mesencephalic locomotor region" (MLR).…”

“…The runningassociated brain activation pattern was predicted based on the results from the studies using other brain imaging techniques (Holschneider et al, 2003;Jordan, 1998;Nguyen et al, 2004;Rhodes et al, 2003). We compared the efficiency of acute s.c. injection of MnCl 2 , a common way of systemic administration in MEMRI studies, and via chronically implanted osmotic pumps, an alternative method of manganese delivery.…”

Monoamine Oxidase A Activity and Norepinephrine Level in Hippocampus Determine Hyperwheel Running in SPORTS Rats

“…Thus, dopaminergic functions might be involved in the control of exercise behavior in SPORTS rats. The DAs in the brain have been implicated in the wheel running of rodents (Rhodes et al, 2003;Leng et al, 2004). Because the hippocampus has only a small population of dopaminergic neurons, we failed to detect measurable DAs in this tissue.…”

“…The hippocampus is sensitive to stress and to physical exercise, both of which activate norepinephrine (NE) terminals deriving from the locus ceruleus (Bremner et al, 1996;Xu et al, 2000;Carter, 1997). Following exercise stimulation, a variety of changes in gene expression and NE metabolism occurred in the hippocampus (Bronikowski et al, 2004;Dunn et al, 1996;Rhodes et al, 2003). Whether hippocampal NE induces voluntary wheel running has not yet been clarified, although genetically or pharmacologically enhanced NE level in brain regions that include the hippocampus increases field locomotor activity in experimental animals (Xu et al, 2000;Cryan et al, 2004;Shishikina et al, 2004;Lahdesmaki et al, 2003;Cases et al, 1995).…”