[Abstract Title]. - Society for Neuroscience

Poster
249. Dyslexia, SLI, and Other Disorders of Cognition and Behavior
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 249.20/V5
Topic: C.05.d. ADHD, SLI, dyslexia and other specific disorders of neurobehavior
Title: Voluntary physical exercise produces sex-dependent changes in attentional orienting and
social behavior in spontaneously hypertensive rats
Authors: *M. SHARMA, M. E. HOPKINS, D. J. BUCCI;
Psychological and Brain Sci., Dartmouth Col., Hanover, NH
Abstract: Voluntary physical exercise improves cognition and increases neurogenesis and the
levels of neurotrophic factors in hippocampus. We have recently examined the effects of exercise
on cognitive function in spontaneously hypertensive rats (SHR), a well-studied model of
Attention-Deficit/Hyperactivity Disorder (ADHD). SHRs exhibit locomotor hyperactivity and
have deficits in attentional function, working memory, and response inhibition that are
reminiscent of impairments typically observed in ADHD. Our recent studies also indicate that
SHRs exhibit hyper-social behavior. The present study examined the effects of voluntary wheel
running on attentional orienting and social interaction in male and female SHRs. Exercise and
control rats were housed in groups of 4 and were 8 weeks old at the start of the experiment. Rats
in the exercise groups were provided 24 hour access to a running wheel attached to the side of
the home cage for 2 weeks prior to behavioral training; control rats did not have access to a
wheel. In the attentional orienting task, rats were placed in individual chambers and first received
12 non-reinforced presentations of a visual stimulus (a panel light) over the course of a single
session. In all groups, presentation of the light evoked unconditioned orienting defined as rearing
up on the hind legs towards the light. The unconditioned orienting response habituated over the
course of the 12 trials as the rats learned that it had no behavioral relevance. Overall, female
SHR rats exhibited more rearing behavior than males. Physical exercise reduced the amount of
rearing observed in females but did not affect rearing behavior in males. In the second phase of
the experiment the light was paired with the delivery of food reward. There were no effects of
exercise on conditioned responding and male and female rats exhibited similar levels of
conditioning. In the social interaction task, the same SHR rats were placed individually in an
open field arena for 10 min with a Wistar-Kyoto rat (control strain) of the same sex. Exercise
decreased the amount of social interaction exhibited by both male and female SHRs. Subsequent
analyses indicated that there were no sex differences or effects of exercise on locomotor activity,
indicating that the results of the orienting and social interactions studies cannot be attributed to
exercise-induced changes in activity or fatigue. Together, these data indicate that exercise has
beneficial effects on cognitive and social function in SHRs. Moreover, the sex differences in
attentional orienting behavior are in line with recent studies indicating that females diagnosed
with ADHD are more cognitively impaired than males.