Pain Mechanisms and Sensory NeuroscienceResearch PaperEnvironmental enrichment differentially modifies specific components of sensory-evoked activity in rat barrel cortex as revealed by simultaneous electrophysiological recordings and optical imaging in vivo
Section snippets
Animals
Male Fischer-344 rats (F344/NHsd; n=31) were used and divided into three experimental groups: non-enriched (Non-E), minimally-enriched (Min-E) and maximally-enriched (Max-E). Animals in the Min-E and Max-E groups were supplied by Harlan (Bicester, UK) at 28-days of age (n=12 in each group) whereas animals in the Non-E group were supplied at 12 months of age (n=7) and only housed briefly before being used in the VSDI/SEP study. As many countries now standardise husbandry and housing conditions
Results
Optical signals evoked by whisker deflection exhibited rapid rise time and gradual decay in all experimental groups; Fig. 1 shows the average spread of activity in Non-E and Max-E groups in response to a single stimulus. Maximal activity in the stimulated barrel in response to the single stimulus was reached by 9.67±1.5 ms (±SD) in the Non-E group, similar to that in Min-E and Max-E groups: 9.67±1.5 ms and 10.0±1.3 ms. Latencies increased slightly with low- and high-frequency stimulation
Discussion
Environmental enrichment has long been known to influence the anatomy and function of sensory systems. The current study is the first to examine how individual components of sensory-evoked cortical responses, each of which relate to specific neural generators, are individually affected. The main finding of the current study was the differential effect of enrichment on specific SEP waveforms, mainly in response to single whisker deflections but not to trains of stimuli. We also report unexpected
Acknowledgments
This work was funded by grants from the Arete Initiative at the University of Chicago, the Mind Science Foundation and the James Martin 21st Century School.
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