Abstract #21603, Date "Monday, Feb 5 2001 1:00PM - 12:00PM " Session "L17 Auditory Pathways, Cortex III "

"Enriched auditory experience increases selectivity, threshold and response strength of rat primary auditory cortex neurons "

Navzer D Engineer , Jessica Lynn Vazquez , Pritesh Pandya , Raluca Moucha , Daniel Rathbun , Michael Paul KILGARD

" Anatomical studies have shown that the richness of sensory experience has a profound effect on the development of cortical circuitry. In this study, we characterize how environmental enrichment affects spectral and temporal response properties of primary auditory cortex neurons. Specifically, we compare frequency selectivity (bandwidth), threshold, response strength, and maximum following rate from two groups of rats raised in either deprived or enriched environments. The enriched group was raised from weaning until three months in a large cage that allowed social interaction and included rich auditory stimulation from motion detectors, bells, a running wheel, and a CD player. To encourage attention to the complex sounds presented via CD player, a subset were paired with food reward. The second group was raised in a standard (impoverished) environment (two per cage with minimal auditory stimulation). Cortical responses were quantified using dense microelectrode mapping techniques. Spectral and temporal response properties of neurons in the primary auditory cortex were recorded from 50-100 sites in each animal. Rats raised in the enriched acoustic environment showed a significant A) increase in frequency selectivity (1.4 vs. 1.7 octaves BW20, p<. 01), B) decrease in intensity threshold (20.0 vs. 23.5dB SPL, p<. 01), and C) increase in the strength of responses (1.3 vs. 0.9 spikes/noise burst, p<.0001). These results indicate that even mild isolation leads to substantial degradation of responses in the primary auditory cortex. "