Early onset of age-related changes on neural processing in rats

Altered perceptual and emotional processing might bind impaired cognitive mechanisms during aging; however the nature of these sensory perception modifications is still unknown. In the present experiment we analyzed in rats, from early to mature life (2 to 11 months old), the response to unattended auditory evoked stimulation (Auditory evoked potential, AEP) and the power spectrum of spontaneous electroencephalogram (EEG), with the aim of unraveling the onset and target functional effects of aging. Somatosensory and cingulate cortex, mediodorsal thalamus and CA3 hippocampus were chosen for examination based on their involvement in sensory processing and age-related deficits. The main finding of this study is the early onset of age-related changes in adult rats as can be established with both AEP's and frequency analyses, and its diversity between brain regions during normal aging.

Research Highlights► It is unknown how sensory processing might be impaired by normal aging. ► An electrophysiological approach in specific target brain regions should be useful to characterize the onset of age-related changes in rats. ► Auditory evoked potentials (AEP) within the cingulated cortex are significantly enhanced as age is increased. ► Power spectrum analysis of spontaneous EEG revealed specific frequency band patterns at different ages in all brain regions evaluated. ► The onset of age-related changes on neural processing seems to occur prior to aging.