Facilitation of electric forepaw stimulation-induced somatosensory activation in rats by additional acoustic stimulation: an fMRI investigation.

The influence of scanner acoustic noise on somatosensory activation pattern in rat cortex was investigated by functional magnetic resonance imaging (fMRI) using the blood oxygenation level-dependent (BOLD) contrast. This was achieved by two approaches. The first approach was to compare a conventional, loud fMRI sequence with a new sequence, in which the noise level was reduced by about 30 dB. In the second approach, the inner ear of the animal was destroyed, resulting in deafness. We compared the activation patterns obtained with both sequences before and after cochleotomy. The activated area was larger when data were sampled with background noise, and was also larger before cochleotomy than after. Thus, facilitation of somatosensory activation is induced by additional acoustic stimulation. Magn Reson Med 44:317-321, 2000.