Focal unilateral mechanical lesion in barrel cortex impairs rat's abilities to discriminate textures

Whiskers are important sensory organs that play a key role in rodents' discriminative and exploration behaviours and unilateral injuries of the somatosensory cortex related to whisker barrel cortex can change the activity of neurons in the intact contralateral barrel cortex. We evaluated the effects of unilateral mechanical lesion of right barrel cortex on novel texture discrimination in behavioural test and neuronal responses of left barrel cortex.

Ten days after a unilateral mechanical lesion in the right barrel cortex, adult male rats were experimented regarding three paired different textures in novel texture discrimination test dependent on whiskers. In addition, responses of left barrel cortical neurons to controlled deflections of right whiskers were recorded using extracellular single-unit recordings technique.

Data analysis showed that the discrimination ratio and preference indexes as criteria to find a novel texture significantly decreased in the lesion group compared to the intact rats (p < .05). In electrophysiological level, the barrel neural cortical spontaneous activity and the ON and OFF response magnitude of intact barrel cortex neurons in the lesion group decreased compared to the intact group (p < .05).

The present study showed that unilateral mechanical lesion in the rats' barrel cortex cause a decrease in their abilities for discriminating textures, as well as, the anaesthetized rats whose response properties of intact barrel cortical area changed to whisker deflection, too. These changes can influence on the ability of rats to differentiate textures.