PubMed | Institute Neurociencias Of Castilla Y Leon Salamanca
Type: | Journal: Frontiers in neuroanatomy | Year: 2010
We tested whether lesions of the excitatory glutamatergic projection from the auditory cortex (AC) to the inferior colliculus (IC) induce plastic changes in neurons of this nucleus. Changes in neuronal activation in the IC deprived unilaterally of the cortico-collicular projection were assessed by quantitative c-Fos immunocytochemistry. Densitometry and stereology measures of sound-induced c-Fos immunoreactivity in the IC showed diminished labeling at 1, 15, 90, and 180days after lesions to the AC suggesting protein down-regulation, at least up to 15days post-lesion. Between 15 and 90days after the lesion, c-Fos labeling recovers, approaching control values at 180days. Thus, glutamatergic excitation from the cortex maintains sound-induced activity in neurons of the IC. Subdivisions of this nucleus receiving a higher density of cortical innervation such as the dorsal cortex showed greater changes in c-Fos immunoreactivity, suggesting that the anatomical strength of the projection correlates with effect strength. Therefore, after damage of the corticofugal projection, neurons of the IC down-regulate and further recover sound-induced c-Fos protein expression. This may be part of cellular mechanisms aimed at balancing or adapting neuronal responses to altered synaptic inputs.