BOLD fMRI of the Visual System in Awake & Anesthetized Rats

Der-Yow Chen¹, Stephen Dodd¹, Afonso Silva¹, Alan Koretsky¹

In the present study, we compare the BOLD fMRI of the visual system in awake and alpha-chloralose anesthetized rats. A head post was implanted to minimize the head motion and rats were trained to accustom to a restrainer. Brain activity in response to various frequencies of flashing light was explored. Awake rats showed significant fMRI activation in the lateral geniculate nucleus, superior colliculus, and the visual cortex, especially in response to high frequencies. On the contrary, less activation were found in these regions of anesthetized rats. These findings indicate that fMRI experiments in awake rats may be more appropriate to study the function of visual system.