We have characterised the c-fos expression patterns in various centers of t
he visual pathway of adult rats monocularly stimulated either by continuous
or flickering light at different frequencies. Results show different immun
ocytochemical patterns in all centers studied, the geniculate lateral compl
ex (LGC), superior colliculus (SC) and primary visual cortex (Oc1), dependi
ng on the physical characteristics of the stimulus (blinking frequency and
light wavelength). After stimulation of the left eye, the ipsilateral pathw
ay presents a substantial density of immunoresponsive cells, which is great
er than expected with respect to the number of fibers that project ipsilate
rally from the retina to the LGC and the superficial layers of the SC. A su
rprisingly high positive immunoresponsiveness is obtained in all cases with
coherent light stimulation in the red spectrum (634 nm). (C) 2000 Elsevier
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