Postsurgical injections of GM1 gangliosides (30 mg/kg IP) reduced neither behavioral deficits in rats following bilateral ablation of the visual cortex nor the extent of retrograde degeneration of neurons in the dorsolateral geniculate nucleus that typically accompanies large lesions of the visual cortex. Our findings are in contrast to previous research, in which ganglioside treatments have been shown to enhance the rate of functional recovery after lesions in other parts of the central nervous system. The negative findings in the present experiment may be due to the disruption of normal circadian rhythms caused by occipital cortex injury.