The effects of frontal lesions on brain hypersynchronous bursting and behavioral activity.

Photically evoked after-discharge (PhAD) bursting was examined in lightly restrained albino rats following frontal and mid-cortical lesions. The initial effect of dorsal frontal lesions was to significantly suppress PhAD occurrence. Spontaneous activity as measured on an open-field arena was examined as a second variable. Frontally lesioned animals were significantly more active than mid-cortically lesioned and non-lesioned control animals in the initial stages of behavioral testing. These results indicate that the frontal cortex has an inhibitory influence on reticular formation (rf) arousal mechanisms which are responsible for behavioral arousal and the modulation of hypersynchronous burst-like phenomena occurring at the level of the cortex.