Human epileptic photosensitivity has been studied in several ways. (a) Visual stimulation that resembles the stimulation normally responsible for seizures, such as that from televisions or videogames, both of which typically use cathode ray tubes in which the display is created in a flickering pattern. Such stimulation is often rendered yet more epileptogenic by programmes with content that also involves flashing or patterned material. (b) Elementary visual stimuli that enable inferences to be drawn concerning the physiological trigger mechanisms. The topographic distribution of epileptiform EEG activity in response to such stimuli has complemented this approach, leading to the inference that the trigger is cortical and requires sychronised mass action of neurons. (c) Stimuli that avoid paroxysmal EEG activity and permit an investigation of the subepileptic response to visual stimuli, using the evoked potential. This has revealed abnormalities in the cortical mechanisms that control the response to strong visual stimulation. Read more...

The present study investigated differences in processing times between positive and negative outcomes to an aggressive reaction to provocation. The effects of outcome, sex, trait aggressiveness and current mood on subsequent subject-generated material were also examined. Fifty subjects read stories line by line on a computer screen. Reading time for the key sentence describing a positive or negative outcome to an aggressive reaction to provocation was recorded and subjects wrote a continuing sentence to half the stories. Subjects took less time to process the negative outcome. The positive outcome resulted in more subject-generated aggression than the negative outcome. There were few sex differences but men wrote more aggressive endings than women for the stories containing physical aggression. Trait aggressiveness was correlated with producing more aggressive content in the continuing sentence for both outcomes. Feeling peaceful was correlated with producing prosocial material to neutral stories. Subjects therefore expect a negative outcome to aggressive behaviour. Reading stories which present a positive outcome to aggression increases the accessibility of aggressive cognitions. Subjects high in trait aggressiveness are not inhibited by a negative outcome. Read more...