The second set of experiments measures distinct aspects of attentional impairment following human brain lesions. The third set of experiments uses functional imaging to measure lateralized brain activity during focused attention to left or right. The most conspicuous result is activation of lateral frontal cortex ipsilateral to the direction of attention. An important component of lateral attentional control may be frontal inhibition of the unattended side. The final experiments measure attentional modulation of single neuron activity in the visual cortex of the monkey.
Results show widespread suppression of response to unattended or nontarget stimuli.