ACTIVATION BY ATTENTION OF THE HUMAN RETICULAR-FORMATION AND THALAMICINTRALAMINAR NUCLEI

It has been known for over 45 years that electrical stimulation of the midbrain reticular formation and of the thalamic intralaminar nuclei of the brain alerts animals. However, lesions of these sectors fail to impair arousal and vigilance in some cases, making the role of the as cending activating reticular system controversial. Here, a positron em ission tomographic study showed activation of the midbrain reticular f ormation and of thalamic intralaminar nuclei when human participants w ent from a relaxed awake state to an attention-demanding reaction-time task. These results confirm the role of these areas of the brain and brainstem in arousal and vigilance.