Brain Areas of Time-To-Contact Perception: an Awake Surgery Study

In the task, participants will see an object approaching toward them. During its movement, the object disappears, and the participants have to press a button to indicate when they estimate the object to contact with them. The motion parameters of the ball will be varied. The pre and post-surgery phases will test the participants in a long duration version of the task, approximately 30 minutes. The per surgery phase will be made of a 5 minutes version of the task, and the participants will receive a direct cortical stimulation for 4 seconds, at an intensity of 1 to 10 milliampere (mA), in the premotor ventral area, or posterior parietal cortex or somesthetic associative areas.

"The patient is first anesthetized for opening the scalp and skull, then awake. During this waking phase, the surgeon passes a few quick and simple tests to the patient, visual (for example, line bisection), language (for example, repeating a list of words) etc. While doing this task, the neurosurgeon disrupts the functioning of certain brain regions by direct electrical stimulation of the cortex in order to identify the regions whose dysfunction will have an impact on the current task.~During the operation, the areas involved in the construction of the peri-personal space will be stimulated by direct electrical stimulation, for a duration of 4 seconds at an intensity of 1 to 10 mA. These areas are:~* Ventral premotor cortex (with the exception of the primary motor cortex controlling the dominant hand, so as not to interfere with the motor response of the patient)~* Posterior parietal cortex~* Associative somesthetic areas"

The Mini Mental State Evaluation, which generally assesses the cognitive state of an individual through his 6 subtests testing both working memory, episodic and semantic praxies as well as spatio-temporal orientation capacity.

The Wechsler Adult Intelligence Scale was selected for two of its subtests: The Subtest Codes checking the processing of information, visuo-constructive abilities but also attention. The subtest Cubes evaluates the capacities of visuospatial and constructive organizations as well as the referencing of the space in relation to the subject.

The State-Trait Anxiety Inventory, consisting of two self-administered questionnaires: Questionnaire A, measuring the state of anxiety of the person on the present moment and B measuring anxiety as a character trait of the person

The Verbal Fluences test, in its oral version. Categorial and lexical fluences make it possible to quickly realize a possible lack of the word of the person as well as disturbances of working memory or the capacity of inhibition.

The board of the Corsi cubes that evaluates the non-verbal visual-spatial working memory of the participants with a reminder location that tests the visuo-spatial notebook and a reminder to who tests the central administrator of the working memory.

The neurocognitive naming test was chosen to verify correct access to both semantic memory and lexicon, as well as to test the early visual process of image processing necessary for our task.

Benton lines are commonly used to determine possible deficits in the localization of isolated objects or judgment of line direction.

The patient will finally pass a depression assessment test, answering Beck's questionnaire.