Transformation of Somatosensory and Visual Coordinate Systems

Study Overview
=================
Brief Summary
-----------------
Manipulation of object is a multisensory experience that includes tactile motion between the object and the fingerpad, visual motion elicited by the motion the object and the movement of the hand, and the active motor commend to control upper limb and hand conformation. It remains to be determined how such a complex interaction between touch and vision could be achieved effortlessly. In the present study, we will investigate how the motion information is transformed between touch and vision using the most novel approaches in human psychophysics, neuropsychology and monkey neurophysiology. Specifically, we will present tactile motion on primate fingerpads using a recently developed ball stimulator with a design in which we vary the direction of motion with respect to the skin surface and also vary the hand conformation and position. This setup allows us to systematically sample the possible scenarios involving coordinate transformation between the somatosensory and visual systems in conditions that could occur in hand exploration and object manipulation in daily life. We will present these tactile stimuli on normal human subject as well as stroke patients such as patients with spatial hemineglect. Finally, we will record from macaque monkeys in cortical areas that are thought to underlie the transformation of coordinates, such as the primary somatosensory cortex and posterior parietal cortex. The results of the present study will contribute to the understanding of multisensory integration and the rehabilitation for patients with impaired use of spatial information.

Official Title
-----------------
The Transformation of Coordinates Between Somatosensory and Visual Systems: a Neurophysiological Study

Conditions
-----------------
Stroke

Participation Criteria
=================
Eligibility Criteria
-----------------
For stoke patients Inclusion Criteria: stroke patients stable medical condition can cooperate in evaluation Exclusion Criteria: peripheral neuropathy limb ambulation

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| hemineglect stroke patients<br>Stroke patients with hemineglect | |
| Control stroke patients<br>Stroke patients without hemineglect | |
| Normal control<br>Normal subjects | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Perceived direction of tactile motion | Detail description for time frame of assessment: (1) for stroke patients, the assessment will be performed in average 6 months after the onset of stroke (2) for normal subjects: assessment will be done when the subject is willing to participate (3) the subject might come to the lab more than once if the experiment can not be completed in one session Assessment: We present tactile motion using tactile stimulators to (1)different digits (2)different hand conformations and (3) different hand positions relative to the trunk | Once; specifically for stroke patients, 6 months after the onset of stroke | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
coordinate system, normal