2. Brain stimulation experiments
A. Reciprocal effects of adaptation in the brain’s motor and sensory systems
- Time commitment: One to two sessions of 2-2.5 hours each.
- Additional eligibility restrictions: Participants must be between 18—45 years of age and right-handed.
- Payment: You will receive a gift card valued at $25 per session after completing the final session.
- There are several different experiments in this study. You may be eligible to complete more than one, if you are interested.
Sensory information is necessary in order to generate appropriate movements of the body. Modulation of sensory information can serve to enhance or disrupt normal movement. In this study we will investigate the effect of different kinds of sensory information on motor regions of the brain. Before and after a reaching task, we will use transcranial magnetic stimulation (TMS) to measure the state of your motor cortex. TMS is a non-invasive brain stimulation that has been in use for decades and is considered very safe. Most people do not find it uncomfortable. For the reaching task, you will be seated at a 2D virtual reality apparatus. You will be asked to point to a series of targets you see in a mirror.
B. Effect of transcranial direct current stimulation on manual dexterity in people with autism spectrum disorders
- Time commitment: 3-4 sessions of 90 minutes each for the brain stimulation version, or 1 session of 45 minutes for the behavioral version
- Additional eligibility restrictions: Participants must be diagnosed with an autism spectrum disorder and between 18-40 years of age.
- Payment: You will receive a $30 gift card after completing the final session of the brain stimulation version, or a $5 gift card after completing the behavioral version.
- This experiment can be done in our lab at IU OR at your place of residence, according to your convenience.
Manipulating the excitability of the motor cortex may help to improve one’s control of movements of the body. In this study we will investigate the effect of noninvasive brain stimulation on a manual dexterity task. First, your proprioception will be assessed to see how you perceive where you index finger is placed in relation to a line on a computer. Second, you will be timed to see how quickly you can place twenty small pegs into a pegboard. You will perform eight trials with one minute of rest between each trial. We will place two wet sponge electrodes on your head. Then, the tDCS (transcranial direct current stimulation) will be turned on. This consists of a weak electric current that is delivered through the sponge electrodes. The tDCS will be turned off and removed once a second block of eight pegboard trials has been completed. Initially, tDCS often causes a slight itching or tingling sensation under the sponges. However, this sensation subsides after a few minutes and most people do not find it uncomfortable. tDCS has been used safely in humans for decades, with no known long-term side effects.
* In the behavioral version of the experiment, you would do only the proprioception and pegboard tasks.