This study will use transcranial magnetic stimulation (TMS) to study how the brain controls
movement of muscles in the face-in particular, those involved in eye blinking. TMS is a
procedure that activates areas of the brain with magnetic pulses that travel through the
scalp and the skull.
Healthy normal volunteers 21 years of age and older may be eligible for this study. They
must be free of any serious medical illness, have no neurological or psychiatric disorders
or history of seizures, and must not be taking any medications that can affect nervous
Participants will undergo TMS and the electrical activity in muscles activated by the
stimulation will be recorded. For TMS, an insulated wire coil is placed on the patient's
scalp, and a brief electrical current is passed through the coil. This creates a magnetic
pulse that travels through the scalp and skull and causes small electrical currents in the
outer part of the brain. If the coil is placed over a nerve that controls muscles, there may
be a twitch in the muscles, sometimes large enough to move the face. In other cases, there
may be a feeling of movement or tingling sensation in the face. Stimulation over the muscles
on the side of the head may cause some discomfort there or twitching of the jaw. During the
stimulation, subjects may be asked to tense certain muscles slightly or perform other simple
Electrical activity of the muscles activated by the stimulation is recorded. This is done
with both metal electrodes taped to the skin over the muscle and with fine needle electrodes
inserted into the muscles around the eyes.
The study usually takes less than 3 hours, with frequent breaks. If more time is required,
the study will be broken into more than one session.
The purpose of this study is to investigate the cortical center for voluntary control of
eyelid closure using transcranial magnetic stimulation (TMS). Conventionally the primary
motor cortex (M1) has been thought to control upper facial movement . However, recent
neuroanatomical and neuroimaging studies suggest that the upper facial muscles are mainly
controlled by the mesial frontal region, not M1 . Recently, we performed a transcranial
magnetic stimulation (TMS) study to investigate the cortical center for the upper facial
muscles, especially those related to blinking, and observed possible cortical responses from
the surface electrodes attached to the orbicularis oculi (OOC) muscles with the stimulation
applied to the mesial frontal region. In this study, we are planning to use monopolar
needle electrodes to confirm that these responses originate from the cortical stimulation.
Inclusion criteria of this study are normal adult volunteers who are greater than or equal
to 21 years old.
Exclusion criteria are those who have either any medico-surgical, neurological and
psychiatric illness, who have been taking any medication with potential influence on
nervous system function;
who have a pacemaker;
an implanted medical pump;
a metal plate or a metal object in the skull or eye (for example, after brain surgery);
who have a history of seizure disorder.