Neurobiological and behavioural aspects of social aggression in healthy volunteers

Social aggression poses a major threat for individuals and society. The
investigation of
the psychobiological underpinnings of this destructive phenomenon is thus of
critical
importance. Recent evidence suggests that hormonal imbalances in steroid
hormones
and aberrant forms of cortical brain communication are associated with social
aggression. However, although the steroid hormones testosterone, cortisol and
estradiol are known to influence information transfer in the brain, the
interrelationships between steroid hormones, brain communication and social
aggression have never been studied directly.

Testosterone, cortisol and estradiol are known to influence information
transfer in the brain, the interrelationships between steroid hormones, brain
communication and social aggression have never been studied directly.
The present study aims to elucidate these relationships using transcranial
magnetic
stimulation (TMS) which is a unique method to measure functional connectivity
in the
human brain. Communication between the cortical hemispheres communication will
be the main dependent variables in the described series of substudies.

Experimental design: hypothesis driven correlational design.
Experimental sessions include: Intake, oral explanation of experimental
procedure, informed consent. Administration of questionnaires, motor treshold
determination, pp-TMS, behavioral tasks.

The main concern when using TMS is its potential to induce a seizure. Safety
guidelines, including the limits of stimulation intensity, monitoring of
subjects, medical management of induced seizures and contraindications to TMS
as described by the International Federation of Clinical Neurophysiology will
be
followed strictly, to minimize seizure risk. Other potential adverse effects of
TMS include induction of a muscle tension headache. These are generally mild
discomforts that respond promptly to common analgesics. It should furthermore
be
noted that volunteers can withdraw from the study at any given time.