Effects of Oxytocin and Lorazepam on Fear-related Intra-amygdalar Activity

Common and Dissociable Effects of Oxytocin and Lorazepam on the Neurocircuitry of Fear - an Ultra-high Field Imaging Study

High-potency benzodiazepines have strong anxiolytic effects accompanied by significant adverse effects including impaired cognitive function, drowsiness, dizziness and impaired motoric abilities. Importantly, the long-term use of benzodiazepines may produce dependence and withdrawal. Therefore, there is considerable scientific and public interest in identifying new anxiolytic agents.

The hypothalamic peptide oxytocin (OXT) has anxiolytic effects both in healthy participants and patients with anxiety disorders by decreasing fear-associated amygdala activity. However, so far no human study has directly compared the underlying anxiolytic mechanisms of OXT and established anxiolytic agents on amygdala activity. Importantly, the amygdala is not a homogenous structure but rather consists of several subdivisions with structural and functional differences.

Therefore, the rationale of the present project is to determine the effects of intranasal OXT and the high-potency benzodiazepine lorazepam on fear-associated responses in intra-amygdalar subregions.

Inclusion Criteria:

• healthy male volunteers
• right-handed

Exclusion Criteria:

• Current or past psychiatric illness
• Current or past physical illness
• Psychoactive medication
• Sedative medication
• MRI contraindication (e.g. metal in body, claustrophobia)