Christine Esslinger | PubMed Health

PubMed2006

Brain activation during mental maze solving.

BACKGROUND: So-called Porteus mazes are used to investigate prefrontal cortex (PFC) functioning in normal subjects and patients with different neuropsychiatric disorders. Here we present data confirming the involvement of the PFC for the first time by means of functional magnetic resonance imaging (fMRI). To minimize motor-related activation, mental mazes were used. METHODS: Mazes as well as pseudo-mazes without any bifurcations were presented to 49 healthy participants during fMRI scans. RESULTS: Both, mazes as well as pseudo-mazes, activated a large network from visual to parietal regions, reflecting the dorsal stream of visual information processing. Mazes but not pseudo-mazes also activated bilateral areas of the PFC indicating their special role in decision processes. In addition, although no motor response was required during maze performance, both tasks activated subcortical and cortical motor areas. CONCLUSIONS: These tasks are suitable for investigating and specifying PFC functioning and its impairment in psychiatric disorders such as schizophrenia. In addition, mental mazes might be a suitable task for the investigation of patients with motor disturbances.

Adolescent↗

PubMed2005

Oxytocin modulates neural circuitry for social cognition and fear in humans.

In non-human mammals, the neuropeptide oxytocin is a key mediator of complex emotional and social behaviors, including attachment, social recognition, and aggression. Oxytocin reduces anxiety and impacts on fear conditioning and extinction. Recently, oxytocin administration in humans was shown to increase trust, suggesting involvement of the amygdala, a central component of the neurocircuitry of fear and social cognition that has been linked to trust and highly expresses oxytocin receptors in many mammals. However, no human data on the effects of this peptide on brain function were available. Here, we show that human amygdala function is strongly modulated by oxytocin. We used functional magnetic resonance imaging to image amygdala activation by fear-inducing visual stimuli in 15 healthy males after double-blind crossover intranasal application of placebo or oxytocin. Compared with placebo, oxytocin potently reduced activation of the amygdala and reduced coupling of the amygdala to brainstem regions implicated in autonomic and behavioral manifestations of fear. Our results indicate a neural mechanism for the effects of oxytocin in social cognition in the human brain and provide a methodology and rationale for exploring therapeutic strategies in disorders in which abnormal amygdala function has been implicated, such as social phobia or autism.

Adolescent↗