Studies using magnetic resonance imaging (MRI) methods have found that individuals with a range of behavioral disorders including schizophrenia, depression, bipolar illness and autism have abnormal amygdala activation in response to facial emotions and other social stimuli. The amygdala, a part of the limbic brain, has emerged as one of the most critical areas influencing how we respond emotionally. It has also been shown to play an important role in emotional learning and in the attribution of emotional significance to stimuli. These MRI findings point to amygdala dysfunction as a potential neurobiological factor in the development of these disorders.
Recent evidence suggests that secretin may modulate the functional response of the amygdala. "We wanted to test the hypothesis that administration of secretin alters amygdala responsiveness to affective stimuli in healthy adult males," notes study author Deborah Yurgelun-Todd, PhD, of McLean Hospital and Harvard Medical School, Belmont, Mass.
The ability to detect and measure the effects of secretin in the brain is important in three ways. It is consistent with animal studies that report altered amygdala response after secretin administration. It also indicates that administration of this agent can be monitored using neuroimaging methods, therefore providing an important method for studying both brain and behavioral effects of secretin. Finally, and perhaps most promising given that abnormalities of amygdala function have been implicated in a variety of behavioral and psychiatric disorders, studies of secretin effects may lead to new treatment interventions for these often debilitating disorders.
"Results of our study support the hypothesis that secretin alters amygdala responsiveness to affective stimuli," concludes Yurgelun-Todd. Inducing these changes in the amygdala may be achieved through a variety of pathways.
This study was supported by Repligen Corporation.
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Editor's Notes: Dr. Yurgelun-Todd will present this research during a scientific session at the 56th Annual Meeting at 4:00 p.m. PT (7:00 p.m. ET), Tuesday, April 27, in Room 301 of the Moscone Convention Center.