A new study suggests that processing of negative emotions can be influenced by tweaking/tuning the excitability of brain cells located in the right frontal part of the brain.
Researchers at University of Münster, Germany used magnetic stimulation outside the brain, a technique called repetitive transcranial magnetic stimulation (rTMS), to stimulate the right frontal brain to reduce a person’s response to fearful images. Excitatory stimulation helped to manage emotions; conversely, inhibitory stimulation of this brain region is currently used to treat depression.
The study, published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, provides support for an approach clinicians use to guide treatment in depression, but has never been verified in a lab.
The investigation clarifies that the right frontal brain is a control center for the emotion-generating structures of the brain.
“This study confirms that modulating the frontal region of the brain, in the right hemisphere, directly effects the regulation of processing of emotional information in the brain in a ‘top-down’ manner,” said Cameron Carter, M.D., Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging,
“These results highlight and expand the scope of the potential therapeutic applications of rTMS,” he said.
In depression, processing of emotion is disrupted in the frontal region of both the left and right brain hemispheres (known as the dorsolateral prefrontal cortices, dlPFC). Scientist believe this area of the brain may have disrupted neural activity. When nerve cells are out of sync this may result in increased negative emotion and diminished positive emotion.
Reducing excitability of the right dlPFC using inhibitory magnetic stimulation has been shown to have antidepressant effects. Researchers explain that even though it’s based on an idea — that this might reduce processing of negative emotion in depression — the theory needs to be fully tested in humans.
The new study did just that as co-first authors Swantje Notzon, M.D., and Christian Steinberg, Ph.D, and colleagues divided 41 healthy participants into two groups to compare the effects of a single-session of excitatory or inhibitory magnetic stimulation of the right dlPFC. They performed rTMS while the participants viewed images of fearful faces to evoke negative emotion, or neutral faces for a comparison.
Excitatory and inhibitory rTMS had opposite effects; excitatory reduced visual sensory processing of fearful faces, whereas inhibitory increased visual sensory processing. Similarly, excitatory rTMS reduced participants’ reaction times to respond to fearful faces and reduced feelings of emotional arousal to fearful faces, which were both increased by inhibitory rTMS.
Although the study was limited to healthy participants, senior author Markus Junghöfer, Ph.D., noted that “…these results should encourage more research on the mechanisms of excitatory and inhibitory magnetic stimulation of the right dlPFC in the treatment of depression.”