Erin Falconer, MS, PhD – Brain Blogger http://brainblogger.com Health and Science Blog Covering Brain Topics Wed, 30 May 2018 15:00:03 +0000 en-US hourly 1 https://wordpress.org/?v=4.9.6 Stressed By His Short Allele http://brainblogger.com/2009/01/12/stressed-by-his-short-allele/ http://brainblogger.com/2009/01/12/stressed-by-his-short-allele/#comments Mon, 12 Jan 2009 12:40:54 +0000 http://brainblogger.com/?p=2192 BioPsychoSocial Health CategoryThe serotonin (neurochemical) system in the brain has long been a target for interventions aimed at reducing depression and stress. Selective Serotonin Reuptake Inhibitors (SSRIs) are often used to balance mood and counteract high levels of anxiety. It is not surprising then that scientists are now finding that individual differences in the genetic makeup of this serotonin system may have a significant impact on one’s vulnerability to mental illness.

Individual differences in the genetic makeup of the serotonin system have been shown to increase one’s vulnerability to depression, anxiety and other psychiatric conditions, particularly if individuals are exposed to stressful events in their lives. Studies are showing that certain people (those that have the short allele of the serotonin transporter gene) have a greater biological reactivity to stressful events, including a larger hormonal response to stress and a greater brain reactivity to threat. In other words, both the hormonal and brain systems (amygdala) involved in fear and anxiety are more active in response to stress in those individuals who have a certain genetic makeup (short allele). This genetic difference may also account for individual differences in personality; those people who have a short allele for the serotonin transporter have been suggested to exhibit more “anxious” personality traits. This means our differences in gene function may bias our brains and our personalities to create a tendency to be more “negative,” “anxious” or reactive to stress.

StressThis begs the question: should modern medicine and psychotherapeutic approaches be extended to better account for these individual genetic variations in the stress response (and the serotonin system)? The idea that we may be able to refine our approach to medicine to account for these types of individual differences (in genetics, personality, the stress response and beyond) is pertinent to the continuing evolution of medicine and science, and one that is indeed increasingly being adopted by clinicians interested in a “personalized medicine” approach to traditional medical treatment and other forms of therapy. Furthermore, looking at a person’s biological make-up has applications for being able to better predict which individuals may be more at risk for mental health difficulties.

While the idea that our genetics may be used to tailor our individual medical treatments and to screen us for vulnerabilities could appear to some like a vision from the movie Gattaca (1997 science fiction film), such refinement in our medical approach may prove to be a significant step forward.

References

I GOTLIB, J JOORMANN, K MINOR, J HALLMAYER (2008). HPA Axis Reactivity: A Mechanism Underlying the Associations Among 5-HTTLPR, Stress, and Depression Biological Psychiatry, 63 (9), 847-851 DOI: 10.1016/j.biopsych.2007.10.008

M MUNAFO, S BROWN, A HARIRI (2008). Serotonin Transporter (5-HTTLPR) Genotype and Amygdala Activation: A Meta-Analysis Biological Psychiatry, 63 (9), 852-857 DOI: 10.1016/j.biopsych.2007.08.016

B S Shastry (2005). Pharmacogenetics and the concept of individualized medicine The Pharmacogenomics Journal, 6 (1), 16-21 DOI: 10.1038/sj.tpj.6500338

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Look Me in the Eyes – From Eye Contact to “Fear Blindness” http://brainblogger.com/2008/12/23/look-me-in-the-eyes-from-eye-contact-to-fear-blindness/ http://brainblogger.com/2008/12/23/look-me-in-the-eyes-from-eye-contact-to-fear-blindness/#comments Tue, 23 Dec 2008 16:34:00 +0000 http://brainblogger.com/?p=2134 Neuroscience and Neurology CategoryEye contact is commonly considered a sign of self-confidence and a means for emotional connection. In contrast, a person who averts their gaze is often considered shy, fearful, embarrassed or lying. Many a self-help manual has touted the power of eye contact, with direct eye contact suggested to help one quickly gain an individual’s attention, create an emotional connection and make a lasting impression. While these are quite common assumptions, scientists are only beginning to unravel the cognitive and brain processes that may underlie and corroborate the significance of eye contact.

Recent studies using brain imaging show that the normal brain may essentially “prefer” to direct attention to the faces of individuals who are engaging in direct eye contact. A direct eye gaze has been shown to rapidly activate a “social brain network”, that involves a greater engagement of brain areas that are important for emotion and attention (fusiform and amygdala). This means that the brain is very rapidly engaged by someone’s direct gaze (even at the very earliest stages of perceiving that person’s face), and that this eye contact directs the brain to put more of its emotional resources into processing that face. The evidence supports the idea that engaging in direct eye contact with someone may indeed have a very significant impact on the way in which that person notices, has an emotional reaction towards, and remembers a face.

Eye ContactInterestingly, eye contact may be so important to our social and emotional functioning that it may even explain the social and emotional disturbances in certain clinical disorders. Autistic children, for example, show very little eye contact, and this may be due to eye contact involving an over-activation of emotional brain centers (amygdala) in these children. This means that autistic children may be perceiving eye contact as a threat, which may in turn lead to problems socializing and connecting with others.

Similarly, a recent study suggests that adolescents with psychopathic traits essentially may have a “fear blindness” that is due to a deficient ability to fixate on people’s eyes. The study at the University of New South Wales assessed adolescent males who scored high on having psychopathic traits. They found that these adolescents had a reduced ability to recognize fear, and that this deficiency was explained by a reduced ability to fixate on another’s eyes. This deficiency in eye fixation was suggested to possibly be linked to a disturbance in key emotional brain centers (amygdala) in these adolescents.

They say that the eyes may be the “windows to the soul” and the “lamp of the body.” These adages may be of significant relevance to the clinical and cognitive neurosciences.

References

MARK R. DADDS, YASMEEN EL MASRY, SUBODHA WIMALAWEERA, ADAM J. GUASTELLA (2008). Reduced Eye Gaze Explains “Fear Blindness” in Childhood Psychopathic Traits Journal of the American Academy of Child & Adolescent Psychiatry, 47 (4), 455-463 DOI: 10.1097/CHI.0b013e31816407f1

Kim M Dalton, Brendon M Nacewicz, Tom Johnstone, Hillary S Schaefer, Morton Ann Gernsbacher, H H Goldsmith, Andrew L Alexander, Richard J Davidson (2005). Gaze fixation and the neural circuitry of face processing in autism Nature Neuroscience DOI: 10.1038/nn1421

N GEORGE, L CONTY (2008). Facing the gaze of others Neurophysiologie Clinique/Clinical Neurophysiology, 38 (3), 197-207 DOI: 10.1016/j.neucli.2008.03.001

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