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Funded Grants

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Season, Light Exposure and Serotonin Transporter Binding

Project Overview

The serotonin transporter (5-HTT) is a protein that clears extracellular serotonin from the synapses and depletion of serotonin is associated with depressive symptoms. Previously, in healthy individuals, we discovered that 5-HTT BPNo, an index of 5-HTT levels, was greater in affect-modulating brain regions in the fall/winter compared to the spring/summer; a finding that was replicated by three independent research groups. In a pilot study, we also evaluated the effect of light therapy on 5-HTT BPNo in healthy humans and found a 15% reduction in the anterior cingulate cortex (ACC), a region which participates heavily in affective control. On the basis of these data, we propose that the winter increase in BPNo, as an index of 5-HTT levels, reflects an important mechanism underlying SAD that can be influenced by the environment (i.e. light exposure). We are investigating this phenomenon in individuals with SAD to develop strategies for prevention and treatment. Hypotheses/Methods: This project will use [1 1C] DASB positron emission tomography (PET) to measure seasonal variation in brain 5-HTT BPNo in SAD and healthy individuals. In this investigation, we will test three hypotheses; (1) in healthy humans, 5-HTT BPNo in affect-modulating brain regions will be significantly greater in winter than in summer applying a within subject design. (2) Seasonal differences in 5-HTT BPNo in affect-modulating brain regions will be greater in SAD individuals as compared to healthy subjects. (3) In SAD subjects, light therapy will be associated with a reduction in 5-HTT BPNo in affect-modulating brain regions as compared to a placebo treatment. To test the first and second hypotheses, healthy and SAD subjects will undergo two PET scans; one scan in the summer and another in the winter. To test the third hypothesis, SAD subjects will have one PET scan prior to one week of daily light therapy or placebo treatment followed by a second scan after treatment completion.

Principal Investigator

Andrea Tyrer , Centre for Addiction and Mental Health

Partners and Donors

Bell Canada

Project Complete

Season, Light Exposure and Serotonin Transporter Binding

  • Grant Type

    Capacity building grants

  • Area of research

    Mental Health

  • Disease Area

    Mental illness

  • Competition

    Bell Mental Health Research Training Awards

  • Province

    Ontario

  • Start Date

    2013

  • Total Grant Amount

    $105,000

  • Health Canada Contribution

    $52,500

Contact Us

1200 McGill College Avenue
Suite 1600, Montreal, Quebec
H3B 4G7

+1 (514) 989-2989 info@braincanada.ca

Please note all online donations will receive an electronic tax receipt, issued by Brain Canada Foundation.

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Territorial acknowledgement

The offices of Brain Canada Foundation are located on the traditional, ancestral territory of the Kanien'kehá:ka Peoples, a place which has long served as a site of meeting and exchange amongst nations. We honour and pay respect to elders past, present and emerging, and dedicate ourselves to moving forward in the spirit of partnership, collaboration, and reconciliation. In our work, we focus our efforts on the Truth and Reconciliation Commission’s Calls to Action, particularly those that pertain to improving health for Indigenous Peoples and that focus on advancing our own learning on Indigenous issues.

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