SPUR 2021: Effects of chromaticity on migraineous light sensitivity


Migraine is associated with an increased sensitivity to the sensory environment – both during, and outside of, the migraine attack. Second only to the head pain, photophobia is the most debilitating symptom reported by people with migraine. Melanopsin containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are thought to play a role in migraine-associated light sensitivity, and may influence chromatic (color-specific) differences in light sensitivity. A better understanding of the effects of chromaticity in migraine-associated photophobia could have widespread benefits, including improving understanding of neural mechanisms and leading to opportunities for individualized therapies (personalized medicine). The current project will examine chromatic specificity of light sensitivity in migraine subjects. In previous work, we have found that severity of photophobia in migraine scales with disease severity, and is associated with shifts in pupillary light responses. These alterations are thought to result from centrally mediated autonomic adaptations to chronic light sensitivity. Emerging data suggests that pupillary responses to light and light sensitivity in migraineurs may be linked by differences ipRGC function. We want to follow-up this prior work by examining the chromatic-specificity of light sensitivity, and their associated pupillary responses in photophobic migraine subjects. Thus, this project will examine differences in light sensitivity in migraineurs exposed to various wavelengths of light.

Student Role

Student research assistants will participate in the design, execution, analysis, and publication of research as appropriate. Project 1 (In-Person): Laboratory based data collection of chromatic light sensitivity thresholds and pupillary light responses in migraine and normal control subjects. Migraine subjects will be tested at baseline, and during a migraine attack. Students participate in recording pupillary light responses and sensory threshold data. Analysis will involve using MATLAB, ImageJ and Excel to visualize, clean and analyze the resultant data. Responsibilities will include running and documenting data collection sessions, summarizing data collected in table and figures, summarizing research findings in reports written to the lab manager, and reviewing/discussing pertinent literature on the project.

Student Learning Outcomes & Benefits

In general, I treat summer undergraduates as if they are visiting graduate students or research interns. Thus, this will be a great experience for students who are trying to determine whether they want to go into graduate school level research. They will gain valuable experience with a number of techniques that will be valuable to potential graduate students, such as study design, recruitment, interaction with research participants, assessing PLRs, psychophysical techniques for the measurement of sensory thresholds, cleaning and analyzing data, and summarizing data. Previous research interns from our lab have gone on to successful applications to medical school and graduate school programs in bioengineering. In addition to presenting at the OUR Summer Symposium, we will ask the student to complete a final presentation for the lab based on what they have learned during their time in the lab. If the project is successful, the student may be asked to be an author on subsequent publications and international conferences where this work is presented.

Remote Contingency Plan

Project 2 (Remote): Web- and cell-phone based data collection. In this scenario, we will use a web-based application to provide a chromatic sensitivity assessment and measure pupillary responses, as well as provide a migraine diary to measure self-reports of sensory sensitivities (emphasis on visual and color sensitivity) and migraine-related symptoms at baseline and during a migraine attack. During both sessions, participants will be asked to report the details of their head pain and participate in a series of light stimuli provided by the display. Under project 2, the student will perform data collection remotely via a web-based application. Here the student’s analysis responsibilities will be similar to project 1, but will also include development of the web-based interface, followed by provision of reminders to study participants submitting remote data.

Melissa Cortez
Associate Professor (Clinical)

School of Medicine

Students in my lab benefit from mentoring activities such as: guided literature reviews, impromptu teaching discussions, teaching during lab meetings, peer mentorship from lab team members, and brainstorming sessions about research and how to improve lab protocols where students are full and valued participants. Within our lab group, the student will work directly with an assigned mentor and PI -- my goal is to teach the scientific process through a “see, do, teach” approach – provided not only by the PI, but by each member of the team. I will provide specific guidance/mentorship on the following throughout their summer experience:

  1. Scientific training - the student will get first hand training as it relates to this project, including applied neurophysiology and psychophysics methods. Core competencies will include data collection, organization, basic analysis, and interpretation. Required training in Human Subject Research and HIPAA compliance will be provided.
  2. Personal development - the student will be encouraged and guided in terms of critical thinking and experience increasing personal responsibility in their project. This will be achieved by the iterative approach of giving additional opportunities to the student during the training period, working toward independence and developing initiative.
  3. Presentation skills - the student will attend and partake in the weekly Team Lab Meetings and Journal Club meetings which will foster this goal. If successful, an expectation will be that the student submits their final research project as an abstract and poster presentation.