BDNF Val66Met Polymorphism Is Related to Motor System Function After Stroke.

Area of Science:

• Neuroscience
• Genetics
• Rehabilitation Medicine

Background:

• The brain-derived neurotrophic factor (BDNF) val(66)met polymorphism is associated with poorer stroke outcomes.
• The underlying mechanism may involve reduced motor system activation, as observed in healthy individuals.

Purpose of the Study:

• To investigate if the BDNF val(66)met polymorphism is associated with diminished motor system activation in stroke patients.
• To explore the genetic influence on motor system function following a stroke.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to assess brain activation during affected hand movement.
• Forty-two stroke patients, tested for the BDNF val(66)met polymorphism, underwent fMRI scans.
• Participants were an average of 12 months post-stroke with varying motor deficits.

Main Results:

• Stroke patients without the BDNF val(66)met polymorphism exhibited significantly larger brain activation volumes in motor networks compared to those with the polymorphism (334 cc vs. 97 cc).
• Reduced activation, particularly in the ipsilesional primary sensorimotor cortex, was observed in participants with the BDNF val(66)met polymorphism.
• Findings were consistent across regional analyses, showing decreased activation volume and magnitude in the ipsilesional primary sensorimotor cortex.

Conclusions:

• The BDNF val(66)met polymorphism is associated with decreased brain activation in motor networks post-stroke, mirroring findings in healthy individuals.
• This suggests that genetic factors influencing brain function persist after stroke.
• The study proposes a potential imaging-based endophenotype for the BDNF val(66)met polymorphism's motor system effects, useful for clinical trials.