title: Plasticity in human motor cortex is in part genetically determined.
abstract: Brain plasticity refers to changes in the organization of the brain as a result of different environmental stimuli. The aim of this study was to assess the genetic variation of brain plasticity, by comparing intrapair differences between monozygotic (MZ) and dizygotic (DZ) twins. Plasticity was examined by a paired associative stimulation (PAS) in 32 healthy female twins (9 MZ and 7 DZ pairs, aged 22.6±2.7 and 23.8±3.6 years, respectively). Stimulation consisted of low frequency repetitive application of single afferent electric stimuli, delivered to the right median nerve, paired with a single pulse transcranial magnetic stimulation (TMS) for activation of the abductor pollicis brevis muscle (APB). Corticospinal excitability was monitored for 30 min following the intervention. PAS induced an increase in the amplitudes of the motor evoked potentials (MEP) in the resting APB, compared to baseline. Intrapair differences, after baseline normalization, in the MEP amplitudes measured at 25-30 min post-intervention, were almost double for DZ (1.25) in comparison to MZ (0.64) twins (P =0.036). The heritability estimate for brain plasticity was found to be 0.68. This finding implicates that genetic factors may contribute significantly to interindividual variability in plasticity paradigms. Genetic factors may be important in adaptive brain reorganization involved in motor learning and rehabilitation from brain injury.
authors.affiliation: Department of Sport Medicine and Biology of Physical Activity, Faculty of Physical Education and Sport Science, University of Athens, Athens, Greece.
authors.forename: Julia
authors.initials: J
authors.lastname: Missitzi
authors.forename: Reinhard
authors.initials: R
authors.lastname: Gentner
authors.forename: Nickos
authors.initials: N
authors.lastname: Geladas
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Politis
authors.forename: Nikos
authors.initials: N
authors.lastname: Karandreas
authors.forename: Joseph
authors.initials: J
authors.lastname: Classen
authors.forename: Vassilis
authors.initials: V
authors.lastname: Klissouras
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008475:Median Nerve / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D009473:Neuronal Plasticity / Q000235:genetics*; D011795:Surveys and Questionnaires; D050781:Transcranial Magnetic Stimulation
chemical_list: D019208:Brain-Derived Neurotrophic Factor