Heritability of intracortical inhibition and facilitation.
The present twin study investigates heritability of motor cortex excitability, measured by the paired pulse transcranial magnetic stimulation technique. Specifically, intracortical facilitation (ICF) and inhibition (ICI) and corticospinal excitability were tested in monozygotic (MZ), dizygotic (DZ), and unrelated pairs (UP). Robust ICF and ICI effects were found, with a higher similarity of MZ than DZ and UP pairs. Heritability estimates (h(2)) were 0.80 for ICI and 0.92 for ICF. However, corticospinal excitability did not show significant differences between MZ and DZ pairs, whereas both significantly differed from UP. Hence, the study provides--for the first time--a clear evidence of heritable individual differences in motor cortex excitability.
Pellicciari
Maria Concetta
MC
Istituto di Ricovero e Cura a Carattere Scientifico San Giovanni di Dio, Fatebenefratelli, Brescia 25125, Italy.
Veniero
Domenica
D
Marzano
Cristina
C
Moroni
Fabio
F
Pirulli
Cornelia
C
Curcio
Giuseppe
G
Ferrara
Michele
M
Miniussi
Carlo
C
Rossini
Paolo Maria
PM
De Gennaro
Luigi
L
D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000235:genetics; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009433:Neural Inhibition / Q000235:genetics*; D011712:Pyramidal Tracts / Q000502:physiology; D011930:Reaction Time / Q000235:genetics; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D018433:Twin Studies as Topic; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*; D055815:Young Adult