In the scope of the research project 347/18 - Driving synaptic plasticity in motor-to-visual neural pathways to enhance action prediction, supported by the BIAL Foundation, Alessio Avenanti published the paper Neurophysiological Markers of Premotor–Motor Network Plasticity Predict Motor Performance in Young and Older Adults in the journal Biomedicines. The study aimed to assess if plasticity in premotor–motor circuits predicts hand motor abilities in young and elderly humans. Changes in motor-evoked potentials (MEPs) during a transcranial magnetic stimulation (TMS) protocol were assessed as an index of ventral premotor cortex (PMv) and primary motor cortex (M1) network plasticity. Results showed lower motor performance and decreased PMv-M1 network plasticity in elderly adults. Moreover, findings suggest that physiological indices of PMv-M1 plasticity predict hand dexterity and speed across young and older healthy humans.
ABSTRACT
Aging is commonly associated with a decline in motor control and neural plasticity. Tuning cortico–cortical interactions between premotor and motor areas is essential for controlling fine manual movements. However, whether plasticity in premotor–motor circuits predicts hand motor abilities in young and elderly humans remains unclear. Here, we administered transcranial magnetic stimulation (TMS) over the ventral premotor cortex (PMv) and primary motor cortex (M1) using the cortico–cortical paired-associative stimulation (ccPAS) protocol to manipulate the strength of PMv-to-M1 connectivity in 14 young and 14 elderly healthy adults. We assessed changes in motor-evoked potentials (MEPs) during ccPAS as an index of PMv-M1 network plasticity. We tested whether the magnitude of MEP changes might predict interindividual differences in performance in two motor tasks that rely on premotor-motor circuits, i.e., the nine-hole pegboard test and a choice reaction task. Results show lower motor performance and decreased PMv-M1 network plasticity in elderly adults. Critically, the slope of MEP changes during ccPAS accurately predicted performance at the two tasks across age groups, with larger slopes (i.e., MEP increase) predicting better motor performance at baseline in both young and elderly participants. These findings suggest that physiological indices of PMv-M1 plasticity could provide a neurophysiological marker of fine motor control across age-groups.
