Vision and proprioception do not influence the excitability of the corticomotoneuronal pathway during upright standing in young and elderly adults

Age-related decrease in motor cortical inhibition during standing under different sensory conditions

“…As the TA exhibits nearly similar density of corticospinal projections as hand muscles (Brouwer and Ashby, 1992; Petersen et al, 2003), results of the present study support the hypothesis of a specific reduction in SICI for muscles with rich corticospinal projections, suggesting that aging further strengthens the corticomotoneuronal pathway by diminishing intracortical inhibition. Nonetheless, this may also reflect a greater contribution of this pathway during upright standing, regardless of leg muscles (Baudry et al, 2014b). …”

“…Many factors have been identified to contribute to the age-related deterioration of postural control, including reduced muscle strength (Boelens et al, 2013), impaired sensory abilities (Proske and Gandevia, 2012), slowed nerve conduction velocity (Nardone et al, 1995), and altered spinal reflexes (Koceja et al, 1995; Baudry and Duchateau, 2012). In addition, the excitability of the corticospinal pathway, including the direct projections (monosynaptic) from cortical neurons to spinal motor neurons, is greater in old compared with young adults during upright standing (Baudry et al, 2014a,b). It is unknown if, in addition to age-related changes in the corticospinal pathway, aging also influences intracortical circuits during upright standing.…”

Aging Changes the Contribution of Spinal and Corticospinal Pathways to Control Balance

“…This is consistent with the results on the excitability of the cortical neurons that directly projects to the The increase in MEP amplitude between seated and standing posture was similar between age groups (P > 0.05). The MEP amplitude is expressed relative to spinal motor neurons during upright standing in different balance conditions (vision/no vision, rigid support/foam support) (5). Regardless of the conditions, the responsiveness of this descending pathway was greater in older rather than young adults and was associated (r 2 = 0.47, P < 0.001) with the background EMG activity of the soleus muscle that was greater in older adults.…”

Effects of short-term training combining strength and balance exercises on maximal strength and upright standing steadiness in elderly adults

“…Subjects stood with the arms at their sides and were instructed to refrain from performing any head or limb movements; this was aided by asking them to fix a target positioned at eye level 1.5 m in front of them. (Baudry and Duchateau, 2012;Baudry et al, 2014b).…”