Age-dependent changes in the neural correlates of force modulation: An fMRI study

Abstract

Functional imaging studies in humans have demonstrated widespread age-related changes in cortical motor networks. However, the relative contribution of cortical regions during motor performance varies not only with age but with task parameters. In this study, we investigated whether motor system activity during a task involving increasingly forceful hand grips was influenced by age. Forty right-handed volunteers underwent functional magnetic brain imaging whilst performing repetitive isometric hand grips with either hand in separate sessions. We found no age-related changes in the average size and shape of the task-related blood oxygen level dependent (BOLD) signal in contralateral primary motor cortex (M1), but did observe reduced ipsilateral M1 deactivation in older subjects (both hands). Furthermore, task-related activity co-varied positively with force output in a number of brain regions, but was less prominent with advancing age in contralateral M1, cingulate sulcus (both hands), sensory and premotor cortices (right hand). These results indicate that a reduced ability to modulate activity in appropriate motor networks when required may contribute to age-related decline in motor performance.

Aging effects on the control of grip force magnitude: An fMRI study

“…This area has been shown to be active in motor tasks involving the hand and the foot and in tasks where the recognition of motor pattern is required (Binkofski and Buccino, 2006). This finding that the older adult group displayed greater activation in this area, could indicate an increased amount of processing by premotor circuitry to produce the same force output as the younger group.A common finding in fMRI studies of age related differences in motor control tasks is that older adults show higher levels of bilateral activation of the SMC (Kim et al, 2010;Naccarato et al, 2006;Ward et al, 2008). The present study found that there were no significant age related differences in the activity level of the ipsilateral sensorimotor cortex.…”

“…A number of studies have found a greater reliance on the ipsilateral primary sensorimotor cortex (SMC) in older adults when compared to young adults (Hutchinson et al, 2002;Kim et al, 2010;Mattay et al, 2002;Naccarato et al, 2006;Ward et al, 2008). These tasks have included a paced thumb opposition task (Naccarato et al, 2006), a visually guided gripping task at a moderate force level of approximately 45% of the participants maximum voluntary contraction (MVC) (Ward et al, 2008), a continuous abduction/adduction task with the index finger and a wrist flexion/extension task (Hutchinson et al, 2002) and an elbow flexion and extension task (Kim et al, 2010). Taken together these data suggest that the motor control demands for these tasks require additional neural resources in older adults to achieve the same performance as younger adults.…”

“…Few studies have used fMRI to specifically analyze the effect of aging while varying the level of the target force that is required. Ward et al (2008) had participants perform a gripping task at 15%, 30% and 45% of their MVC. They found that the increase in activation of the contralateral primary motor cortex (M1), the contralateral primary sensory cortex (S1), contralateral posterior cingulate motor areas and contralateral dorsal premotor cortex in response to higher force levels is lower in magnitude for older adults.…”

Differential involvement of cortical and cerebellar areas using dominant and nondominant hands: An FMRI study

“…Previous fMRI GF studies focused on the effect of different forces applied using the DH [Keisker et al, 2009; Kuhtz‐Buschbeck et al, 2008; Spraker et al, 2012; Talelli et al, 2008; Ward et al, 2006, 2007, 2008]. In these studies, the regions responded in a linear fashion and were mainly localised with the CL M1 and IL cerebellum.…”

“…In terms of the paradigm, an external visually guided cue has been widely used in previous published work [Alahmadi et al, 2015; Galléa et al, 2008; Hilty et al, 2011; Keisker et al, 2009, 2010; Kuhtz‐Buschbeck et al, 2008; Neely et al, 2013; Spraker et al, 2007, 2009, 2012; Sulzer et al 2011; Vaillancourt et al, 2003; Ward, 2004; Ward and Frackowiak, 2003, Ward et al, 2008; Wong et al, 2007]. To underline that such motor paradigms are visually guided, they are often referred to as “visuomotor.”…”