The effects of age and postural constraints on prehension

Origin, identity, and function of terminal Schwann cells

The highly specialized nonmyelinating glial cells present at somatic peripheral nerve endings, known collectively as terminal Schwann cells (TSCs), play critical roles in the development, function and repair of their motor and sensory axon terminals and innervating tissue. Over the past decades, research efforts across various vertebrate species have revealed that while TSCs are a diverse group of cells, they share a number of features among them. In this review, we summarize the state-of-knowledge about each TSC type and explore the opportunities that TSCs provide to treat conditions that afflict peripheral axon terminals.

Postural Stability When Grasping an Object While Standing: Younger and Older Adults (Fallers and Non-Fallers)

We investigated postural stability through the margin of stability (MoS) while reaching and grasping an object with increasing difficulty levels in younger, fallers and non-fallers. Forty-five individuals distributed into three groups participated in this study: younger adults (YA), non-fallers (OA), and fallers (FOA). They stood upright and reached and grasped a dowel. Six conditions combining the stability of the dowel's base and obstacles close to the dowel were manipulated to characterize different difficulty levels. We computed the MoS in both anterior-posterior (AP) and medial-lateral (ML) directions in the interval between reaching onset and dowel contact. From the MoS time series, we analyzed the minimum and maximum, including the time of occurrence of these events. The MoS was smaller for OA than for YA in both directions. In the ML direction, the minimum MoS was smaller for FOA than for YA. The minimum MoS took place earlier for FOA than YA in the AP direction. FOA and OA exhibited similar behavior with reduced MoS, suggesting impaired postural control during reaching-to-grasping in a standing posture. FOA used a more cautious strategy by reverting the MoS earlier than YA, allowing them to increase their MoS before YA when preparing to grasp the dowel.