Veit Kraft

Each of us learns new motor skills from early to old age. This can be our first steps, playing an instrument or a sporting movement. Various factors can influence how quickly we learn something and how well our brain consolidates such motor memories. For example, how these motor sequences are consolidated changes depending on the level of awareness. However, other factors influence how well we learn and consolidate motor memories, such as acute cardiovascular exercise, which arguably can have remarkably positive effects if it occurs shortly after motor learning and is highly intense. Therefore, we measure motor learning and the influence of acute cardiovascular stress on the consolidation of learned memory content. As a first step, this is done with young and healthy subjects. In a further step, we aim to investigate how such an exercise load affects participants of advanced age. In addition, we are interested in possible mechanisms that could potentially improve motor performance at the neuronal level, using transcranial magnetic stimulation to infer brain plasticity through corticospinal excitability.

Literature:

Cristini, J., Kraft, V. S., Heras, B. De, Rodrigues, L., & Parwanta, Z., Hermsdörfer, J., Steib, S. & Roig, M. (2023). Differential effects of acute cardiovascular exercise on explicit and implicit motor memory : The moderating effects of fitness level. Neurobiology of Learning and Memory, 205. doi.org/10.1016/j.nlm.2023.107846

Luisa Roeder

Humans grasp and handle numerous types of objects and tools very skilfully in daily life. For instance, we are able to pick up a glass of water without slipping, tipping, spilling or crushing the glass. Astonishingly, our nervous system is able to scale the grip force needed to lift an object highly economically and precisely. Generally, we scale our grip force so that it is just slightly higher than necessary to prevent slipping, but not too high which would cause fatigue and damage fragile objects. We usually estimate physical properties of the objects (such as weight, shape and surface) based on visual cues (e.g., size), if they are available and accurate.

Research over the past decades has identified various brain areas that are associated with the scaling of grip force according to object characteristics. But the interactions between brain areas and between brain and muscles are not clear to date.

In this study, we record electrical brain and muscle activity via electroencephalography (EEG) and electromyography (EMG), as well as grip forces during grasping and lifting of objects. We test different conditions in which object properties can either be estimated based on visual cues or not. We aim to identify dynamic brain and muscle networks during grasping.

Publications:

Schneider & Hermsdörfer (2016) https://link.springer.com/chapter/10.1007/978-3-319-47313-0_10

Roeder et al. (2018) https://journals.physiology.org/doi/full/10.1152/jn.00613.2017

Roeder et al. (2020) https://www.nature.com/articles/s41598-020-59810-w?proof=t

Kinematic analyses of activities of daily living

Stephanie Schmidle, Philipp Gulde, Joachim Hermsdörfer

Sensorimotor impairments or decline of memory, orientation, and cognitive capacity due to neurological disease can severely impair the capability of patients and lead to dependency to care. In order to thoroughly assess complex activities of daily living (e.g., data filing, preparing tea) in subject with sensorimotor and cognitive impairments, for instance apraxia and action disorganization syndrome following stroke or dementia, we combine clinical established measures (questionnaires), qualitative (observation of behavior) and quantitative methods (eye-tracking to assess gaze behavior and motion-tracking to kinematically quantify behavior). Research with healthy controls and neurological patients provide valuable knowledge and data to classify individual movement behavior and strategy, predict clinical outcomes, and develop assistive devices and environments. In long-term, we hope to improve quality of life and support independency of patients, as well as to relieve caring relatives and the health care system.

Literature: Gulde et al., Exp Brain Res (in press), Gulde et al., Frontiers in Neurol (2018),  Gulde & Hermsdörfer, Frontiers in Neurol (2018), Gulde & Hermsdörfer, Exp Brain Res (2017), Gulde et al., Frontiers in Hum Neurosci (2017), Bienkiewicz et al., Brain and Behavior (2015), Gulde et al., Eng Solutions in Neurorehabil Biosys & Biorob (2014)

Thomas Schneider, Joachim Hermsdörfer

Skilled object manipulation in everyday life is not possible without predictive consideration of the physical object properties into the planning of hand-object interaction. During grasping and lifting our finger forces have to adapt the weight and surface of the object and also must avoid object tilt, which for example would cause spillage of a lifted cup of coffee. To prevent tilt, we must predict the external torque and produce a counteracting torque already at the moment of lift-off. In our studies, we use a natural-like manipulandum, which allows overt and hidden variations of the center of gravity, to investigate finger forces and finger positions during predictive torque planning in healthy young and elderly persons as well as in patients with central nervous system diseases. We evaluate the influence of previous manipulations and of current geometric cues on the precision of torque planning. We also test the effect of different grip surfaces and the effect of ageing on the performance. In addition, we evaluate how motor planning influences the perception of object properties.

Literature: Schneider, T. & Hermsdörfer, J. (2016) Schneider, T., Buckingham, G. & Hermsdörfer, J. (2019)

Robotic light touch support during locomotion in balance impaired humans

David Kaulmann

In clinical settings, caregivers provide manual support during locomotion to patients with impaired body balance. Thus, interpersonal manual support represents an ecologically valid and effective strategy for controlling a patients' fall risk in dynamic postural activities. From a therapeutic point of view, however, restricting patient's movement degrees of freedom by grasping his body to support his weight has to be considered inadequate for the purpose of practicing own control of body balance. A more promising strategy is balance support provided in a 'light touch' fashion, for example by lightly resting a hand on the back or shoulder of a patient without taking patient's weight. We like to ask which are the qualities that make an expert healthcare provider so efficient in the provision of adaptive manual balance support? We believe the answer is associated with the ability to anticipate a patient's dynamics. The scientific aim of the research project is, therefore to improve the understanding of interpersonal dynamics of light touch in general and the caregiver-patient interaction during light interpersonal touch stabilisation in particular. Our engineering aim is the translation of the principles of human-to-human interpersonal coordination for light tactile balance support into a robotic solution. Major outcomes will be measures of the contact receiver's postural stability and interpersonal coordination with the provider but also autonomic measures of the receiver's state anxiety of falling. The later will express human acceptance of the robotic balance support.