Faculty of Health

Sensorimotor neuroscience and ageing

Expertise: Sensorimotor neuroscience and ageing



Keywords

  • Human motor control
  • Ageing
  • Non-invasive brain stimulation
  • Transcranial direct current stimulation
  • TMS
  • Transcranial magnetic stimulation
  • Motor function
  • Dementia
  • Neuroplasticity

Normal ageing is associated with progressive decline in cognitive and motor functions, with even modest declines impacting negatively on quality of life and the ability to live independently. A striking feature of ageing and dementia, however, is the large variation across individuals in level of cognitive and motor performance and rate of decline. While some people show high functioning into their eighth and ninth decades, others show severe impairment and dementia early in senescence.  These differences suggest that functional decline is not an inherent consequence of ageing. 

Using our expertise in the state-of-the-art electrophysiological techniques, EEG and non-invasive brain stimulation (NBS), we are investigating the premise that variations in the efficiency of the mechanisms of neuroplasticity underlie the large individual differences that are observed in levels of performance in old age, and in the associated response to cognitive and motor skill training.

In the research, the duration and magnitude of changes in brain activity following NBS is taken as an indication of the efficiency of a person's cortical plasticity mechanisms. We are also investigating how factors such as age, genotype, physical fitness, and lifestyle influence the efficiency of cortical plasticity mechanisms.

Projects

The Ageing Brain: Plasticity and training. The use of non-invasive brain stimulation (NBS) to enhance cognitive and motor function in older adults. (Funding: ARC Discovery grant)

The study will investigate the use of transcranial direct current stimulation (tDCS), a NBS technique, to enhance cognitive and motor function in older adults. Of particular importance in the first experiment is the determination of the optimum timing of tDCS delivery to produce the greatest facilitation of cognitive or motor task performance. tDCS will be applied either immediately before, during, or immediately after task performance.


The mechanisms of repetitive transcranial magnetic stimulation: A translational approach. (Funding NHMRC project grant).

A second area of interest relates to the mechanisms of NBS. Although there has been an explosion in the use of NBS to modify cortical plasticity, the physiological mechanisms underlying the NBS-induced behavioural change are largely unknown. In collaboration with colleagues conducting animal research we are concurrently using both human and rodent models to investigate the effect of NBS protocols on brain function. In the human stream we are using EEG to measure the effects of a theta burst NBS protocol on the neural connectivity between and within brain regions. The animal stream is examining, in transgenic mice, the effect of NBS on structural synaptic plasticity in terms of the formation and enlargement of dendritic spines and axonal sprouting.


How ageing affects the role of the motor cortex in standing (Funding NHMRC Early Career Fellowship)

The role of the cerebral cortex in bipedal human standing and balance is poorly understood. An increased understanding of these processes is needed in order to provide treatment for people with balance disorders. The overall aims of this project are, firstly, to understand how the cortical contributions to standing balance change with age, and secondly, to investigate how sensory input is processed by the cortex to control balance.

  • Main contact: Dr Rebecca St George

Trust your training: Improving movement stability in older people by manipulating cognitive uncertainty through cortical stimulation, cognitive and motor learning. (Funding: Robert-Bosch (Germany) Postdoctoral Research Fellowship).

This project aims to investigate the influence of cognitive uncertainty during motor decision making on the stability of the subsequent movement in older people. Further, it aims to investigate the neural correlates of the interplay of cognitive uncertainty and movement stability. Lastly, this project aims to study the influence of cognitive or motor training on movement stability in the healthy elderly.

  • Main contact: Dr Melanie Kruger