Supervisory team
Dr Jen Davies, Cardiff University, School of Healthcare Sciences
Dr Will Young, University of Exeter, Sport and Health Sciences
Background and project aim
Many older people become fearful of falling and develop excessive postural stiffening and cautious movement patterns. Paradoxically, this can serve to increase fall risk. We (Dr Young) have previously proposed that overly cautious gait emerges when an individual is not able to inhibit the conscious processing of stepping movements. Older adults with poor ability to inhibit a prepared movement are more likely to exhibit characteristics of cautious gait. Inhibitory networks within the motor cortex (M1) contribute to volitional inhibition of a prepared movement of the hand. However, it is not known whether these networks contribute to volitional inhibition of movements such as walking or stepping, and whether they are involved in the expression of overly cautious walking behaviour.
The overall aim of this studentship is to ask: “Is anxiety-related overly cautious walking behaviour in older adults associated with the responsiveness of inhibitory networks within M1?”
This will first be addressed in healthy adults (see Project Overview). However, the impact of fear and anxiety on movement is also pervasive across patient groups. Fear is known to be a particular problem for people with Parkinson’s disease, especially those with a specific pathology known as ‘freezing of gait’ (the feeling that one’s feet are glued to the floor). In these patients, anxiety is known to exacerbate freezing symptoms, often culminating in observable ‘knee trembling’; thought to represent defective and uninhibited attempts to produce anticipatory postural adjustments required to initiate walking. The studentship will move on to study the responsiveness of inhibitory networks within M1 in people with Parkinson’s disease and freezing of gait (see Project Overview).
Project overview
This project consist of four specific objectives: (1) Develop an ecologically valid task to evaluate the inhibition of prepared movements relevant to walking (akin to aborting a pre-planned step); (2) Evaluate whether inhibitory networks within M1 contribute to volitional inhibition of the prepared step in no-go trials; (3) Evaluate whether impaired inhibition within M1 is associated with gait characteristics indicative of cautious walking behaviour in older adults under conditions of low and high anxiety; (4) replicate objective 2 in the specific cohort of people with Parkinson’s disease and freezing of gait.
Inhibition within M1 will be evaluated using transcranial magnetic stimulation (TMS), a type of non-invasive brain stimulation that can be used to probe cortical processes with high temporal resolution. We (Dr Davies) have developed and validated a system that allows TMS during upright balance and walking. This is integrated within a gait real-time interactive laboratory at Cardiff University that provides a unique and highly valuable system with which to experimentally manipulate postural threat and probe the effects of this on the control of movement.
The system can deliver single- or paired-pulse TMS at a consistent location over M1 at defined points in a task, and the response to this stimulation can be measured using surface electromyography. The response to paired-pulse TMS indicates the responsiveness of inhibitory networks within M1. With guided support, the student will take ownership of the approaches used to evaluate inhibition of prepared movements and experimentally manipulate anxiety.
Student development
The core structure of the proposed projects has been designed to allow the student to pursue their own interests and create an emphasis of their choosing on different aspects of sensorimotor and cognitive processes. Whether you choose to specialise more in physiological or psychological mechanisms, relevant expertise is readily available within the supervisory team.
The project is highly interdisciplinary. Rarely are projects able to bridge gaps between pure physiology and both social sciences (e.g. cognitive psychology) and applied clinical sciences. The student will emerge from the PhD being well-versed in neurophysiology, psychology, computer science and healthcare (specific to ageing and neurorehabilitation).
Requirements
Applicants for a studentship must have obtained, or be about to obtain, a UK degree, or the equivalent qualification gained outside the UK, in an appropriate area of medical sciences, computing, mathematics or the physical sciences. Please check the entry requirements of the home institution for each project of interest before completing an application. Academic qualifications are considered alongside significant relevant non-academic experience.
If English is not your first language you will need to meet the English language requirements of Cardiff University by the start of the programme. Please refer to the relevant university for further information.
Enquiries and applications
Informal enquiries about the project are welcomed and should be directed to Dr Jen Davies at [Email Address Removed]
Enquires about the funding scheme or applications process should be directed to [Email Address Removed]
How to apply
A list of all available projects and how to apply is available on the GW4 website at gw4biomed.ac.uk. You may apply for up to two projects.
Please complete the online application form by 5.00pm on Wednesday, 2nd November 2022. If you are shortlisted for interview, you will be notified by Friday 16th December 2022. Interviews will be held virtually on 25th and 26th January 2023.
IMPORTANT: You do NOT need to apply to Cardiff University at this stage – only those applicants who are successful in obtaining an offer of funding from the DTP will be required to submit an application for an offer of study from Cardiff University.
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