Ash Frazer

Dr Frazer's research interests are in the area of neurophysiology, genetics and exercise physiology. Her research specifically focusses on the effect of experimentally inducing homeostatic plasticity of the primary motor cortex prior to different modes of exercise (strength training, motor learning and cross-education) to improve motor function. Her research also explores how certain genetic polymorphisms (such as BDNF) affect the induction of neuroplasticity and how it relates to motor function. She uses complex electrophysiological and molecular biology techniques such as Transcranial Magnetic Stimulation, Transcranial Direct Current Stimulation and PCR. The overall aim of her research is to understand how the induction of homeostatic plasticity may affect motor learning.

Recent Publications:

1. Frazer, A, Williams, J, Spittle M, and Kidgell, DJ (2017). Cross-education of muscular strength is facilitated by homeostatic plasticity. European Journal of Applied Physiology, 117: 665–677. (Impact Factor 2.4).

2. A Frazer, D Kidgell, M Spittle, J Williams (2017). Bilateral effects of unilateral anodal tDCS on motor cortex plasticity and the cross-transfer of strength, Clinical Neurophysiology, 128 (3), e149. (Impact Factor 2.9).

3. Kidgell, D, Frazer, A, Bonnano, D, Howatson, G, and Pearce, A (2017). Corticospinal responses following strength training: a systematic review and meta-analysis. European Journal of Neuroscience, accepted, August 17. (Impact Factor, 2.94).

4. Mason, J, Frazer, A, Horvath, D, Pearce, A, Avela, J, Howatson, G, and Kidgell, D (2017). Ipsilateral corticomotor responses are confined to the homologous muscle following cross-education of muscular strength. Applied Physiology, Nutrition, and Metabolism, doi.org/10.1139/apmn-2017-047. (Impact Factor 2.6)

5. Mason, J, Frazer, A, Horvath, D, Pearce, A, Avela, J, Howatson, G, and Kidgell, D (2017). Adaptations in corticospinal excitability and inhibition are not spatially confined to the agonist muscle following strength training. European Journal of Applied Physiology, DOI: 10.1007/s00421-017-3624-Y​. (Impact Factor 2.023).

6. Kidgell, D, Frazer, A, and Pearce, A (2017). The effect of task complexity influencing bilateral transfer. International Journal of Exercise Science.

7. A Frazer, D Kidgell, M Spittle, J Williams (2017). Bilateral effects of unilateral anodal tDCS on motor cortex plasticity and the cross-transfer of strength, Clinical Neurophysiology, 128 (3), e149. (Impact Factor 2.9).

8. Coombs, T, Frazer, A, Horvath, D, Pearce, AJ, Howatson, G, and Kidgell, DJ (2016). Cross-education of wrist extensor strength is not influenced by non-dominant training in right-handers. European Journal of Applied Physiology 116:1757-69. (Impact Factor 2.4).

9. Frazer, AK, Williams, J, Spittles, M, Rantalainen, T, and Kidgell, DJ (2016). Anodal transcranial direct current stimulation of the motor cortex increases cortical voluntary activation and neural plasticity. Muscle & Nerve, 54:903-913. (Impact factor 2.8).

10. Kidgell DJ, Mason J, Frazer AK, Pearce AJ (2016). I-wave periodicity transcranial magnetic stimulation (iTMS) on corticospinal excitability. A systematic review of the literature. Neuroscience, 322: 262-272. (Impact factor 3.5).

11. Kidgell DJ, Frazer AK, Rantalainen T, Ruotsalainen I, Ahtiainen J, Avela J, Howatson G (2015). Increased cross-education of muscle strength and reduced corticospinal inhibition following eccentric strength training. Neuroscience, DOI: 10.1016/j.neuroscience.2015.05.057 (Impact factor 3.5).

12. A Frazer, T Rantalainen, D Kidgell (2015). Non-invasive brain stimulation increases cortical activation: Implications for rehabilitation. Journal of Science and Medicine in Sport 19: e18. (Impact Factor 3.8).

13. Kidgell DJ, Frazer AK, Goodwill AM, Daly RM (2013). Induction of cortical plasticity and improved motor performance following unilateral and bilateral transcranial direct current stimulation of the primary motor cortex. Neuroscience 14:64 (Impact Factor 3.1).

14. D Kidgell, A Goodwill, A Frazer, R Daly (2013). Unilateral and bilateral tDCS of the human motor cortex does not differentially modulate motor function in healthy adults. Clinical Neurophysiology 124: e107-e108. (Impact Factor 2.9

Conference Proceedings:

1. Frazer AK, Rantalainen T, Kidgell DJ (2015). Non-invasive brain stimulation increases cortical activation: implications for rehabilitation. Australian Conference of Science and Medicine in Sport, QLD, Australia.

2. Kidgell DJ, Frazer AK (2015). Increased cross-education of muscle strength and reduced corticospinal inhibition following eccentric strength training. Australian Conference of Science and Medicine in Sport, QLD, Australia.

3. Kidgell DJ, Frazer AK (2014). Ipsilateral and contralateral corticospinal response to unilateral strength training are similar for both the dominant and non-dominant limb. Australian Conference of Science and Medicine in Sport, Canberra, Australia.

4. Kidgell DJ, Frazer AK, Daly RM, Howatson G (2014). Ipsilateral motor cortical responses to TMS following short-term unilateral eccentric and concentric training strength training. 6th Exercise & Sports Science Australia Conference & Sports Dietitians Australia Update: Research to Practice, Adelaide, Australia.

Mapping the corticospinal responses following heavy-load strength training:

During the early phases of a strength training program, there is a rapid increase in muscle strength that preceeds any morphological changes. The general concensus suggests that this rapid increase in strength must occur to due changes in the nervous system, particular the primary motor cortex and the corticospinal tract.  However, to date there are no studies that have mapped the motor cortical responses to strength training from a single session to weeks, whereby there are likely to be changes at a cellular synpatic level early on to later structural changes that may occur. Understanding the timing of these adaptations are clinicaly important as they will allow for targeted exercise prescription to enhance muscle strength following neurological injury or disease.

Enhancement of motor consolidation by post-training transcranial direct current stimulation following cross-education motor training:

Applying non-invasive brain stimulation techniques such as transcranial direct current simulation prior to exercise or motor learning (a process knowns as homeostatic plasticity) improves on-line motor learning presumably by increased motor cortex plasticity. However, the long-term benefits of motor training also require complex off-line neural process that improve long-term motor performance. However, the effect of applying trancranial direct current stimulation following motor practice remains unknown. I have a series of experiments that are trying to map the effect of inducing plasticity following motor learning and its effect on the rate of motor learning. Again, this has clinical benefits as we may be able to accelerate the rate of motor learning following injury by inducing plasticity during the off-line motor learning period.