John Semmler

Associate Professor John Semmler

Associate Professor

School of Biomedicine

Faculty of Health and Medical Sciences

Eligible to supervise Masters and PhD - email supervisor to discuss availability.


I am a teaching and research academic with expertise that spans Neuroscience, Physiology and Exercise Science disciplines. My research involves detailed human physiological studies on the mechanisms responsible for changes in motor performance throughout the lifespan. This research is regularly supported by major funding bodies, is presented at numerous national and international conferences, and is published in the best journals in the field. I have a long history of successful research supervision and training, which includes mentoring externally funded research fellows, graduating numerous PhD students, and regularly supporting honours and undergraduate placements in the laboratory. I have also held numerous senior University administrative roles, such as the Convenor of the University of Adelaide Human Research Ethics Committee, and I serve on the editorial board of the Journal of Applied Physiology.

NEUROPHYSIOLOGY OF HUMAN MOVEMENT GROUP

I am an experienced neurophysiologist and Director of the Neurophysiology of Human Movement group. Research within this group focuses on the neural mechanisms responsible for changes in human movement throughout the life span. We specialise in the use of brain stimulation techniques to painlessly and non-invasively measure and modify the brain’s control of skeletal muscles under diverse conditions, such as ageing, exercise, training, fatigue and mild traumatic brain injury. The overall goal is to understand how the healthy nervous system functions to control movements in different situations, and how it may adapt in conditions involving neurological or neuromuscular injury.

AVAILABLE PROJECTS

Project 1

Title: Brain plasticity and motor function in older adults

Description: Recent studies from our group show that specific brain circuits important for motor system plasticity are altered in older adults. Do changes in these circuits contribute to impaired motor performance and learning in older adults? Can we modify plasticity and learning by strengthening these circuits in older adults? Several studies using brain stimulation and electroencephalography (EEG) in human participants are planned to address these research questions. These projects are funded by the Australian Research Council (ARC).

Projects available for: Honours and HDR

Location: Helen Mayo Building (Frome Rd)

Research project start: Semester 1 and 2

Special Requirements: None.

 

Project 2

Title: Neurophysiology of Exercise

Description: It is now well accepted that physical activity and exercise is capable of providing benefits to the central nervous system (CNS) that can maintain or enhance brain and motor function. However, it is not known how different types of exercise (aerobic, fatiguing, eccentric) influences brain and motor function. Several studies using brain stimulation, electroencephalography (EEG) and motor skill learning will be performed to examine the neural mechanisms that influence brain and motor function with different types of exercise in humans.

Projects available for: Honours and HDR

Location: Helen Mayo Building (Frome Rd)

Research project start: Semester 1 and 2

Special Requirements: None.

 

Project 3

Title: Factors Influencing Motor Skill Learning in Humans

Description: The ability to learn new motor skills is a fundamental requirement for participation in modern society, but this ability often deteriorates with neurological injury. Many factors are known to influence motor skill learning even in healthy individuals, such as practice structure, fatigue, handedness, exercise, gender and advancing age. The aim of this project is to explore one or more of these factors in an effort to understand the parameters that produce the optimum conditions for improved motor skill learning in humans.

Projects available for: Undergraduate

Location: Helen Mayo Building (Frome Rd)

Research project start: Semester 1 or 2

Special Requirements: None.

 

CURRENT RESEARCH PROJECTS AND COLLABORATORS

  • Brain Plasticity and Connectivity in Older Adults (Opie, Ziemann, Semmler).  To investigate the role of age-related changes in specific brain networks to differences in motor performance and learning.
  • Motor Cortex Excitability and Lower Limb Muscles (Hand, Opie, Sidhu, Semmler). To investigate the TMS parameters for optimal stimulation of cortical representations to lower limb muscles.
  • Brain Plasticity and Learning in Endurance Athletes (Hand, Opie, Sidhu, Semmler). To examine the effect of chronic endurance training on motor cortical plasticity and motor skill learning.
  • Acute Exercise and Plasticity in Endurance Athletes (Hand, Opie, Sidhu, Semmler).  To examine the effect of acute exercise on motor cortical plasticity in experienced cyclists.
  • Ageing and TMS-Induced I wave Facilitation (Sasaki, Opie, Hand, Semmler). To examine the relationship between the modulation of late I-waves and short-interval intracortical facilitation in young and old adults.
  • Intracortical Inhibition and TMS-EEG (Sasaki, Opie, Semmler). To examine the relationship between different measures of intracortical inhibition and the TMS-evoked EEG potential.
  • Mild Traumatic Brain Injury and Brain Plasticity (Opie, Foo, Vo, Gatley, Semmler). To investigate if the hyperplasticity previously observed within motor cortex following mTBI varies over time, and to assess relationships with functional deficiencies.
  • Mild Traumatic Brain injury within Cognitive Domains (Opie, Foo, Vo, Gatley, Semmler). To assess effects of mTBI on neuroplasticity and intracortical function within premotor cortex, and to investigate how physiological alterations contribute to functional deficits.
  • Age-related Changes in Cerebellar-Motor Connectivity (Opie, Semmler). To investigate if the ageing process alters the magnitude or modulation of cerebellar-cortical connectivity, and to assess if such changes contribute to reductions in cortical plasticity and motor learning.  
  • Predicting Brain Plasticity in Older Adults (Fujiyama, Hinder, Vallence, Sidhu, Opie, Semmler). To assess the validity of two different screening procedures for predicting the response to transcranial direct current stimulation in older adults.
  • Fatigue and Brain Function in Older Adults (Otieno, Semmler, Sidhu). To quantify the change in cortical inhibition and motor learning with fatigue in younger and older adults.
  • Cerebellum and Intracortical Excitation in M1 (Liao, Semmler, Opie). To assess the influence of cerebellar projections on I-wave plasticity and excitability.
    Expand
  • Journals

    Year Citation
    2021 Otieno, L. A., Semmler, J. G., & Sidhu, S. K. (2021). Single joint fatiguing exercise decreases long but not short-interval intracortical inhibition in older adults.. Exp Brain Res, 239(1), 47-58.
    DOI Scopus1 WoS1 Europe PMC1
    2021 Sghirripa, S., Graetz, L., Merkin, A., Rogasch, N. C., Semmler, J. G., & Goldsworthy, M. R. (2021). Load-dependent modulation of alpha oscillations during working memory encoding and retention in young and older adults. Psychophysiology, 58(2), 1-15.
    DOI Scopus2 WoS2 Europe PMC1
    2021 Sghirripa, S., Graetz, L., Merkin, A., Rogasch, N. C., Ridding, M. C., Semmler, J. G., & Goldsworthy, M. R. (2021). The role of alpha power in the suppression of anticipated distractors during verbal working memory. Brain Topography: journal of functional neurophysiology, 34(1), 102-109.
    DOI
    2021 Opie, G. M., & Semmler, J. G. (2021). Preferential activation of unique motor cortical networks with transcranial magnetic stimulation: a review of the physiological, functional, and clinical evidence. Neuromodulation, 24(5), 813-828.
    DOI Scopus1 WoS4 Europe PMC2
    2021 Opie, G. M., Sasaki, R., Hand, B. J., & Semmler, J. G. (2021). Modulation of motor cortex plasticity by repetitive paired-pulse TMS at late I-wave intervals is influenced by intracortical excitability. Brain Sciences, 11(1), 121-1-121-14.
    DOI Scopus1 WoS1 Europe PMC1
    2021 Semmler, J. G., & Opie, G. M. (2021). Boosting brain plasticity in older adults with non-invasive brain co-stimulation. Clinical Neurophysiology, 132(6), 1334-1335.
    DOI
    2021 Sghirripa, S., Graetz, L., Rogasch, N., Semmler, J., & Goldsworthy, M. (2021). Does predictive cueing of encoding stimulus duration modulate alpha power and facilitate visual working memory performance in younger and older adults?.
    DOI
    2021 Opie, G. M., Liao, W. -Y., & Semmler, J. G. (2021). Interactions between cerebellum and the intracortical excitatory circuits of motor cortex: a mini-review. The Cerebellum, 1-8.
    DOI Scopus2 WoS2 Europe PMC2
    2021 Semmler, J. G., Hand, B. J., Sasaki, R., Merkin, A., & Opie, G. M. (2021). Age-related changes in motor cortex plasticity assessed with non-invasive brain stimulation: an update and new perspectives. Experimental Brain Research, 239(9), 2661-2678.
    DOI
    2021 Merkin, A., Sghirripa, S., Graetz, L., Smith, A., Hordacre, B., Harris, R., . . . Goldsworthy, M. (2021). Age differences in aperiodic neural activity measured with resting EEG.
    DOI
    2021 Hand, B. J., Opie, G. M., Sidhu, S. K., & Semmler, J. G. (2021). Motor cortex plasticity and visuomotor skill learning in upper and lower limbs of endurance-trained cyclists. European Journal of Applied Physiology, 16 pages.
    DOI
    2020 Cirillo, J., Semmler, J. G., Mooney, R. A., & Byblow, W. D. (2020). Primary motor cortex function and motor skill acquisition: insights from threshold-hunting TMS. Experimental Brain Research, 238(7-8), 1745-1757.
    DOI Scopus4 Europe PMC2
    2020 Opie, G. M., Pourmajidian, M., Ziemann, U., & Semmler, J. (2020). Investigating the influence of paired-associative stimulation on multi-session skill acquisition and retention in older adults. Clinical Neurophysiology, 131(7), 1497-1507.
    DOI Scopus4 WoS4 Europe PMC2
    2020 Opie, G. M., & Semmler, J. G. (2020). Characterising the influence of cerebellum on the neuroplastic modulation of intracortical motor circuits.. PLoS One, 15(7), e0236005.
    DOI
    2020 Hand, B. J., Opie, G. M., Sidhu, S. K., & Semmler, J. G. (2020). TMS coil orientation and muscle activation influence lower limb intracortical excitability. Brain Research, 1746, 147027-1-147027-9.
    DOI Scopus4 WoS2 Europe PMC1
    2020 Opie, G. M., Otieno, L. A., Pourmajidian, M., Semmler, J. G., & Sidhu, S. K. (2020). Older adults differentially modulate transcranial magnetic stimulation-electroencephalography measures of cortical inhibition during maximal single-joint exercise. Neuroscience, 425, 181-193.
    DOI Scopus3 WoS3
    2019 Otieno, L. A., Opie, G., Semmler, J., Ridding, M., & Sidhu, S. (2019). Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition. Journal of neurophysiology, 121(2), 471-479.
    DOI Scopus7 WoS8 Europe PMC5
    2019 Opie, G. M., Foo, N., Killington, M., Ridding, M. C., & Semmler, J. G. (2019). Transcranial magnetic stimulation-electroencephalography measures of cortical neuroplasticity are altered after mild traumatic brain injury. Journal of Neurotrauma, 36(19), 2774-2784.
    DOI Scopus7 WoS7 Europe PMC4
    2019 Opie, G. M., & Semmler, J. G. (2019). Acute Exercise at Different Intensities Influences Corticomotor Excitability and Performance of a Ballistic Thumb Training Task.. Neuroscience, 412, 29-39.
    DOI Scopus13 WoS13 Europe PMC4
    2019 Opie, G. M., Hand, B. J., Coxon, J. P., Ridding, M. C., Ziemann, U., & Semmler, J. G. (2019). Visuomotor task acquisition is reduced by priming paired associative stimulation in older adults. Neurobiology of Aging, 81, 67-76.
    DOI Scopus6 WoS6 Europe PMC3
    2019 Opie, G., Hand, B., & Semmler, J. (2019). Age-related changes in late synaptic inputs to corticospinal neurons and their functional significance: a paired-pulse TMS study. Brain Stimulation, 13(1), 239-246.
    DOI Scopus9 WoS9 Europe PMC4
    2018 Opie, G., Sidhu, S., Rogasch, N., Ridding, M., & Semmler, J. (2018). Cortical inhibition assessed using paired-pulse TMS-EEG is increased in older adults. Brain Stimulation, 11(3), 545-557.
    DOI Scopus12 WoS13 Europe PMC8
    2018 Green, P., Ridding, M., Hill, K., Semmler, J., Drummond, P., & Vallence, A. (2018). Supplementary motor area—primary motor cortex facilitation in younger but not older adults. Neurobiology of Aging, 64, 85-91.
    DOI Scopus14 WoS15 Europe PMC4
    2018 Opie, G., Cirillo, J., & Semmler, J. (2018). Age-related changes in late I-waves influence motor cortex plasticity induction in older adults. The Journal of physiology, 13(13), 2597-2609.
    DOI Scopus14 WoS14 Europe PMC7
    2018 Cirillo, J., Semmler, J., Mooney, R., & Byblow, W. (2018). Conventional or threshold-hunting TMS? A tale of two SICIs. Brain Stimulation, 11(6), 1296-1305.
    DOI Scopus8 WoS6 Europe PMC3
    2017 Sidhu, S., Pourmajidian, M., Opie, G., & Semmler, J. (2017). Increasing motor cortex plasticity with spaced paired associative stimulation at different intervals in older adults. European Journal of Neuroscience, 46(11), 2674-2683.
    DOI Scopus7 WoS6 Europe PMC3
    2017 Opie, G., Vosnakis, E., Ridding, M., Ziemann, U., & Semmler, J. (2017). Priming theta burst stimulation enhances motor cortex plasticity in young but not old adults. Brain Stimulation, 10(2), 298-304.
    DOI Scopus41 WoS40 Europe PMC24
    2017 Hicks, A., Cori, J., Jordan, A., Nicholas, C., Kubin, L., Semmler, J., . . . Trinder, J. (2017). Mechanisms of the deep, slow-wave, sleep-related increase of upper airway muscle tone in healthy humans. Journal of Applied Physiology, 122(5), 1304-1312.
    DOI Scopus9 WoS9 Europe PMC6
    2017 Opie, G., Post, A., Ridding, M., Ziemann, U., & Semmler, J. (2017). Modulating motor cortical neuroplasticity with priming paired associative stimulation in young and old adults. Clinical Neurophysiology, 128(5), 763-769.
    DOI Scopus15 WoS15 Europe PMC6
    2017 Berghuis, K., Semmler, J., Opie, G., Post, A., & Hortobágyi, T. (2017). Age-related changes in corticospinal excitability and intracortical inhibition after upper extremity motor learning: a systematic review and meta-analysis. Neurobiology of Aging, 55, 61-71.
    DOI Scopus28 WoS28 Europe PMC12
    2017 Opie, G., Rogasch, N., Goldsworthy, M., Ridding, M., & Semmler, J. (2017). Investigating TMS–EEG indices of long-interval intracortical inhibition at different interstimulus intervals. Brain Stimulation, 10(1), 65-74.
    DOI Scopus25 WoS20 Europe PMC8
    2016 Redmond, C., Morris, T., Otto, C., Zerella, T., Semmler, J., Human, T., . . . Bain, G. (2016). Functional outcomes after distal biceps brachii repair: a case series. International Journal of Sports Physical Therapy, 11(6), 962-970.
    Europe PMC5
    2016 Opie, G. M., Vosnakis, E., Ridding, M. C., Ziemann, U., & Semmler, J. G. (2016). Priming theta burst stimulation enhances motor cortex plasticity in young but not old adults. Brain Stimulation.
    DOI
    2016 Opie, G., & Semmler, J. (2016). Intracortical inhibition assessed with paired-pulse transcranial magnetic stimulation is modulated during shortening and lengthening contractions in young and old adults. Brain Stimulation, 9(2), 258-267.
    DOI Scopus10 WoS11 Europe PMC4
    2016 Opie, G., Evans, A., Ridding, M., & Semmler, J. (2016). Short-term immobilization influences use-dependent cortical plasticity and fine motor performance. Neuroscience, 330, 247-256.
    DOI Scopus10 WoS11 Europe PMC7
    2016 Goldsworthy, M., Vallence, A., Hodyl, N., Semmler, J., Pitcher, J., & Ridding, M. (2016). Probing changes in corticospinal excitability following theta burst stimulation of the human primary motor cortex. Clinical Neurophysiology, 127(1), 740-747.
    DOI Scopus20 WoS20 Europe PMC13
    2016 Sale, M., Lavender, A., Opie, G., Nordstrom, M., & Semmler, J. (2016). Increased intracortical inhibition in elderly adults with anterior-posterior current flow: a TMS study. Clinical Neurophysiology, 127(1), 635-640.
    DOI Scopus26 WoS23 Europe PMC15
    2015 Opie, G., Ridding, M., & Semmler, J. (2015). Task-related changes in intracortical inhibition assessed with paired- and triple-pulse transcranial magnetic stimulation. Journal of Neurophysiology, 113(5), 1470-1479.
    DOI Scopus13 WoS12 Europe PMC8
    2015 Pitcher, J., Doeltgen, S., Goldsworthy, M., Schneider, L., Vallence, A., Smith, A., . . . Ridding, M. (2015). A comparison of two methods for estimating 50% of the maximal motor evoked potential. Clinical Neurophysiology, 126(12), 2337-2341.
    DOI Scopus22 WoS22 Europe PMC16
    2015 Kubin, L., Jordan, A., Nicholas, C., Cori, J., Semmler, J., & Trinder, J. (2015). Crossed motor innervation of the base of human tongue. Journal of Neurophysiology, 113(10), 3499-3510.
    DOI Scopus10 WoS10 Europe PMC8
    2015 Opie, G., Ridding, M., & Semmler, J. (2015). Age-related differences in pre- and post-synaptic motor cortex inhibition are task dependent. Brain Stimulation, 8(5), 926-936.
    DOI Scopus18 WoS18 Europe PMC9
    2015 Vallence, A., Goldsworthy, M., Hodyl, N., Semmler, J., Pitcher, J., & Ridding, M. (2015). Inter- and intra-subject variability of motor cortex plasticity following continuous theta-burst stimulation. Neuroscience, 304, 266-278.
    DOI Scopus63 WoS63 Europe PMC38
    2015 Woods, M., Nicholas, C., Semmler, J., Chan, J., Jordan, A., & Trinder, J. (2015). Common drive to the upper airway muscle genioglossus during inspiratory loading. Journal of Neurophysiology, 114(5), 2883-2892.
    DOI Scopus4 WoS4 Europe PMC1
    2014 Opie, G., & Semmler, J. (2014). Modulation of short- and long-interval intracortical inhibition with increasing motor evoked
    potential amplitude in a human hand muscle. Clinical Neurophysiology, 125(7), 1440-1450.

    DOI
    2014 Opie, G., & Semmler, J. (2014). Age-related differences in short- and long-interval intracortical inhibition in a human hand muscle. Brain Stimulation, 7(5), 665-672.
    DOI Scopus37 WoS36 Europe PMC26
    2014 Opie, G., & Semmler, J. (2014). Modulation of short- and long-interval intracortical inhibition with increasing motor evoked potential amplitude in a human hand muscle. Clinical Neurophysiology, 125(7), 1440-1450.
    DOI Scopus18 WoS18 Europe PMC9
    2014 Semmler, J. (2014). Motor unit activity after eccentric exercise and muscle damage in humans. Acta Physiologica, 210(4), 754-767.
    DOI Scopus21 WoS19 Europe PMC10
    2013 Trinder, J., Woods, M., Nicholas, C., Chan, J., Jordan, A., & Semmler, J. (2013). Motor unit activity in upper airway muscles genioglossus and tensor palatini. Respiratory Physiology and Neurobiology, 188(3), 362-369.
    DOI Scopus8 WoS8 Europe PMC7
    2013 Semmler, J., Ebert, S., & Amarasena, J. (2013). Eccentric muscle damage increases intermuscular coherence during a fatiguing isometric contraction. Acta Physiologica (Print Edition), 208(4), 362-375.
    DOI Scopus29 WoS27 Europe PMC16
    2013 Opie, G., Catcheside, P., Usmani, Z., Ridding, M., & Semmler, J. (2013). Motor cortex plasticity induced by theta burst stimulation is impaired in patients with obstructive sleep apnoea. European Journal of Neuroscience, 37(11), 1844-1852.
    DOI Scopus19 WoS19 Europe PMC14
    2013 McDonnell, M., Buckley, J., Opie, G., Ridding, M., & Semmler, J. (2013). A single bout of aerobic exercise promotes motor cortical neuroplasticity. Journal of Applied Physiology, 114(9), 1174-1182.
    DOI Scopus93 WoS92 Europe PMC57
    2012 Pitman, B., & Semmler, J. (2012). Reduced short-interval intracortical inhibition after eccentric muscle damage in human elbow flexor muscles. Journal of Applied Physiology, 113(6), 929-936.
    DOI Scopus14 WoS15 Europe PMC6
    2012 Cirillo, J., Hughes, J., Ridding, M., Thomas, P., & Semmler, J. (2012). Differential modulation of motor cortex excitability in BDNF Met allele carriers following experimentally induced and use-dependent plasticity. European Journal of Neuroscience, 36(5), 2640-2649.
    DOI Scopus58 WoS58 Europe PMC41
    2011 Cirillo, J., Todd, G., & Semmler, J. (2011). Corticomotor excitability and plasticity following complex visuomotor training in young and old adults. European Journal of Neuroscience, 34(11), 1847-1856.
    DOI Scopus83 WoS81 Europe PMC55
    2011 Beumer, J., Karoo, R., Caplash, Y., Semmler, J., & Taylor, J. (2011). The medial sural artery as recipient vessel and the impact on the medial gastrocnemius. Annals of Plastic Surgery, 67(4), 382-386.
    DOI Scopus7 WoS8 Europe PMC5
    2011 Carroll, T., Selvanayagam, V., Riek, S., & Semmler, J. (2011). Neural adaptations to strength training: Moving beyond transcranial magnetic stimulation and reflex studies. Acta Physiologica (Print Edition), 202(2), 119-140.
    DOI Scopus102 WoS104 Europe PMC77
    2011 Dartnall, T., Nordstrom, M., & Semmler, J. (2011). Adaptations in biceps brachii motor unit activity after repeated bouts of eccentric exercise in elbow flexor muscles. Journal of Neurophysiology, 105(3), 1225-1235.
    DOI Scopus28 WoS27 Europe PMC17
    2010 Todd, G., Kimber, T., Ridding, M., & Semmler, J. (2010). Reduced motor cortex plasticity following inhibitory rTMS in older adults. Clinical Neurophysiology, 121(3), 441-447.
    DOI Scopus65 WoS66 Europe PMC47
    2010 Cirillo, J., Rogasch, N., & Semmler, J. (2010). Hemispheric differences in use-dependent corticomotor plasticity in young and old adults. Experimental Brain Research, 205(1), 57-68.
    DOI Scopus58 WoS59 Europe PMC47
    2009 Cirillo, J., Lavender, A., Ridding, M., & Semmler, J. (2009). Motor cortex plasticity induced by paired associative stimulation is enhanced in physically active individuals. Journal of Physiology-London, 587(24), 5831-5842.
    DOI Scopus119 WoS115 Europe PMC78
    2009 Rogasch, N., Dartnall, T., Cirillo, J., Nordstrom, M., & Semmler, J. (2009). Corticomotor plasticity and learning of a ballistic thumb training task are diminished in older adults. Journal of Applied Physiology, 107(6), 1874-1883.
    DOI Scopus126 WoS120 Europe PMC82
    2009 Dartnall, T., Rogasch, N., Nordstrom, M., & Semmler, J. (2009). Eccentric Muscle Damage Has Variable Effects on Motor Unit Recruitment Thresholds and Discharge Patterns in Elbow Flexor Muscles. Journal of Neurophysiology, 102(1), 413-423.
    DOI Scopus31 WoS28 Europe PMC25
    2008 Dundon, J., Cirillo, J., & Semmler, J. (2008). Low-frequency fatigue and neuromuscular performance after exercise-induced damage to elbow flexor muscles.. Journal of Applied Physiology, 105(4), 1146-1155.
    DOI Scopus35 WoS35 Europe PMC22
    2008 Turner, T., Tucker, K., Rogasch, N., & Semmler, J. (2008). Impaired neuromuscular function during isometric, shortening, and lengthening contractions after exercise-induced damage to elbow flexor muscles. Journal of Applied Physiology, 105(2), 502-509.
    DOI Scopus18 WoS15 Europe PMC12
    2008 Dartnall, T., Nordstrom, M., & Semmler, J. (2008). Motor Unit Synchronization is Increased in Biceps Brachii after Exercise-Induced Damage to Elbow Flexor Muscles. Journal of Neurophysiology, 99(2), 1008-1019.
    DOI Scopus75 WoS70 Europe PMC57
    2007 Semmler, J., Tucker, K., Allen, T., & Proske, U. (2007). Eccentric Exercise Increases EMG Amplitude and Force Fluctuations During Submaximal Contractions of Elbow Flexor Muscles. Journal of Applied Physiology, 103(3), 979-989.
    DOI Scopus78 WoS76 Europe PMC59
    2006 Duchateau, J., Semmler, J., & Enoka, R. (2006). Training adaptations in the behavior of human motor units. Journal of Applied Physiology, 101(6), 1766-1775.
    DOI Scopus208 WoS183 Europe PMC124
    2006 Semmler, J., & Miles, T. (2006). Exercise, effort, and limb position sense. Journal of Applied Physiology, 100(4), 1099-1100.
    DOI Scopus2 WoS2
    2006 Mochizuki, G., Semmler, J., Ivanova, T., & Garland, S. (2006). Low-frequency common modulation of soleus motor unit discharge is enhanced during postural control in humans. Experimental Brain Research, 175(4), 584-595.
    DOI Scopus50 WoS50 Europe PMC34
    2006 Kidgell, D., Sale, M., & Semmler, J. (2006). Motor unit synchronization measured by cross-correlation is not influenced by short-term strength training of a hand muscle. Experimental Brain Research, 175(4), 745-753.
    DOI Scopus17 WoS16 Europe PMC11
    2006 Semmler, J., Kornatz, K., Meyer, F., & Enoka, R. (2006). Diminished task-related adjustments of common inputs to hand muscle motor neurons in older adults. Experimental Brain Research, 172(4), 507-518.
    DOI Scopus25 WoS23 Europe PMC18
    2005 Sale, M., & Semmler, J. (2005). Age-related differences in corticospinal control during functional isometric contractions in left and right hands. Journal of Applied Physiology, 99(4), 1483-1493.
    DOI Scopus125 WoS119 Europe PMC102
    2005 Mottram, C., Jakobi, J., Semmler, J., & Enoka, R. (2005). Motor-unit activity differs with load type during a fatiguing contraction. Journal of Neurophysiology, 93(3), 1381-1392.
    DOI Scopus124 WoS121 Europe PMC95
    2005 Mottram, C. J., Jakobi, J. M., Semmler, J. G., & Enoka, R. M. (2005). Erratum: Motor-unit activity differs with load type during a fatiguing contraction (Journal of Neurophysiology (March 2005) 93 (1381-1392) DOI:10.1152/jn.00837.2004). Journal of Neurophysiology, 94(1), 901.
    DOI
    2004 Semmler, J., Sale, M., Meyer, F., & Nordstrom, M. (2004). Motor-unit coherence and its relation with synchrony are influenced by training. Journal of Neurophysiology, 92(6), 3320-3331.
    DOI Scopus77 WoS75 Europe PMC66
    2003 Semmler, J., Kornatz, K., & Enoka, R. (2003). Motor-unit coherence during isometric contractions is greater in a hand muscle of older adults. Journal of Neurophysiology, 90(2), 1346-1349.
    DOI Scopus60 WoS55 Europe PMC47
    2003 Enoka, R., Christou, E., Hunter, S., Kornatz, K., Semmler, J., Taylor, A., & Tracy, B. (2003). Mechanisms that contribute to differences in motor performance between young and old adults. Journal of Electromyography and Kinesiology, 13(1), 1-12.
    DOI Scopus382 WoS363 Europe PMC288
    2002 Enoka, R., & Semmler, J. (2002). Muscle endurance after limb immobilization - Reply. Muscle & Nerve, 25(6), 923-925.
    DOI
    2002 Semmler, J. (2002). Motor unit synchronization and neuromuscular performance. Exercise and Sport Sciences Reviews, 30(1), 8-14.
    DOI Scopus150 WoS143 Europe PMC111
    2002 Semmler, J., Kornatz, K., Dinenno, D., Zhou, S., & Enoka, R. (2002). Motor unit synchronisation is enhanced during slow lengthening contractions of a hand muscle. Journal of Physiology-London, 545(2), 681-695.
    DOI Scopus102 WoS96
    2002 Bodor, M. (2002). Muscle endurance after limb immobilization.. Muscle & nerve, 25(6), 923-924.
    DOI Europe PMC1
    2002 Semmler, J. G., Kornatz, K. W., Dinenno, D. V., Zhou, S., & Enoka, R. M. (2002). Motor unit synchronisation is enhanced during slow lengthening contractions of a hand muscle.. The Journal of physiology, 545(2), 681-695.
    DOI Europe PMC82
    2001 Kern, D., Semmler, J., & Enoka, R. (2001). Long-term activity in upper and lower-limb muscles of humans. Journal of Applied Physiology, 91(5), 2224-2232.
    DOI Scopus94 WoS86 Europe PMC60
    2000 Semmler, J. G., Kutzscher, D. V., & Enoka, R. M. (2000). Limb immobilization alters muscle activation patterns during a fatiguing isometric contraction. Muscle and Nerve, 23(9), 1381-1392.
    DOI Scopus53 WoS52 Europe PMC50
    2000 Semmler, J., Steege, J., Kornatz, K., & Enoka, R. (2000). Motor-unit synchronization is not responsible for larger motor-unit forces in old adults. Journal of Neurophysiology, 84(1), 358-366.
    DOI Scopus97 WoS95 Europe PMC57
    2000 Russo, A., Smout, A., Kositchaiwat, C., Rayner, C., Sattawatthamrong, Y., Semmler, J., . . . Sun, W. (2000). The effect of hyperglycaemia on cerebral potentials evoked by rapid rectal distension in healthy humans. Journal of Dental Research, 79(4), 512-518.
    1999 Rayner, C., Smout, A., Sun, W., Russo, A., Semmler, J., Sattawatthamrong, Y., . . . Horowitz, M. (1999). Effects of hyperglycemia on cortical response to esophageal distension in normal subjects. Digestive Diseases and Sciences, 44(2), 279-285.
    DOI Scopus29 WoS25 Europe PMC22
    1999 Russo, A., Smout, A. J. P. M., Kositchaiwat, C., Rayner, C., Sattawatthamrong, Y., Semmler, J., . . . Sun, W. M. (1999). The effect of hyperglycaemia on cerebral potentials evoked by rapid rectal distension in healthy humans. European Journal of Clinical Investigation, 29(6), 512-518.
    DOI Scopus8 WoS7 Europe PMC6
    1999 Semmler, J. G., Kutzscher, D. V., & Enoka, R. M. (1999). Gender differences in the fatigability of human skeletal muscle. Journal of Neurophysiology, 82(6), 3590-3593.
    DOI Scopus66 WoS66 Europe PMC35
    1999 Kimber, T., Tsai, C., Semmler, J., Brophy, B., & Thompson, P. (1999). Voluntary movement after pallidotomy in severe Parkinson's disease. Brain, 122(5), 895-906.
    DOI Scopus29 WoS32 Europe PMC16
    1999 Semmler, J., & Nordstrom, M. (1999). A comparison of cross-correlation and surface EMG techniques used to quantify motor unit synchronization in humans. Journal of Neuroscience Methods, 90(1), 47-55.
    DOI Scopus42 WoS41 Europe PMC37
    1998 Semmler, J., & Nordstrom, M. (1998). Hemispheric differences in motor cortex excitability during a simple index finger abduction task in humans. Journal of Neurophysiology, 79(3), 1246-1254.
    DOI WoS47 Europe PMC30
    1998 Semmler, J., & Nordstrom, M. (1998). Motor unit discharge and force tremor in skill- and strength-trained individuals. Experimental Brain Research, 119(119), 27-38.
    DOI Scopus155 WoS142 Europe PMC118
    1998 Russo, A., Smout, A. J. P. M., Kositchaiwat, C., Sattawatthamrong, Y., Rayner, C., Semmler, J., . . . Sun, W. M. (1998). The effect of hyperglycemia on cerebral potentials evoked by rapid rectal distension in healthy humans.. GASTROENTEROLOGY, 114(4), A828.
    DOI
    1998 Rayner, C. K., Smout, A. J. P. M., Sun, W. M., Russo, A., Semmler, J., Sattawatthamrong, Y., . . . Horowitz, M. (1998). Effects of hyperglycemia on the cortical response to esophageal distension.. GASTROENTEROLOGY, 114(4), A826.
    DOI
    1998 Semmler, J., & Nordstrom, M. (1998). Hemispheric differences in motor cortex index finger abduction task in humans. Journal of Neurophysiology, 79(3), 1246-1254.
    DOI Scopus50
    1998 Tsai, C., Semmler, J., Kimber, T., Thickbroom, G., Stell, R., Mastaglia, F., & Thompson, P. (1998). Modulation of primary orthostatic tremor by magnetic stimulation of the motor cortex. Journal of Neurology, Neurosurgery and Psychiatry, 64(1), 33-36.
    DOI Scopus33 WoS26 Europe PMC20
    1997 Semmler, J., Nordstrom, M., & Wallace, C. (1997). Relationship between motor unit short-term synchronization and common drive in human first dorsal interosseous muscle. Brain Research, 767(2), 314-320.
    DOI Scopus52 WoS51 Europe PMC47
    1995 Semmler, J., & Nordstrom, M. (1995). Influence of handedness on motor unit discharge properties and physiological tremor. Experimental Brain Research, 104(1), 115-125.
    DOI Scopus70 WoS66 Europe PMC51
    1994 Semmler, J., & Türker, K. (1994). Compound group I excitatory input is differentially distributed to motoneurones of the human tibialis anterior. Neuroscience Letters, 178(2), 206-210.
    DOI Scopus24 WoS24 Europe PMC19
  • Conference Papers

    Year Citation
    2019 Otieno, L. A., Semmler, J., & Sidhu, S. (2019). Age-related changed in GABA-mediated inhibition with fatiguing single joint exercise.. In Proceedings of the ANS Sensorimotor Control Satellite Meeting. Adelaide.
    2011 Trinder, J., Nicholas, C., Heckel, L., Jordan, A., Woods, M., Waloszek, J., . . . Semmler, J. (2011). Common pre-motor drive to genioglossus and tensor palatini motor neurons. In JOURNAL OF SLEEP RESEARCH Vol. 20 (pp. 19-20). Sydney, AUSTRALIA: WILEY-BLACKWELL.
  • Conference Items

    Year Citation
    2009 Todd, G., Kimber, T., Ridding, M., & Semmler, J. (2009). Reduced motor cortex plasticity following inhibitory rTMS in older adults. Poster session presented at the meeting of Journal of Physiological Sciences. Kyoto, Japan: Springer.

I have enjoyed regular support from major funding bodies since 2002. I have been awarded 1 NIH RO1 grant (Co-Principal Investigator), 3 NHMRC Project grants (2 as CIA, 1 as CIB), 3 ARC Discovery Project grants (2 as CIA, 1 as CIB), and numerous external competitive and intramural infrastructure and equipment grants; total of > $2 million in external competitive support.

Over the last 15 years I have been teaching a wide variety of courses in Neuroscience, Exercise Science and Physiology. My teaching experience includes subject coordination, curriculum development, preparation and delivery of lectures, tutorials and laboratory classes, student assessment and mentorship. In these roles, I have developed and implemented a teaching philosophy that supports engaging students in the science, and teaching techniques involving blended learning and flipped classrooms to promote life-long learning. My current teaching responsibilities include the development, coordination and delivery of a third year course that contributes to a major in Neuroscience and Medical Sciences, and teaching in second year Physiology, and first year Medicine and Dentistry.

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  • Current Higher Degree by Research Supervision (University of Adelaide)

    Date Role Research Topic Program Degree Type Student Load Student Name
    2021 Principal Supervisor Modulating cortical plasticity and connectivity to improve motor learning in older adults Doctor of Philosophy Doctorate Full Time Mr Wei-Yeh Merrick Liao
    2021 Principal Supervisor Exercise Interventions to Manipulate Neuroplasticity in Ageing Doctor of Philosophy under a Jointly-awarded Degree Agreement with Doctorate Full Time Mrs Nishadi Nivanthika Gamage
    2019 Principal Supervisor Brain Rhythms and Cognition in Healthy Ageing Doctor of Philosophy Doctorate Full Time Miss Sabrina Sghirripa
    2018 Principal Supervisor Impact of Fatigue on Corticospinal Excitability and Motor Skill Performance in Young and Old Adults Doctor of Philosophy Doctorate Full Time Miss Lavender Achieng Otieno
    2018 Principal Supervisor Examining the Effect of Exercise on Brain Function and Plasticity Doctor of Philosophy Doctorate Full Time Mr Brodie Hand
  • Past Higher Degree by Research Supervision (University of Adelaide)

    Date Role Research Topic Program Degree Type Student Load Student Name
    2012 - 2015 Principal Supervisor Investigating Intracortical Inhibitory Mechanisms Contributing to Age-related Deficits in Motor Function Doctor of Philosophy Doctorate Full Time Dr George McKenzie Opie
    2010 - 2012 Principal Supervisor Human Motor Cortex Plasticity Induction is Influenced by Multiple Factors Doctor of Philosophy Doctorate Full Time Mr John Cirillo
    2006 - 2008 Co-Supervisor High Protein Dietary Patterns and Type 2 Diabetes Doctor of Philosophy Doctorate Full Time Mrs Karma Louise Pearce
    2006 - 2010 Principal Supervisor Motor Unit Activity and Neuromuscular Function after Exercise-Induced Damage to Elbow Flexor Muscles Doctor of Philosophy Doctorate Full Time Ms Tamara Dartnall
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  • Committee Memberships

    Date Role Committee Institution Country
    2020 - ongoing Member Adelaide Medical School Research Committee The University of Adelaide Australia
    2013 - 2014 Chair Human Research Ethics Committee University of Adelaide Australia
    2006 - 2014 Member Human Research Ethics Committee University of Adelaide
  • Editorial Boards

    Date Role Editorial Board Name Institution Country
    2020 - ongoing Board Member Experimental Brain Research The University of Adelaide Australia
    2006 - ongoing Board Member Journal of Applied Physiology
  • Position: Associate Professor
  • Phone: 83137192
  • Email: john.semmler@adelaide.edu.au
  • Fax: 8313 4362
  • Campus: North Terrace
  • Building: Helen Mayo South, floor 4
  • Room: S418
  • Org Unit: Medical Sciences

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