Associate Lecturer
Overview
Jacob is currently a teaching and research academic within the School of Biomedical Sciences at The University of Queensland and is looking to recruit prospective honours students interested in studying the neurophysiology of human movement. Potential students can send him an email (j.thorstensen@uq.edu.au) to chat about projects on offer, or to suggest an idea for a project.
Jacob’s PhD was in human neurophysiology (Griffith University, Australia), where he studied how endogenously released neuromodulators (e.g., monoamines such as serotonin and dopamine) control the excitability of cortico-motoneuronal pathways and muscle activation in healthy human subjects. Jacob also has postdoctoral training in clinical neuroscience (through The University of Queensland, based at the Queensland Children’s Hospital), where he further developed his expertise in neuromodulation by investigating the use of non-invasive neurostimulation techniques (e.g., repetitive transcranial magnetic stimulation, rTMS) as a clinical intervention after nervous system injury.
Overall, Jacob’s research involves direct electrophysiological data collection from awake human participants, and his work spans across basic and clinical neurophysiology, neuropharmacology, and exercise science. He has a strong background in mechanistic human neurophysiology experiments, and extensive experience with non-invasive brain, spinal cord and peripheral nerve stimulation techniques that quantify or modulate the output of the human nervous system and muscles.
Within the School of Biomedical Sciences at UQ, Jacob is currently conducting studies in the following areas/topics (see Available Projects):
1) Using high-density surface electromyography and peripheral nerve stimulation to study human motoneuron excitability
2) Investigating the influence of changes in joint angles and body position on human motoneuron activity
Research Interests
- Human Neurophysiology
- Neuromodulation
- Exercise Science
- Transcranial Magnetic Stimulation
Qualifications
- Doctor of Philosophy, Griffith University
- Bachelor of Exercise Science , Griffith University
- Bachelor of Exercise Science (Honours), Griffith University
Publications
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Journal Article: Serotonergic and noradrenergic contributions to motor cortical and spinal motoneuronal excitability in humans
Thorstensen, Jacob R., Henderson, Tyler T. and Kavanagh, Justin J. (2023). Serotonergic and noradrenergic contributions to motor cortical and spinal motoneuronal excitability in humans. Neuropharmacology, 242 109761, 109761. doi: 10.1016/j.neuropharm.2023.109761
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Journal Article: Muscle responses to motor cortical stimulation: Can we get more out of surface electromyography?
Thorstensen, Jacob R. (2023). Muscle responses to motor cortical stimulation: Can we get more out of surface electromyography?. The Journal of Physiology, 601 (14), 2763-2764. doi: 10.1113/jp284738
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Journal Article: Excitatory drive to spinal motoneurones is necessary for serotonin to modulate motoneurone excitability via 5-HT2 receptors in humans
Henderson, Tyler T., Taylor, Janet L., Thorstensen, Jacob R. and Kavanagh, Justin J. (2023). Excitatory drive to spinal motoneurones is necessary for serotonin to modulate motoneurone excitability via 5-HT2 receptors in humans. European Journal of Neuroscience. doi: 10.1111/ejn.16190
Available Projects
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Can high-density surface electromyography (HDsEMG) be used to study spinal cord reflexes?
Although the combined use of peripheral electrical nerve stimulation and EMG has been employed to study the reflexive activation of human motoneurons for several decades, standard bipolar single-channel surface EMG only provides an index of the summed activity of a sample of motor units. Thus, it is not possible to study the activity of individual motor units. HDsEMG, which is what this project will use to study motor unit activity, improves the spatial resolution of muscle EMG recordings (as opposed to conventional single-channel surface EMG that only samples summed activity from a small area of the muscle). HDsEMG recordings can be analysed offline with specialised algorithms to identify, track, and quantify the firing patterns of a sample of individual motor units. By using HDsEMG to study motor unit activity to peripheral nerve stimulation, we can study the reflexive recruitment of individual motoneurons and gain a better insight into how human motoneuron pools (and their inputs) function.
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How does joint angle and body position affect human motoneuron activity?
Using standard single-channel bipolar EMG and HDsEMG, measures of muscle torque, and peripheral nerve stimulation, this project will investigate motoneuron excitability and the voluntary activation of muscle. Motoneuron excitability and muscle activation will be studied across various joint angles (and hence muscle lengths) and in different body positions (e.g., standing up, lying down, or sitting), which are known to alter the magnitude of background afferent and descending excitation and/or inhibition of motoneurons.
Publications
Journal Article
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Thorstensen, Jacob R., Henderson, Tyler T. and Kavanagh, Justin J. (2023). Serotonergic and noradrenergic contributions to motor cortical and spinal motoneuronal excitability in humans. Neuropharmacology, 242 109761, 109761. doi: 10.1016/j.neuropharm.2023.109761
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Muscle responses to motor cortical stimulation: Can we get more out of surface electromyography?
Thorstensen, Jacob R. (2023). Muscle responses to motor cortical stimulation: Can we get more out of surface electromyography?. The Journal of Physiology, 601 (14), 2763-2764. doi: 10.1113/jp284738
-
Henderson, Tyler T., Taylor, Janet L., Thorstensen, Jacob R. and Kavanagh, Justin J. (2023). Excitatory drive to spinal motoneurones is necessary for serotonin to modulate motoneurone excitability via 5-HT2 receptors in humans. European Journal of Neuroscience. doi: 10.1111/ejn.16190
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Henderson, Tyler T., Taylor, Janet L., Thorstensen, Jacob R., Tucker, Murray G. and Kavanagh, Justin J. (2022). Enhanced availability of serotonin limits muscle activation during high-intensity, but not low-intensity, fatiguing contractions. Journal of Neurophysiology, 128 (4), 751-762. doi: 10.1152/jn.00182.2022
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Persistent inward currents in spinal motoneurones: how can we study them in human participants?
Thorstensen, Jacob R. (2022). Persistent inward currents in spinal motoneurones: how can we study them in human participants?. The Journal of Physiology, 600 (13), 3021-3023. doi: 10.1113/jp283249
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Thorstensen, Jacob R., Taylor, Janet L. and Kavanagh, Justin J. (2022). 5‐HT2 receptor antagonism reduces human motoneuron output to antidromic activation but not to stimulation of corticospinal axons. European Journal of Neuroscience, 56 (1), 3674-3686. doi: 10.1111/ejn.15672
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Henderson, T. T., Thorstensen, J. R., Morrison, S., Tucker, M. G. and Kavanagh, J. J. (2021). Physiological tremor is suppressed and force steadiness is enhanced with increased availability of serotonin regardless of muscle fatigue. Journal of Neurophysiology, 127 (1), 27-37. doi: 10.1152/jn.00403.2021
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Human corticospinal-motoneuronal output is reduced with 5-HT<sub>2</sub> receptor antagonism
Thorstensen, Jacob R., Taylor, Janet L. and Kavanagh, Justin J. (2021). Human corticospinal-motoneuronal output is reduced with 5-HT2 receptor antagonism. Journal of Neurophysiology, 125 (4), 1279-1288. doi: 10.1152/jn.00698.2020
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Thorstensen, Jacob R., Taylor, Janet L., Tucker, Murray G. and Kavanagh, Justin J. (2020). Enhanced serotonin availability amplifies fatigue perception and modulates the TMS‐induced silent period during sustained low‐intensity elbow flexions. The Journal of Physiology, 598 (13), 2685-2701. doi: 10.1113/jp279347
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Thorstensen, Jacob R., Tucker, Murray G. and Kavanagh, Justin J. (2018). Antagonism of the D2 dopamine receptor enhances tremor but reduces voluntary muscle activation in humans. Neuropharmacology, 141, 343-352. doi: 10.1016/j.neuropharm.2018.08.029
Possible Research Projects
Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.
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Can high-density surface electromyography (HDsEMG) be used to study spinal cord reflexes?
Although the combined use of peripheral electrical nerve stimulation and EMG has been employed to study the reflexive activation of human motoneurons for several decades, standard bipolar single-channel surface EMG only provides an index of the summed activity of a sample of motor units. Thus, it is not possible to study the activity of individual motor units. HDsEMG, which is what this project will use to study motor unit activity, improves the spatial resolution of muscle EMG recordings (as opposed to conventional single-channel surface EMG that only samples summed activity from a small area of the muscle). HDsEMG recordings can be analysed offline with specialised algorithms to identify, track, and quantify the firing patterns of a sample of individual motor units. By using HDsEMG to study motor unit activity to peripheral nerve stimulation, we can study the reflexive recruitment of individual motoneurons and gain a better insight into how human motoneuron pools (and their inputs) function.
-
How does joint angle and body position affect human motoneuron activity?
Using standard single-channel bipolar EMG and HDsEMG, measures of muscle torque, and peripheral nerve stimulation, this project will investigate motoneuron excitability and the voluntary activation of muscle. Motoneuron excitability and muscle activation will be studied across various joint angles (and hence muscle lengths) and in different body positions (e.g., standing up, lying down, or sitting), which are known to alter the magnitude of background afferent and descending excitation and/or inhibition of motoneurons.
