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- Boudreau, Shellie A., et al.
(author)
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Features of cortical neuroplasticity associated with multidirectional novel motor skill training: a TMS mapping study
- 2013
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In: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 225:4, s. 513-526
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Journal article (peer-reviewed)abstract
- Given the evidence that the primary motor cortex (MI) consists of subpopulations of upper motor neurons tuned to different directional parameters of a motor movement, this study hypothesized that novel motor skill training involving either a bidirectional or more complex multidirectional tongue-typing movement should produce distinct training-related features of tongue MI neuroplasticity in humans. Novel motor skill training consisted of tongue typing using custom-made intra-oral keypads for 30-min over two consecutive days. The bidirectional keypad consisted of three sensors positioned along the upper palatal midline as a 3 x 1 array, whereas the multidirectional keypad consisted of nine sensors arranged as a 3 x 3 array that was centred along the upper palatal midline. Each sensor corresponded to one letter and participants were asked to type sequences of letters by accurately placing the tongue over the correct sensor. Before and after each training session, excitability of the tongue MI was assessed with transcranial magnetic stimulation (TMS)-motor evoked potentials (MEPs) over 13 motor map sites and TMS-MEP stimulus-response curves were constructed for the first dorsal interosseous (FDI, as an internal control). Tongue-typing performance improved within and across training days for both groups; although bidirectional training displayed greater success. Bidirectional and multidirectional training were associated with increases and decreases in a number of cortical motor map sites from where tongue activity could be evoked, however; multidirectional training was associated with a greater number of cortical motor map sites with increased excitability and a shift in the centre of gravity of the motor map. No effects of training were found on the FDI TMS-MEP stimulus-response curves. This study revealed distinct training-related features of tongue MI neuroplasticity and proposes that a greater amount of functionally related neuronal populations may be 'trained' by the inclusion of different and more complex directional parameters within a novel motor task.
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| 2. |
- Sessle, Barry J, et al.
(author)
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Orofacial pain
- 2022. - 2
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In: Clinical Pain Management. - : John Wiley & Sons. - 9781119701156 - 9781119701170 ; , s. 343-354
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Book chapter (peer-reviewed)abstract
- This chapter first highlights the peripheral and central neurobiological mechanisms underlying orofacial pain and then outlines the clinical features of some of the most common or perplexing chronic orofacial pain conditions. Injury or inflammation of peripheral tissues, including nerves, may also lead to phenotypic changes, sprouting or abnormal discharges of the nociceptive afferents and be of pathophysiological significance in certain chronic pain conditions. From the trigeminal ganglion, trigeminal afferents project into the brainstem and terminate on neurons especially in the trigeminal brainstem sensory nuclear complex. Orofacial pain covers a wide range of conditions with different clinical manifestations. Temporomandibular disorders cover an umbrella of common and related pain conditions in the jaw muscles, temporomandibular joint and associated structures. The International Classification of Orofacial Pain divides idiopathic orofacial pain into four different types: burning mouth syndrome, persistent idiopathic facial pain, persistent idiopathic dentoalveolar pain and constant unilateral facial pain with additional attacks.
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| 3. |
- Shah, Farhan, et al.
(author)
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Tooth extraction and subsequent dental implant placement in Sprague-Dawley rats induce differential changes in anterior digastric myofibre size and myosin heavy chain isoform expression
- 2019
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In: Archives of Oral Biology. - : Elsevier. - 0003-9969 .- 1879-1506. ; 99, s. 141-149
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Journal article (peer-reviewed)abstract
- Objective: to determine if tooth loss and dental implant placement in rats induce changes in the morphological and histochemical features of the Anterior Digastric muscle.Design: Adult male Sprague-Dawley rats had their right maxillary molar teeth extracted. ‘Extraction-1’ and ‘Extraction-2 groups were sacrificed, respectively, 4 or 8 weeks later, and an Implant group had an implant placement 2 weeks after the molar extraction, and rats were sacrificed 3 weeks later (n = 4/group). Naive rats (n = 3) had no treatment. Morphometric and immunohistochemical techniques quantified Anterior Digastric muscle myofibres’ cross-sectional area (CSA) and myosin heavy chain (MyHC) isoform proportions. Significant ANOVAs were followed by post-hoc tests; p < 0.05 and 0.1 were considered to reflect levels of statistical significance.Results: In naïve rats, the peripheral regions of the Anterior Digastric muscle was dominated by MyHC-IIx/b isoform and there were no MyHC-I isoforms; the central regions dominated by MyHC-IIx/b and MyHC-IIa isoforms. Compared with naive rats, tooth extraction produced, 8 (but not 4) weeks later, a decreased proportion of fast-contracting fatigue-resistant MyHC-IIa isoform (p = 0.08), and increased proportion of fast and intermediate fatigue-resistance MyHC-IIa/x/b isoform (p = 0.03). Dental implant placement following tooth extraction attenuated the extraction effects but produced a decreased proportion of fast-contracting fatiguable MyHC-llx/b isoform (p = 0.03) in the peripheral region, and increased inter-animal variability in myofibre-CSAs.Conclusions: Given the crucial role that the Anterior Digastric muscle plays in many vital oral functions (e.g., chewing, swallowing), these changes may contribute to the changes in oral sensorimotor functions that occur in humans following such treatments.
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