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Horinouchi T, Nezu T, Saita K, Date S, Kurumadani H, Maruyama H, Kirimoto H. Transcutaneous auricular vagus nerve stimulation enhances short-latency afferent inhibition via central cholinergic system activation. Sci Rep 2024; 14:11224. [PMID: 38755234 PMCID: PMC11099104 DOI: 10.1038/s41598-024-61958-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 05/12/2024] [Indexed: 05/18/2024] Open
Abstract
The present study examined the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on short-latency afferent inhibition (SAI), as indirect biomarker of cholinergic system activation. 24 healthy adults underwent intermittent taVNS (30 s on/30 s off, 30 min) or continuous taVNS at a frequency of 25 Hz (15 min) along with earlobe temporary stimulation (15 min or 30 min) were performed in random order. The efficiency with which the motor evoked potential from the abductor pollicis brevis muscle by transcranial magnetic stimulation was attenuated by the preceding median nerve conditioning stimulus was compared before taVNS, immediately after taVNS, and 15 min after taVNS. Continuous taVNS significantly increased SAI at 15 min post-stimulation compared to baseline. A positive correlation (Pearson coefficient = 0.563, p = 0.004) was observed between baseline SAI and changes after continuous taVNS. These results suggest that 15 min of continuous taVNS increases the activity of the cholinergic nervous system, as evidenced by the increase in SAI. In particular, the increase after taVNS was more pronounced in those with lower initial SAI. This study provides fundamental insight into the clinical potential of taVNS for cholinergic dysfunction.
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Affiliation(s)
- Takayuki Horinouchi
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Tomohisa Nezu
- Department of Clinical Neuroscience and Therapeutics, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Kazuya Saita
- Department of Psychosocial Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shota Date
- Department of Analysis and Control of Upper Extremity Function, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Kurumadani
- Department of Analysis and Control of Upper Extremity Function, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hirofumi Maruyama
- Department of Clinical Neuroscience and Therapeutics, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Hikari Kirimoto
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
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Lenizky MW, Meehan SK. The effects of verbal and spatial working memory on short- and long-latency sensorimotor circuits in the motor cortex. PLoS One 2024; 19:e0302989. [PMID: 38753604 PMCID: PMC11098330 DOI: 10.1371/journal.pone.0302989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
Multiple sensorimotor loops converge in the motor cortex to create an adaptable system capable of context-specific sensorimotor control. Afferent inhibition provides a non-invasive tool to investigate the substrates by which procedural and cognitive control processes interact to shape motor corticospinal projections. Varying the transcranial magnetic stimulation properties during afferent inhibition can probe specific sensorimotor circuits that contribute to short- and long-latency periods of inhibition in response to the peripheral stimulation. The current study used short- (SAI) and long-latency (LAI) afferent inhibition to probe the influence of verbal and spatial working memory load on the specific sensorimotor circuits recruited by posterior-anterior (PA) and anterior-posterior (AP) TMS-induced current. Participants completed two sessions where SAI and LAI were assessed during the short-term maintenance of two- or six-item sets of letters (verbal) or stimulus locations (spatial). The only difference between the sessions was the direction of the induced current. PA SAI decreased as the verbal working memory load increased. In contrast, AP SAI was not modulated by verbal working memory load. Visuospatial working memory load did not affect PA or AP SAI. Neither PA LAI nor AP LAI were sensitive to verbal or spatial working memory load. The dissociation of short-latency PA and AP sensorimotor circuits and short- and long-latency PA sensorimotor circuits with increasing verbal working memory load support multiple convergent sensorimotor loops that provide distinct functional information to facilitate context-specific supraspinal control.
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Affiliation(s)
- Markus W. Lenizky
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Sean K. Meehan
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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Brotherton EJ, Sabapathy S, Dempsey LM, Kavanagh JJ. Short-latency afferent inhibition is reduced in people with multiple sclerosis during fatiguing muscle contractions. Eur J Neurosci 2024; 59:2087-2101. [PMID: 38234172 DOI: 10.1111/ejn.16253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/19/2024]
Abstract
Understanding how inhibitory pathways influence motor cortical activity during fatiguing contractions may provide valuable insight into mechanisms associated with multiple sclerosis (MS) muscle activation. Short-latency afferent inhibition (SAI) reflects inhibitory interactions between the somatosensory cortex and the motor cortex, and although SAI is typically reduced with MS, it is unknown how SAI is regulated during exercise-induced fatigue. The current study examined how SAI modulates motor evoked potentials (MEPs) during fatiguing contractions. Fourteen people with relapsing-remitting MS (39 ± 6 years, nine female) and 10 healthy individuals (36 ± 6 years, six female) participated. SAI was induced by stimulation of the median nerve that was paired with TMS over the motor representation of the abductor pollicis brevis. A contraction protocol was employed that depressed force generating capacity using a sustained 3-min 15% MVC, immediately followed by a low-intensity (15% MVC) intermittent contraction protocol so that MEP and SAI could be measured during the rest phases of each duty cycle. Similar force, electromyography and MEP responses were observed between groups. However, the MS group had significantly reduced SAI during the contraction protocol compared to the healthy control group (p < .001). Despite the MS group reporting greater scores on the Fatigue Severity Scale and Modified Fatigue Impact Scale, these scales did not correlate with inhibitory measures. As there were no between-group differences in SSEPs, MS-related SAI differences during the fatiguing contractions were most likely associated with disease-related changes in central integration.
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Affiliation(s)
- Emily J Brotherton
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Surendran Sabapathy
- Exercise Physiology Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Lisa M Dempsey
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Justin J Kavanagh
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
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Boran HE, Alaydın HC, Kılınç H, Tankişi H, Samusyte G, Howells J, Koltzenburg M, Cengiz B. Long-interval afferent inhibition measurement using two different methods: Normative values, repeatability and reliability. Neurophysiol Clin 2024; 54:102940. [PMID: 38382141 DOI: 10.1016/j.neucli.2023.102940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 02/23/2024] Open
Abstract
BACKGROUND The mechanism of Short-Latency Afferent Inhibition (SAI) is relatively well understood. In contrast, Long-Latency Afferent Inhibition (LAI) has not been as extensively studied as SAI, and its underlying mechanism remains unclear. OBJECTIVE/HYPOTHESIS This study had two primary objectives: first, to determine the optimal ISIs for LAI measured by amplitude changes (A-LAI) using high-resolution ISI ranges; and second, to compare measurements of LAI by threshold-tracking (T-LAI). METHODS Twenty-eight healthy volunteers (12 males aged 24- 45 years) participated in the study. Paired peripheral electrical and transcranial magnetic stimulation (TMS) stimuli (TS1mv) were applied at varying (ISIs)- 100, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800, 900, 1000 ms. RESULTS Both A-LAI and T-LAI showed that LAI decreased progressively from a peak at 200 or 250 ms to 1000 ms. Using the A-LAI method, pronounced inhibition was observed at three specific ISIs: 100 ms, 250 ms and 450 ms. When A-LAI values were converted to equivalent threshold changes, they did not differ significantly from T-LAI. Reliability at distinguishing individuals, as indicated by intraclass correlation coefficient (ICC) was greater for A-LAI, with a peak value of 0.82 at 250 ms. CONCLUSION(S) The study demonstrates that ISIs of 100 ms and 250 ms can be reliably used in amplitude measurement LAI. The study demonstrates that both LAI measurements record a similar decline of inhibition with increasing ISI.
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Affiliation(s)
- Hürrem Evren Boran
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500 Ankara, Turkey; Gazi University Neuropsychiatry of Education, Research and Application Center, Ankara, Turkey; NOROM, Neuroscience and Neurotechnology Center of Excellence, Ankara, Turkey
| | - Halil Can Alaydın
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500 Ankara, Turkey
| | - Hasan Kılınç
- Gazi University Neuropsychiatry of Education, Research and Application Center, Ankara, Turkey
| | - Hatice Tankişi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Ginte Samusyte
- Department of Neurology, Lithuanian University of Health Sciences, Hospital Kauno klinikos Kaunas, Lithuania; Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Martin Koltzenburg
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom; Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, WC1N 3BG London, United Kingdom; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom
| | - Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500 Ankara, Turkey; Gazi University Neuropsychiatry of Education, Research and Application Center, Ankara, Turkey; NOROM, Neuroscience and Neurotechnology Center of Excellence, Ankara, Turkey.
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Disinhibition of short-latency but not long-latency afferent inhibition of the lower limb during upper-limb muscle contraction. Neuroreport 2023; 34:280-286. [PMID: 36881752 DOI: 10.1097/wnr.0000000000001889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Research has demonstrated that motor and sensory functions of the lower limbs can be modulated by upper-limb muscle contractions. However, whether sensorimotor integration of the lower limb can be modulated by upper-limb muscle contractions is still unknown. [AQ: NR Original articles do not require structured abstracts. Hence, abstract subsections have been deleted. Please check.]Human sensorimotor integration has been studied using short- or long-latency afferent inhibition (SAI or LAI, respectively), which refers to inhibition of motor-evoked potentials (MEPs) elicited via transcranial magnetic stimulation by preceding peripheral sensory stimulation. In the present study, we aimed to investigate whether upper-limb muscle contractions could modulate the sensorimotor integration of the lower limbs by examining SAI and LAI. Soleus muscle MEPs following electrical tibial nerve stimulation (TSTN) during rest or voluntary wrist flexion were recorded at inter-stimulus intervals (ISIs) of 30 (i.e. SAI), 100, and 200 ms (i.e. LAI). The soleus Hoffman reflex following TSTN was also measured to identify whether MEP modulation occurred at the cortical or the spinal level. Results showed that lower-limb SAI, but not LAI, was disinhibited during voluntary wrist flexion. Furthermore, the soleus Hoffman reflex following TSTN during voluntary wrist flexion was unchanged when compared with that during the resting state at any ISI. Our findings suggest that upper-limb muscle contractions modulate sensorimotor integration of the lower limbs and that disinhibition of lower-limb SAI during upper-limb muscle contractions is cortically based.
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Ramdeo KR, Rehsi RS, Foglia SD, Turco CV, Toepp SL, Nelson AJ. Experimental environment improves the reliability of short-latency afferent inhibition. PLoS One 2023; 18:e0281867. [PMID: 36812217 PMCID: PMC9946256 DOI: 10.1371/journal.pone.0281867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Evidence indicates attention can alter afferent inhibition, a Transcranial Magnetic Stimulation (TMS) evoked measure of cortical inhibition following somatosensory input. When peripheral nerve stimulation is delivered prior to TMS, a phenomenon known as afferent inhibition occurs. The latency between the peripheral nerve stimulation dictates the subtype of afferent inhibition evoked, either short latency afferent inhibition (SAI) or long latency afferent inhibition (LAI). While afferent inhibition is emerging as a valuable tool for clinical assessment of sensorimotor function, the reliability of the measure remains relatively low. Therefore, to improve the translation of afferent inhibition within and beyond the research lab, the reliability of the measure must be improved. Previous literature suggests that the focus of attention can modify the magnitude of afferent inhibition. As such, controlling the focus of attention may be one method to improve the reliability of afferent inhibition. In the present study, the magnitude and reliability of SAI and LAI was assessed under four conditions with varying attentional demands focused on the somatosensory input that evokes SAI and LAI circuits. Thirty individuals participated in four conditions; three conditions were identical in their physical parameters and varied only in the focus of directed attention (visual attend, tactile attend, non- directed attend) and one condition consisted of no external physical parameters (no stimulation). Reliability was measured by repeating conditions at three time points to assess intrasession and intersession reliability. Results indicate that the magnitude of SAI and LAI were not modulated by attention. However, the reliability of SAI demonstrated increased intrasession and intersession reliability compared to the no stimulation condition. The reliability of LAI was unaffected by the attention conditions. This research demonstrates the impact of attention/arousal on the reliability of afferent inhibition and has identified new parameters to inform the design of TMS research to improve reliability.
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Affiliation(s)
| | - Ravjot S. Rehsi
- Department of Kinesiology, McMaster University, Hamilton, Canada
| | - Stevie D. Foglia
- School of Biomedical Engineering, McMaster University, Hamilton, Canada
| | - Claudia V. Turco
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Stephen L. Toepp
- Department of Kinesiology, McMaster University, Hamilton, Canada
| | - Aimee J. Nelson
- Department of Kinesiology, McMaster University, Hamilton, Canada
- School of Biomedical Engineering, McMaster University, Hamilton, Canada
- * E-mail:
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Kato T, Sasaki A, Nakazawa K. Short-and long-latency afferent inhibition of the human leg motor cortex by H-reflex subthreshold electrical stimulation at the popliteal fossa. Exp Brain Res 2023; 241:249-261. [PMID: 36481937 PMCID: PMC9870969 DOI: 10.1007/s00221-022-06497-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/20/2022] [Indexed: 12/14/2022]
Abstract
In humans, peripheral sensory stimulation inhibits subsequent motor evoked potentials (MEPs) induced by transcranial magnetic stimulation; this process is referred to as short- or long-latency afferent inhibition (SAI or LAI, respectively), depending on the inter-stimulus interval (ISI) length. Although upper limb SAI and LAI have been well studied, lower limb SAI and LAI remain under-investigated. Here, we examined the time course of the soleus (SOL) muscle MEP following electrical tibial nerve (TN) stimulation at the popliteal fossa at ISIs of 20-220 ms. When the conditioning stimulus intensity was three-fold the perceptual threshold, MEP amplitudes were inhibited at an ISI of 220 ms, but not at shorter ISIs. TN stimulation just below the Hoffman (H)-reflex threshold intensity inhibited MEP amplitudes at ISIs of 30, 35, 100, 180 and 200 ms. However, the relationship between MEP inhibition and the P30 latency of somatosensory evoked potentials (SEPs) did not show corresponding ISIs at the SEP P30 latency that maximizes MEP inhibition. To clarify whether the site of afferent-induced MEP inhibition occurs at the cortical or spinal level, we examined the time course of SOL H-reflex following TN stimulation. H-reflex amplitudes were not significantly inhibited at ISIs where MEP inhibition occurred but at an ISI of 120 ms. Our findings indicate that stronger peripheral sensory stimulation is required for lower limb than for upper limb SAI and LAI and that lower limb SAI and LAI are of cortical origin. Moreover, the direct pathway from the periphery to the primary motor cortex may contribute to lower limb SAI.
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Affiliation(s)
- Tatsuya Kato
- grid.26999.3d0000 0001 2151 536XGraduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, 153-8902 Tokyo, Japan ,grid.54432.340000 0001 0860 6072Japan Society for the Promotion of Science, Tokyo, 102-0083 Japan
| | - Atsushi Sasaki
- grid.54432.340000 0001 0860 6072Japan Society for the Promotion of Science, Tokyo, 102-0083 Japan ,grid.136593.b0000 0004 0373 3971Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Osaka, 560-8531 Japan
| | - Kimitaka Nakazawa
- grid.26999.3d0000 0001 2151 536XGraduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, 153-8902 Tokyo, Japan
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Snow NJ, Kirkland MC, Downer MB, Murphy HM, Ploughman M. Transcranial magnetic stimulation maps the neurophysiology of chronic noncancer pain: A scoping review. Medicine (Baltimore) 2022; 101:e31774. [PMID: 36401490 PMCID: PMC9678597 DOI: 10.1097/md.0000000000031774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Chronic noncancer pain is a global public health challenge. It is imperative to identify biological markers ("biomarkers") to understand the mechanisms underlying chronic pain and to monitor pain over time and after interventions. Transcranial magnetic stimulation (TMS) is a promising method for this purpose. OBJECTIVES To examine differences in TMS-based outcomes between persons with chronic pain and healthy controls (HCs) and/or before versus after pain-modulating interventions and relationships between pain measures and TMS outcomes; To summarize the neurophysiological mechanisms underlying chronic pain as identified by TMS. METHODS We searched the PubMed database for literature from January 1, 1985, to June 9, 2020, with the keywords "pain" and "transcranial magnetic stimulation." Eligible items included original studies of adult human participants with pain lasting for ≥ 6 months. We completed a narrative synthesis of the study findings stratified by chronic pain etiology (primary pain, neuropathic pain, and secondary musculoskeletal pain). RESULTS The search yielded 1265 records. The final 12 articles included 244 patients with chronic pain (192 females, aged 35-65 years) and 169 HCs (89 females, aged 28-59 years). Abnormalities in TMS outcomes that reflect GABAergic and glutamatergic activities were associated with many of the disorders studied and were distinct for each pain etiology. Chronic primary pain is characterized by reduced intracortical inhibition and corticospinal excitability, chronic neuropathic pain shows evidence of increased excitation and disinhibition, and chronic secondary musculoskeletal pain involves low corticospinal excitability. DISCUSSION TMS could be a useful tool for delineating the neurophysiological underpinnings of chronic pain syndromes.
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Affiliation(s)
- Nicholas Jacob Snow
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Megan Christine Kirkland
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Matthew Bruce Downer
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Hannah Margaret Murphy
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
- * Correspondence: Michelle Ploughman, Recovery and Performance Laboratory, Rehabilitation Research Unit of NL, Faculty of Medicine, Memorial University of Newfoundland & Labrador, Dr. Leonard A. Miller Centre, Room 400, 100 Forest Road, St. John’s, Newfoundland and Labrador A1A 1E5, Canada (e-mail: )
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9
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Davidson PSR, Karpov G, Giguère L, Castro AW, Tremblay F. Older adults' episodic memory is related to a neurophysiological marker of brain cholinergic activity. Exp Brain Res 2022; 240:2269-2276. [PMID: 35907032 DOI: 10.1007/s00221-022-06420-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 07/09/2022] [Indexed: 11/25/2022]
Abstract
Episodic memory is vulnerable to aging and may be influenced by age-related decline in the neurotransmitter acetylcholine. We probed this relation using a novel, minimally invasive transcranial magnetic stimulation marker of brain acetylcholine: short-latency afferent inhibition (SAI). We used neuropsychological testing to construct a composite score of episodic memory in N = 19 community-dwelling older adults, and stratified older adults into Higher- (N = 9) versus Lower-memory (N = 10) groups before SAI. The Higher-memory group showed significantly stronger SAI than the Lower-memory group, indicating an association between higher brain acetylcholine levels and better episodic memory. The two memory groups were equivalent in the potential confounds of age, education, mood, subjective sleep quality, and executive function. These data converge with others to suggest that episodic memory is related to acetylcholine in older adults. This relation should be further investigated, especially with pharmacology and neuroimaging.
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Affiliation(s)
- Patrick S R Davidson
- School of Psychology, University of Ottawa, Ottawa, Canada.
- Bruyère Research Institute, University of Ottawa, Ottawa, Canada.
| | - Galit Karpov
- School of Psychology, University of Ottawa, Ottawa, Canada
| | | | - Alex W Castro
- School of Psychology, University of Ottawa, Ottawa, Canada
| | - François Tremblay
- School of Psychology, University of Ottawa, Ottawa, Canada
- Bruyère Research Institute, University of Ottawa, Ottawa, Canada
- School of Rehabilitation Sciences, University of Ottawa, Ottawa, Canada
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Bonnesen MT, Fuglsang SA, Siebner HR, Christiansen L. The recent history of afferent stimulation modulates corticospinal excitability. Neuroimage 2022; 258:119365. [PMID: 35690256 DOI: 10.1016/j.neuroimage.2022.119365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/01/2022] [Accepted: 06/07/2022] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) is widely used to probe corticospinal excitability and fast sensorimotor integration in the primary motor hand area (M1-HAND). A conditioning electrical stimulus, applied to the contralateral hand, can suppress the motor evoked potential (MEP) elicited by TMS of M1-HAND when the afferent stimulus arrives in M1-HAND at the time of TMS. The magnitude of this short-latency afferent inhibition (SAI) is expressed as the ratio between the conditioned and unconditioned MEP amplitude. OBJECTIVE/HYPOTHESIS We hypothesized that corticospinal excitability and SAI are influenced by the recent history of peripheral electrical stimulation. METHODS In twenty healthy participants, we recorded MEPs from the right first dorsal interosseus muscle. MEPs were evoked by single-pulse TMS of the left M1-HAND alone (unconditioned TMS) or by TMS preceded by electrical stimulation of the right index finger ("homotopic" conditioning) or little finger ("heterotopic" conditioning). The three conditions were either pseudo-randomly intermixed or delivered in blocks in which a single condition was repeated five or ten times. MEP amplitudes and SAI magnitudes were compared using linear mixed-effect models and one-way ANOVAs. RESULTS All stimulation protocols consistently produced SAI, which was stronger after homotopic stimulation. Randomly intermingling the three stimulation conditions reduced the relative magnitude of homotopic and heterotopic SAI as opposed to blocked stimulation. The apparent attenuation of SAI was caused by a suppression of the unconditioned but not the conditioned MEP amplitude during the randomly intermixed pattern. CONCLUSION(S) The recent history of afferent stimulation modulates corticospinal excitability. This "history effect" impacts on the relative magnitude of SAI depending on how conditioned and unconditioned responses are intermixed and needs to be taken into consideration when probing afferent inhibition and corticospinal excitability.
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Affiliation(s)
- Marie Trolle Bonnesen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Søren Asp Fuglsang
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Christiansen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark.
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Syvertsen Mykland M, Uglem M, Petter Neverdahl J, Rystad Øie L, Wergeland Meisingset T, Dodick DW, Tronvik E, Engstrøm M, Sand T, Moe Omland P. Sleep restriction alters cortical inhibition in migraine: A transcranial magnetic stimulation study. Clin Neurophysiol 2022; 139:28-42. [DOI: 10.1016/j.clinph.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/22/2022] [Accepted: 04/05/2022] [Indexed: 11/28/2022]
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Cengiz B, Boran HE, Alaydın HC, Tankisi H, Samusyte G, Howells J, Koltzenburg M, Bostock H. Short latency afferent inhibition: comparison between threshold-tracking and conventional amplitude recording methods. Exp Brain Res 2022; 240:1241-1247. [PMID: 35192042 DOI: 10.1007/s00221-022-06327-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/05/2022] [Indexed: 11/04/2022]
Abstract
Short-latency afferent inhibition (SAI), which is conventionally measured as a reduction in motor evoked potential amplitude (A-SAI), is of clinical interest as a potential biomarker for cognitive impairment. Since threshold-tracking has some advantages for clinical studies of short-interval cortical inhibition, we have compared A-SAI with a threshold-tracking alternative method (T-SAI). In the T-SAI method, inhibition was calculated by tracking the required TMS intensity for the targeted MEP amplitude (200 uV) both for the test (TMS only) and paired (TMS and peripheral stimulation) stimuli. A-SAI and T-SAI were recorded from 31 healthy subjects using ten stimuli at each of 12 inter-stimulus intervals, once in the morning and again in the afternoon. There were no differences between morning and afternoon recordings. When A-SAI was normalized by log conversion it was closely related to T-SAI. Between subjects, variability was similar for the two techniques, but within-subject variability was significantly smaller for normalized A-SAI. Conventional amplitude measurements appear more sensitive for detecting changes within-subjects, such as in interventional studies, but threshold-tracking may be as sensitive as detecting abnormal SAI in a patient.
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Affiliation(s)
- Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey.
| | - H Evren Boran
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey
| | - Halil Can Alaydın
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Gintaute Samusyte
- Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Martin Koltzenburg
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK.,Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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Preserved central cholinergic functioning to transcranial magnetic stimulation in de novo patients with celiac disease. PLoS One 2021. [PMID: 34914787 DOI: 10.1371/journal.pone.0261373.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Celiac disease (CD) is now viewed as a systemic disease with multifaceted clinical manifestations. Among the extra-intestinal features, neurological and neuropsychiatric symptoms are still a diagnostic challenge, since they can precede or follow the diagnosis of CD. In particular, it is well known that some adults with CD may complain of cognitive symptoms, that improve when the gluten-free diet (GFD) is started, although they may re-appear after incidental gluten intake. Among the neurophysiological techniques, motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) can non-invasively probe in vivo the excitation state of cortical areas and cortico-spinal conductivity, being also able to unveil preclinical impairment in several neurological and psychiatric disorders, as well as in some systemic diseases affecting the central nervous system (CNS), such as CD. We previously demonstrated an intracortical disinhibition and hyperfacilitation of MEP responses to TMS in newly diagnosed patients. However, no data are available on the central cholinergic functioning indexed by specific TMS measures, such as the short-latency afferent inhibition (SAI), which might represent the neurophysiological correlate of cognitive changes in CD patients, also at the preclinical level. METHODS Cognitive and depressive symptoms were screened by means of the Montreal Cognitive Assessment (MoCA) and the 17-item Hamilton Depression Rating Scale (HDRS), respectively, in 15 consecutive de novo CD patients and 15 healthy controls. All patients were on normal diet at the time of the enrolment. Brain computed tomography (CT) was performed in all patients. SAI, recorded at two interstimulus intervals (2 and 8 ms), was assessed as the percentage amplitude ratio between the conditioned and the unconditioned MEP response. Resting motor threshold, MEP amplitude and latency, and central motor conduction time were also measured. RESULTS The two groups were comparable for age, sex, anthropometric features, and educational level. Brain CT ruled out intracranial calcifications and clear radiological abnormalities in all patients. Scores at MoCA and HDRS were significantly worse in patients than in controls. The comparison of TMS data between the two groups revealed no statistically significant difference for all measures, including SAI at both interstimulus intervals. CONCLUSIONS Central cholinergic functioning explored by the SAI of the motor cortex resulted to be not affected in these de novo CD patients compared to age-matched healthy controls. Although the statistically significant difference in MoCA, an overt cognitive impairment was not clinically evident in CD patients. Coherently, to date, no study based on TMS or other diagnostic techniques has shown any involvement of the central acetylcholine or the cholinergic fibers within the CNS in CD. This finding might add support to the vascular inflammation hypothesis underlying the so-called "gluten encephalopathy", which seems to be due to an aetiology different from that of the cholinergic dysfunction. Longitudinal studies correlating clinical, TMS, and neuroimaging data, both before and after GFD, are needed.
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The distribution and reliability of TMS-evoked short- and long-latency afferent interactions. PLoS One 2021; 16:e0260663. [PMID: 34905543 PMCID: PMC8670708 DOI: 10.1371/journal.pone.0260663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 11/13/2021] [Indexed: 11/30/2022] Open
Abstract
Short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI) occur when the motor evoked potential (MEP) elicited by transcranial magnetic stimulation (TMS) is reduced by the delivery of a preceding peripheral nerve stimulus. The intra-individual variability in SAI and LAI is considerable, and the influence of sample demographics (e.g., age and biological sex) and testing context (e.g., time of day) is not clear. There are also no established normative values for these measures, and their reliability varies from study-to-study. To address these issues and facilitate the interpretation of SAI and LAI research, we pooled data from studies published by our lab between 2014 and 2020 and performed several retrospective analyses. Patterns in the depth of inhibition with respect to age, biological sex and time of testing were investigated, and the relative reliability of measurements from studies with repeated baseline SAI and LAI assessments was examined. Normative SAI and LAI values with respect to the mean and standard deviation were also calculated. Our data show no relationship between the depth of inhibition for SAI and LAI with either time of day or age. Further, there was no significant difference in SAI or LAI between males and females. Intra-class correlation coefficients (ICC) for repeated measurements of SAI and LAI ranged from moderate (ICC = 0.526) to strong (ICC = 0.881). The mean value of SAI was 0.71 ± 0.27 and the mean value of LAI was 0.61 ± 0.34. This retrospective study provides normative values, reliability estimates, and an exploration of demographic and testing influences on these measures as assessed in our lab. To further facilitate the interpretation of SAI and LAI data, similar studies should be performed by other labs that use these measures.
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Lanza G, Fisicaro F, D’Agate CC, Ferri R, Cantone M, Falzone L, Pennisi G, Bella R, Hadjivassiliou M, Pennisi M. Preserved central cholinergic functioning to transcranial magnetic stimulation in de novo patients with celiac disease. PLoS One 2021; 16:e0261373. [PMID: 34914787 PMCID: PMC8675755 DOI: 10.1371/journal.pone.0261373] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Celiac disease (CD) is now viewed as a systemic disease with multifaceted clinical manifestations. Among the extra-intestinal features, neurological and neuropsychiatric symptoms are still a diagnostic challenge, since they can precede or follow the diagnosis of CD. In particular, it is well known that some adults with CD may complain of cognitive symptoms, that improve when the gluten-free diet (GFD) is started, although they may re-appear after incidental gluten intake. Among the neurophysiological techniques, motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) can non-invasively probe in vivo the excitation state of cortical areas and cortico-spinal conductivity, being also able to unveil preclinical impairment in several neurological and psychiatric disorders, as well as in some systemic diseases affecting the central nervous system (CNS), such as CD. We previously demonstrated an intracortical disinhibition and hyperfacilitation of MEP responses to TMS in newly diagnosed patients. However, no data are available on the central cholinergic functioning indexed by specific TMS measures, such as the short-latency afferent inhibition (SAI), which might represent the neurophysiological correlate of cognitive changes in CD patients, also at the preclinical level. METHODS Cognitive and depressive symptoms were screened by means of the Montreal Cognitive Assessment (MoCA) and the 17-item Hamilton Depression Rating Scale (HDRS), respectively, in 15 consecutive de novo CD patients and 15 healthy controls. All patients were on normal diet at the time of the enrolment. Brain computed tomography (CT) was performed in all patients. SAI, recorded at two interstimulus intervals (2 and 8 ms), was assessed as the percentage amplitude ratio between the conditioned and the unconditioned MEP response. Resting motor threshold, MEP amplitude and latency, and central motor conduction time were also measured. RESULTS The two groups were comparable for age, sex, anthropometric features, and educational level. Brain CT ruled out intracranial calcifications and clear radiological abnormalities in all patients. Scores at MoCA and HDRS were significantly worse in patients than in controls. The comparison of TMS data between the two groups revealed no statistically significant difference for all measures, including SAI at both interstimulus intervals. CONCLUSIONS Central cholinergic functioning explored by the SAI of the motor cortex resulted to be not affected in these de novo CD patients compared to age-matched healthy controls. Although the statistically significant difference in MoCA, an overt cognitive impairment was not clinically evident in CD patients. Coherently, to date, no study based on TMS or other diagnostic techniques has shown any involvement of the central acetylcholine or the cholinergic fibers within the CNS in CD. This finding might add support to the vascular inflammation hypothesis underlying the so-called "gluten encephalopathy", which seems to be due to an aetiology different from that of the cholinergic dysfunction. Longitudinal studies correlating clinical, TMS, and neuroimaging data, both before and after GFD, are needed.
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Affiliation(s)
- Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
- * E-mail:
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Carmela Cinzia D’Agate
- Gastroenterology and Endoscopy Unit, University Hospital Policlinico “G. Rodolico-San Marco”, Catania, Italy
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Mariagiovanna Cantone
- Department of Neurology, Sant’Elia Hospital, ASP Caltanissetta, Caltanissetta, Italy
| | - Luca Falzone
- Epidemiology and Biostatistics Unit, Instituto Nazionale Tumori-IRCCS “Fondazione G. Pascale, Napoli, Italy
| | - Giovanni Pennisi
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, Catania, Italy
| | - Marios Hadjivassiliou
- Academic Department of Neurosciences, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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