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Non-invasive recording of high-frequency signals from the human spinal cord. Neuroimage 2022; 253:119050. [PMID: 35276364 DOI: 10.1016/j.neuroimage.2022.119050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/16/2022] [Accepted: 03/01/2022] [Indexed: 11/24/2022] Open
Abstract
Throughout the somatosensory system, neuronal ensembles generate high-frequency signals in the range of several hundred Hertz in response to sensory input. High-frequency signals have been related to neuronal spiking, and could thus help clarify the functional architecture of sensory processing. Recording high-frequency signals from subcortical regions, however, has been limited to clinical pathology whose treatment allows for invasive recordings. Here, we demonstrate the feasibility to record 200-1200 Hz signals from the human spinal cord non-invasively, and in healthy individuals. Using standard electroencephalography equipment in a cervical electrode montage, we observed high-frequency signals between 200 and 1200 Hz in a time window between 8 and 16 ms after electric median nerve stimulation (n = 15). These signals overlapped in latency, and, partly, in frequency, with signals obtained via invasive, epidural recordings from the spinal cord in a patient with neuropathic pain. Importantly, the observed high-frequency signals were dissociable from classic spinal evoked responses. A spatial filter that optimized the signal-to-noise ratio of high-frequency signals led to submaximal amplitudes of the evoked response, and vice versa, ruling out the possibility that high-frequency signals are merely a spectral representation of the evoked response. Furthermore, we observed spontaneous fluctuations in the amplitude of high-frequency signals over time, in the absence of any concurrent, systematic change to the evoked response. High-frequency, "spike-like" signals from the human spinal cord thus carry information that is complementary to the evoked response. The possibility to assess these signals non-invasively provides a novel window onto the neurophysiology of the human spinal cord, both in a context of top-down control over perception, as well as in pathology.
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Long-term effects of concussion on relevancy-based modulation of somatosensory-evoked potentials. Clin Neurophysiol 2021; 132:2431-2439. [PMID: 34454270 DOI: 10.1016/j.clinph.2021.06.027] [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: 03/17/2021] [Revised: 05/15/2021] [Accepted: 06/12/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The purpose of this investigation was to better understand the effects of concussions on the ability to selectively up or down-regulate incoming somatosensory information based on relevance. METHODS Median nerve somatosensory-evoked potentials (SEPs) were elicited from electrical stimulation and recorded from scalp electrodes while participants completed tasks that altered the relevance of specific somatosensory information being conveyed along the stimulated nerve. RESULTS Within the control group, SEP amplitudes for task-relevant somatosensory information were significantly greater than for non-relevant somatosensory information at the earliest cortical processing potentials (N20-P27). Alternatively, the concussion history group showed similar SEP amplitudes for all conditions at early processing potentials, however a pattern similar to controls emerged later in the processing stream (P100) where both movement-related gating and facilitation of task-relevant information were present. CONCLUSIONS Previously concussed participants demonstrated impairments in the ability to up-regulate relevant somatosensory information at early processing stages. These effects appear to be chronic, as this pattern was observed on average several years after participants' most recent concussion. SIGNIFICANCE Given the role of the prefrontal cortex in relevancy-based facilitation during movement-related gating, these findings lend support to the notion that this brain area may be particularly vulnerable to concussive forces.
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Insola A, Mazzone P, Scarnati E, Restuccia D, Valeriani M. Contribution of different somatosensory afferent input to subcortical somatosensory evoked potentials in humans. Clin Neurophysiol 2021; 132:2357-2364. [PMID: 34454262 DOI: 10.1016/j.clinph.2021.06.033] [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: 03/04/2021] [Revised: 06/04/2021] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To investigate the subcortical somatosensory evoked potentials (SEPs) to electrical stimulation of either muscle or cutaneous afferents. METHODS SEPs were recorded in 6 patients suffering from Parkinson's disease (PD) who underwent electrode implantation in the pedunculopontine (PPTg) nucleus area. We compared SEPs recorded from the scalp and from the intracranial electrode contacts to electrical stimuli applied to: 1) median nerve at the wrist, 2) abductor pollicis brevis motor point, and 3) distal phalanx of the thumb. Also the high-frequency oscillations (HFOs) were analysed. RESULTS After median nerve and pure cutaneous (distant phalanx of the thumb) stimulation, a P1-N1 complex was recorded by the intracranial lead, while the scalp electrodes recorded the short-latency far-field responses (P14 and N18). On the contrary, motor point stimulation did not evoke any low-frequency component in the PPTg traces, nor the N18 potential on the scalp. HFOs were recorded to stimulation of all modalities by the PPTg electrode contacts. CONCLUSIONS Stimulus processing within the cuneate nucleus depends on modality, since only the cutaneous input activates the complex intranuclear network possibly generating the scalp N18 potential. SIGNIFICANCE Our results shed light on the subcortical processing of the somatosensory input of different modalities.
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Affiliation(s)
- Angelo Insola
- Unità Operativa di Neurofisiopatologia, CTO, Rome, Italy
| | - Paolo Mazzone
- Unità Operativa di Neurochirurgia funzionale e stereotassica, CTO, Rome, Italy
| | - Eugenio Scarnati
- Dipartimento di Scienze Cliniche e Biotecnologiche Applicate, Università dell'Aquila, Italy
| | - Domenico Restuccia
- Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Massimiliano Valeriani
- Divisione di Neurologia, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark.
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Lanzone J, Boscarino M, Ricci L, Insola A, Tombini M, Di Lazzaro V, Assenza G. The effects of antiepileptic drugs on high-frequency oscillations in somatosensory evoked potentials. Clin Neurophysiol 2020; 131:1917-1924. [PMID: 32599275 DOI: 10.1016/j.clinph.2020.05.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 01/11/2023]
Abstract
OBJECTIVES High frequency oscillations (HFOs) of Somatosensory evoked potentials (SEPs) reflect the activity of thalamo-cortical and cortical neurons from the sensory pathway. Antiepileptic-drugs (AEDs) reduce seizures acting on the balance between excitation and inhibition. We aimed to study the effect of AED mono and polytherapy on SEP-HFO's components. METHODS Twenty-five patients with focal epilepsy were enrolled for the purpose of this study. Patients were divided in 3 groups according to the number of AEDs (1, 2 or 3 AEDs). Patients in group 1 underwent SEP-HFOs recording in drug naïve condition and at 1 month after AED titration. HFOs were compared in duration, amplitude and latency among the three groups. RESULTS The amplitude and duration of late HFOs of the affected hemisphere (AH) are different between groups and inversely correlated with the number of AEDs. In naïve patients monotherapy reverts the asymmetry in totHFOs (total HFOs) duration. CONCLUSION Our results demonstrate that SEP-HFOs are sensitive to the action of AEDs on cortical excitability. This effect seems to affect mainly the cortical component of HFOs in the AH and it is related to the number of AEDs taken. SIGNIFICANCE SEP-HFOs might be a viable tool to probe cortical excitability changes induced by AEDs.
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Affiliation(s)
- Jacopo Lanzone
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy.
| | - Marilisa Boscarino
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Lorenzo Ricci
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | | | - Mario Tombini
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Vincenzo Di Lazzaro
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Giovanni Assenza
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
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Assenza G, Lanzone J, Insola A, Amatori G, Ricci L, Tombini M, Di Lazzaro V. Thalamo-cortical network dysfunction in temporal lobe epilepsy. Clin Neurophysiol 2019; 131:548-554. [PMID: 31818685 DOI: 10.1016/j.clinph.2019.10.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 10/02/2019] [Accepted: 10/25/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Imaging and neurophysiological data shows that the cortical disfunction caused by focal epilepsy is not limited to the epileptic focus, thus raising the modern vision of focal epilepsy as a network disorder. The involvement of deep thalamo-cortical projections in temporal lobe epilepsy is a clear example. We aimed at demonstrating the interictal functional impairment of thalamo-cortical network in drug-naïve TLE patients through the study of high frequency oscillations of somatosensory evoked potentials (HF-SEP). METHODS Twelve healthy controls (HC; 8 females, 52.2 ± 17.3 years-old) and 12 drug-naïve TLE patients (8 females, 55.5 ± 21.5 years-old) underwent bilateral median HF-SEP, recorded by scalp electrodes. Cp3'-Fz and Cp4'-Fz traces were filtered (400-800 Hz) to evidence HF-SEP. RESULTS HF-SEP duration in the affected hemisphere was significantly longer when compared to that of both the unaffected hemisphere and HC hemispheres. No significant inter-hemispheric differences were found in areas, powers and latencies of HF-SEP wavelets. CONCLUSION Our results demonstrate that TLE induces early interictal functional impairments of the thalamo-cortical network. SIGNIFICANCE Our data strongly corroborates the vision of focal epilepsy as a network disorder and offers a new neurophysiological tool to test pharmacological, surgical and neuromodulatory therapies.
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Affiliation(s)
- Giovanni Assenza
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy.
| | - Jacopo Lanzone
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | | | - Giulia Amatori
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Lorenzo Ricci
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Mario Tombini
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Vincenzo Di Lazzaro
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
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Insola A, Di Lazzaro V, Assenza G. Cortical inhibitory dysfunction in epilepsia partialis continua: A high frequency oscillation somatosensory evoked potential study. Clin Neurophysiol 2019; 130:439-444. [PMID: 30769270 DOI: 10.1016/j.clinph.2019.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 01/11/2023]
Abstract
OBJECTIVE The pathophysiology of epilepsia partialis continua (EPC) is still unclear, a thalamo-cortical circuit dysfunction has been hypothesized. The aim of present study is the functional evaluation of the thalamo-cortical network in EPC by means of the study of low- and high-frequency somatosensory evoked potentials (LF-SEP and HF-SEP). METHODS Median LF-SEP and HF-SEP were recorded in 3 patients with EPC and in 2 patients with rolandic lesions without EPC (non-EPC). Recording electrodes were placed on P3, C3, F3 and P4, C4, F4 of scalp regions. HF-SEP were obtained by an offline 400-800 Hz filtering of P3-F3 and P4-F4 traces. RESULTS In EPC patients, we found a significant suppression of post-synaptic HF-SEP burst and an amplitude reduction of the P24 wave of the LF-SEPs. Both these components are related to cortical inhibitory interneuron activity. HF-SEP and LF-SEP were normal in non-EPC patients. CONCLUSION The different results obtained in patients with a rolandic lesion with and without EPC supports the hypothesis that EPC might be correlated to a dysfunction of gabaergic interneurons of a cortical sensory-motor network. SIGNIFICANCE Our results might contribute to the understanding of the physiological basis of the cortical dysfunction causing epilepsia partialis continua.
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Affiliation(s)
| | - Vincenzo Di Lazzaro
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Giovanni Assenza
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy.
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Macerollo A, Brown MJ, Kilner JM, Chen R. Neurophysiological Changes Measured Using Somatosensory Evoked Potentials. Trends Neurosci 2018; 41:294-310. [DOI: 10.1016/j.tins.2018.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 02/10/2018] [Accepted: 02/12/2018] [Indexed: 01/05/2023]
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Insola A, Mazzone P, Valeriani M. Dorsal column nuclei evoked activity recorded from the human pedunculopontine nucleus. Neurophysiol Clin 2016; 46:315-317. [DOI: 10.1016/j.neucli.2016.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 01/25/2016] [Indexed: 11/26/2022] Open
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Hauck M. Intracranial SEPs recordings - The new way to go? Clin Neurophysiol 2015; 126:2251-2. [PMID: 25936842 DOI: 10.1016/j.clinph.2015.04.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Michael Hauck
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; Department of Neurophysiology, University Medical Center Hamburg-Eppendorf, Germany
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