scholarly journals Intraoperative mapping of pre-central motor cortex and subcortex: a proposal for supplemental cortical and novel subcortical maps to Penfield’s motor homunculus

2021 ◽  
Author(s):  
Prajwal Ghimire ◽  
Jose Pedro Lavrador ◽  
Asfand Baig Mirza ◽  
Noemia Pereira ◽  
Hannah Keeble ◽  
...  
Keyword(s):  
Brain Mapping ◽  
Retrospective Cohort ◽  
Corticospinal Tract ◽  
Brain Lesions ◽  
Body Parts ◽  
Single Institution ◽  
Motor Representation ◽  
Motor Mapping ◽  
Subcortical Stimulation ◽  
Motor Maps

AbstractPenfield’s motor homunculus describes a caricaturised yet useful representation of the map of various body parts on the pre-central cortex. We propose a supplemental map of the clinically represented areas of human body in pre-central cortex and a novel subcortical corticospinal tract map. We believe this knowledge is essential for safe surgery in patients with eloquent brain lesions. A single-institution retrospective cohort study of patients who underwent craniotomy for motor eloquent lesions with intraoperative motor neuromonitoring (cortical and subcortical) between 2015 and 2020 was performed. All positive cortical and subcortical stimulation points were taken into account and cartographic maps were produced to demonstrate cortical and subcortical areas of motor representation and their configuration. A literature review in PubMed was performed. One hundred and eighty consecutive patients (58.4% male, 41.6% female) were included in the study with 81.6% asleep and 18.4% awake craniotomies for motor eloquent lesions (gliomas 80.7%, metastases 13.8%) with intraoperative cortical and subcortical motor mapping. Based on the data, we propose a supplemental clinical cortical and a novel subcortical motor map to the original Penfield’s motor homunculus, including demonstration of localisation of intercostal muscles both in the cortex and subcortex which has not been previously described. The supplementary clinical cortical and novel subcortical motor maps of the homunculus presented here have been derived from a large cohort of patients undergoing direct cortical and subcortical brain mapping. The information will have direct relevance for improving the safety and outcome of patients undergoing resection of motor eloquent brain lesions.

scholarly journals Intraoperative mapping of pre-central motor cortex and subcortex: a proposal for supplemental cortical and novel subcortical maps to Penfield’s motor homunculus

2020 ◽  
Author(s):  
Prajwal Ghimire ◽  
Jose Lavrador ◽  
Asfand Mirza ◽  
Noemia Pereira ◽  
Hannah Keeble ◽  
...  
Keyword(s):  
Brain Mapping ◽  
Retrospective Cohort ◽  
Corticospinal Tract ◽  
Brain Lesions ◽  
Body Parts ◽  
Single Institution ◽  
Motor Representation ◽  
Motor Mapping ◽  
Subcortical Stimulation ◽  
Motor Maps

Abstract Introduction: Penfield’s motor homunculus describes a caricaturised yet useful representation of the map of various body parts on the pre-central cortex. We propose a supplemental map of the clinically represented areas of human body in pre-central cortex and a novel subcortical corticospinal tract map that are accurate and essential for safe surgery in patients with eloquent brain lesions. Materials and methods: A single-institution retrospective cohort study of patients who underwent craniotomy for motor eloquent lesions with intraoperative motor neuromonitoring (cortical and subcortical) between 2015 and 2020 was performed. All positive cortical and subcortical stimulation points were taken into account and cartographic maps were produced to demonstrate cortical and subcortical areas of motor representation and their configuration. A literature review in PubMed was performed. Results: 180 patients (58.4% male, 41.6% female) were included in the study with 81.6% asleep and 18.4% awake craniotomies for motor eloquent lesions (gliomas 80.7%, metastases 13.8%) with intraoperative cortical and subcortical motor mapping. Based on the data, we propose a supplemental clinical cortical and a novel subcortical motor map to the original Penfield’s motor homunculus, including demonstration of localisation of intercostal muscles both in the cortex and subcortex which has not been previously described. Conclusion: The supplementary clinical cortical and novel subcortical motor maps of the homunculus presented here have been derived from a large cohort of patients undergoing direct cortical and subcortical brain mapping. The information will have direct relevance for improving the safety and outcome of patients undergoing resection of motor eloquent brain lesions.

scholarly journals Short-Interval Intracortical Facilitation Improves Efficacy in nTMS Motor Mapping of Lower Extremity Muscle Representations in Patients with Supra-Tentorial Brain Tumors

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3233
Author(s):  
Haosu Zhang ◽  
Petro Julkunen ◽  
Axel Schröder ◽  
Anna Kelm ◽  
Sebastian Ille ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Corticospinal Tract ◽  
Short Interval ◽  
Single Pulse ◽  
Brain Lesions ◽  
Motor Mapping ◽  
Lower Extremity Muscle ◽  
Biphasic Pulse ◽  
Motor Maps ◽  
Using Data

Navigated transcranial magnetic stimulation (nTMS) is increasingly used for mapping of motor function prior to surgery in patients harboring motor-eloquent brain lesions. To date, single-pulse nTMS (sp-nTMS) has been predominantly used for this purpose, but novel paired-pulse nTMS (pp-nTMS) with biphasic pulse application has been made available recently. The purpose of this study was to systematically evaluate pp-nTMS with biphasic pulses in comparison to conventionally used sp-nTMS for preoperative motor mapping of lower extremity (lE) muscle representations. Thirty-nine patients (mean age: 56.3 ± 13.5 years, 69.2% males) harboring motor-eloquent brain lesions of different entity underwent motor mapping of lE muscle representations in lesion-affected hemispheres and nTMS-based tractography of the corticospinal tract (CST) using data from sp-nTMS and pp-nTMS with biphasic pulses, respectively. Compared to sp-nTMS, pp-nTMS enabled motor mapping with lower stimulation intensities (61.8 ± 13.8% versus 50.7 ± 11.6% of maximum stimulator output, p < 0.0001), and it provided reliable motor maps even in the most demanding cases where sp-nTMS failed (pp-nTMS was able to provide a motor map in five patients in whom sp-nTMS did not provide any motor-positive points, and pp-nTMS was the only modality to provide a motor map in one patient who also did not show motor-positive points during intraoperative stimulation). Fiber volumes of the tracked CST were slightly higher when motor maps of pp-nTMS were used, and CST tracking using pp-nTMS data was also possible in the five patients in whom sp-nTMS failed. In conclusion, application of pp-nTMS with biphasic pulses enables preoperative motor mapping of lE muscle representations even in the most challenging patients in whom the motor system is at high risk due to lesion location or resection.

scholarly journals Forearm and hand muscles exhibit high coactivation and overlapping of cortical motor representations

2021 ◽  
Author(s):  
Gabriela Pazin Tardelli ◽  
Victor Hugo Souza ◽  
Renan Hiroshi Matsuda ◽  
Marco Antonio Cavalcanti Garcia ◽  
Maria Nazarova ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Functional Organization ◽  
Motor Representation ◽  
Motor Mapping ◽  
Hand Muscles ◽  
Cortical Motor ◽  
Forearm Muscles ◽  
Motor Maps ◽  
Motor Representations ◽  
Intrinsic Hand Muscles

Most of the motor mapping procedures using navigated transcranial magnetic stimualiton (nTMS) follows the conventional somatotopic organization of the primary motor cortex (M1) by assessesing the representation of a particular target muscle, disregarding the possible coactivation of synergistic muscles. In turn, multiple reports describe a functional organization of the M1 with an overlapping among motor representations acting together to execute movements. In this context, the overlap degree among cortical representations of synergistic hand and forearm muscles remains an open question. This study aimed to evaluate the muscle coactivation and representation overlapping common to the grasping movement and its dependence on the mapping parameters. The nTMS motor maps were obtained from one carpal muscle and two intrinsic hand muscles during rest. We quantified the overlappig motor maps in terms of the size (area and volume overlap degree) and topography (similarity and centroid's Euclidian distance) parameters. We demonstrated that these muscle representations are highly overlapped and similar in shape. The overlap degrees involving the forearm muscles were significantly higher than only among the intrinsic hand muscles. Moreover, the stimulation intensity had a stronger effect on the size compared to the topography parameters. Our study contributes to a more detailed cortical motor representation towards a synergistic, functional arrangement of M1. Understanding the muscle group coactivation may provide more accurate motor maps when delineating the eloquent brain tissue during pre-surgical planning.

scholarly journals Continuous subcortical motor evoked potential stimulation using the tip of an ultrasonic aspirator for the resection of motor eloquent lesions

2015 ◽  
Vol 123 (2) ◽  
pp. 301-306 ◽  
Author(s):  
Ehab Shiban ◽  
Sandro M. Krieg ◽  
Thomas Obermueller ◽  
Maria Wostrack ◽  
Bernhard Meyer ◽  
...  
Keyword(s):  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Neurophysiological Monitoring ◽  
Subtotal Resection ◽  
Motor Mapping ◽  
Monopolar Stimulation ◽  
Subcortical Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

OBJECT Resection of a motor eloquent lesion has become safer because of intraoperative neurophysiological monitoring (IOM). Stimulation of subcortical motor evoked potentials (scMEPs) is increasingly used to optimize patient safety. So far, scMEP stimulation has been performed intermittently during resection of eloquently located lesions. Authors of the present study assessed the possibility of using a resection instrument for continuous stimulation of scMEPs. METHODS An ultrasonic surgical aspirator was attached to an IOM stimulator and was used as a monopolar subcortical stimulation probe. The effect of the aspirator’s use at different ultrasound power levels (0%, 25%, 50%, 75%, and 100%) on stimulation intensity was examined in a saline bath. Afterward monopolar stimulation with the surgical aspirator was used during the resection of subcortical lesions in the vicinity of the corticospinal tract in 14 patients in comparison with scMEP stimulation via a standard stimulation electrode. During resection, the stimulation current at which an MEP response was still measurable with subcortical stimulation using the surgical aspirator was compared with the corresponding stimulation current needed using a standard monopolar subcortical stimulation probe at the same location. RESULTS The use of ultrasound at different energy levels did result in a slight but irrelevant increase in stimulation energy via the tip of the surgical aspirator in the saline bath. Stimulation of scMEPs using the surgical aspirator or monopolar probe was successful and almost identical in all patients. One patient developed a new permanent neurological deficit. Transient new postoperative paresis was observed in 28% (4 of 14) of cases. Gross-total resection was achieved in 64% (9 of 14) cases and subtotal resection (> 80% of tumor mass) in 35% (5 of 14). CONCLUSIONS Continuous motor mapping using subcortical stimulation via a surgical aspirator, in comparison with the sequential use of a standard monopolar stimulation probe, is a feasible and safe method without any disadvantages. Compared with the standard probe, the aspirator offers continuous information on the distance to the corticospinal tract.

Neurophysiologic Mapping of Thalamocortical Tract in Asleep Craniotomies: Promising Results From an Early Experience

2020 ◽  
Author(s):  
Mirela V Simon ◽  
Daniel K Lee ◽  
Bryan D Choi ◽  
Pratik A Talati ◽  
Jimmy C Yang ◽  
...  
Keyword(s):  
General Anesthesia ◽  
Corticospinal Tract ◽  
Sensory Function ◽  
Motor Deficit ◽  
Motor Deficits ◽  
Central Sulcus ◽  
Postcentral Gyrus ◽  
Subcortical Stimulation ◽  
Subcortical Mapping

Abstract BACKGROUND Subcortical mapping of the corticospinal tract has been extensively used during craniotomies under general anesthesia to achieve maximal resection while avoiding postoperative motor deficits. To our knowledge, similar methods to map the thalamocortical tract (TCT) have not yet been developed. OBJECTIVE To describe a neurophysiologic technique for TCT identification in 2 patients who underwent resection of frontoparietal lesions. METHODS The central sulcus (CS) was identified using the somatosensory evoked potentials (SSEP) phase reversal technique. Furthermore, monitoring of the cortical postcentral N20 and precentral P22 potentials was performed during resection. Subcortical electrical stimulation in the resection cavity was done using the multipulse train (case #1) and Penfield (case #2) techniques. RESULTS Subcortical stimulation within the postcentral gyrus (case #1) and in depth of the CS (case #2), resulted in a sudden drop in amplitudes in N20 (case #1) and P22 (case #2), respectively. In both patients, the potentials promptly recovered once the stimulation was stopped. These results led to redirection of the surgical plane with avoidance of damage of thalamocortical input to the primary somatosensory (case #1) and motor regions (case #2). At the end of the resection, there were no significant changes in the median SSEP. Both patients had no new long-term postoperative sensory or motor deficit. CONCLUSION This method allows identification of TCT in craniotomies under general anesthesia. Such input is essential not only for preservation of sensory function but also for feedback modulation of motor activity.

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