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Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping
Published on: June 26, 2012
Glioma-induced neural functional remodeling in the hand motor cortex: precise mapping with ECoG grids during awake
Tao Chang1, Yihan Wu2,3, Yuxin Quan1
1Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China.
Background:
The dilemma of achieving 'onco-functional balance' in gliomas affecting the motor cortex highlights the importance of functionally-guided resection strategies. While accurate mapping of eloquent areas often requires frequent electrical stimulation, this practice can lead to side effects like seizures and postoperative deficits. To enhance safety in functional mapping, we studied how gliomas impact hand movement areas and assessed the effectiveness of cortical electrical activity for functional mapping in this setting.
Materials And Methods:
We recruited patients with gliomas affecting the motor cortex and individuals with an unaffected motor cortex for awake craniotomy. During the procedures, electrocorticography (ECoG) grids were employed to record signals under three conditions: resting state, finger movements, and wrist movements. We then quantified the distances from the positively stimulated sites to the specific anatomical landmarks. Additionally, we analyzed the relationship between the ECoG power features and the stimulation responses.
Results:
The cortical layout for finger activity in the motor cortex glioma (MCG) group was more dispersed and overlapped, typically clustering near the central sulcus and Sylvian fissure. The predictive performance of ECoG mapping exhibited significant variability across different frequency bands and clinical scenarios. Specifically, the area under the curve (AUC) for the non-MCG group during the resting state reached its peak, with a value of 0.802 for Gamma3 (95% CI = 0.729-0.875) and 0.865 for broadband (95% CI = 0.804-0.926). In contrast, the MCG group achieved the highest AUC during wrist movements, with Gamma3 at 0.785 (95% CI = 0.719-0.849) and broadband at 0.824 (95% CI = 0.753-0.890).
Conclusion:
Gliomas in the motor cortex disrupt the distribution of hand activity, complicating intraoperative functional mapping. As a novel and reliable approach, ECoG technique can complement and guide direct cortical stimulation for precise mapping, potentially reducing its frequency, minimizing the risk of functional deficits, and achieving a balance between maximal tumor resection and neurological preservation.
Insights
Motor cortex gliomas disrupt hand movement mapping. Electrocorticography (ECoG) offers a safer, more precise method for functional mapping during surgery, balancing tumor removal and neurological function.
Area of Science:
- Neurosurgery
- Neuro-oncology
- Brain mapping
Background:
- Gliomas in the motor cortex present a challenge for achieving 'onco-functional balance' during surgical resection.
- Current functional mapping relies on electrical stimulation, which carries risks like seizures and postoperative deficits.
- Understanding how gliomas affect hand motor areas is crucial for improving surgical safety.
Purpose of the Study:
- To investigate the impact of motor cortex gliomas on hand movement representation.
- To evaluate the effectiveness of electrocorticography (ECoG) for functional mapping in patients with motor cortex gliomas.
- To assess ECoG as a tool to enhance safety and precision in functionally-guided tumor resection.
Main Methods:
- Recruited patients with motor cortex gliomas (MCG) and a control group for awake craniotomy.
- Utilized electrocorticography (ECoG) grids to record cortical electrical activity during resting, finger, and wrist movements.
- Quantified distances between stimulated sites and anatomical landmarks, and analyzed ECoG power features against stimulation responses.
Main Results:
- Motor cortex gliomas caused a more dispersed and overlapping cortical layout for finger activity, often near the central sulcus and Sylvian fissure.
- Electrocorticography (ECoG) mapping performance varied by frequency band and clinical condition, with significant predictive power.
- The highest predictive accuracy (AUC) for the glioma group was observed during wrist movements (Gamma3: 0.785, broadband: 0.824), while the control group peaked during rest (Gamma3: 0.802, broadband: 0.865).
Conclusions:
- Motor cortex gliomas significantly alter the organization of hand motor activity, complicating intraoperative functional mapping.
- Electrocorticography (ECoG) serves as a reliable technique to complement direct cortical stimulation for precise functional mapping.
- ECoG can potentially reduce the frequency of electrical stimulation, minimize risks of neurological deficits, and aid in balancing tumor resection with neurological preservation.
