Functional alterations in cortical processing of speech in glioma-infiltrated cortex

Area of Science:

• Neuroscience
• Oncology
• Computational Neuroscience

Background:

• Malignant gliomas interact with neurons, affecting local brain circuit excitability.
• The capacity of glioma-infiltrated cortex to participate in neural computations remains unclear.
• Gliomas may disrupt neural synchronization or alter spatiotemporal activity patterns.

Purpose of the Study:

• To investigate how glioma-infiltrated cortex participates in neural activity during speech production.
• To compare neural activity patterns in glioma-infiltrated versus normal-appearing cortex.
• To assess the impact of glioma on the brain's ability to encode information for cognitive tasks.

Main Methods:

• Subdural electrocorticography (ECoG) was used to record brain activity from both normal-appearing and glioma-infiltrated cortex during speech tasks.
• Analysis focused on synchronous activity, spatial recruitment, temporal signal entropy, and decoding of word complexity (monosyllabic vs. polysyllabic).

Main Results:

• Glioma-infiltrated cortex exhibited synchronous activity during speech, similar to normal-appearing cortex, but utilized a more diffuse spatial network.
• Signals from glioma-infiltrated cortex showed decreased temporal entropy, suggesting impaired information encoding.
• Temporal decoding of word complexity was feasible in normal-appearing cortex but not in glioma-infiltrated cortex.

Conclusions:

• Glioma-infiltrated cortex retains some capacity for synchronized activity but with altered spatial and temporal dynamics.
• Reduced signal entropy and decoding deficits in glioma-infiltrated cortex may impair cognitive functions, such as speech production.
• Findings offer insights into cognitive processing in glioma patients and inform neuromodulation/prosthetic strategies.