Spectral changes in motor thalamus field potentials during movement

Area of Science:

• Neuroscience
• Sensorimotor Integration
• Electrophysiology

Background:

• The motor thalamus integrates sensorimotor information, but its spectral activity during movement is not fully understood.
• Movement-associated spectral changes in the motor cortex are known, but corresponding thalamic activity, especially broadband power, remains unclear.

Purpose of the Study:

• To characterize spectral changes in the human motor thalamus during hand movements.
• To investigate broadband power changes in the motor thalamus.
• To explore potential electrophysiological biomarkers for thalamic functional mapping and deep brain stimulation (DBS).

Main Methods:

• Analysis of field potential recordings from 15 subjects undergoing awake DBS surgery targeting the ventral intermediate (Vim) nucleus.
• Examination of power changes in low-frequency oscillations (<30 Hz) and broadband power (65-115 Hz) during hand movements.
• Inclusion of an imagined movement task in one subject.

Main Results:

• Widespread decreases in low-frequency oscillations (<30 Hz) were observed with movement, consistent with prior studies.
• Significant increases in broadband power (65-115 Hz) were found to be spatially discrete, mainly at inferior recording sites in the ventral thalamus.
• Low-frequency oscillations were suppressed during an imagined movement task.

Conclusions:

• Movement-associated spectral changes, particularly focal broadband power increases, occur in the human motor thalamus.
• These findings suggest broadband power changes can serve as biomarkers for intraoperative thalamic functional mapping.
• The identified biomarkers may enhance DBS targeting and enable closed-loop device applications.