Cortical Stimulation Site Mapping Using Heart Rate Feedback
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Solution Overview
Problem
Existing methods for targeting cortical areas for neuromodulation techniques, such as TMS, are often inaccurate and rely on anatomical assumptions, failing to account for functional connectivity to deeper brain regions like the ventromedial prefrontal cortex, which may limit therapeutic efficacy.
Innovation Solution
A method and system using transcranial magnetic stimulation (TMS) to identify cortical stimulation sites by measuring psychophysiological signals, particularly heart rate changes, to optimize targeting of the ventromedial prefrontal cortex, including the subgenual and rostral anterior cingulate, through trans-synaptic connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If anatomical assumptions are used to target cortical areas for neuromodulation, then the targeting process is simple, but the accuracy of identifying functionally connected cortical areas to deep brain regions is poor
Solution Approach 1:
The system employs real-time feedback by monitoring psychophysiological signals (heart rate, skin conductance, respiration) during TMS stimulation to identify cortical areas with functional connectivity to deep brain regions. The feedback loop allows dynamic adjustment of stimulation parameters and identification of target areas based on actual physiological responses rather than static anatomical assumptions.
Solution Approach 2:
Psychophysiological signals serve as intermediaries that bridge the gap between cortical stimulation and deep brain region activity. These measurable signals (heart rate variability, skin conductance) act as proxies for unconscious autonomic nervous system activity, allowing indirect measurement of functional connectivity to deep brain structures like the amygdala and insula.
2Reliability
If transcranial magnetic stimulation is applied to identify cortical areas connected to deep brain regions, then functional connectivity can be mapped, but the procedure becomes more complex and time-consuming
Solution Approach 1:
The system performs preliminary identification of functionally connected cortical areas through TMS mapping before actual therapeutic treatment begins. This preliminary phase establishes the optimal stimulation targets based on individual functional connectivity patterns, ensuring that subsequent therapy is applied to the most effective locations for each patient.
Solution Approach 2:
The identification process uses periodic TMS pulses delivered at systematic intervals across different cortical locations, with each pulse followed by measurement of psychophysiological responses. This periodic stimulation pattern allows efficient mapping of functional connectivity across the cortical surface without requiring continuous stimulation.
3Ease of operation
If anatomical landmarks are used for TMS coil positioning, then the procedure is easy to perform, but the precision of targeting specific functional cortical areas is insufficient
Solution Approach 1:
The system replaces reliance on mechanical/anatomical landmarks for positioning with a functional mapping approach. Instead of using skull surface anatomy to estimate cortical locations, the system uses TMS-evoked psychophysiological responses to identify functionally relevant areas, substituting mechanical positioning with physiological feedback-based localization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Precisely identifies functional cortical areas for neuromodulation, enhancing therapeutic efficacy by directly targeting the ventromedial prefrontal cortex, which is otherwise inaccessible due to its depth, and allowing real-time verification of stimulation accuracy.
Implementation Method 1
applying pulses of a second a focal-neuromodulation technique to different cortical areas of said subject; wherein the second focal-neuromodulation technique comprises transcranial stimulation
Data Source
Figure 1
AI summary
The invention relates to a method for identifying at least one cortical stimulation site in a subject for the application as a target that can be used for treatment of a psychiatric or neurological disorder related to a deep brain region of the ventromedial prefrontal cortex including the subgenual and rostral anterior cingulate by using a first focal-neuromodulation technique, said method comprising: -applying pulsesof a second a focal-neuromodulation technique to different cortical areas of said subject; -simultaneously with the application of said pulses at a said cortical area measuring a psychophysiological signal representative of a heart rate of said subject for said cortical area, and -when observing a systematic change in said psychophysiological signal, identifying a corresponding cortical area as said at least one cortical stimulation site that is functionally connected to said deep brain region of the ventromedial prefrontal cortex including the subgenual and rostral anterior cingulate for presenting said target for said treatment.