Non-invasive Neuromodulation Targeting Approach by Mapping Stimulations and Lesions That Modify Visual Memory

Area of Science:

• Neuroscience
• Cognitive Neurology
• Neuromodulation

Background:

• Therapeutic brain stimulation aims to target specific neural networks, but precise targeting for memory remains challenging.
• Current methods often map connectivity of lesions and stimulation sites to symptoms, yielding networks for global memory but lacking specificity for distinct memory types.

Purpose of the Study:

• To identify and map neural networks associated with specific memory types, particularly visual memory, using connectivity data from stimulation and lesion studies.
• To investigate the influence of age at the time of injury or stimulation on these memory networks.
• To identify optimal neuromodulation targets for memory enhancement based on derived networks.

Main Methods:

• Connectivity mapping of stimulation sites, lesions, and atrophy patterns across three datasets (TMS, head trauma, stroke) totaling 544 individuals.
• Analysis of age-dependent effects on visual memory networks, validated in a preclinical Alzheimer's disease dataset (N=1240).
• Electrical field modeling of transcranial magnetic stimulation (TMS) sites to identify optimal neuromodulation targets intersecting with identified networks.

Main Results:

• A distinct network linked to visual memory changes was identified, with lesion and stimulation effects showing an inverted direction based on age.
• This age-dependent effect was replicated in an independent cohort with preclinical Alzheimer's disease.
• Derived neuromodulation targets intersected with known effective sites like the precuneus and dorsolateral prefrontal cortex, with peak intersections in the medial posterior parietal lobe and angular gyrus.

Conclusions:

• Neuromodulation targets for visual memory are distinct and show age-dependent effects.
• The medial posterior parietal lobe and angular gyrus are promising targets for neuromodulation aimed at visual memory.
• Further clinical trials are necessary to compare the efficacy of these identified targets.