Lesion network mapping

Lesion network mapping is a neuroimaging technique that analyzes the connectivity pattern of brain lesions to identify neuroanatomic correlates of symptoms.^[1][2][3] The scientific validity of these methods has been widely disputed.^[4][5] The technique was developed by Aaron Boes to understand the network anatomy of lesion induced neurologic and psychiatric symptoms that can not be explained by focal anatomic localization.^[6][7] Lesion network mapping applies a network-based approach to identify connected brain networks, rather than focal brain regions, that correlate with a specific symptom.

In focal neuroanatomic localization, developed by Paul Broca and others, specific symptoms that occur due to brain lesions can be understood by identifying a specific brain region that is injured by lesions to establish brain-symptom relationships.^[2] However, a number of neurologic symptoms, such as peduncular hallucinosis, are not amenable to this approach since the lesions associated with the symptom do not map to one focal brain location.^[1] Lesion network mapping helps to explain these lesion-induced syndromes by showing that lesion locations associated with a given symptom all map to a shared brain network even if they do not all map to a focal brain region.^[2] The technique maps the location of lesions associated with a specific symptom and analyzes the connectivity pattern of the lesions compared to large, standardized human brain atlases. While initially developed using resting-state fMRIs such as the Human Connectome Project,^[1] the technique has been expanded to include large structural network atlases ^[8] and multimodal-connectome datasets.^[9] Software tools for that facilitate lesion network mapping exist within the Lead-DBS framework,^[10] which is also used for a related technique, DBS network mapping.

Lesion network mapping has helped map the network anatomy of numerous rare neurologic syndromes (peduncular hallucinosis,^[1] delusional misidentification,^[11] reduplicative paramensia,^[12] akinetic mutism,^[13] blindsight,^[14] visual anosognosia^[15]), common neurologic syndromes (seizures,^[16] aphasia,^[17] amnesia,^[18] parkinsonism,^[19] topographical disorientation^[20]), psychiatric syndromes^[21] (depression,^[22][23] mania^[24]), as well as complex human behaviors (spirituality,^[25] religious fundamentalism,^[26] consciousness,^[27][28] free will,^[13] criminality,^[29] addiction^[30]). The technique has been successfully applied to a broad range of diseases and lesion types including lesions due to stroke,^[1] traumatic brain injury,^[25] tuberous sclerosis^[31][32] and multiple sclerosis.^[33][34] The technique has been broadened to map the connectivity of locations from transcranial magnetic stimulation^[23] and deep brain stimulation^[35] sites to understand treatment responsiveness.

Research findings based on lesion network mapping have been reported in the New York Times,^[36] Scientific American^[37] and USA Today^[38] and the term has been included in the New England Journal of Medicine's general medical glossary.^[3]