Lesion network mapping is a

neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the neuroanatomy, structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive ...

technique that analyzes the connectivity pattern of brain lesions to identify

neuroanatomic Neuroanatomy is the study of the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defin ...

correlates of symptoms. The technique was developed by

Michael D. Fox Michael D. Fox is an American neurologist and Professor of Neurology at Harvard Medical School where he holds the Raymond Delacy Adams , Raymond D. Adams Distinguished Chair in Neurology and directs the Center for Brain Circuit Therapeutics at ...

and Aaron Boes to understand the network anatomy of lesion induced neurologic and psychiatric symptoms that can not be explained by focal anatomic localization. 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

localization, developed by

Paul Broca Pierre Paul Broca (, also , , ; 28 June 1824 – 9 July 1880) was a French physician, anatomist and anthropologist. He is best known for his research on Broca's area, a region of the frontal lobe that is named after him. Broca's area is involve ...

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. 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. 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. 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 atlas A brain atlas is composed of serial sections along different anatomical planes of the healthy or diseased developing or adult animal or human brain where each relevant brain structure is assigned a number of coordinates to define its outline or vol ...

es. While initially developed using resting-state fMRIs such as the

Human Connectome Project The Human Connectome Project (HCP) was a five-year project (later extended to 10 years) sponsored by sixteen components of the National Institutes of Health, split between two consortia of research institutions. The project was launched in July 20 ...

, the technique has been expanded to include large structural network atlases and multimodal-connectome datasets. Software tools for that facilitate lesion network mapping exist within the

Lead-DBS Lead-DBS is an open-source toolbox for reconstructions and modeling of Deep Brain Stimulation electrodes based on pre- and postoperative MRI & CT imaging. Lead-DBS is available as a MATLAB toolbox or standalone binary for Windows, OS X and Linux ...

framework, 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 Peduncular hallucinosis (PH) is a rare neurological disorder that causes vivid visual hallucinations that typically occur in dark environments and last for several minutes. Unlike some other kinds of hallucinations, the hallucinations that patient ...

, delusional misidentification, reduplicative paramensia,

akinetic mutism Akinetic mutism is a medical condition where patients tend neither to move ( akinesia) nor speak (mutism). It is the most extreme disorder of diminished motivation. Akinetic mutism was first described in 1941 as a mental state where patients lac ...

blindsight Blindsight is the ability of people who are cortically blind to respond to visual stimuli that they do not consciously see due to lesions in the primary visual cortex, also known as the striate cortex or Brodmann Area 17. The term was coined ...

, visual anosognosia), common neurologic syndromes (

seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

aphasia Aphasia, also known as dysphasia, is an impairment in a person's ability to comprehend or formulate language because of dysfunction in specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine, but aph ...

amnesia Amnesia is a deficit in memory caused by brain damage or brain diseases,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be temporarily caused by t ...

parkinsonism Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia (slowed movements), Rigidity (neurology), rigidity, and balance disorder, postural instability. Both hypokinetic features (bradykinesia and akinesia) and hyperkinetic f ...

topographical disorientation Topographical disorientation is the inability to orient oneself in one's surroundings, sometimes as a result of focal brain damage. This disability may result from the inability to make use of selective spatial information (e.g., environmental l ...

), psychiatric syndromes ( depression,

mania Mania, also known as manic syndrome, is a Psychiatry, psychiatric Abnormality (behavior), behavioral syndrome defined as a state of Abnormality (behavior), abnormally elevated arousal, affect (psychology), affect, and energy level. During a mani ...

), as well as complex human behaviors (spirituality, religious fundamentalism, consciousness, free will, criminality, addiction). The technique has been successfully applied to a broad range of diseases and lesion types including lesions due to stroke, traumatic brain injury, tuberous sclerosis and multiple sclerosis. The technique has been broadened to map the connectivity of locations from

transcranial magnetic stimulation Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation technique in which a changing magnetic field is used to induce an electric current in a targeted area of the brain through electromagnetic induction. A device called a st ...

and

deep brain stimulation Deep brain stimulation (DBS) is a type of neurostimulation therapy in which an implantable pulse generator is stereotactic surgery, surgically implanted subcutaneous tissue, below the skin of the chest and connected by Lead (electronics), leads ...

sites to understand treatment responsiveness. Research findings based on lesion network mapping have been reported in the

New York Times ''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of ...

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...

and

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and the term has been included in the

New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. Founded in 1812, the journal is among the most prestigious peer-reviewed medical journals. Its 2023 impact factor was ...

's general medical glossary.

References

{{Reflist Neuroimaging Neurology Neural networks Cognitive neuroscience Brain disorders Data analysis