Injury to specific brain connections could explain some people’s criminal behavior, study finds

Over the past decades, some lawyers have started using brain imaging scans as evidence during criminal trials, to provide a possible explanation for the criminal behavior of defendants. This was justified by recent neuroscientific studies, which found that some people who commit crimes present differences in specific parts of the brain. Yet a key question remains: are these brain changes causal, compensatory or incidental to the behavior?

To answer this question, researchers at Brigham and Women’s Hospital, Harvard Medical School and other institutes in the U.S. analyzed the locations of brain injury temporally associated with a new onset of criminality.

They found evidence suggesting that lesions to a specific white matter tract could be causally implicated in the behavior of individuals who start committing crimes after injury.

Their findings, published in Molecular Psychiatry, could help inform future juridical and medical practices, helping lawyers, judges and neurologists to identify individuals who might have been prompted to commit crimes as a result of injuries, strokes or other diseases.

“During my Behavioral Neurology training I had the unique opportunity to evaluate patients who began committing acts of violence with the onset of brain tumors or degenerative diseases,” Isaiah Kletenik, MD and first author of the paper, told Medical Xpress.

“While it is generally accepted that brain injury can lead to problems with memory or motor function, the role of the brain in guiding social behaviors like criminality is more controversial as it touches on the concepts of moral culpability and free will.

“These clinical cases prompted my curiosity into the brain basis of moral decision-making and led me to learn new network-based neuroimaging techniques at the Center for Brain Circuit Therapeutics at Brigham and Women’s Hospital and Harvard Medical School.”

The primary objective of the recent study by Kletenik and his colleagues was to pin-point specific patterns of brain injury that are associated with newly exhibited violent and criminal behavior, particularly in individuals that were previously unaggressive and law-abiding.

To unveil these patterns, they studied rare clinical cases, specifically those from patients who started committing crimes after a brain injury.

“We mapped the locations of brain injury from 17 cases of lesion-induced criminality and calculated the structural connections from a large brain atlas derived from 178 healthy controls,” explained Kletenik. “We then compared the connections associated with criminality to 706 control lesions from brain injuries associated with other symptoms such as memory loss or depression.”

When they analyzed the imaging data of the 17 patients and compared it to that of individuals with no history of criminality, Kletenik and his colleagues uncovered a pattern of brain injury that appeared to be most strongly linked to the emergence of criminal behavior, particularly violent offenses. This pattern was characterized by lesions to a specific white matter tract known as the right uncinate, which connects brain regions responsible for emotion processing with other regions involved in decision-making.

“Structural brain imaging is increasingly being introduced as evidence in criminal trials, yet there is limited scientific research to guide how such data is interpreted,” said Kletenik.

“A key question in the courtroom is often whether a specific white matter brain injury identified on a brain scan is incidental, correlated or causal to a behavior. Our results suggest that if an individual has a new brain injury to specific white matter locations, especially to the right uncinate fasciculus, and has new onset criminal behavior, there is an increased likelihood that the injury plays a causal role in the behavior.”

The results of this recent study suggest that lesions to the right uncinate fasciculus, whether as a result of physical trauma or a disease, can help to explain why some injured individuals suddenly start committing crimes.

Further research could examine the link between these specific lesions and criminal behavior, potentially examining an even larger pool of clinical cases.

“These findings can help assess whether focal brain injuries may be implicated in new-onset criminality and contribute to our growing knowledge about how social behavior is mediated by the brain,” added Kletenik.

© 2025 Science X Network

Over the past decades, some lawyers have started using brain imaging scans as evidence during criminal trials, to provide a possible explanation for the criminal behavior of defendants. This was justified by recent neuroscientific studies, which found that some people who commit crimes present differences in specific parts of the brain. Yet a key question remains: are these brain changes causal, compensatory or incidental to the behavior?

To answer this question, researchers at Brigham and Women’s Hospital, Harvard Medical School and other institutes in the U.S. analyzed the locations of brain injury temporally associated with a new onset of criminality.

They found evidence suggesting that lesions to a specific white matter tract could be causally implicated in the behavior of individuals who start committing crimes after injury.

Their findings, published in Molecular Psychiatry, could help inform future juridical and medical practices, helping lawyers, judges and neurologists to identify individuals who might have been prompted to commit crimes as a result of injuries, strokes or other diseases.

“During my Behavioral Neurology training I had the unique opportunity to evaluate patients who began committing acts of violence with the onset of brain tumors or degenerative diseases,” Isaiah Kletenik, MD and first author of the paper, told Medical Xpress.

“While it is generally accepted that brain injury can lead to problems with memory or motor function, the role of the brain in guiding social behaviors like criminality is more controversial as it touches on the concepts of moral culpability and free will.

“These clinical cases prompted my curiosity into the brain basis of moral decision-making and led me to learn new network-based neuroimaging techniques at the Center for Brain Circuit Therapeutics at Brigham and Women’s Hospital and Harvard Medical School.”

The primary objective of the recent study by Kletenik and his colleagues was to pin-point specific patterns of brain injury that are associated with newly exhibited violent and criminal behavior, particularly in individuals that were previously unaggressive and law-abiding.

To unveil these patterns, they studied rare clinical cases, specifically those from patients who started committing crimes after a brain injury.

“We mapped the locations of brain injury from 17 cases of lesion-induced criminality and calculated the structural connections from a large brain atlas derived from 178 healthy controls,” explained Kletenik. “We then compared the connections associated with criminality to 706 control lesions from brain injuries associated with other symptoms such as memory loss or depression.”

When they analyzed the imaging data of the 17 patients and compared it to that of individuals with no history of criminality, Kletenik and his colleagues uncovered a pattern of brain injury that appeared to be most strongly linked to the emergence of criminal behavior, particularly violent offenses. This pattern was characterized by lesions to a specific white matter tract known as the right uncinate, which connects brain regions responsible for emotion processing with other regions involved in decision-making.

“Structural brain imaging is increasingly being introduced as evidence in criminal trials, yet there is limited scientific research to guide how such data is interpreted,” said Kletenik.

“A key question in the courtroom is often whether a specific white matter brain injury identified on a brain scan is incidental, correlated or causal to a behavior. Our results suggest that if an individual has a new brain injury to specific white matter locations, especially to the right uncinate fasciculus, and has new onset criminal behavior, there is an increased likelihood that the injury plays a causal role in the behavior.”

The results of this recent study suggest that lesions to the right uncinate fasciculus, whether as a result of physical trauma or a disease, can help to explain why some injured individuals suddenly start committing crimes.

Further research could examine the link between these specific lesions and criminal behavior, potentially examining an even larger pool of clinical cases.

“These findings can help assess whether focal brain injuries may be implicated in new-onset criminality and contribute to our growing knowledge about how social behavior is mediated by the brain,” added Kletenik.

© 2025 Science X Network