Summary: Researchers report that otherwise healthy people who experience subtle psychotic-like symptoms—such as brief hallucinations or unusual beliefs—exhibit altered patterns of brain activity over time.
Source: Elsevier.
New research published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging finds that healthy adults who report psychotic-like experiences (PLEs) spend less time in recurring brain activity patterns associated with typical cognitive function. Instead, these participants more often occupy brain states marked by excessive communication among visual regions and reduced coordination within the default mode network. These dynamic changes—how the brain moves between discrete, reoccurring states—offer a potential biomarker for subclinical psychosis and help explain why subtle symptoms can affect social and occupational functioning.
Past studies of PLEs focused mainly on altered connections within specific brain networks. This study extends those findings by showing that it is not only which networks are connected that matters, but also the amount of time the brain spends in certain states. In other words, shifts in the temporal dynamics of brain network activity may contribute to the emergence of psychotic-like symptoms even in individuals without a diagnosed disorder.
“These altered brain dynamics are important because they provide a new biomarker for subclinical psychosis,” said Dr. Anita Barber of the Feinstein Institute for Medical Research in New York, the study’s lead author. Although the participants were considered healthy by clinical standards, those reporting PLEs displayed distinct fluctuations across functional brain states that could help identify risk or early signs of psychosis.
Using resting-state functional MRI data from the Human Connectome Project, Dr. Barber and colleagues analyzed 76 participants who endorsed PLEs and 153 matched control participants. The team applied dynamic functional connectivity methods—specifically Dynamic Conditional Correlation combined with k-means clustering—to identify recurrent large-scale brain states and to measure how long individuals remained in each state and how often they transitioned between them.
Compared with controls, participants reporting PLEs spent significantly less time in a state characterized by strong, well-organized within-network connectivity and clear anti-correlations of the default mode network—an arrangement associated with goal-directed thought and flexible cognition. Instead, the PLE group spent more time in a state showing hyper-connectivity in visual brain regions alongside hypo-connectivity in the default mode network. The increased engagement of visual sensory processing networks may underlie visual hallucinations and related perceptual disturbances observed in psychosis, while reduced default mode coordination may reflect diminished internal cognitive integration.
The study also linked these dynamic patterns to cognitive performance. Within the PLE group, poorer executive function correlated with more time spent in the visual-hyperconnected state and with more transitions into that state, as well as with less time spent in states reflecting typical connectivity. These relationships suggest that dynamic brain measures capture behaviorally meaningful variation related to everyday functioning.
Dr. Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, noted that the work demonstrates how advanced analyses of time-varying brain activity can reveal subtle risk states. Tracking transitions between mental states over time may offer sensitive markers to identify individuals at elevated risk and to monitor trajectories from subclinical symptoms to clinically significant disorders.
These findings carry potential clinical implications. Because PLEs affect a larger portion of the population than the subset who later develop psychotic disorders, identifying dynamic brain signatures could improve early detection and prevention strategies. Dr. Barber suggests that interventions promoting goal-directed activities and reducing excessive engagement of visual sensory processing might help restore healthier brain dynamics and reduce symptom impact, although clinical trials would be needed to test such approaches.
Source: Rhiannon Bugno – Elsevier
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Dynamic Functional Connectivity States Reflecting Psychotic-Like Experiences” by Anita D. Barber, Martin A. Lindquist, Pamela DeRosse, Katherine H. Karlsgodt in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online September 28, 2017. doi:10.1016/j.bpsc.2017.09.008
MLA: Elsevier. “People with Psychotic-Like Experiences Spend Less Time in Healthy Brain States.” NeuroscienceNews. NeuroscienceNews, 1 November 2017.
APA: Elsevier (2017, November 1). People with Psychotic-Like Experiences Spend Less Time in Healthy Brain States. NeuroscienceNews. Retrieved November 1, 2017.
Chicago: Elsevier. “People with Psychotic-Like Experiences Spend Less Time in Healthy Brain States.” (accessed November 1, 2017).
Abstract
Dynamic Functional Connectivity States Reflecting Psychotic-Like Experiences
Background
Psychotic-like experiences (PLEs) are associated with reduced social and occupational functioning and with lower executive function. Emerging evidence indicates that PLEs reflect neural dysfunction similar to that observed in psychotic disorders, suggesting shared mechanistic features across the psychosis spectrum.
Methods
This study examined dynamic functional connectivity in an otherwise-healthy adult sample from the Human Connectome Project. The analysis focused on a PLE measure derived from the Achenbach Adult Self-Report. The final sample included 76 participants endorsing PLEs and 153 control participants. To characterize large-scale network dynamics, the researchers applied Dynamic Conditional Correlation (DCC) to resting-state fMRI data and clustered recurring connectivity patterns with k-means clustering.
Results
Three distinct dynamic states emerged. Compared with controls, the PLE-endorsing group spent more time in State 1, characterized by hyper-connectivity within visual regions and hypo-connectivity in the default mode network. They spent less time in State 2, a state showing robust within-network connectivity across major networks and pronounced default mode anti-correlations. Within the PLE group, poorer executive function was linked to greater time spent in and more transitions into State 1, and to reduced time spent in and fewer transitions into State 3.
Conclusions
Psychotic-like experiences are associated with altered large-scale brain dynamics that shift the system away from typical connectivity patterns and toward states marked by visual hyper-connectivity and default mode hypo-connectivity. These dynamic measures may serve as biomarkers for subclinical psychosis and help guide future prevention and intervention efforts.
“Dynamic Functional Connectivity States Reflecting Psychotic-Like Experiences” by Anita D. Barber, Martin A. Lindquist, Pamela DeRosse, Katherine H. Karlsgodt in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online September 28, 2017. doi:10.1016/j.bpsc.2017.09.008