The speed of human thought does not always move at the same pace. While it reacts immediately to imminent danger, it pauses to contemplate in the face of complex judgments. The brain simultaneously handles information that requires instantaneous reactions and interprets context and meaning while processing information slowly. This characteristic of the brain, where quick reactions and slow thinking operate simultaneously, seems so obvious, yet the way it is coordinated has not been clearly explained for a long time.
According to new research recently revealed, different areas of the brain operate with distinct internal clocks and share information from different time zones through white matter networks. The efficiency with which the white matter network coordinates the fast and slow information processing of each brain area affects the efficiency of thought, decision-making, and behavior, which can lead to differences in cognitive abilities among individuals.
Recently, a research team led by Professor Linden Parks from Rutgers University’s Department of Psychiatry has elucidated how the brain connects areas with different 'internal times' to create cognitive functions, publishing their findings in the latest issue of the international journal ⟪Nature Communications⟫, as reported by science media such as Science Daily.
The study found that different areas of the brain do not operate at the same speed and function with unique information retention times, known as 'intrinsic neural timescales (INTs)'. By coordinating these differences in time scales through the white matter network, the brain integrates quick reactions and slow reflections into a single functional system.
Professor Parks stated, "To respond to the environment through behavior, it is necessary to combine information processed at different time scales," and explained, "The brain utilizes white matter connectivity to share this information, and this integration process plays a crucial role in human behavior and cognitive function."
The research team analyzed brain imaging data from a total of 960 individuals to construct individual brain connectivity maps. They then applied a mathematical model that explains the temporal changes in complex systems to track how each brain area's intrinsic neural time scale is determined through structural connectivity. This clarified the direct relationship between local information processing characteristics and the information-sharing methods among brain networks.
The analysis revealed that the arrangement of neural time scales across the cerebral cortex significantly impacts the efficiency of transitions between large-scale brain activity patterns associated with behavior. Notably, these temporal structures showed individual differences, and it was confirmed that these differences contribute to variations in cognitive abilities.
Professor Parks stated, "We have confirmed that the differences in how the brain processes information at different speeds can be a mechanism explaining the differences in cognitive abilities among individuals." The research team also found that these temporal patterns are associated with the genetic, molecular, and cellular characteristics of brain tissue. Similar associations were observed in mouse brains, suggesting that this mechanism may be conserved across species.
The research team explained, "The more effectively the white matter connectivity links the fast and slow information processing of each brain area, the higher the overall cognitive ability tends to be." This indicates that the structural connectivity of the brain is a key element in the temporal integration of information beyond simple information transmission pathways.
Based on the results of this study, the research team is currently applying the same analytical approach to major neuropsychiatric disorders such as schizophrenia, bipolar disorder, and depression. By elucidating how changes in brain connectivity affect the processing of information over time, the goal is to understand the pathophysiology of mental disorders from a new perspective.
