Researchers from Cedars-Sinai Medical Center, the University of Toronto, and collaborators studied how the human brain maintains task context in working memory as goals change. Analyzing neural recordings from 25 treatment-resistant epilepsy patients with surgically implanted electrodes while participants completed rule-based tasks over several minutes, the team found that medial frontal cortex neurons sustained a stable activity pattern to represent a rule even after cues disappeared, while hippocampal neurons generated a flexible rule representation whose format shifted depending on required behavior.Published in Nature Human Behaviour (2026), the work highlights how the brain encodes the same information through patterns of differing stability and flexibility to support rapid behavioral generalization.
- The medial frontal cortex region, including the pre-supplementary motor area (preSMA) and dorsal anterior cingulate cortex (dACC), was studied; all electrode locations were aligned to a brain atlas and color-coded by region.
- Authors proposed embedding durable, time-stable rule representations like those in preSMA/dACC to address generalization failures in large language models and other machine-learning architectures.
- The medial frontal cortex region, including the pre-supplementary motor area (preSMA) and dorsal anterior cingulate cortex (dACC), was studied; all electrode locations were aligned to a brain atlas and color-coded by region.
- Authors proposed embedding durable, time-stable rule representations like those in preSMA/dACC to address generalization failures in large language models and other machine-learning architectures.
Michał Januszewski and Viren Jain write that researchers have released a complete wiring diagram of the male fruit fly's brain and central nervous system, marking it as the largest brain map to date. In collaboration with HHMI Janelia, this project utilized computing and advanced techniques to create an annotated cellular-scale map containing over 166,000 neurons and 125 million synaptic connections. This foundational resource aims to help scientists understand how nervous systems function and may eventually assist in understanding complex human brain processes like memory or disease.
- The connectome includes the ventral nerve cord, which functions similarly to a spinal cord.
- Researchers are using similar mapping techniques on vertebrates, including fish and mice.
- This map complements previously released female fruit fly connectomes, allowing for studies of sexual dimorphism in behavior like courtship or aggression.
- The connectome includes the ventral nerve cord, which functions similarly to a spinal cord.
- Researchers are using similar mapping techniques on vertebrates, including fish and mice.
- This map complements previously released female fruit fly connectomes, allowing for studies of sexual dimorphism in behavior like courtship or aggression.
Allison Parshall writes that psilocybin creates a hidden order amid brain chaos, potentially underlying the psychedelic sense of oneness, with sensory networks less connected to the brain and higher-level networks more integrated.
In a Nature study of 62 healthy adults scanned at rest, meditating, listening to music and watching a movie after dosing, participants reporting strong embeddedness showed more similar brain activity patterns across tasks than those with weaker effects.
The findings suggest the brain actively maintains the self-world boundary that psychedelics temporarily reduce, offering a neurobiological basis for context-dependent experiences.
In a Nature study of 62 healthy adults scanned at rest, meditating, listening to music and watching a movie after dosing, participants reporting strong embeddedness showed more similar brain activity patterns across tasks than those with weaker effects.
The findings suggest the brain actively maintains the self-world boundary that psychedelics temporarily reduce, offering a neurobiological basis for context-dependent experiences.
A new study from NYU Langone Health reveals how the brain's hippocampal CA1 region functions as a memory switchboard to balance learning new information with protecting old memories. By using divergent firing patterns, a core group of neurons can manage both incoming and outgoing signals without crossing lines or overwriting existing data. This mechanism helps maintain stability in long-term memory storage while allowing for continuous plasticity during experience.
- The CA1 region acts as a physical hub connecting the CA3 region to the retrosplenial cortex.
- Divergent firing patterns allow shared neurons to serve separate incoming and outgoing communication channels.
- Hub cells remain active during sleep through sharp-wave ripples to facilitate memory consolidation.
- Research provides potential insights into Alzheimer's disease and methods to prevent catastrophic forgetting in artificial intelligence.
- The CA1 region acts as a physical hub connecting the CA3 region to the retrosplenial cortex.
- Divergent firing patterns allow shared neurons to serve separate incoming and outgoing communication channels.
- Hub cells remain active during sleep through sharp-wave ripples to facilitate memory consolidation.
- Research provides potential insights into Alzheimer's disease and methods to prevent catastrophic forgetting in artificial intelligence.
Researchers have identified the first definitive neural evidence of how the brain creates and reuses abstract symbols to facilitate creative thinking. By studying primate models, scientists located this symbolic processing engine within the ventral premotor cortex. This region serves as a mediator between high-level planning in the prefrontal cortex and physical execution in the motor cortex, acting much like a mental typewriter that specifies symbolic building blocks before movement occurs.
Mammalian brains function through a constant balance of cooperation and competition between specialized circuits. While internal circuits cooperate, long-range competitive interactions manage limited resources and prevent excessive synchronization. This mechanism allows different brain systems to take turns shaping overall dynamics, facilitating complex cognitive processes like decision-making, attention, and memory.
This study investigates whether the human brain has an organized baseline state of function that is suspended during goal-directed tasks. Researchers used positron-emission tomography (PET) to measure the oxygen extraction fraction (OEF)—the ratio of oxygen used by the brain to oxygen delivered by blood—in resting adults.
Key findings include:
1. Uniformity at Rest: Despite significant differences in blood flow and oxygen consumption between gray and white matter, the OEF remains remarkably uniform across the brain during a resting state (eyes closed, awake).
2. Defining Baseline: The researchers propose that this uniform OEF represents an equilibrium state of local neuronal activity, serving as a true physiological baseline.
3. Deactivation Patterns: Many brain regions, particularly in the visual system, consistently show decreases in activity (deactivations) during cognitive tasks.
4. Validation: By measuring the OEF at rest, the study confirms that these task-induced decreases are not merely artifacts of an undefined control state but represent a genuine drop from a stable baseline level of brain function.
The results suggest the existence of a default mode of brain function that is active when specific goal-directed behaviors are not being performed.
Key findings include:
1. Uniformity at Rest: Despite significant differences in blood flow and oxygen consumption between gray and white matter, the OEF remains remarkably uniform across the brain during a resting state (eyes closed, awake).
2. Defining Baseline: The researchers propose that this uniform OEF represents an equilibrium state of local neuronal activity, serving as a true physiological baseline.
3. Deactivation Patterns: Many brain regions, particularly in the visual system, consistently show decreases in activity (deactivations) during cognitive tasks.
4. Validation: By measuring the OEF at rest, the study confirms that these task-induced decreases are not merely artifacts of an undefined control state but represent a genuine drop from a stable baseline level of brain function.
The results suggest the existence of a default mode of brain function that is active when specific goal-directed behaviors are not being performed.
New experiments reveal how astrocytes tune neuronal activity to modulate our mental and emotional states, suggesting that neuron-only brain models are insufficient for understanding brain function.
Neuroscience research suggests that scientists may have been undervaluing the most ancient regions of the human brain when studying consciousness. Evidence indicates that the subcortex and cerebellum may play a more significant role than previously thought, and could even be sufficient for basic forms of consciousness.
Scientists have mapped the activity that takes place across a mouse's entire brain as it decides how to complete a task - and the results could explain the origin of our gut feelings.
