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.
Researchers from the Chinese Academy of Sciences have identified a new organizational principle within the default mode network (DMN) that explains how it supports both internal thoughts and external perceptions. The study reveals that the DMN is composed of distinct subregions acting as either senders or receivers of information, allowing the brain to flexibly shift between memory-driven thought and sensory perception.
Key findings include:
* Identification of receiver-like subregions that support information integration during perception through stronger connectivity with heteromodal association networks.
* Identification of sender-like subregions that guide memory-based behavior via coupling with sensorimotor systems.
* Evidence that these subdivisions correspond to specific cognitive modes, such as face recognition versus memory-guided decisions.
Key findings include:
* Identification of receiver-like subregions that support information integration during perception through stronger connectivity with heteromodal association networks.
* Identification of sender-like subregions that guide memory-based behavior via coupling with sensorimotor systems.
* Evidence that these subdivisions correspond to specific cognitive modes, such as face recognition versus memory-guided decisions.
Eon Systems has reportedly achieved a breakthrough in whole-brain emulation by simulating the 125,000 neurons and 50 million synaptic connections of an adult fruit fly's brain. This simulated brain was then integrated into a virtual environment, allowing the fly to interact with a digital world. The experiment utilized a pre-existing wiring diagram of the fruit fly brain and a physics-based simulation framework.
Researchers claim this is the first demonstration of a whole-brain emulation exhibiting multiple behaviors, paving the way for more complex simulations, potentially including mouse and eventually human brains.
Researchers claim this is the first demonstration of a whole-brain emulation exhibiting multiple behaviors, paving the way for more complex simulations, potentially including mouse and eventually human brains.
A study found that wild mice, and other animals like frogs, rats, and shrews, will voluntarily use a running wheel placed in their environment, suggesting play is an innate behavior, not just a result of captivity.
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.
Researchers from Japan and Seattle's Allen Institute have created a detailed supercomputer simulation of a mouse cortex, featuring nearly 10 million neurons and 26 billion synapses, using the world's fastest supercomputer Fugaku. This breakthrough could lead to new methods for studying brain diseases like Alzheimer's and epilepsy.
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.
It is with profound sadness that we announce the passing of Prof. Lucia Vaina, a remarkable woman whose life was a testament to compassion, perseverance, and an unyielding pursuit of knowledge. She left us on July 25, 2025.
