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Category: neuroscience – Page 252

Central learning and memory hubs change in response to sex hormones. A new study in Nature Mental Health by Rachel Zsido and Julia Sacher of the Max Planck Institute for Human Cognitive and Brain Sciences and the University Clinic in Leipzig, Germany, links rhythmic oscillations in ovarian hormone levels in women during the menstrual cycle to changes in brain structure.

Ovarian hormones have significant effects on the brain, and early menopause may be associated with an increased risk of accelerated brain aging and dementia later in life. However, the effects of ovarian hormone fluctuations on earlier in life are less defined. In their current study, Zsido and Sacher show that fluctuations in ovarian hormones affect structural plasticity in key brain regions during the reproductive years.

To do this, the scientists collected from 27 female study participants, used ultrasound to track follicle growth in the ovaries to pinpoint ovulation timing, and utilized ultra-high field 7 Tesla MRI to zoom into subregions of the medial temporal lobe and hippocampus. That’s because these regions are dense with sex hormone receptors and are critical for cognitive function, such as episodic memory.

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In a move that echoes a sci-fi series, researchers have developed a super-small material that was able to not only stimulate nerves in rodents, but reconnect them as well. The finding could lead to injectable particles that take the place of larger implants.

In creating the particles, researchers at Rice University started with two layers of a metallic glass alloy called Metglas and wedged a piezoelectric layer of lead zirconium titanate in between them. Piezoelectric materials generate electricity when they have mechanical forces applied to them. Metglas is a magnetostrictive material, which means it changes its shape when it has a magnetic field applied to it. In this case, the change in shape of the Metglas in the presence of magnetic pulses caused the piezoelectric material inside to generate an electrical signal. Materials that do this are known as magnetoelectric.

“We asked, ‘Can we create a material that can be like dust or is so small that by placing just a sprinkle of it inside the body you’d be able to stimulate the brain or nervous system?’” said lead author Joshua Chen, a Rice doctoral alumnus. “With that question in mind, we thought that magnetoelectric materials were ideal candidates for use in neurostimulation. They respond to magnetic fields, which easily penetrate into the body, and convert them into electric fields – a language our nervous system already uses to relay information.”

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In a suite of 21 papers published in the journals Science (12), Science Advances , and Science Translational Medicine , a large consortium of researchers shares new knowledge about the cells that make up our brains and the brains of other primates. It’s a huge leap from previously published work, with studies and data that reveal new insights about our nervous systems’ cellular makeup across many regions of the brain and what is distinctive about the human brain.

The research consortium is a concerted effort to understand the and its modular, functional nature. It was brought together by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative.

Hundreds of scientists from around the world worked together to complete a range of studies exploring the cellular makeup of the human and those of other primates, and to demonstrate how a transformative new suite of scalable techniques can be used to study the detailed organization of the human brain at unprecedented resolution.

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Speeding up communication between humans is surprisingly tricky.

Last week, a post by Elon Musk on X (formerly known as Twitter) caught my eye. The entrepreneur claimed that sticking electrodes in people’s heads is going to lead to a huge increase in the rate of data transfer out of, and into, human brains.

The occasion of Musk’s post was the announcement by Neuralink, his brain-computer interface (BCI) company, that it was officially seeking the first volunteer to receive the “N1,” an implant comprising 1,024 electrodes able to listen in on brain neurons.

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That’s one idea for how the brain organizes itself to support our thoughts, feelings, and emotions. But if the brain’s information processing dynamics are like waves, what happens when there’s turbulence?

In fact, the brain does experience the equivalent of neural “hurricanes.” They bump into one another, and when they do, the resulting computations correlate with cognition.

These findings come from a unique study in Nature Human Behavior that bridges neuroscience and fluid dynamics to unpack the inner workings of the human mind.

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A study finds a material that is 120 times faster than similar ones, demonstrating its precision in remotely stimulating neurons and repairing severed sciatic nerves in rats.

A new study is paving the way for alternative approaches to treating brain and nerve problems gently without the need for major surgery by introducing a magnetoelectric material.

Despite challenges such as nerve cells not responding well to the signals made by these materials, Researchers wanted to find a way to make these signals easier for our nerves to understand.

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The vast set of information has been detailed in a series of 21 papers.

The majority of our actions are initiated by the brain, which plays a pivotal role in processing sensory information, making decisions, coordinating movements, and regulating bodily functions.

Overall, the human brain is an incredibly complex organ. It contains over 86 billion neurons – perhaps around the number of stars in the Milky Way galaxy.

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Spina bifida is the most common birth defect of the central nervous system and the second most common of all structural birth defects. To learn more about it, From the Labs sat with Dr. Richard H. Finnell, whose lab at Baylor College of Medicine focuses on discovering the role of folic acid in the prevention of birth defects and in identifying the genes that determine susceptibility to human neural tube defects such as spina bifida.

FTL: What is spina bifida?

RHF: Spina bifida is a condition that occurs during very early development affecting the neural tube, which will give rise to the spinal cord and brain. It can be diagnosed during pregnancy or after the baby is born. Typically, the neural tube closes by the 28th day after conception. In babies with spina bifida, a portion of the neural tube doesn’t close properly, resulting in a malformed spinal cord and problems in the bones of the spine. The neural tube exposed to amniotic fluid results in bladder and bowel dysfunction and in orthopedic problems that limit the child’s ability to walk.

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The anterior cingulate cortex (ACC) is believed to be involved in many cognitive processes, including linking goals to actions and tracking decision-relevant contextual information. ACC neurons robustly encode expected outcomes, but how this relates to putative functions of ACC remains unknown. Here, we approach this question from the perspective of population codes by analyzing neural spiking data in the ventral and dorsal banks of the ACC in two male monkeys trained to perform a stimulus-motor mapping task to earn rewards or avoid losses. We found that neural populations favor a low dimensional representational geometry that emphasizes the valence of potential outcomes while also facilitating the independent, abstract representation of multiple task-relevant variables. Valence encoding persisted throughout the trial, and realized outcomes were primarily encoded in a relative sense, such that cue valence acted as a context for outcome encoding. This suggests that the population coding we observe could be a mechanism that allows feedback to be interpreted in a context-dependent manner. Together, our results point to a prominent role for ACC in context setting and relative interpretation of outcomes, facilitated by abstract, or untangled, representations of task variables.

SIGNIFICANCE STATEMENT The ability to interpret events in light of the current context is a critical facet of higher-order cognition. The ACC is suggested to be important for tracking contextual information, whereas alternate views hold that its function is more related to the motor system and linking goals to appropriate actions. We evaluated these possibilities by analyzing geometric properties of neural population activity in monkey ACC when contexts were determined by the valence of potential outcomes and found that this information was represented as a dominant, abstract concept. Ensuing outcomes were then coded relative to these contexts, suggesting an important role for these representations in context-dependent evaluation. Such mechanisms may be critical for the abstract reasoning and generalization characteristic of biological intelligence.

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