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3D maps reveal hidden microenvironments shaping mouse brain connectivity

Recent technological and scientific advances have opened new possibilities for neuroscience research, which is in turn leading to interesting new discoveries. Over the past few years, many groups of neuroscientists worldwide have been trying to map the structure of the brain and its underlying regions with increasing precision, while also probing their involvement in specific mental functions.

As mapping the human brain in detail is often challenging and requires significant resources, many studies focus on other mammals, particularly mice or other rodents. Most mouse brain atlases delineated to date map the density of neurons or other brain cells (i.e., how many cells are packed in specific parts of the brain). In contrast, fewer works also tried to map the shape of neurons in the mouse brain and interactions between them.

Researchers at Fudan University and Southeast University recently set out to map dendrites (i.e., branch-like extensions of neurons via which they receive signals from other cells) in the mouse brain. Their paper, published in Nature Neuroscience, unveils groups of structures in the mouse brain that influence how neurons function and connect to other neurons, also known as microenvironments.

Astrocyte diversity across space and time charted in new atlas

When it comes to brain function, neurons get a lot of the glory. But healthy brains depend on the cooperation of many kinds of cells. The most abundant of the brain’s non-neuronal cells are astrocytes, star-shaped cells with a lot of responsibilities. Astrocytes help shape neural circuits, participate in information processing, and provide nutrient and metabolic support to neurons. Individual cells can take on new roles throughout their lifetimes, and at any given time, the astrocytes in one part of the brain will look and behave differently than the astrocytes somewhere else.

After an extensive analysis by researchers at MIT, neuroscientists now have an atlas detailing astrocytes’ dynamic diversity. Its maps depict the regional specialization of astrocytes across the brains of both mice and marmosets—two powerful models for neuroscience research—and show how their populations shift as brains develop, mature, and age.

The open-access study, reported in the Nov. 20 issue of the journal Neuron, was led by Guoping Feng, the James W. (1963) and Patricia T. Poitras Professor of Brain and Cognitive Sciences at MIT.

How Agentic BAS AI Turns Threat Headlines Into Defense Strategies

Picus Security explains why relying on LLM-generated attack scripts is risky and how an agentic approach maps real threat intel to safe, validated TTPs. Their breakdown shows how teams can turn headline threats into reliable defense checks without unsafe automation.

Comprehensive map reveals neuronal dendrites in the mouse brain in greater detail

Understanding the shape or morphology of neurons and mapping the tree-like branches via which they receive signals from other cells (i.e., dendrites) is a long-standing objective of neuroscience research. Ultimately, this can help to shed light on how information flows through the brain and pin-point differences associated with specific neurological or psychiatric disorders.

The X. William Yang Lab at the Jane and Terry Semel Institute and the Department of Psychiatry and Biobehavioral Sciences at University of California, Los Angeles (UCLA) have devised new sophisticated methods to map neuronal dendrites in the mouse brain, which combine large-scale data collection with genetic labeling techniques and computational tools.

Their research approach, outlined in a paper published in Nature Neuroscience, allowed them to create a comprehensive map of two genetic types of neurons in the mouse brain, known as D1-and D2-type striatal medium spiny neurons (MSNs).

Seeing physics as a mountain landscape for classification of nonlinear systems

Imagine standing on top of a mountain. From this vantage point, we can see picturesque valleys and majestic ridges below, and streams wind their way downhill. If a drop of rain falls somewhere on this terrain, gravity guides it along a path until it settles in one of the valleys. The trajectory traced by this droplet is known as a flow line, a path that indicates the direction of movement determined by the landscape’s gradient.

The complete network of valleys, ridges, and flow lines forms a topographic (or cartographic) map that captures the organization of the landscape. This organization, which remains stable as long as the terrain does not change, corresponds to a kind of “topological invariant,” as physicists would call it: It characterizes the global structure of the flows without reference to local details.

Now imagine that a jolt goes through the landscape and it changes, with new valleys appearing, others merging and ridges shifting. The flow lines reorganize accordingly, forming a new pattern of connections. Comparing these patterns—like two maps placed next to each other—reveals how the system’s topology evolves when its underlying conditions change.

X-ray imaging captures the brain’s intricate connections

An international team of researchers led by the Francis Crick Institute, working with the Paul Scherrer Institute, has developed a new imaging protocol to capture mouse brain cell connections in precise detail. In work published in Nature Methods, they combined the use of X-rays with radiation-resistant materials sourced from the aerospace industry.

The images acquired using this technique allowed the team to see how nerve cells connect in the mouse brain, without needing to thinly slice biological tissue samples.

Volume electron microscopy (volume EM) has been the gold standard for imaging how nerve cells connect as ‘“circuitry” inside the brain. It has paved the way for scientists to create maps called connectomes, of entire brains, first in fruit fly larvae and then the adult fruit fly. This imaging involves cutting 10s of nm thin slices (tens of thousands per mm of tissue), imaging each slice and then building the images back into their 3D structure.

Vicarious body maps bridge vision and touch in the human brain

A central question in sensory neuroscience is how inputs from vision and touch are combined to generate cohesive representations of the external world. Here we reveal a widespread mode of brain organization in which aligned topographic maps bridge vision and somatosensation. We developed a computational model that revealed somatotopic structure in dorsolateral visual cortex. Somatotopic tuning in these regions was predictive of visual field locations more dorsally and visual body part selectivity more ventrally. These results suggest more extensive cross-modal overlap than traditionally assumed: the computational machinery classically attributed to the somatosensory system is also embedded within and aligned with that of the visual system. These aligned visual and bodily maps are a likely brain substrate for internalized somatosensory representations of visual signals, and are a candidate human homologue of findings in mice whereby somatomotor responses dominate visual cortex36.

Consistent with embodied perception theories, our model-based quantifications of somatotopic and retinotopic connectivity revealed that dorsolateral visual cortical responses to naturalistic stimuli are best explained by selectivities in both modalities, as opposed to visual selectivity alone. The necessity of incorporating body-referenced processing into models of dorsolateral visual cortex supports evidence that its role extends beyond passive visual analysis, encompassing perceptual, semantic and bodily functions optimized for behavioural interactions with the world25.

Consistent with visuospatial alignment of somatosensory tuning, we found that body part preferences in dorsolateral visual cortex predicted visual field tuning. Such alignment, previously reported at the terminus of the dorsal visual pathway around the postcentral sulcus28, therefore extends far into dorsal and lateral streams of the visual system. This alignment may be reinforced by shared developmental influences, as somatotopic and retinotopic maps are shaped trophically from birth: dorsal regions represent the upper body and visual field, and ventral regions to the lower body and visual field22, providing a roughly aligned sensory periphery optimized for efficient environmental sampling and action. The explicit interweaving of touch and retinal coordinates may subserve efficient perception of environmental affordances and a cohesive sense of spatial self-representation.

Musicians drift less in blindfolded walk: Could musical training be utilized in cognitive rehabilitation?

A multi-institutional team of researchers led by Université de Montréal report that extensive musical training can steady the body in space, both with and without guiding sounds, during a blindfolded stepping test.

Spatial cognition is at the heart of everyday movement, linking mental maps of the environment with the body’s position and orientation. Spatial abilities support tasks such as mental rotation, navigation, walking through space, and maintaining spatial information in working memory, all of which depend on a stable sense of where the body is located.

Body representation provides a solution to what some researchers describe as the computational “where” problem of the body, knitting together inputs from vision, touch, and the vestibular system. Auditory cues join this network as well, supplying information that can help stabilize posture and guide movement when other senses are limited or absent, as described in prior work on postural control and ambulation.

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