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Category: neuroscience – Page 28

Functional ultrasound neuroimaging reveals mesoscopic organization of saccades in the lateral intraparietal area

An amazing paper (link:) where functional ultrasound imaging (fUSI) is used to explore how brain activity in the lateral intraparietal cortex (LIP) can predict visual saccades (eye movements) in two monkeys. An impressive array of computational analyses are used to extract insights from the imaged regions. Indeed, predictive models developed by the authors remained fairly stable over the course of up to 900 days! I happen to know two of the authors (Sumner L Norman and Mikhail Shapiro): congratulations to them and their colleagues on this excellent publication!

Our results demonstrate that PPC contains subregions tuned to different directions. These tuned voxels were predominately within LIP and grouped into contiguous mesoscopic subpopulations. Multiple subpopulations existed within a given coronal plane, i.e., there were multiple preferred directions in each plane. A rough topography exists where anterior LIP had more voxels tuned to contralateral downwards saccades and posterior LIP had more voxels tuned to contralateral upwards saccades. These populations remained stable across more than 100–900 days.

We observed large effect sizes with changes in CBV on the order of 10–30% from baseline activity (Fig. 3). This is much larger than observed with BOLD fMRI where the effect size was ~0.4–2% on similar saccade-based event-related tasks27,32. Our results support a growing evidence base that establishes fUSI as a sensitive neuroimaging technique for detecting mesoscopic functional activity in a diversity of model organisms, including pigeons, rats, mice, nonhuman primates, ferrets, and infant and adult humans23,24,25,33,34,35,36,37,38,39,40.

Several studies have reported a patchiness in direction selectivity with many neighboring neurons tuned to approximately the same direction followed by an abruption to a patch of a different preferred direction13,14,41. These results match very closely with the results observed in this study where we found clusters within LIP tightly tuned to one direction with differently tuned clusters in close proximity within a given plane. These results further emphasize the high spatial resolution of fUSI for functional mapping of neuronal activity. These results also closely match a previous study that used fUSI to identify the tonotopic mapping of the auditory cortex and inferior colliculus in awake ferrets where the authors found a functional resolution of 100 µm for voxel responsiveness and 300 µm for voxel frequency tuning34.

The right dose for the brain: Selenomethionine’s role in protecting dopaminergic neurons

Dopamine is often called the brain’s “motivation molecule,” but for me, it represents something deeper, a window into how fragile our neurons can be. The cells that produce dopamine, known as dopaminergic neurons, are among the first to die in Parkinson’s disease, leading to the motor symptoms that gradually rob patients of movement and independence.

To understand what makes these neurons so vulnerable, I used an in-vitro model where I exposed N27 dopaminergic cells to 6-hydroxydopamine (6-OHDA), a toxin that triggers oxidative stress, like what occurs in the Parkinsonian brain. Then, I introduced Selenomethionine (SeMet), an organic form of selenium, to test whether this compound could counteract the damage and help the neurons survive.

Selenium has long intrigued scientists for its paradoxical nature. It is a trace element essential for antioxidant defense, yet in excess it can become toxic. I wanted to see whether a specific range of SeMet concentrations could offer meaningful protection without tipping that balance. My study, carried out at Charles University and the National Institute of Mental Health (NUDZ) in the Czech Republic, set out to define that “safe and effective window.” It is published in the journal In vitro models.

Holographic optogenetics could enable faster brain mapping for new discoveries

Recent technological advances have opened new possibilities for neuroscience research, allowing researchers to map the brain’s structure and synaptic connectivity (i.e., the junctions via which neurons communicate with each other) with increasing precision.

Despite these developments, most widely employed methods to image synaptic connectivity are slow and fail to precisely record changes in the connections between in vivo, or in other words, while animals are awake and engaging in specific activities.

Two different research groups, one based at Columbia University and UC Berkeley, and the other at the Vision Institute of Sorbonne University in Paris, introduced a promising approach to study synapses in vivo. Their proposed mapping strategies, outlined in two Nature Neuroscience papers, combine holographic optogenetics, a method to selectively and precisely stimulate or silence specific neuron populations, with .

Scientists Have Discovered a Way to Boost Memory in Aging Brains

Virginia Tech scientists found that age-related memory loss stems from molecular changes in the brain. Memory decline might not be just a natural part of aging. Researchers at Virginia Tech have discovered that it is connected to particular molecular changes in the brain, and that fine-tuning these

Problems with modern Philosophical Solutions to Chalmer’s Hard Problem of Consciousness; and how the loss of the Primal Eye in early evolution seemingly gave rise to (waking and sleeping) ‘Subjectivity’

In this paper, I explore the limitations of various modern philosophical approaches to Chalmers’ Hard Problem of Consciousness, highlighting how the MVT/absent Primal Eye framework offers a compelling explanation for the qualitative nature of experience. We invite you to read these findings and share your thoughts on this intriguing intersection of philosophy and consciousness.

(https://www.academia.edu/144710257/Problems_with_modern_Philosophical_Solutions_to_Chalmer_s_Hard_Problem_of_Consciousness_and_how_the_loss_of_the_Primal_Eye_in_early_evolution_seemingly_gave_rise_to_waking_and_sleeping_Subjectivity)

Posthuman University Journal, October, 2025.

Materialist reductions fail to bridge the Explanatory Gap, functionalism fails to capture qualia, dissolutionism fails to account for phenomenal reality, and panpsychism collapses under the weight of the Combination Problem. The MVT/ absent Primal Eye philosophical framework seems to successfully explain the qualitative nature of experience without either denying its existence or creating an equally intractable set of metaphysical mysteries.

How to Turn Genes On or Off to Protect Brain Cells From Dementia

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What they discovered.

Kampmann’s work, supported by the National Institutes of Science (NIH), maps cellular “decision points” that determine whether brain cells survive or die — laying the groundwork for treatments that intervene before irreversible brain damage occurs.

Using CRISPR-based gene targeting technology that his team helped develop and pioneer the use of in brain cells, Kampmann has identified genes and cellular processes that influence the buildup of amyloid plaque and tau in the brain, two primary contributors to dementia. Thanks to this technology, called CRISPR interference and CRISPR activation, select genes in the laboratory can be turned on or off to protect brain cells from decline.

“We can conduct large-scale experiments that target all the genes in the human genome — 20,000 of them,” said Kampmann, explaining his work after receiving the Byers Award earlier this year. “And that way, we can basically have a little knob on each gene to ask which of all of the genes play a role in a disease.”

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