Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: neuroscience – Page 625

Summary: A new mouse study reveals that exposure to BPA at levels 25 times lower than deemed safe has an impact on brain development.

Source: University of Calgary.

Humans are exposed to a bath of chemicals every day. They are in the beds where we sleep, the cars that we drive and the kitchens we use to feed our families. With thousands of chemicals floating around in our environment, exposure to any number is practically unavoidable. Through the work of researchers like Dr. Deborah Kurrasch, PhD, the implications of many of these chemicals are being thoroughly explored.

Read more | >

In January 2020 we released the fly “hemibrain” connectome — an online database providing the morphological structure and synaptic connectivity of roughly half of the brain of a fruit fly (Drosophila melanogaster). This database and its supporting visualization has reframed the way that neural circuits are studied and understood in the fly brain. While the fruit fly brain is small enough to attain a relatively complete map using modern mapping techniques, the insights gained are, at best, only partially informative to understanding the most interesting object in neuroscience — the human brain.

Today, in collaboration with the Lichtman Laboratory at Harvard University, we are releasing the “H01” dataset, a 1.4 petabyte rendering of a small sample of human brain tissue, along with a companion paper, “A connectomic study of a petascale fragment of human cerebral cortex.” The H01 sample was imaged at 4nm-resolution by serial section electron microscopy, reconstructed and annotated by automated computational techniques, and analyzed for preliminary insights into the structure of the human cortex. The dataset comprises imaging data that covers roughly one cubic millimeter of brain tissue, and includes tens of thousands of reconstructed neurons, millions of neuron fragments, 130 million annotated synapses, 104 proofread cells, and many additional subcellular annotations and structures — all easily accessible with the Neuroglancer browser interface.

Read more | >

Global brain activity seen on fMRI, and its connection with cerebrospinal fluid flow weaker in brains of individuals with Alzheimer’s disease risk or related toxin buildup.

Evidence of sleep-dependent low-frequency (0.1 Hz) global brain activity in the clearance of Alzheimer’s disease-related toxin buildup is presented in research published today (June 1, 2021) in the open access journal PLOS Biology by Xiao Liu and colleagues at The Pennsylvania State University. This neuronal activity was more strongly linked with cerebrospinal fluid flow in healthy controls than higher risk groups and patients, and the findings could serve as a potential imaging marker for clinicians in evaluating patients.

The development of Alzheimer’s disease is believed to be driven by the buildup of the toxic proteins amyloid-β and tau in the brain. The brain’s glymphatic system plays a crucial role in clearing these toxins and previous work has shown a possible relationship between sleep-dependent global brain activity and the glymphatic system by showing this activity is coupled by cerebrospinal fluid flow essential for the glymphatic system.

Read more | >

😀

This sample tissue was anonymously donated from patients that have undergone surgery to treat epilepsy at the Massachusetts General Hospital in Boston (MGH). It was then given to researchers at Harvard’s Lichtman laboratory.

The Harvard researchers cut the tissue into ~5300 individual 30 nanometer sections using an automated tape collecting ultra-microtome, mounted those sections onto silicon wafers, and then imaged the brain tissue at 4 nm resolution in a customized 61-beam parallelized scanning electron microscope for rapid image acquisition.

The end result was 225 million individual 2D images that Google then computationally stitched and aligned into a 3D volume with thousands of Google Cloud TPUs were leveraged in the process. This human brain map is now accessible through Google’s web-based Neuroglancer visualization tool.

Continue reading “Google helps map one cubic millimeter of human brain tissue” | >

Using a mouse model, Chen and the team delivered a viral construct containing TRPV1 ion channels to genetically-selected neurons. Then, they delivered small burst of heat via low-intensity focused ultrasound to the select neurons in the brain via a wearable device. The heat, only a few degrees warmer than body temperature, activated the TRPV1 ion channel, which acted as a switch to turn the neurons on or off.

Neurological disorders such as Parkinson’s disease and epilepsy have had some treatment success with deep brain stimulation, but those require surgical device implantation. A multidisciplinary team at Washington University in St. Louis has developed a new brain stimulation technique using focused ultrasound that is able to turn specific types of neurons in the brain on and off and precisely control motor activity without surgical device implantation.

The team, led by Hong Chen, assistant professor of biomedical engineering in the McKelvey School of Engineering and of radiation oncology at the School of Medicine, is the first to provide direct evidence showing noninvasive, cell-type-specific activation of neurons in the brain of mammal by combining ultrasound-induced heating effect and genetics, which they have named sonothermogenetics. It is also the first work to show that the ultrasound-genetics combination can robustly control behavior by stimulating a specific target deep in the brain.

Continue reading “New tool activates deep brain neurons” | >

A study of gene activity in the brain’s hippocampus, led by UT Southwestern researchers, has identified marked differences between the region’s anterior and posterior portions. The findings, published today in Neuron, could shed light on a variety of brain disorders that involve the hippocampus and may eventually help lead to new, targeted treatments.

“These new data reveal molecular-level differences that allow us to view the anterior and posterior hippocampus in a whole new way,” says study leader Genevieve Konopka, Ph.D., associate professor of neuroscience at UTSW.

She and study co-leader Bradley C. Lega, M.D., associate professor of neurological surgery, neurology, and psychiatry, explain that the human hippocampus is typically considered a uniform structure with key roles in memory, spatial navigation, and regulation of emotions. However, some research has suggested that the two ends of the hippocampus—the anterior, which points downward toward the face, and the posterior, which points upward toward the back of the head—take on different jobs.

Read more | >

Summary: Disruptions in how the body converts cholesterol into bile acids may play a key role in the development of dementia.

Source: PLOS

The blood-brain barrier is impermeable to cholesterol, yet high blood cholesterol is associated with increased risk of Alzheimer’s disease and vascular dementia. However, the underlying mechanisms mediating this relationship are poorly understood.

Read more | >