Brain::Science

Results reveal how individual neurons in the thalamus can merge signals from different regions of the cortex.

New study by researchers at the University of Chicago and the US Department of Energy’s (DOE) Argonne National Laboratory has revealed a convergence or a fusion of sensory and motor information in the thalamus. Such findings could lead to new treatment options for schizophrenia, epilepsy and other brain disorders.

To more fully understand the role of the thalamus, the team relied on tools from a variety of scientific fields, including genetics, virology, molecular biology, and microbiology, as well as various imaging techniques, using electron microscopy, to collect thousands of brain angles. of mice.

Through image reconstructions, they found that individual neurons can merge signals coming from different regions of the cortex. For example, a single neuron in a region of the thalamus called the medial posterior nucleus (POm) could receive both sensory and motor information. They also determined that POm neurons receive similar inputs from unknown sources.

“Our understanding of how sensory and motor information is integrated in the thalamus will be important for learning how information generally flows in the brain,” said Andrew J. Miller-Hansen, a neuroscience student at the University of Chicago and a member of the team. “We want to know if this pattern of convergence is specific to sensory and motor integration or if it is a common circuit pattern that supports other forms of integration in the brain,” he added.

Clarifying the processing and signaling capabilities of thalamic neurons could change the way medicine treats schizophrenia, epilepsy and other brain diseases where thalamic dysfunction appears to be linked to clinical problems.

The report on the publication is available at the Neuroscience News website.

The paper featuring the research may be retrieved from the DOI: 10.1073/pnas.2104137118

Some populations of neurons simultaneously process sensations and memories. New work shows how the brain rotates these representations to avoid interference.

To find out how the brain prevents new sensory information and short-term memories from mixing, Timothy Buschman, a neuroscientist at Princeton University, and Alexandra Libby, a graduate student in his lab, decided to focus on auditory perception in mice. The results showed that the brain rotates memories and thus manages to preserve them.

The researchers had the animals passively listen to four-chord sequences repeatedly, which allowed the mice to establish associations between sets of notes so that, upon hearing an initial chord, they could predict which sounds would follow.

Buschman and Libby observed how these patterns changed as the mice built their associations. They found that over time, the neural representations of associated chords began to resemble one another.

The researchers wanted to determine how the brain must be correcting this feedback interference to preserve accurate memories. Then, they trained another classifier to identify and differentiate neural patterns that represented memories of the chords in the sequences. The classifier found intact patterns of activity in the memories of the actual chords that were heard.

Memory representations have been organized into what neuroscientists describe as an “orthogonal” dimension to sensory representations, all within the same population of neurons.

Buschman likened this to running out of space on a paper while taking handwritten notes. “When that happens, you will rotate your piece of paper 90 degrees and start writing in the margins. And that’s basically what the brain is doing,” he said.

Analyzing experimentally, the scientists noticed that the activity of neurons could be neatly divided into two categories. Some were “stable” in their behavior during sensory and memory representations, while other “switch” neurons changed their response patterns for each use. To the researchers’ surprise, this combination of stable and mutating neurons was enough to spin sensory information into memory. “That’s all the magic,” Buschman said.

The full report on the publication is available at the Quanta Magazine website.

O artigo que apresenta a pesquisa pode ser acessado por meio do DOI: 10.1038/s41593-021-00821-9

Drinking more than six cups of coffee per day increases the risk of dementia and brain diseases, such as stroke, by 53%. Moderating consumption is the way out

Research from the University of South Australia found that high coffee consumption is associated with lower total brain volumes and a higher risk of dementia. The study evaluated 17,702 participants and indicated that those who drank more than six cups of coffee daily had a 53% higher risk of dementia and also of brain diseases such as stroke.

Dementia is a degenerative brain disease that affects memory, thinking, behavior and the ability to perform daily tasks. In Australia, dementia is the second leading cause of death, with around 250 people diagnosed each day. A Cerebrovascular accident, more known as a stroke, is a condition in which the blood supply to the brain is interrupted, resulting in lack of oxygen, brain damage and loss of function. Globally, one in four adults over the age of 25 will have a stroke in their lifetime.

According to researcher Elina Hyppönen, the key is moderation. “The way is to find a balance between the volume consumed and what is healthy”. While unit measurements may vary, a daily pair of cups of coffee is usually a good volume. “However, if coffee consumption exceeds more than six cups a day, it’s time to rethink.”

The news story on the publication is available on the News Medical website.

The paper featuring the research may be retrieved from the DOI: 10.1080/1028415X.2021.1945858

Researchers have discovered three distinct types of responses in the brain, responsible for controlling hunger, appetite and food intake.

Researchers from the Department of Bioengineering at Imperial College London analyzed the brain activity of 16 people with type 2 diabetes or pre-diabetes who underwent weight-loss surgery.

For the first time, they found that there were three distinct types of responses in the brain, responsible for controlling hunger, appetite and food intake, that were different from a separate group of people who used a low-calorie diet to lose weight.

According to the study’s lead author, Dr. Victoria Salem, Senior Clinical Lecturer in Endocrinology in the Department of Bioengineering, Imperial College London, “This study is unique in that we bring together three interconnected theories of brain changes that explain why patients who have lost weight in surgery find it much easier to maintain weight loss compared to those who have been on a controlled diet.”

First, using MRI, the researchers observed that when the surgical participants looked at images of food, there was a significant reduction in the areas of the brain associated with the ‘reward’ response to food. In contrast, in those on the low-calorie diet (VLCD), there was an increase in inactivation.

Second, in the VLCD group, after viewing photos of food, there was an increase in activation of brain areas associated with restriction of overeating. This was not found in the surgical group. Lastly, the team found that the hypothalamus – an area of ​​the brain that subconsciously controls appetite and weight – is more strongly linked to higher brain centers, which are involved in conscious thinking, after surgery compared to the VLCD group.

The team believes that the three types of brain responses are interlinked and may explain why after bariatric surgery, people lose weight for a long time, but after VLCD, people tend to regain the weight.

The report on the publication is available at the Neuroscience News website.

The paper featuring the research may be retrieved from the DOI: 10.2337/dc20-2641

Study opens the door to new effective discoveries in the fight against diseases such as Alzheimer’s and dementia

In our brain, there is not enough space for stored energy. Based on this, the University of Maryland School of Medicine and University of Vermont researchers demonstrated how blood vessels respond to the command given by our brain and how they direct flow to specific brain regions.

Researchers say in a new paper published in Science Advances that studying how the brain directs energy to itself can help show us what goes wrong in diseases where blood flow is defective, which indicates cognitive impairment.

Dr. Thomas Andrew Longden and his colleagues at the University of Maryland, together with the efforts of Michael Kotlikoff’s team at Cornell University, located in Ithaca, New York, experimented on mice, using a protein that emits green light when calcium increases in the cell.

The team found that when neurons fire electrical signals, they cause an increase in calcium in the cells lining blood vessels. With this, the enzymes detect this calcium and direct the cells to produce nitric oxide. Nitric oxide is a hormone (and a gas) that causes the muscle-like cells around blood vessels to relax, which then widens the vessels allowing more blood to flow in. The discovery of the functioning of this system opens the door to new studies in diseases such as Alzheimer’s and dementia, bringing with it hopes that one day these diseases can be effectively fought.

The news story on the publication is available on the News Medical website.

The paper featuring the research may be retrieved from the DOI: 10.1126/sciadv.abh0101