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Category: neuroscience – Page 6

Dopamine Doesn’t Work in Our Brains Quite The Way We Thought

Dopamine is one of the most extensively studied chemical messengers in the human brain, and yet scientists are still figuring out how it works to accomplish so much.

For years, the classic view has been that, when released, dopamine slowly diffuses through the brain like a chemical megaphone, broadcasting information far and wide to numerous target cells.

Recently, however, that perspective has changed. Newer research suggests that dopamine is also capable of short, sharp whispers, precisely directed within milliseconds to neighboring cells.

Blood plasma reveals shared pathways in neurodegenerative diseases

Scientists know that many proteins and pathways are involved in the development and progression of neurodegenerative conditions such as Alzheimer’s disease, Parkinson’s disease and frontotemporal dementia (FTD), and that these proteins can be detected in the plasma of people with the conditions.

But it hasn’t been clear exactly which proteins are distinct to one disease vs. shared among two or more of them, adding to the difficulty both of diagnosing these complex diseases from and of developing effective treatments.

A new study by Washington University School of Medicine in St. Louis researchers, published in Nature Medicine, provides some answers. Led by Carlos Cruchaga, the Barbara Burton & Reuben Morriss III Professor in the Department of Psychiatry and director of the NeuroGenomics and Informatics Center at WashU Medicine, the researchers analyzed in more than 10,500 blood plasma samples from patients with Alzheimer’s disease, Parkinson’s disease or FTD.

APOE ε4 variant reveals hidden risk factors beyond Alzheimer’s

Further analysis for immune-specific processes revealed APOE ε4 enrichment in various infection-related pathways, including herpes, influenza A, hepatitis, measles, and Epstein-Barr virus (EBV). Significant enrichment was also observed for B-cell, T-cell, and inflammatory signaling cascades. Next, immune cell subtype enrichment analysis revealed the most APOE ε4 enrichment in intermediate and non-classical monocytes among innate immune cells.

Among adaptive immune cells, memory cluster of differentiation 8 (CD8) T cells, regulatory T (Treg) cells, and memory CD4 T cells were the most enriched. Besides, γδ T cells and natural killer (NK) cells showed APOE ε4 enrichment. In the liver, a cell-type-specific enrichment analysis revealed the most APOE ε4 enrichment in Kupffer cells and hepatocytes.

Next, the researchers examined whether APOE ε4 CSF proteome changes were reflected in the plasma and used the GNPC dataset for plasma proteome profiling of AD, PDD, FTD, PD, ALS, and non-impaired controls. Fifty-eight plasma proteins associated with the APOE genotype were identified in non-impaired controls. CART modeling revealed that these 58 proteins could strongly differentiate between APOE ε4 carriers and non-carriers across neurodegenerative diseases, and this signature was found to be consistent across different sexes and racial groups.

Psychopathic traits linked to distinct brain networks in new neuroscience research

Psychopathy is often associated with impulsivity, aggression, and antisocial behavior. While past studies have focused heavily on how different brain regions function in people with psychopathic traits, less is known about how these regions are structurally connected. Structural connectivity refers to the physical links between brain areas—similar to the brain’s wiring system. The researchers aimed to go beyond earlier work that focused only on specific brain circuits and instead look across the entire brain to identify any structural patterns linked to psychopathy.

The researchers were especially interested in understanding whether structural differences in the brain might explain the relationship between psychopathic traits and externalizing behaviors. Previous models have suggested two possible brain-based explanations for these behaviors. One theory emphasizes problems in how people process emotional threats, while another highlights difficulties in attention control. Both theories have some support, but no study had comprehensively examined how structural brain networks might connect psychopathy with real-world behavioral problems.

The research team analyzed data from 82 young adults who participated in the Leipzig Mind-Brain-Body study. All participants were screened to rule out medical or psychological conditions that might affect the results. Psychopathic traits were assessed using a questionnaire designed to capture both interpersonal-affective characteristics (like manipulation and lack of empathy) and behavioral traits (like impulsivity and rule-breaking). Externalizing behaviors were also measured with a separate questionnaire that included items on aggression, defiance, and similar tendencies.

Each participant underwent high-resolution brain imaging using diffusion MRI, a technique that maps the white matter tracts—essentially the brain’s wiring—connecting different regions. The researchers used a method called connectome-based predictive modeling, which relies on machine learning to identify patterns in the brain’s structural connectivity that relate to individual differences in behavior.

This method allowed them to identify two kinds of networks: positive networks, where stronger connections were linked to higher psychopathy scores, and negative networks, where weaker connections were related to those same scores. They also tested whether specific connections within these networks helped explain the relationship between psychopathic traits and externalizing behaviors.

The results showed that psychopathic traits were significantly associated with both stronger and weaker connections in different parts of the brain. The positive network—made up of connections that increased with psychopathy—was better at predicting psychopathic traits than the negative network alone. But when both networks were combined, the prediction became even more accurate.

Many of the connections in the positive network were located within the brain’s frontal and parietal lobes, which are involved in decision-making, emotional processing, and attention. These connections included pathways like the uncinate fasciculus, which links the frontal cortex with areas involved in emotion, and the arcuate fasciculus, which supports language and auditory processing. Other connections involved the cingulum bundle, associated with emotional regulation and social behavior, and the posterior corticostriatal pathway, which plays a role in reward processing and learning.

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‘Universal cancer vaccine’ trains the immune system to kill any tumor

Following on from their breakthrough human trial that successfully reprogrammed the immune system to overpower glioblastoma, an aggressive brain tumor, the same scientists have now further developed the mRNA vaccine to fight not one but any cancer. It has the potential to do away with chemotherapy, surgery and radiation treatment.

University of Florida (UF) scientists have developed an experimental vaccine that dramatically boosts the immune system’s ability to fight tumors – even without targeting a specific cancer type. This “general purpose” mRNA jab works in a similar way to a Covid-19 vaccine but with a different target; it instructs the body’s immune cells to rally and hit any kind of tumor in the same way they would attack a viral spike protein.

“This paper describes a very unexpected and exciting observation: that even a vaccine not specific to any particular tumor or virus – so long as it is an mRNA vaccine – could lead to tumor-specific effects,” said Elias Sayour, a pediatric oncologist and principal investigator at the RNA Engineering Laboratory at UF. “This finding is a proof of concept that these vaccines potentially could be commercialized as universal cancer vaccines to sensitize the immune system against a patient’s individual tumor.”

Mapping DNA repeats: Newly found genes may explain brain evolution and language disorders

What makes the human brain distinctive? A new study published in Cell identifies two genes linked to human brain features and provides a road map to discover many more. The research could lead to insights into the functioning and evolution of the human brain, as well as the roots of language disorders and autism.

Wellesley team’s new research on anesthesia unlocks important clues about the nature of consciousness

For decades, one of the most fundamental and vexing questions in neuroscience has been: what is the physical basis of consciousness in the brain? Most researchers favor classical models, based on classical physics, while a minority have argued that consciousness must be quantum in nature, and that its brain basis is a collective quantum vibration of “microtubule” proteins inside neurons.

New research by Wellesley College professor Mike Wiest and a group of Wellesley College undergraduate students has yielded important experimental results relevant to this debate, by examining how anesthesia affects the brain. Wiest and his research team found that when they gave rats a drug that binds to microtubules, it took the rats significantly longer to fall unconscious under an anesthetic gas. The research team’s microtubule-binding drug interfered with the anesthetic action, thus supporting the idea that the anesthetic acts on microtubules to cause unconsciousness.

“Since we don’t know of another (i.e,. classical) way that anesthetic binding to microtubules would generally reduce brain activity and cause unconsciousness,” Wiest says, “this finding supports the quantum model of consciousness.”

The Role of Innovation Technology in the Rehabilitation of Patients Affected by Huntington’s Disease: A Scoping Review

Huntington’s disease is an autosomal dominant neurodegenerative disease caused by the repetition of cytosine, adenine, and guanine trinucleotides on the short arm of chromosome 4p16.3 within the Huntingtin gene. In this study, we aim to examine and map the existing evidence on the use of innovations in the rehabilitation of Huntington’s disease. A scoping review was conducted on innovative rehabilitative treatments performed on patients with Huntington’s disease. A search was performed on PubMed, Embase, Web of Science, and Cochrane databases to screen references of included studies and review articles for additional citations. Of an initial 1,117 articles, only 20 met the search criteria. These findings showed that available evidence is still limited and that studies generally had small sample sizes and a high risk of bias.