Yale School of Medicine (YSM) scientists have discovered a molecular difference in the brains of autistic people compared to their neurotypical counterparts.

Autism is a neurodevelopmental condition associated with behavioral differences including difficulties with social interaction, restrictive or intense interests, and repetitive movements or speech. But it’s not clear what makes autistic brains different.

Now, a study in the American Journal of Psychiatry has found that the brains of autistic people have fewer of a specific kind of receptor for glutamate, the most common excitatory neurotransmitter in the brain. The reduced availability of these receptors may be associated with various characteristics linked to autism.

More than 7 million Americans have Alzheimer’s disease, and two-thirds of them are women, according to the Alzheimer’s Association. The O’Banion Lab at the Del Monte Institute for Neuroscience at the University of Rochester has long been studying this disease and is looking more closely at the differences between male and female brains.

“It is well documented that males and females are diagnosed with Alzheimer’s disease at different rates,” said M. Kerry O’Banion, MD, Ph.D., professor of Neuroscience and Neurology. “But we still do not have a great understanding of why this is the case. We can only improve any possible treatment or prevention of this disease if we know the why, when, and where these differences are occurring.”

Scientists at the Carney Institute for Brain Science have discovered specific patterns of electrical signals in the brain that may help forecast whether a person will go on to develop Alzheimer’s disease. Using a specialized tool designed to examine the electrical signals produced by neurons, sci

The amygdala consists of nuclei which can be grouped into (i) the basolateral nuclear group (BLA), (ii) the superficial cortex-like laminated region (sCLR) which contains the cortical nuclei (Co), and (iii) the centromedial nuclear group.¹ The BLA consists of the lateral nucleus (LA) and basal nucleus (BA). In turn, the BA consists of the basolateral nucleus and the basomedial nucleus. The centromedial nuclear group consists of the central nucleus (Ce), medial nucleus (Me), and intercalate cell mass (IC). In turn, Ce consists of a lateral (CeL) subdivision and a medial (CeM) subdivision. The centromedial nuclear group (Ce, Me, and IC) along with the bed nucleus of the stria terminalis (BNST) and sublenticular substantia innominata together comprise the centromedial extended amygdala.

The cellular composition of the BLA nuclei and the sCLR’s Co nuclei resembles that of the cerebral cortex in that the majority of the neurons are pyramidal-like glutamatergic cells while the rest are local GABAergic inhibitory interneurons.¹ The inhibitory interneurons include parvalbumin-containing neurons which mainly synapse on the soma and proximal dendrites of the pyramidal cells and somatostatin-containing neurons which mainly synapse on the distal dendrites of the pyramidal neurons. By contrast, the composition of the Ce and Me nuclei resembles the striatum in that many of the neurons are similar to GABAergic medium spiny neurons.

Investigators looked at laboratory mice with spinal cord injury and found that lesion-remote astrocytes (LRAs) play an important role in supporting nervous system repair. They saw strong evidence of the same mechanism in tissue samples from human patients with spinal cord injury.

The Lab identified one LRA subtype that sends out a protein called CCN1 to signal to immune cells called microglia.

“One function of microglia is to serve as chief garbage collectors in the central nervous system,” the senior author said. “After tissue damage, they eat up pieces of nerve fiber debris—which are very fatty and can cause them to get a kind of indigestion. Our experiments showed that astrocyte CCN1 signals the microglia to change their metabolism so they can better digest all that fat.”

The author said this efficient debris clearing might have a role in the spontaneous recovery found in many patients with spinal cord injury. In the absence of the astrocyte-derived CCN1 protein, the investigators found that recovery is drastically impaired.

“If we remove astrocyte CCN1, the microglia eat, but they don’t digest. They call in more microglia, which also eat but don’t digest,” the author said. “Big clusters of debris-filled microglia form, heightening inflammation up and down the spinal cord. And when that happens, the tissue doesn’t repair as well.”

When investigators looked at spinal cord tissue from human patients with multiple sclerosis, they found the same mechanism at work, the author said and added that these fundamental principles of tissue repair likely apply to any sort of injury of the brain or spinal cord.

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Two major trials investigating the potential of the psychedelic drug LSD for reducing anxiety are set to conclude in 2026. Scientists are feeling positive after the drug’s success in an earlier-stage trial, which could mean the treatment will be available in the US as early as 2027.

Generalised anxiety disorder is a common condition where people feel very anxious about lots of different things. It is typically treated with antidepressants and talking therapies, but around half of people don’t respond to such treatments.

Other psychedelic drugs like psilocybin and MDMA are already used to treat particularly severe cases of depression and post-traumatic stress disorder in some countries, such as Australia and Switzerland. LSD is increasingly being explored as a mental health treatment, partly because research shows it triggers profound emotional experiences in some people, and it seems to enhance the brain’s ability to rewire itself and form new thought patterns.

Image: TUMEGGY/SCIENCE PHOTO LIBRARY/GETTY IMAGES

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Two later-stage trials investigating LSD for treating anxiety are due to conclude in 2026, which could lead to the drug being approved for the common mental health condition.

By Carissa Wong