Brain

How genetic changes lead to familial Alzheimer's disease

How genetic changes lead to familial Alzheimer's disease

Mutations in the presenilin-1 gene are the most common cause of inherited, early-onset forms of Alzheimer's disease. In a new study, published in Neuron, scientists replaced the normal mouse presenilin-1 gene with Alzheimer's-causing forms of the human gene to discover how these genetic changes may lead to the disorder. Their surprising results may transform the way scientists design drugs that target these mutations to treat inherited or familial Alzheimer's, a rare form of the disease that affects approximately 1 percent of people with the disorder.

Dark neural patches in the neostriatum

Dark neural patches in the neostriatum

Researchers at the Okinawa Institute of Science and Technology Graduate University's Brain Mechanisms for Behaviour Unit have found a surprise upon mapping the precise connectivity inside a brain structure called the neostriatum. The cell groups here do not seem to be talking to each other, and are less interdependent in their functioning than previously suspected. Their findings were published in Brain Structure and Function.

Brain structure varies with trust level

Brain structure varies with trust level

A recent study shows differences in brain structure according to how trusting people are of others.

The psychologists used two measures to determine the trust levels of 82 study participants. Participants filled out a self-reported questionnaire about their tendency to trust others. They also were shown pictures of faces with neutral facial expressions and asked to evaluate how trustworthy they found each person in the picture. This gave researchers a metric, on a spectrum, of how trusting each participant was of others.

Teen cannabis users have poor long-term memory in adulthood

Teens who were heavy marijuana users - smoking it daily for about three years -- had an abnormally shaped hippocampus and performed poorly on long-term memory tasks, reports a new Northwestern Medicine study.

The hippocampus is important to long-term memory (also known as episodic memory), which is the ability to remember autobiographical or life events.

The brain abnormalities and memory problems were observed during the individuals' early twenties, two years after they stopped smoking marijuana.

Psychedelic drug use could reduce psychological distress, suicidal thinking

A history of psychedelic drug use is associated with less psychological distress and fewer suicidal thoughts, planning and attempts, according to new research from Johns Hopkins and the University of Alabama at Birmingham.

'Switches' that shaped the evolution of the human brain mapped

Thousands of genetic "dimmer" switches, regions of DNA known as regulatory elements, were turned up high during human evolution in the developing cerebral cortex, according to new research from the Yale School of Medicine.

Unlike in rhesus monkeys and mice, these switches show increased activity in humans, where they may drive the expression of genes in the cerebral cortex, the region of the brain that is involved in conscious thought and language. This difference may explain why the structure and function of that part of the brain is so unique in humans compared to other mammals.

People with anorexia, body dysmorphic disorder share brain anomalies

People with anorexia nervosa and with body dysmorphic disorder have similar abnormalities in their brains that affect their ability to process visual information, according to a new study.

People with anorexia have an intense fear of gaining weight and can starve themselves even when they are dangerously thin. Body dysmorphic disorder is a psychiatric condition characterized by an obsessive preoccupation with a perceived flaw in physical appearance.

Multitasking hunger neurons also control compulsive behaviors

In the absence of food, neurons that normally control appetite initiate complex, repetitive behaviors seen in obsessive-compulsive disorder (OCD), and anorexia nervosa, according to a new study by Yale School of Medicine researchers.

The findings are published in the March 5 online issue of the journal Cell.

Oxytocin nasal spray causes men to eat fewer calories

A synthetic nasal formulation of the hormone oxytocin reduced caloric intake in healthy men, particularly consumption of fatty foods, after a single treatment, a new study finds. The results, to be presented Sunday at The Endocrine Society's 97th annual meeting in San Diego, confirm those of animal studies showing oxytocin reduces food intake.

Exposure to endocrine disruptors while pregnant affects brain two generations later

Prenatal exposure to low doses of the environmental contaminants polychlorinated biphenyls, or PCBs, change the developing brain in an area involved in metabolism, and some effects are apparent even two generations later, a new study finds. Performed in rats, the research will be presented Friday at the Endocrine Society's 97th annual meeting in San Diego.

Hereditary effects included increased body weight, but only in descendants of females--and not males--exposed to PCBs in the womb, said study co-author Andrea Gore, PhD, professor at the University of Texas at Austin.