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Archive - Jun 17, 2019


Schizophrenia: Adolescence Is Game-Changer--Researchers Discover That Development of Hippocampus Is Severely Impacted in Adolescence at Time of First Psychotic Symptoms

Schizophrenia causes hallucinations and memory or cognition problems in those who have it. This psychiatric illness affects 0.5% of the general population, and it can be related to genetic abnormalities of chromosome 22, known as 22q11 deletion syndrome. However, not everyone who has this deletion syndrome necessarily develops psychotic symptoms. So, what triggers the illness? Researchers at the University of Geneva (UNIGE), Switzerland, have provided an initial answer after observing and analyzing several years of patients with deletion syndrome. The scientists found that the size of the hippocampus (image), the area of the brain responsible for memory and emotions, was smaller than normal but followed the same developmental curve as in healthy subjects. Yet, when the first psychotic symptoms appear - generally in adolescence - the hippocampus atrophies dramatically. The new results, which were reported online on June 4, 2019 in Molecular Psychiatry, open up new avenues for understanding the causes of schizophrenia. The article is titled “Positive Psychotic Symptoms Are Associated with Divergent Developmental Trajectories of Hippocampal Volume During Late Adolescence in Patients With 22q11ds.” 22q11 deletion syndrome is a neurogenetic disorder that targets chromosome 22. Thirty percent of people affected by the syndrome end up developing psychotic symptoms specific to schizophrenia, such as auditory hallucinations, memory problems, disorders affecting their perception of reality, and difficulties in social interactions characterized by strong paranoia.

Large Elk Populations in Yellowstone Elk Have Means to Adapt Their Migration Times to Changing Climate Cues; Migratory Shifts May Have Unknown Ripple Effects Throughout the Region

Every spring, tens of thousands of elk follow a wave of green growth up onto the high plateaus in and around Yellowstone and Grand Teton national parks, where they spend the summer calving and fattening on fresh grass. And every fall, the massive herds migrate back down into the surrounding valleys and plains, where lower elevations provide respite from harsh winters. These migratory elk rely primarily on environmental cues, including a retreating snowline and the greening grasses of spring, to decide when to make these yearly journeys, shows a new study led by University of California (UC), Berkeley, researchers. The study combined GPS tracking data from more than 400 animals in nine major Yellowstone elk populations with satellite imagery to create a comprehensive model of what drives these animals to move. "We found that the immediate environment is a very effective predictor of when migration occurs," said Gregory Rickbeil, PhD, who conducted the analysis as a postdoctoral researcher in Dr. Arthur Middleton's lab at UC Berkeley. This is in contrast with some other species, such as migratory birds, which rely on changing day length to decide when to move, Dr. Rickbeil pointed out. The results, published in the July 2019 issue of Global Change Biology, suggest that, as climate change reshapes the weather and environment of the park, elk should have the means to adjust their migratory patterns to match the new conditions.