Tag: autism and brain

Synchronization of Memory Cells Critical For Learning and Forming Memories

Credit: UNH

On the left is an enlarged image showing many hippocampal neurons, most of which are silent and only a few are active. On the right are close ups of three highly active neurons, or memory cells, which become synchronized after memory formation

The phrase “Pavlov’s dogs” has long evoked images of bells, food and salivating dogs. Even though this tried-and-true model of repetitive patterns mimics a variety of learning processes, what happens on a cellular level in the brain isn’t clear. Researchers at the University of New Hampshire took a closer look at the hippocampus, the part of the brain critical for long-term memory formation, and found that the neurons involved in so-called Pavlovian learning shift their behavior during the process and become more synchronized when a memory is being formed – a finding that helps better understand memory mechanisms and provides clues for the development of future therapies for memory-related diseases like dementia, autism and post-traumatic stress disorder (PTSD).

“There are tens of millions of neurons in the hippocampus but only a small fraction of them are involved in this learning process” said Xuanmao (Mao) Chen, assistant professor of neurobiology. “Before engaging in Pavlovian conditioning, these neurons are highly active, almost chaotic, without much coordination with each other, but during memory formation they change their pattern from random to synchronized, likely forging new connecting circuits in the brain to bridge two unrelated events.

In the study, recently published in The FASEB Journal, researchers looked at Pavlovian learning patterns, or respondent conditioning, in mice. In the beginning, before any repetitive learning exercises, the mice did not know what to expect and using special imaging with an endomicroscope the researchers saw that the neural activity was disorderly. But after repeating different tasks associated with a conditional stimulus, like a tone or bell, the mice began to recognize the pattern and the highly active neurons became more synchronized. The researchers hypothesize that without forming synchronization, animals cannot form or retrieve this type of memory.

In the 1890’s, Russian psychologist, Ivan Pavlov discovered classical conditioning through repetitive patterns of bell ringing which signaled to his dogs that food was on its way and stimulated salivation. This same learned behavior is important for episodic knowledge which is the basis for such things as learning vocabulary, textbook knowledge, and memorizing account passwords. Abnormal learning processing and memory formation are associated with a number of diseases like dementia, autism, and PTSD. People who struggle with these cognitive dysfunction-related disorders may have trouble retaining memories or can even form too strong a memory, as with PTSD patients. The UNH researchers believe that understanding the fundamentals of how classical conditioning shape neural connections in the brain could speed up the development of treatments for these disorders in the future.

Contributing to these findings are Yuxin Zhou, doctoral candidate; Liyan Qiu, research scientist; both at UNH, and Haiying Wang, assistant professor at the University of Connecticut.

This work was supported by the National Institutes of Health (NIH) and the Cole Neuroscience and Behavioral Faculty Research Awards.

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Autism Diagnosis Test Needs Improvement

Photo by Porapak Apichodilok on Pexels.com

Study finds inconsistencies in a broadly used autism test

Rutgers researchers have found that a test widely used to diagnose whether children have autism is less reliable than previously assumed.

The study is published in the journal Neural Computation.

The standardized test, known as the Autism Diagnostic Observation Schedule (ADOS), assesses communication skills, social interaction and play for children who may have autism or other developmental disorders.

The researchers digitized the test by attaching wearable technology, like an Apple Watch, to two clinicians and 52 children who came in four times and took two different versions of the test. 

When researchers looked at the scores of the entire cohort, they found they did not distribute normally – which could mean a chance of false positives inflating the prevalence of autism, among other implications.

The results showed that switching clinicians may change a child’s scores and consequently influences the diagnosis. The researchers found similar results when they analyzed open-access data of 1,324 people ages 5 to 65, said Elizabeth Torres, associate professor of psychology in Rutgers’ School of Arts and Sciences, and director of The New Jersey Autism Center of Excellence.

“The ADOS test informs and steers much of the science of autism, and it has done great work thus far,” said Torres, whose expertise has brought emerging computer science technology to autism. “However, social interactions are much too complex and fast to be captured by the naked eye, particularly when the grader is biased to look for specific signs and to expect specific behaviors.”

The researchers suggest combining clinical observations with data from wearable biosensors, such as smartwatches, smartphones and other off-the-shelf technology.

By doing so, they argue, researchers may make data collection less invasive, lower the rate of false positives by using empirically derived statistics rather than assumed models, shorten the time to diagnosis, and make diagnoses more reliable, and more objective for all clinicians.

Torres said autism researchers should aim for tests that capture the accelerated rate of change of neurodevelopment to help develop treatments that slow down the aging of the nervous system.

“Autism affects one out of 34 children in New Jersey,” she said. “Reliance on observational tests that do not tackle the neurological conditions of the child from an early age could be dangerous. Clinical tests score a child based on expected aspects of behaviors. These data are useful, but subtle, spontaneous aspects of natural behaviors, which are more variable and less predictable, remain hidden. These hidden aspects of behavior may hold important keys for personalized treatments, like protecting nerve cells against damage, or impairment, which could delay or altogether stop progression.”

The study was co-authored by Richa Rai, a graduate student in psychology at Rutgers University, Sejal Mistry, a former Rutgers Biomathematics student now at the University of Utah Medical School, and Brenda Gupta from Montclair State University.