Long-term memory formation

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NYU scientists find that growth factors that build brains also build memories New York University "A team of New York University neuroscientists has determined how a pair of growth factor molecules contributes to long-term memory formation, a finding that appears in the journal Neuron. "These results give us a better understanding of memory's architecture and, specifically, how molecules act as a network in creating long-term memories," explains the paper's senior author, Thomas Carew, a professor in NYU's Center for Neural Science and dean of NYU's Faculty of Arts and Science. "More importantly, this marks another step toward elucidating the intricacies of memory function, which is vital in the development of cognitive therapies to address related afflictions." The importance of growth factor molecules (GFs) has long been known. They are critical in building brains beginning in utero and until adulthood. Moreover, over time, it's been established that GFs are "recycled" from brain builders to engineers of long-term memories. Less clear, however, is how the wide range of GF families, as well as different members within each family, act to help us create these memories. In working to address this question, the NYU research team, which also included graduate student Ashley Kopec, the study's lead author, and research scientist Gary Philips, focused on two GF families: TrkB and TGFβr-II, which represent two distinct classes of GFs that utilize different types of receptors to exert their actions in the brain. In their study, the researchers examined GFs in Aplysia californica, the California sea slug. Aplysia is a model organism that is quite powerful for this type of research because its neurons are 10 to 50 times larger than those of higher organisms, such as vertebrates, and it possesses a relatively small network of neurons--characteristics that readily allow for the examination of molecular signaling during memory formation. Specifically, to produce a form of "threat memory" called sensitization in a simple reflex system of Aplysia, the researchers presented the sea slugs with a pair of mild tail shocks delivered 45 minutes apart--the first to instill a "molecular context" in the neurons of the reflex and the second to use that context to drive molecular mechanisms that are required to form a long-term memory -- and then examined GF activity at both periods, Time 1 and Time 2. Their results showed differences in the role of these two GF families across two dimensions: time and space. At Time 1, when the context for the memory is first created, TrkB plays a critical role while TGFβr-II is irrelevant. However, at Time 2, when a long-term memory is actually formed, the roles are reversed: TGFβr-II is active, but TrkB is insignificant. In addition, the results showed spatial differences. In Aplysia, the simple neural circuit that mediates the reflex modified by learning is made up of unique sensory neurons and motor neurons. The sensory neurons' cell bodies live in one compartment of the brain while their companion synapses, which pass along signals to other cells, reside in another. In the Neuron study, the researchers found that the TrkB effects are exerted only at synapses while TGFβr-II functions only at the cell body. Overall the study provides new insights into how different GF families play unique roles both in time and in space, thus helping to elucidate the "when," "where," and "how" of memory formation." ### The research was supported by grants from the National Institute of Mental Health (RO1 MH 041083, F31 MH 100889). For more information on memory, please visit Aging and Long Term Care CE Course

The More Hemispheric Lateralization, the Better Thinking Performance

By examining activity of the living human brain at rest via fMRI, NIMH intramural scientists have discovered a secret to how it enhances thinking ability. It turns out that left brain regions are biased to talk more to each other, while right brain regions talk more evenly with both hemispheres. These biases are most pronounced in brain regions associated with the specialized functions of the two hemispheres – e.g., language and motor control on the left and visual/spatial attention on the right. Such lateralization is associated with enhanced cognition, say Drs. Stephen Gotts, Hang Joon Jo, Alex Martin, and colleagues of the NIMH Cognitive Neuropsychology Section, Laboratory of Brain and Cognition. The more such lateral specialization subjects showed at rest, the better they performed on verbal and spatial tasks later. For more information, see PNAS Blog: Brain Halves Interact Differently with Each Other CBT - How to Implement Trauma-Focused Cognitive Behavioral Therapy Two types of lateralization

Reference Two distinct forms of functional lateralization in the human brain. Gotts SJ, Jo HJ, Wallace GL, Saad ZS, Cox RW, Martin A. Proc Natl Acad Sci U S A. 2013 Aug 19. [Epub ahead of print] PMID: 23959883

Bullying Exerts Psychiatric Effects into Adulthood

Once considered a childhood rite of passage, bullying lingers well into adulthood. Bullies and victims alike are at risk for psychiatric problems such as anxiety, depression, substance abuse, and suicide when they become adults, reported a study partially funded by the National Institute of Mental Health (NIMH) that was published in the April issue of JAMA Psychiatry. Background Bullying is a repetitive, aggressive act done to abuse or intimidate others. It can take on various forms—primarily verbal, emotional, and physical, although cyberbullying is also on the rise. Typically these scenes occur inside school or on the playground, but they can also happen at home or at work. A power imbalance usually is involved in which one child or a group of children torments another child who is considered “weaker.” Methods employed by bullies include threats, rumor-spreading, and exclusion. Most of what experts know about the effects of bullying comes from short-term observational studies. These studies reflect general society’s view that most people overcome these events by the time they become adults. “Initially I too was skeptical about these long-term effects,” says study author William Copeland, Ph.D., at Duke University, who as an epidemiologist knew of other traumatic events that do not linger psychologically, such as maltreatment and physical abuse. “Yet this is something that stays with people. A large number of people express lasting effects decades after their childhood experiences.” Copeland and his colleagues tapped into a local population sample of 1,420 children from 11 Western North Carolina counties. Starting at the ages of 9, 11, and 13, the kids, along with their parents, were interviewed annually until the age of 16, fielding questions about peer relations and home and community settings. The participating children were again interviewed at 19, 21, and 24 to 26 years of age. Four groups emerged from this longitudinal study: people who were never involved in bullying, people who were victims, people who were bullies, and people who were both. Results of the Study More than half of the study’s youth reported being neither a bully nor a victim. Around a quarter of the study group claimed that they were victimized. About 7 percent confessed to being a bully. A similar percentage said that they were both, a group the researchers labeled as “bully-victims.” Compared to those who went through childhood unscathed, victims had four times the prevalence of agoraphobia, generalized anxiety, and panic disorder when they became adults. Overall, bullies had four times the risk of developing antisocial personality disorder. These disorders still stood even after other factors were taken into account, such as preexisting psychiatric problems or family hardships. Bully-victims fared the worst. Also known as “loners,” these individuals start out with less developed social skills and are seen as more impulsive and aggressive. When picked on, they respond by picking on others. Their numbers, compared to those never involved in bullying, tell the story: 14 times the risk of panic disorder, 5 times the risk of depressive disorders, and 10 times the risk of suicidal thoughts and behavior. “Victims report the greatest anxiety problems. They might become successful people later on, but they still think about the event and hold onto it. Bullies are socially adept and may find ways in adulthood to use these skills in a pro-social manner. Folks really underestimate who are the bully-victims. These are the ones who end up having the most significant emotional problems including suicidality,” explained Copeland, who is also a father of two Social Worker Continuing Education Significance All these disorders impart a great emotional and financial cost to society. Lowering and/or preventing bullying could possibly reduce human suffering and long-term health costs—not to mention creating a safer environment for children to grow up in. Research into resilience or why some are able to bounce back in adulthood is ongoing. Some key molecules and brain circuit pathways have been identified in animals. Other research areas under exploration include physiology, genetics, epigenetics, and cognitive therapies. What’s Next Studies looking into which interventions work best for bullying are underway. Once these interventions are identified, research is needed to see at what stages in life they should they be administered. Lastly, other factors that play a role in bullying and victimization, such as sexual orientation, need exploration. “This study suggests that we should pay attention to what’s going on between peers,” said Copeland, adding that kids spend more time each day with their peers, including school and online, than with their parents. “What happens to kids when they’re with their peers is as important, or may be more important, than what happens at home,” said Copeland. Reference Copeland WE, Wolke D, Angold A, Costello EJ. Adult Psychiatric Outcomes of Bullying and Being Bullied by Peers in Childhood and Adolescence. JAMA Psychiatry, published April 2013. Grant number: K23 MH080230