Tag Archives: neuroscience

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By Karene Booker
Reprinted from Cornell Chronicle, February 20, 2012

Depue
Depue

Personality disorders could be more effectively diagnosed by identifying and targeting the disrupted neurobiological systems where the disorders originate, report Cornell researchers.

The way that these mental illnesses are now classified -- based on particular patterns of thought and behavior -- is misguided and has little hard evidence to support it, reports Cornell neuroscientist Richard Depue and his colleague in a special issue of the Journal of International Review of Psychiatry (23:3).

"The behavioral features used to diagnose personality disorders do not coalesce into coherent disorders in any research," says Depue, professor of human development in the College of Human Ecology, who co-authored the article with graduate student Yu Fu. "As currently defined, the different personality disorders have overlapping behavioral symptoms that also merge imperceptibly with normal behavior. A diagnosis should define a coherent behavioral pattern and predict a particular course, prognosis and treatment. No personality disorder diagnosis can do that."

Their findings fly in the face of current medical practice. Nearly one in 10 Americans suffers from a personality disorder, a group of disabling conditions characterized by serious, sometimes catastrophic, problems with relationships and work. Behavioral features can vary widely, from pervasive disregard for the law and the rights of others (antisocial personality disorder) to extreme mood instability (borderline personality disorder).

The researchers drew their conclusions by conducting a detailed review of the brain systems that underlie the major human personality traits.

Humans have about six major personality traits, each with its own neurobiological foundation that influences such behaviors as how anxious or impulsive we are, Depue notes. For example, the underlying systems and associated personality traits in their model include anxiety/stress-reactivity (thought to underlie neuroticism and negative emotionality) and neural constraint (thought to underlie conscientiousness), among others. The variety of behaviors associated with personality disorders arise from the influence of an individual's genetic make-up and environment on neurobiological functioning, they say.

In their multidimensional model, a person's personality traits can be plotted in three-dimensional space where the axes represent the underlying neurobehavioral systems. The patterns of behavior associated with personality disorders emerge from the interaction of extremely high or low values or levels of normal traits; such extremes lead to impaired interactions, they say.

"Our model links personality traits with the underlying neurobiology, which provides a better framework for understanding how and why personality disorders develop and how they can be treated," he says. "It allows us to better predict interventions, such as certain drugs and/or environmental interventions, which may be of benefit. We can also start thinking of treatments that modify multiple neurobiological variables, rather than just one or two."

And recent discoveries in neuroscience point to the important role environment plays, particularly during early childhood, in how genes are expressed, Depue says. "So, risks for personality disorders can be either magnified or reduced by the interaction of the individual's circumstances with their genetic make-up, in a process called epigenetics. We see evidence for this in personality disorders, which are much more prevalent in those who have suffered from a variety of childhood stresses and abuse."

Their theoretical analysis has implications for the criteria used for classifying personality disorders in the Diagnostic and Statistical Manual of Mental Disorders. It also contributes to a growing body of evidence that calls for a rethinking of the approach to classifying these illnesses, based on the underlying biochemical and neural processes that result in the symptoms.

The research was supported by a grant from the National Institute of Mental Health.

Karene Booker is an extension support specialist in the Department of Human Development.

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By Karene Booker
Reprinted from Cornell Chronicle, December 15, 2011 

Reyna
Reyna

Teenage brains undergo big changes, and they won't look or function like adult brains until well into one's 20s. In the first book on the adolescent brain and development of higher cognition, a Cornell professor helps highlight recent neuroscience discoveries about how the brain develops and their implications for real-world problems and how we teach young people and prepare them to make healthy life choices.

For the new book, "The Adolescent Brain: Learning, Reasoning, and Decision Making" (APA Books), Valerie Reyna, professor of human development in the College of Human Ecology and co-director of Cornell's Center for Behavioral Economics and Decision Research, brought together an interdisciplinary group of leading scientists to focus on brain development and higher cognition, which is necessary for students to learn math and science and make good decisions. Higher cognition is the set of thinking skills students use to manipulate information and ideas in ways that lead to problem solving and new insights.

"A major implication of the provocative research highlighted in this book is the contrast between adolescents' cognitive skills, which are at a lifetime peak, and their frequent inability to use this competence in everyday decision making," said Reyna, who co-edited the volume with Sandra Chapman, director of the Center for Brain Health at the University of Texas at Dallas; Michael Dougherty, professor of psychology at University of Maryland; and Jere Confrey, professor of mathematics education at North Carolina State University.

"But the evidence suggests that the way young people learn, reason and decide changes [during this period] and can be changed," said Reyna. "We must move education beyond rote learning to fostering the cognitive skills essential for academic achievement and economic well-being in our knowledge-based economy. Higher cognition is a foundation critical for individuals and our country to be competitive. This volume introduces a new framework for interdisciplinary collaboration among scientists in neuroscience, psychology and education."

"The Adolescent Brain" addresses the major changes in memory, learning and decision making experienced by adolescents as they mature, beginning with a review of the changes in brain anatomy and physiology based on extensive neuroimaging studies. The ensuing chapters examine the developing capacity of the adolescent brain, covering such topics as the underpinnings of intelligence and problem solving, strategies for training teen reasoning abilities, effectively teaching mathematical concepts, the effects of emotion on reasoning, and factors that promote teen engagement in health-related behaviors.

The book wraps up with a chapter by Reyna and Ph.D. student Christina Chick that integrates the behavioral and neuroscience evidence in a process model of adolescent risky decision making. Chick and Reyna explain, for example, how massive pruning of gray matter in late adolescence fits with the growth of adolescents' ability to connect the dots and understand the underlying meaning of situations. This gist thinking facilitates recognition of danger and protects against unhealthy risk-taking, they say.

The book is intended for researchers, students and professionals in the fields of cognitive neuroscience and psychology and for education policymakers and educators, especially in mathematics.

Reyna will present a talk on the "Adolescent Brain" March 1 at 4-5:30 p.m., 160 Mann Library.

Karene Booker is extension support specialist in the Department of Human Development.

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Videos are now online from the 2011 Bronfenbrenner Conference, “The Neuroscience of Risky Decision Making.”

At the conference, neuroscientists, neuroeconomists and social scientists explored scientific theories about the brain mechanisms underlying risky decision-making, paving the way for translation of basic science into policy and practice.

The conference, co-organized by Valerie Reyna, professor of human development and co-director for Cornell's new Magnetic Resonance Imaging Facility, and Vivian Zayas, assistant professor of psychology, drew scholars from as far away as Europe to share research on such topics as brain maturation, neural responses to rewards and punishments at different ages, emotional regulation and self-control. Many of those who participated are founders in their field.

Presenters:

Antoine Bechara, University of Southern California
Eveline Crone, Leiden University
Paul Glimcher, New York University
Jay Giedd, National Institute of Mental Health
Scott Huettel, Duke University
Brian Knutson, Stanford University
Beatriz Luna, University of Pittsburgh Medical Center
Kevin Ochsner, Columbia University
Philip Zelazo, University of Minnesota

Links:

Presentations, discussions, Q & A, and panel conversations

Article: Experts explore links between risk-taking, brain mechanisms

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By Karene Booker
Reprinted from Cornell Chronicle, October 7, 2011

Anthony Bechara
Conference participants Antoine Bechara and Kevin Ochsner. Photo by Jason Koski, University Photography

Most diseases people die from are those borne of bad choices. Whether the decision is to have unprotected sex, smoke, drink and drive, not save for retirement, or to eat fries with that burger, risky decisions permeate our lives, sometimes with disastrous consequences, which is why researchers gathered on campus Sept. 22-23 to better understand risk-taking.

At the Third Biennial Urie Bronfenbrenner Conference, "The Neuroscience of Risky Decision Making," neuroscientists, neuroeconomists and social scientists explored scientific theories about the brain mechanisms underlying risky decision-making, paving the way for translation of basic science into policy and practice.

"From neurons to basic psychological processes, such as memory and meaning, to complex social and economic behavior, we need to build a dialogue across disciplines," said Valerie Reyna, professor of human development in the College of Human Ecology and co-director for Cornell's Center for Behavioral Economics and Decision Research. "We need a common language and collaboration to improve educational and health outcomes and to advance neuroscience research."

The conference, co-organized by Reyna and Vivian Zayas, Cornell assistant professor of psychology, drew scholars from as far away as Europe to share research on such topics as brain maturation, neural responses to rewards and punishments at different ages, emotional regulation and self-control.

Many of those who participated are founders in their field. Paul Glimcher, a professor in New York University's Center for Neural Science and of psychology and economics, for example, literally wrote the book on neuroeconomics in 2003 when he released his seminal work on the biological foundations of economic behavior. At the conference, he reported on some of his findings, such as work that suggests that neural networks are connected -- hungry people, for example, make riskier decisions not just about food, but also about money.

Antoine Bechara, professor of psychology and neuroscience at the University of Southern California, researches the decision-making capabilities of patients with brain damage, such as the case of the 40-cigarette-a-day smoker who no longer had the urge to smoke after suffering a stroke. Bechara's findings shed light on the workings of the brain systems involved in decision-making and addiction.

One of the developmental neuroscientist pioneers, University of Pittsburgh's Beatriz Luna, focuses on the transition from adolescence to adulthood. She reported that incentives have a magnified effect on cognitive control in adolescents, compared with adults. Adolescents performing a particular cognitive control task seem to require incentives in order to succeed, she said, suggesting immaturities in their reward system.

Participants, including program officials from the National Institutes of Health and the National Science Foundation, also debated core assumptions about reward sensitivity and self-control, and their implications for practice and policy.

"There is such tremendous synergy among fields," said Reyna. "Collaborating and thinking together is important for setting a research agenda that will shape the field and have big payoffs in terms of public health and well-being."

The event was the kickoff to multiple interdisciplinary initiatives on campus, including the acquisition of a new neuroimaging facility to be housed in the College of Human Ecology. The American Psychological Association plans to publish a book based on the papers presented at the conference.

The Bronfenbrenner Center for Translational Research, Center for Behavioral Economics and Decision Research, and Institute for the Social Sciences, all at Cornell, co-sponsored the conference.

Karene Booker is an extension support specialist in the Department of Human Development.

Related Links:
The Neuroscience of Risky Decision Making
College of Human Ecology
Valerie Reyna
ISS Judgment, Decision Making and Social Behavior

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By Karene Booker

Barbara GanzelYou’ve had a hard day at work or at home or both and you’re feeling “stressed out.” Now you have even more reason to worry!

It turns out that repeated exposure to stress causes changes in the brain that can set the stage for a multitude of mental and physical health problems, from depression to heart disease.

Now a recent paper in Psychological Review, explains why.  Drawing on research across multiple fields, Barbara Ganzel, neuroscientist in the Department of Human Development, and her colleagues Pamela Morris from New York University and Elaine Wethington in the Department of Human Development developed a new model of the stress process and how it affects the brain and body over time.

“We needed a framework that would integrate the emerging insights from neuroscience with research in other fields so we could really understand the interplay between stress exposure, regulation of body processes and health outcomes,” said Ganzel.

Here's how it works.

Your body’s stress response kicks in when you perceive a threat. Your heart beats faster and your blood pressure increases along with other changes which prepare your brain and body for action. This is a remarkable survival system for responding to danger. But most daily stressors are not life-threatening. They are more individualized. We perceive and respond to a situation in the context of our current environment and health, influenced by our past environment and health, upon the foundation of our genetics.

A set of brain regions which includes the amygdala and basal ganglia is the hub of our response to threats and rewards. Processing of such emotional stimuli is regulated by neurotransmitters and neurohormones within these regions.

These core emotional regions of the brain work in conjunction with other brain areas to interpret the situation and generate a behavioral response. Together, the core emotional regions of the brain function as the first responders to threat. This central response then drives all of the other stress-related changes in the body. 

In response to a stressor, neurochemical signals generated by the core emotional regions of the brain activate the hypothalamus in the brain, pituitary gland at the bottom of the brain, and the adrenal glands.  The adrenal glands then produce cortisol and adrenaline which have global preparatory and modulating effects on the rest of the body’s systems such as the immune system, cardiovascular system and digestion.

An individual’s response to stress is influenced by their environment. There are potential risks that may confound and resources that may help the individual undergoing the stressor. For instance, research has shown that social support can buffer the impact of negative events on mental and physical health. Intriguingly, results from fMRI studies indicate that the availability of social support can prevent or reduce the brain’s initial emotional reactivity to stress, though more research needs to be done to fully understand this relationship.

Over time the process of responding to stress causes wear and tear on the brain and body. While minor stressors may function as healthy challenges that leave little or no negative effects, larger stressors make greater demands. Under chronic or repeated stress, the long term physiological costs of the sustained accommodation to stress continue to accumulate.

In the authors’ model, mental health is affected by the stress response process in the brain and physical health is affected by the stress response process in the body. And, of course, each affects the other. Accumulated wear and tear and the associated mental and physical health outcomes feed into the individual’s environmental risks. Importantly, accumulated wear and tear also directly affects the individual’s mental and physical capacity to respond to a current stressor.

An example is blood pressure, which increases in response to perceived danger. Repeated exposure can result an upward regulation of the blood pressure set point to more permanently accommodate the stressful environment. Chronic high blood pressure, in turn, can lead to a host of other health problems which feed back into the dynamics of an individual’s neural response to stress.

Genetics and gene-environment interactions, importantly, enter into the model. Individual differences in genetics affect the biology of the current stress response as well as the accumulation of wear and tear. Individual differences modify an individual’s first and subsequent responses to stressors in the environment. One example is the natural genetic variation in a serotonin transporter gene. Carriers of one version are more sensitive to negative stimuli. Under stressful conditions such individuals have an increased risk for depression.

Research has identified multiple indicators of accumulated stress load on the body. Chronic high blood pressure is but one example. Emerging evidence from neuroimaging studies confirms that there are long-term effects of stress on the healthy human brain as well.  Since the emotional systems of the brain are the focal point for response to stress, indicators of wear and tear would be expected to show up as structural, functional or neurochemical shifts in these brain systems. These, in turn, translate into alterations in behavior such as increased startle response or anxiety.  Ganzel found just such effects in her earlier research on 9/11 survivors in which adults closer to the disaster had smaller more stress-reactive amygdalae.

”In our whole group, amygdale reactivity and amygdale gray matter volume was related to lifetime trauma exposure and predicted anxiety and symptoms of post traumatic stress syndrome,” said Ganzel. There is evidence from a broad set of research findings that severe, chronic or repeated stress plays a role in a multitude of health issues such as anxiety, depression, and suppressed immunity.”

This model provides a framework for better understanding those links and designing new approaches to medical and social problems – from heart disease to child abuse. 

Reference

Ganzel, B.L., Morris, P.A. and Wethington, E. (2010). Allostasis and the human brain: Integrating models of stress from the social and life sciences. Psychological Review, 117(1), 134-174. 

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Gary Evans, developmental and environmental psychologist at Cornell University, is PI on a Grand Opportunity award from the National Institutes of Health called "Childhood Poverty and Brain Development: The Role of Chronic Stress and Parenting." Evans is the Elizabeth Lee Vincent Professor of Human Ecology in the Departments of Design and Environmental Analysis and of Human Development. One fifth of America's children grow up in poverty.  While there is good evidence that this is harmful to health, achievement, and socio-emotional adjustment, very little is known about the brain basis that mediates the detrimental effects of poverty.

The two-year research plan will utilize a well-characterized longitudinal sample of low- and middle-income individuals in combination with a comprehensive set of conceptually derived, innovative and validated neuroimaging tests to address two critical questions: How childhood poverty influences adult brain structure and function; and what underlying mechanisms might account for childhood poverty - brain relationships.  The invesitgators hypothesize that chronic physiological stress dysregulation as well as harsh, unresponsive parenting during childhood will account for some of the expected linkages between childhood poverty - adult brain structure and function - particularly in the hippocampus, amygdala, and the anterior cingulate/medial prefrontal cortex.

The project will utilize a 14 year, ongoing longitudinal research program of low and middle-income individuals focused on childhood poverty, physiological stress, and socio-emotional development conducted by Evans. Half of this sample (now age 22) grew up below the poverty line and half are middle income.  The sample is well characterized over their life course in terms of socioeconomic status and other demographic variables, as well as both physical and psychosocial risk exposures.  Primary outcome variables for this longitudinal cohort include multiple methodological indicators of physiological stress (neuroendocrine, cardiovascular, and metabolic) along with parental, self, and teacher ratings of socioemotional development (internalization, externalization, self regulation. In depth data on parenting are also included.

The neuroimaging work will be conducted in the Department of Psychiatry, University of Michigan by Israel Liberzon, with expertise in the neuroimaging of stress in health and mental illness, and by James Swain a child psychiatrist studying the brain basis of parenting.

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