Eric R. Kandel is a neuropsychiatrist who won a Nobel prize in 2000 for his research on the physiological basis of memory storage in neurons. You may have seen Kandel co-hosting the Brain Series with Charlie Rose on PBS.

On September 8, 2013 in the Sunday Review of The New York Times, Kandel published an op-ed titled, “The New Science of Mind.” The article sums up four key points for better understanding the biology of mental disorders.

Kandel begins the op-ed by debunking the myth that current brain imaging can offer insights that allow us to fully understand the biological basis of our higher mental processes. Kandel says, “In fact, recent newspaper articles have argued that psychiatry is a “semi-science” whose practitioners cannot base their treatment of mental disorders on the same empirical evidence as physicians who treat disorders of the body can. The problem for many people is that we cannot point to the underlying biological bases of most psychiatric disorders. In fact, we are nowhere near understanding them as well as we understand disorders of the liver or the heart. But this is starting to change.”

I wrote about the limitations of current brain imaging technology and the need for a new brain mapping initiative in a Psychology Today blog titled “Why Obama’s BRAIN Initiative is Important” if you’d like to read more on this topic.

These are revolutionary times for the biology of psychology. Kandel believes that we are on the forefront of “a unified science of mind that uses the combined power of cognitive psychology and neuroscience to examine the great remaining mysteries of mind: how we think, feel and experience ourselves as conscious human beings.”

Eric R. Kandel believes that the new science of mind is founded on the principle that our mind and our brain are inseparable. Kandel emphasizes,“The brain is a complex biological organ possessing immense computational capability: it constructs our sensory experience, regulates our thoughts and emotions, and controls our actions. It is responsible not only for relatively simple motor behaviors like running and eating, but also for complex acts that we consider quintessentially human, like thinking, speaking and creating works of art. Looked at from this perspective, our mind is a set of operations carried out by our brain. The same principle of unity applies to mental disorders.”

The Biology of Depression: Brodmann Area 25 and the Right Anterior Insula

Regarding the biology of depression, Kandel says that scientists are beginning to untangle how complex neural circuitry malfunctions in depressive illnesses. Two key brain regions in the neural tapestry that Kandel highlights are Brodmann Area 25, which mediates our unconscious and motor responses to emotional stress; the other is the right anterior insula, a region where self-awareness and interpersonal experience come together.

Kandel says, "These two regions connect to the hypothalamus, which plays a role in basic functions like sleep, appetite and libido, and to three other important regions of the brain: the amygdala, which evaluates emotional salience; the hippocampus, which is concerned with memory; and the prefrontal cortex, which is the seat of executive function and self-esteem. All of these regions can be disrupted in depressive illnesses."

Kandel highlights the work of Helen Mayberg, at Emory University, who is using brain-scanning techniques to deconstruct the components of complex neural circuitry in depression. In a recent study of depression, Professor Mayberg gave participants one of two types of treatment: cognitive behavioral therapy (CBT) or antidepressants.

Mayberg found that people who started with below-average baseline activity in the right anterior insula responded well to CBT, but not to antidepressants. On the flip side, people with above-average activity in this region responded to antidepressants, but did not respond well to CBT. From these findings, Professor Mayberg realized that she could predict a depressed person’s response to specific treatments from the baseline activity in the right anterior insula.

Kandel believes there are 4 keys to understanding the biology of mental disorders:

  1. The neural circuits disturbed by psychiatric disorders are likely to be very complex.
  2. If doctors are able to identify specific, measurable markers of a mental disorder, these biomarkers can predict the best treatment options: psychotherapy and/or medication.
  3. Psychotherapy itself is biological treatment. Psychotherapy is literally a brain therapy. It produces lasting, detectable physical changes in our brain, much as learning does.
  4. The effects of psychotherapy can (and should) be studied empirically.

Kandel reminds us that Aaron Beck, who pioneered the use of cognitive behavioral therapy, insisted that psychotherapy has an empirical basis – it is a science. Kandel points out that other forms of psychotherapy have been slower to move towards studying their empirical foundation. He believes this is because a number of psychotherapists consider human behavior too messy to study in scientific terms.

Genetics Influence: Body, Brain, Mind, and Behavior

Kandel states, “ANY discussion of the biological basis of psychiatric disorders must include genetics. And, indeed, we are beginning to fit new pieces into the puzzle of how genetic mutations influence brain development.”

Interestingly, the same day Kandel published his op-ed, researchers at Albert Einstein College of Medicine of Yeshiva University published a study in the online journal of Science showing that inner-ear dysfunction may lead to neurological changes that increase hyperactivity.

The researchers hypothesized that inner-ear defects cause abnormal functioning of the striatum, a central brain area that controls movement. From a perspective of the link between the cerebrum and cerebellum (up brain-down brain respectively) this new study offers many clues.

The inner ear consists of two structures, the cochlea (responsible for hearing) and the vestibular system (responsible for balance). Inner-ear disorders are typically caused by genetic defects but can also result from infection or injury.  

The idea for the study arose when Michelle W. Antoine, a Ph.D. student at Einstein at the time, noticed that some mice in Dr. Hébert's laboratory were unusually active — in a state of near-continual movement, chasing their tails in a circular pattern. Scientists have observed that many children and adolescents with severe inner-ear disorders – particularly disorders affecting both hearing and balance – also have behavioral problems, such as hyperactivity. This study is the first to show that ear disorders and behavioral problems are actually linked.

"Our study provides the first evidence that a sensory impairment, such as inner-ear dysfunction, can induce specific molecular changes in the brain that cause maladaptive behaviors traditionally considered to originate exclusively in the brain," said study leader Jean M. Hébert, Ph.D., professor in the Dominick P. Purpura Department of Neuroscience and of genetics at Einstein.

The researchers established that the animals' inner-ear problems were due to a mutation in a gene called Slc12a2, which mediates the transport of sodium, potassium, and chloride molecules in various tissues, including the inner ear and central nervous system (CNS). The gene is also found in humans.

"Our study also raises the intriguing possibility that other sensory impairments not associated with inner-ear defects could cause or contribute to psychiatric or motor disorders that are now considered exclusively of cerebral origin," said Dr. Hébert. "This is an area that has not been well studied." Other studies have found that, unlike declarative memory, the incremental acquisition of a new visuomotor skill depends upon the integrity of both the striatum and the cerebellum, but not of the cerebral frontal lobes. 

This finding is one of many leading to our revolutionary understanding of the biology of psychology. What many would tag as “behavioral abnormalities” traditionally thought to originate in the brain have a biological basis and can originate from other parts of the body.

Mind, body, brain, and behavior are intertwined at a deep genetic level. Kandel illustrates another example of the genetic link to behavioral problems in his op-ed based on the research of Matthew State, from the University of California, San Francisco. Mattew State has discovered a remarkable copy number variation involving chromosome 7.

An extra copy of a particular segment of chromosome 7 dramatically increases the risk of autism, which is characterized by social isolation. Conversely, the loss of that same segment of chromosome 7 results in Williams syndrome, a disorder characterized by intense sociability. A single segment of chromosome 7 contains about 25 of the 21,000 or so genes in our genome. The impact of just one additional copy vs. a single missing copy has a profound effect on social behavior.

It’s mind boggling that so many things go right for us psychologically considering that the variation of a single segment of a single chromosome deeply impacts how someone is biologically wired to interact with the world.

Conclusion: Much of Psychology is Biological in Nature

Eric R. Kandel concludes, “In years to come, this increased understanding of the physical workings of our brain will provide us with important insight into brain disorders, whether psychiatric or neurological. But if we persevere, it will do even more: it will give us new insights into who we are as human beings.”

People with depressive illnesses are often stigmatized. The revolution taking place with the biology of psychology allows doctors and patients new ways to understand and treat mental health. Kandel says,” Our understanding of the biology of mental disorders has been slow in coming, but recent advances like these have shown us that mental disorders are biological in nature, that people are not responsible for having schizophrenia or depression, and that individual biology and genetics make significant contributions.”

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