Psychiatry And The Brain

How does a healthy brain work?

We really don't how the healthy brain works. It's a real enigma; it's the million dollar question. I think a lot of people imagine that the brain works like a circuit board with various components, interacting and talking to each other. I think that there is some evidence that that occurs, and we certainly know how different parts of the brain are constructed, and the pathways that connect them to other parts of the brain. However, how the brain all works together to create consciousness, or to create the experience of pleasure, that's something that's really eluded us.

What is a "neurotransmitter"?

The term neurotransmitter refers to a whole collection of chemicals that serve to connect neurons together. We typically think of neurons coming together at a place that we call the synapse. Neurotransmitters are typically released from one neuron; they travel across the space, where they interact with a receptor in sort of a lock and key manner. There are a lot of different neurotransmitter systems in the brain. You may have heard of some of these, such as the serotonin system, the dopamine system, the norepinephrine system; these are some of the most prominent ones that have been studied for many years. However, there are probably 40 to 50 other chemicals that are also very important in this neuronal communication. We know that a lot of the medications that we use for treating mental illness have their effect on specific neurotransmitter systems. Sometimes they can affect how much of a neurotransmitter is released, and they can also affect how they bind to that receptor on the other side of the synapse.

How do neurotransmitters affect behavior?

These various chemical messengers are integral parts to neurotransmitter pathways or circuits and you can imagine that the brain is constructed somewhat like a circuit board in which you have different areas communicating with others. This communication occurs through the use of neurotransmitters. Exactly how that creates conscience thought, decision making, and perception of experiences, we don't really know.

What is "serotonin"?

Serotonin is a monoamine neurotransmitter, it's derived in the brain stem of the brain, it's the lower part of the brain and it's very important for a number of functions. It's important in sleep regulation. But, in psychiatry we look at it as having an important role in behavior restraint. So, serotonin can be thought of as a important in giving us pause when making a decision. Serotonin is one of the neurotransmitters that we know is important in depression. A lot of the medications that we use affect the serotonin system. However, we also know it has an important role in anxiety disorders as well as schizophrenia.

What is "dopamine"?

Dopamine is a monoamine neurotransmitter that's broadly distributed throughout the brain. Dopamine has a number of very important functions including motivation and behavioral activation. We know that when a person consumes cocaine or amphetamine they tend to become much more active, moving around, and that is very likely to be due to the profound action on the dopamine system. Dopamine's also important in cognition. It is present in the frontal lobes of the brain and is important in a lot of those high level cognitive abilities including decision-making and memory. We also know that it has a key role in the award systems. To that end dopamine is very relevant to substance abuse.

What is "norepinephrine"?

Norepinephrine is another monoamine neurotransmitter that's important in arousal. It's derived from a brain region called the locus ceruleus and when you increase norepinephrine you have a number of typical physical phenomena. These include: increased heart rate, increased breathing and increased muscle tension. This is important from an evolutionary standpoint because it's part of the fight or flight response. Norepinephrine amps up a person's or an animal's ability to deal with a sudden stressful situation.

What are the most common causes of mental disorders?

The cause of mental illness has really remained a mystery, that's really the million-dollar question in our field. We've really gone a long way in understanding various genetic links and we have a lot of indications from, for example: brain imaging studies to highlight dysfunction in certain areas, but we really don't have good answers. It's clear that biology makes a significant contribution, but we also know that the environment, various things that occur during normal development, are also very important, such as certain events which lead to <a href="http://www.videojug.com/interview/post-traumatic-stress-disorder">post traumatic stress</a>.