1:07:15 – Joe and Dr. Patrick discuss the complexities involved in the prescription of drugs. Different people have different polymorphisms responsible for how we make, fire and metabolize neurotransmitters. Studies have shown that when subjects are injected with endotoxins (chemicals secreted during inflammation), subjects begin to express depressive symptoms. Subjects given a placebo did not experience this. Subjects who felt the depressive symptoms were given 2 grams of EPA. They were alleviated of their depressive symptoms – to the point where they were gone. Clearly depressive symptoms can be created through inflammatory means. Subjects who were injected with the endotoxins also saw their dopamine levels diminish and their reward system tampered with; this did not happen to the placebo group. The endotoxins have such an effect because they cross the blood brain barrier. There has been recent discoveries that show that the lymphatic system is directly connected to the brain through the meninges; this means an immune response can tamper with our brain.
1:11:58 – Stress and inflammation. Beyond a poor diet, stressful situations and anything that causes you to release stress hormones like cortisol will cause an inflammatory response in the gut. The vagus nerve connects the brain and the gut; it is a two way street where the gut can affect the brain and visa versa. It has been shown that cortical release can be communicated to the gut via the vagal nerve and trigger immune cells in the gut which activate proteases. These proteases can consume the gut barrier, opening up the bacteria in the gut to immune cells outside of the gut. This triggers a large inflammatory reaction. This is a reason why you should not get your blood tested after a stressful situation.
1:15:11 – The antidepressant is not a magic bullet, not by a long shot. Not when it has shown to be 40% effective versus the 30% efficacy of a placebo. [more on this in the previous summary]
Exercise and Depression
1:16:00 – Exercise shown to help depression. When inflammation occurs, the body diverts tryptophan from conversion into serotonin to the inflammatory response. Tryptophan becomes converted into kynuramine; immune cells need it to make different kinds of immune cells. Kynuramine gets converted into quinolinic acid, which is a neurotoxin that crosses the blood brain barrier; has been shown to cause depression. Where does exercise fit in? Exercise allows the muscles to absorb the kynuramine and limit the quinolinic acid production. Exercise also diverts the tryptophan towards the serotonin conversion pathway rather than the inflammatory pathways; this occurs due to the fact that exercise calls upon other branched chain amino acids to go to the body rather than the brain, which alleviates tryptophan’s competition. BDNF also plays a role in preventing depression; exercise produces this as well.
1:29:01 – Lying. When someone lies, even when someone tells a white lie, a connection is established in the brain that can provide a neural foundation for lying. This makes it earlier to lie.
Transcranial Direct Current Stimulation (tDCS)
1:29:45 – Transcranial direct current stimulation. Studies have shown that you can stimulate the connection that is involved in motivation. Subjects exposed to this treatment were more motivated to go workout. Some people may have a strong connection in this region responsible for motivation; others do not. Doing something that induces discomfort followed by a sensitivity to endorphins can strengthen this connection.
1:30:53 – Joe discusses the 9-volt nirvana episode of Radiolab. A women goes to sniper training and performs very poorly. She performed the task again with exposure to the tDCS (transcranial direct current stimulation) applied to the part of the brain responsible for learning; she was significantly more effective and the 20 minute session felt like 5 minutes, according to her. Dr. Patrick brings up a very interesting study on tDCS and consciousness. A subject was reading a book and when a current was applied to a part of her head, she stopped reading, didn’t speak, and stared blankly at the researchers (almost zombie like). When the current was changed [Dr. Patrick says that she was zapped again – this could be a mistake], the subject picked up reading right where she left off and had no recollection of stopping the reading.