My guest today is Dr. Steve Cole PhD, professor of Medicine, Psychiatry and Behavioral Science in the UCLA School of Medicine. What are signal transduction pathways? It's a way of basically perceiving, at the cellular level, what's going on outside and changing cellular behavior by increasing or decreasing rates of RNA transcription from the DNA genome at specific sites in the genome. A standard signal transduction cascade would have some kind of a receptor on the surface of the cell that detects let's say, a neurotransmitter, or a bacteria or something like that. It relays information from outside the cell, through the cell membrane into the interior of the cell, where it can then kick off a chain reaction of different chemical events, that ultimately leads to turning on or turning off a gene in our DNA genome inside the nucleus of the cell. We discuss one of Steve’s recent papers, Black mothers in racially segregated neighborhoods embodying structural violence: PTSD and depressive symptoms on the South Side of Chicago. In this study, Steve and his team conceptualize the environment as social phenomena and examine its consequences on the body. They asked themselves: Why do these women have heart attacks more often? Why do they get neurodegenerative diseases more often? Why do they get cancer more often? They found that feeling trapped, significantly predicted increased mental distress in the form of PTSD, depressive symptoms, and glucocorticoid receptor gene regulation that's involved in producing inflammation. The reason we pay a lot of attention to that is that in addition to healing wounds,  when inflammatory activity is persistent, even at a low level for a long period of time, that kind of molecular scenario acts as a fertilizer for the development of most chronic diseases such as  heart disease, neurodegenerative diseases, metastatic cancers, all of the diseases that are the major causes of death in the West. Moving onto a new subject: cytokines. Initially cytokines were discovered to increase communication between immune cells, to  enable them to talk to each other. recently it was learned that brain cells could also hear the signal sent by the cytokines.  That opened up this really fascinating area of science, trying to understand how changes in immune biology changed people's neurobiology, and perhaps, as a consequence of that change their psychological experience and their, their behavior in the real world. One area where this is known to happen, is what we call sickness behaviors. When people get sick, and they feel tired and fatigued and achy, and they have fevers, it turns out, none of that is actually caused by the pathogen. All of that is caused by the cytokines that go to the brain, and they say, ‘Hey, brain, I want you to activate the behavioral package that we call sickness.’ And so the brain, which has essentially learned to do this over millions of years of evolution says, ‘Great, you're sick. So I'm going to stop you from expending a lot of energy by immobilizing you. I'm not going to let you run around, I'm going to make you tired. I especially don't want you to run around infecting other people or getting into fights with other people. So I'm going to make you antisocial and irritable as well.’ In the course of our meeting, we spoke about many other subjects and ended by  talking about the surprising power of pro social behavior for writing many of the wrongs that arise from stress and threat. If I'm anxious, and th If you liked this podcast please tell your friends about it, subscribe to this podcast wherever you listen to podcasts and/or write a brief note on apple podcasts, check out my blogs on Psychology Today at https://www.psychologytoday.com/intl/contributors/thomas-r-verny-md