Jaime Tartar tells us about how the brain interprets what is stressful, how it determines our behavioral and physiological response to stressors, and how it can be damaged by stress.
She will discuss how the body’s reaction to acute stress has protective and adaptive effects in the short run while chronic stress can lead to poor health consequences such as decreased memory performance and depression.
“The title of my talk is “Stress and the brain: the good, the bad, and the misunderstood.” Another title that I could have given the talk is “In defense of stress,” because we all talk about stress as if it were a bad thing, but the point of this series is to inspire you so I’d like to inspire you.”
Millions of years of evolution have ensured that your stress system does exactly what it’s supposed to do. It works perfectly. You’re the problem. And I’m going to show you why you’re the problem.
Stress and why it matters. The first thing that we need to do, and we’re going to have kind of a fun lecture, but just get a little bit of biology out of the way, quick and dirty.
When we have a stressor, the first thing that happens is we have a fight or flight response. This happens immediately. There’s this part of your brain, very deep down, the locus coeruleus, he’s going to tell your adrenal gland, “Ahh! I’m getting eaten by a tiger, release epinephrine.” If you’re in Europe, you can call it adrenaline; it’s the same chemical, it doesn’t matter. You’re going to release adrenaline.
The sympathetic nervous system does a very good job of doing what we in college like to refer to as the four Fs: fight, flight, fright, and sex. These are the four things that it does. It’s going to keep you alive whether you like it or not, no conscious choice here. Or keep you alive in the future.
This system acts very, very quickly. A little bit later on, we get this sort of slower acting system. This little part of our brain up here, the hypothalamus, which is really the CEO of all of the hormones in your body. The hypothalamus is going to say, “Oh my god, we’re stressed.” He’s going to tell the pituitary gland, “Hey, release this other hormone, ACTH.” ACTH is going to fall down, and then he is also going to tell the adrenal gland, the adrenal cortex, the same place that squirts out all that epinephrine, he’s going to say, “Release cortisol,” and we’ve all heard about cortisol.
Cortisol makes you fat. Cortisol does horrible things to you. Oh, we hate cortisol. But cortisol keeps you alive. If there’s a tiger who’s going to come eat you, cortisol will keep you alive. So the problem isn’t cortisol, the problem is the dysregulation of cortisol.
What cortisol does, then, is it’s going to go back up to all those places who originally released it, and it’s going to say, “Whoa, slow down.” The major place in our body that binds cortisol is the hippocampus. So you listened to Matt’s talk, we all know what the hippocampus does, right?
It’s important for? Memory! It’s also important for cortisol. And all those cortisol receptors are in the hippocampus, and it binds to the hippocampus and it says, “Hey… stop.” But if you have too much cortisol being released, the cells can’t handle it and they just die, like, “Oh, we can’t handle it, we’re going to die.” And they kill themselves.
And then you get more cortisol released, you have even less cells to handle it, you see what’s happening here? And so the HPA, the hypothalamic–pituitary–adrenal gland, this axis just sort of spurts out of control. OK, and this is where some of the problems arise.
This can happen acutely, or this can happen chronically, right? You get stressed, this stuff happens to you. You get stressed over and over and over again, it’s this idea of chronic stress.
But it turns out we have 2 different ways of responding to stress. We do have this biological process that occurs, the sympathetic nervous system and the HPA axis, but then in our brains, we’re going to respond differently to different types of stress in slightly different ways. And the major way of differentiating those is between physical stress and psychological stress. So the difference between getting eaten by a tiger – there were some real pictures, but it wasn’t pleasant – or this. OK.
Or, if you’re Ryan Gosling, you might be stressed because your picture’s all over the Internet these days. OK, we all have these kinds of stressors. And as my colleague alluded to earlier, it’s very stressful not to be able to use copyrighted images, so I wanted to give you this.
What is stress? So stress for us isn’t getting eaten by a tiger. Our body is ready to respond to that, it’s ready to respond to starvation. It’s very, very well adapted to responding to someone wanting to punch you in the face, someone trying to steal your meat. It does a very good job of that, but what we’ve experienced is daily life hassles. That’s really our stress. And does this happen acutely, or does this happen all the time, multiple times a day?
I wanted to give you an example, and I couldn’t use copyrighted images so I’m going to tell you the things that stress me, but I imagine that you have some of the same things going on in your life. So the first thing that stresses me are my colleagues. They make me nuts.
Except the ones who are here, they’re wonderful. OK, my bosses, who are not here tonight, make me crazy. So I imagine you have bosses who give you stress too for different reasons. He may look nice. He scares me. This guy used to be a hostage negotiator, and now he’s my boss.
And evidently, I’m kind of glad to hear so many of the presenters tonight get stressed by students texting in their class, because it’s one of the major things that stresses me out, because I’m trying to lecture and no one’s paying attention to what I’m saying, and I think it’s very important, and I have theory of mind, so I’m thinking about what they’re talking about and thinking about and texting, and I’m not thinking about what I should be thinking about; it’s awful. It’s a whole thing, then I start to shake and leave the classroom.
You can imagine looking out at this, trying to talk and educate young minds and this is what you see.
My husband. We’re working on it. My children. They’re twins, and they’re five. It’s not that my husband and children are enough to drive me crazy, but they have a dog. It’s their dog. It’s my source of stress. OK, so you get the idea.
These are probably the same types of things that are happening to all of us every day, multiple times a day. So it’s not just that it happens to some people, and it doesn’t happen to other people. Some people are more at risk of succumbing to some of the health consequences of all of these things.
These are the kind of things that are going to put you at risk; keeping in mind, this is what your stress response system has evolved to do; this is what it’s really doing, right? Dealing with all of these things. So the things that are going to kill you, basically, is unremitting stress. It turns out, it’s not just unremitting stress. If you really want to kill somebody, you don’t want to use pharmacology, you don’t want to go to jail.
The good way to do it is unremitting, unpredictable stress. So if I wanted to kill my husband – and I don’t, he’s a wonderful person and a biologist, but if I did – if I went in every day, and I punched him in the face at 2 pm, every day I go and punch him in the face at 2 pm, what’s going to happen, is he going to get really stressed? He might divorce me. Is he going to get really, really stressed? No, because what’s going to happen? He’s going to say, “Oh, I know she’s going to come punch me in the face.” So what you really want to do is you want to give somebody stress, but they don’t know it’s going to happen and it’s never ending; that’s the good stuff.
One of the worst things you can do for yourself, one of the worst careers you can do – and I’m sorry if you do this – is long-term care givers. These guys are in a host of trouble. You never know if Johnny’s going to have a good day, a bad day, you can’t control what’s happening. This is awful for your health; make your aunt do it. Don’t be that guy.
The inability to adjust to stress. And this is me; I’m a high-responder rat. And you know who these people are too. These are the people who just react to everything, right? My boss yells at me, I freak out. My colleague said, “Oh, you were late today,” and I’m worried about it. Everything gives us increased heart rate very easily. This is not a good way to live your life.
The other thing is reactivation to stress, and you know who you are, and you know who these other people are because they don’t leave you alone. These are the people who something happens to them, “My boss yells at me,” then I go home like, “Oh my god, you’re not going to believe what my boss did, he yelled at me.” I say the whole thing, then I call my ten closest friends and tell them what happened, and every time I do this I’m reactivating that same HPA axis. I don’t need the tiger to bite me. I can make that stuff happen just by thinking about it.
And the last thing is- I guess these would be the psychopaths. So a blunted HPA activation. It’s also not good to not respond to stress at all. You need a little bit of stress to respond. So we don’t want our HPA axes to get dysregulated. We don’t want to die of stress. We want to live healthy lives. So I know you’re really depressed right now. So the good news is:
Because the source of stress for us is in our heads, we’re making it up. No one’s punching us in the face. Nobody’s starving us. We’re all living long and healthy lives, hopefully. All the stress that we have is coming from here. It’s processive; it’s psychological.
It’s that kind of stress that we’re constantly thinking about. So the good news is you won’t die from stress, maybe, if I show you the next few slides. You are in control of your stress.
I’m going to give you some human displacement activities. This is what we do for animals in stress labs, when we want them not to succumb to stress, and as human animals, we can do the same things.
The first thing you could do is psychotherapy. It’s a lot of work, but it has been demonstrated that psychotherapy does produce genuine, real changes in that neuroplasticity in your brain; it just takes a long time to do it, but if you do it, you can get real changes in your brain.
Exercise, believe it or not. Exercise does a very good job at relieving some of the symptoms of stress. You can read an enlightening book. These are things that have been clinically demonstrated to relieve the consequences of stress. You can have good social support, like our nice presenter here, Leanne Boucher. You could have good sleep hygiene. This may include – I study sleep too -this may include taking a nap during the day.
That’s OK, you can do that. Or whatever works for you. This is my colleague, Jason Gershman, who likes to race cars, and that’s a great way for him to relieve his stress.
The other thing that I wanted to talk to you about, if those things didn’t work for you, there’s a lot of really cool research right now coming out of one particular lab at the University of Wisconsin at Madison, this professor Richard Davidson, and some of the things that he’s shown in his lab, he’s actually gotten the Dalai Lama and Tibetan monks to come in and he’s looked at their brains. And what he’s demonstrated is – and these monks, they actually show real differences in their EEGs – so some of the brain waves that we associate with higher processing, high mental function, seem to be much higher in the monks than they are in controls.
And some of the brain regions that we associate with love, understanding, and empathy, the insula and the left pre-frontal cortex seem to be more activated. These monks tend to do compassion meditation, but I’m guessing this would work for all forms of meditation. They even trained regular guys like you and me to do meditation, and we can show these changes, so this is very cool.
The hard part is, I should tell you, that these monks had 10,000 hours of training, so it did take a long time. But if you’re willing to do it, you can just be happy like a monk, do some meditating.
If that doesn’t work for you, you can always take Prozac. Better living through chemistry, as Dr. Ray said. Whereas going to therapy takes a long time, therapy would be the analogy of going to the gym. We all want big muscles. We all want to be healthy. We all want to look great. But if you go to the gym, it takes a long time to get big muscles, look great, and have a great cardiovascular health. If I gave you a pill that could do all of those things… come on.
This sort of does what psychotherapy does. Dr. Ray will tell you if there’s consequences to it. So the good news is, remember I told you, when you have all those super high levels of cortisol, it kills those hippocampal cells? Well, it turns out – and the dirty secret behind Prozac, and Dr. Ray, I’m sorry, is that we have no idea how it works. No clue. No clue. If I give you Prozac, your serotonin levels are going to be pretty high right away, but when are you going to start to feel better? This is what the pharmacologists don’t want you to know.
We don’t know how most of this stuff really works. It takes a while to feel better, but it turns out one of the mechanisms by which it may be working is increasing new neurons in the hippocampus. You get increased neurogenesis in the hippocampus. So it might be that as cortisol goes up, starts to destroy those hippocampal neurons, you have fewer hippocampal neurons, and you get into the cascade that one researcher calls the glucocorticoid cascade hypothesis; when you give somebody Prozac, it may increase the amount of neurons and help to restore some of the functioning of the hippocampus.
Prozac does increase neurogenesis in the hippocampus. And if you block neurogenesis in the hippocampus, you also block the behavioral effects of Prozac. So that’s sort of interesting. It’s new research so we’ll see where it goes.
I’d say the bottom line today is to keep in mind your stress system is fine, it’s working properly. It wants to keep you alive. It wants to keep you alive for the next five minutes. It doesn’t care if you’re going to live to 100. So I would say try to do all of those things. Recognize that you’re in control of how stressed you become.
And that’s all I have for you. Hopefully you have a new beginning. Thank you.
Jaime Tartar, Ph.D., is an Associate Professor in the Department of Psychology and Neuroscience at NSU’s College of Psychology. Dr. Tartar completed Postdoctoral Training at Harvard Medical School, where she studied the neurobiology of sleep and earned a certificate in Sleep Medicine from the Division of Sleep Medicine. She is widely published in many areas of neuroscience with topics ranging from basic cell physiology to clinical neurological impairments. Her research interests are focused on the mechanisms and consequences of acute and chronic stress in humans and the impact of normal sleep and sleep deprivation on emotion processing and physiological functioning.