Pershing Square Professor of Human Neuroscience, Harvard
One thing that still keeps me awake at night about the human brain is what makes it uniquely human - why are our brains so different to those of other animals, and what evolutionary switch caused us to develop the capacity for complex thought, language, and social structures? Transcript: "What is one thing about the human brain which still keeps you awake at night? Well, let me start by saying that I try not to let the human brain keep me awake at night. One thing we've learned over the years is how important sleep is to our mental health, our physical health, our stress reactivity, our learning, our memory, and our brain health-- that I really take it seriously. I try very much to get good sleep. So yeah, my daughter might wake me up, my dog might wake me up, but I try not to let thinking about the human brain keep me awake at night. Having said that, there are some things I wonder about the human brain. So one of them is, what makes a human brain human? So if we look at brains and what they look like and how they function across species, there aren't that many differences. If we look at our closest primate relatives and their brains, we have the same basic parts, the same basic functions, and the same basic parts. And the neurons work roughly the same. And in fact, as scientists, we take advantage of that. We study other animals to get insight into human brain function. But we know that, of course, humans are very different than other animals in many important ways. We have generative language. We have this ability to have complex thoughts and communicate them with each other-- sort of infinite number of potential thoughts. We have complex societies and structures that govern how we operate in the world that other animals don't have. So there must be something that happened in brain development, some switch that occurred that made humans and their brains different, that enabled all these things that make us uniquely humans. But I have no idea what that switch is because when I look at the brains, they don't look so drastically different. So what is it about human brains that make us human? I have no idea. That's something I wonder about."
In the past 20 years, brain research has been greatly influenced by functional magnetic resonance imaging (fMRI) technology. This technique allows researchers to study brain activity while individuals are performing psychological tasks. This has allowed psychologists to gain more insight into psychological constructs and create a more comprehensive understanding of the human mind. Transcript: "How has psychology in the study of our brain changed in the past 20 years? Well, this is a really big question, but I want to start by saying, you know, we've known for a very long time that specific regions of the brain are related to specific psychological function. So for instance in the 1800's Paul broca and Carl Wernicke showed that patients who had very specific lesions and parts of the brain, show different patterns of impairment in language processing. So this type of research Has been around for a very long time, but what's changed in the last 20 years, really? The last 30 years is a technique called functional. Magnetic resonance imaging has come to dominate, human brain research. So fmri was introduced about 30 years ago and what it does is it uses a standard MRI machine but allows you to look at brain activity changes when people perform psychological tasks. So this so for instance, I could take A healthy individual and undergraduate, put them in an MRI scanner. Ask them to do something like a memory task and try to say, you know, what's going on in the brain. When they perform that memory task, this technique has exploded and it's used in Psychology. It's not the only Technique we have for studying the brain and of course, like all techniques, we have for studying the brain or psychology, there are pluses and minuses to this technique, but it makes studying the brain readily available to the point where now psychology Miss routinely have MRI machines. So there's an MRI machine here in the basement of my office building at Harvard that I can use to study the brain function of individuals while they perform psychological tasks. So, I would say, brain research has started to really influence and become an integral part of how we understand psychological function. We can still think about them as different levels of analysis. I can understand the behavior of their mental constructs. Yes. But if I can also understand the brain function, I can get more information about those psychological constructs and produce a better more, complete science."
Research on the Psychology and Neuroscience of emotion and cognition has shown that emotion and cognition are intertwined from the earliest stages of perceptual processing. The amygdala, a brain region responsible for responding to highly salient events, has reciprocal connections with visual cortex and other regions of the brain. These connections allow for more detailed perception of emotional events, enhance attention to them and lay memories down more strongly. Transcript: "What have you uncovered regarding the impact of emotions and their effect on cognition? Let me start by saying that many people have this naive idea that emotion and reason or two separate processes in the mind. And this idea dates back to the early Greek philosophers, who talked about the passions as being shared with other animals and reason is being unique to humans but research on the Psychology and Neuroscience of emotion and cognition has told us that nothing could be further from the truth. Emotion and cognition are intertwined from the earliest stages of perceptual processing. Complex reasoning. Now, if you think about what emotion is or what the function of emotion is, this makes a lot of sense. So emotion tells you what is important, what matters to you what Salient and you know our code cognition should be tuned to process those things a little bit differently so let me give you an example. The amygdala is a brain region that responds to highly saline events, particularly threatening events and the amygdala has reciprocal connections with lots of regions of the brain including their visual cortex. And even early visual cortical areas. And so, one consequence of this is, is that if you're cute, was something emotional between, particularly something threatening, you're actually going to perceive some of the details a little bit better. Now, let's move to attention. So, let's say you're driving down the highway and there's a car accident on the side of the road. It's very hard not to attend to that car accident. It's almost like your attention system is saying, pay attention to the things that are highly emotional and in fact the brain regions that are involved in shift Your attention between different things. Actually it worked slightly less well when there's something highly emotional there so it really is hard to look away from that car accident. Now, let's get to memory. So, when you're highly aroused, you know, the amygdala now has connections with the hippocampus, which is important to memory, so that it actually lays memories down a little bit better. So, they're a little stronger. You retain them a little bit better. And so all of these are examples of the ways that that emotion can influence cognition. And so, you know, emotion and cognition are not really separate processes. They're intertwined from early perception to complex reasoning."
The science of our brains has evolved since the discovery of brain Imaging, primarily due to the technique of functional magnetic resonance imaging (fMRI). This technique allows us to look at the entire brain in action, giving us a better understanding of how different parts of the brain work together to produce behaviors. Additionally, this technique has helped us understand intrinsic networks that move with each other when we rest or engage in complex thought. Transcript: "How is the science of our brains evolved since the discovery of brain Imaging? Well, I should point out that there have been techniques to image the brain around for quite a while. But what I think you're referring to here are techniques to image the human brain in action when we engage in thoughts, or behaviors. And the primary one that has really transformed. Human Neuroscience. Research is functional magnetic resonance imaging and this was first introduced in the early 1990s and it uses a standard. MRI machine to look at changes in the blood oxygenation levels that we think is related to neuronal activity. And with this, we can look at sort of the brain in action. And one of the things that has emerged from this technique is that we are looking at the entire brain at once prior to techniques like functional brain Imaging, almost all brain science focused on specific regions of the brain are the you had a lesion to specific region of the brain and you look to see what was the behavior. Ural consequence, or you stuck an electrode in a particular region of the brain to say, how do the neurons there respond? And so we were evolving this science of brain Parts. You know, what is this region doing? What does that region do? And then we kind of had to speculate about how they all come together to form complex. Behaviors, one thing that functional Imaging, brings to the table is now we're looking at the whole brain and action. So, you know, when we started to do functional Imaging studies in humans, we did similar things, as we did with other techniques. We Several, what is this brain region do. Let's try to see how this brain region changes, but all these other brain regions were also involved. And what has what has emerged now, is a greater understanding of how different parts of the brain works together to produce behaviors. And there's been some science showing that we sort of have these intrinsic networks that move with each other. You know, when we're resting, or when we're engaging in complex thought, you know, we're trying to figure out what did these networks do to enable complex behaviors and So, sort of being able to look at the entire brain at once, has really transformed how we talk about, how brain function produces Behavior."
I'm Liz Phelps, a professor of human neuroscience at Harvard University. My area of focus is researching how emotion changes, how we learn, remember and decide. I combine techniques from psychology and neuroscience to answer these questions. Transcript: "Hi, I'm Liz, Phelps, and I'm the Pershing Square, professor of human neuroscience at Harvard University. Most people call me Liz. I am in the department of psychology here at Harvard and I'm an experimental psychologist by training, which means I conduct research to understand the human mind and behavior. My area of focus is how emotion changes, how we learn. Remember and decided to answer these questions. I try to combine techniques from psychology with techniques from neuroscience."