Welcome to our course series on principles of fMRI. This course is part one of a multi-part series on principles. The purpose of this module is to introduce you to fMRI and establish some basic ground rules. There are many types of human neuroimaging available today including EEG, SPECT, PET, fMRI, invasive optical imaging, and intracranial recording or ECoG. But among all these, PET and fMRI have emerged as widely used and dominant technologies. In PET, the idea is to measure blood flow and neurochemistry, and we can measure tracers like opioids and dopamine and their release in the brain. With fMRI, we can measure brain structure and brain dynamics. So now we can get a whole brain in approximately one second. Which consists of about 100 to 200,000 pieces of information every second. So we can look at dynamics across networks. Human neuroimaging especially fMRI and PET are growing new field with now thousands of publications per year. So why all the excitement? One of the goals of neuroimaging is a movement toward multidisciplinary science. This is one thing that we're particularly excited about. For many years, people in different fields have been studying different aspects of the mind, the brain, and the body. And there are fields devoted to each of these different things and specific aspects of each of those different things. So for example, the study of the mind, Psychology, Economics, Political Science, and others. What's happening now is there's a merging of these different fields together, and new fields are being created that are interdisciplinary or multidisciplinary. So Cognitive Neuroscience, and Affective Neuroscience, and other varieties of that field lie at the intersection between mind and brain. And other fields lie at the intersection of mind and body, body and brain, or even all three. MRI and cognitive science is one of the origins of the popularity of functional neuroimaging. And the study of the mind involves sensation and perception, attention, learning, memory, reasoning, decision making, other topics. And their relationships with behavior have been core topics in psychology and in cognitive science for a long time. And cognitive science is defined as the interdisciplinary study of the human mind and its various aspects. When we include the brain in the picture, then we end up with new fields, cognitive neuroscience, affective neuroscience, decision neuroscience, social neuroscience, and others are being created even as we speak. What's central to all of these fields is the concept of brain representation which is the physical basis from mental experience, how does the brain give rise to mental phenomena? What's the mapping between them? And how can we understand and measure mental processes at a brain or neurophysiological level. So cognitive neuroscience simulated fields are concerned with this link between mind and behavior and brain. And other fields are concerned with mental health, traditionally, psychology and psychiatry. And brain health, neurology, and now biological psychiatry. Other fields are concerned with the relationships between the brain, and the body. So called information transfer assistance between the brain and the autonomic nervous system, and the HPA axis, hypothylamic pituitary adrenal axis, among other hormonal systems. And fields like psychophysiology and stress science are concerned with these relationships, and these systems impact the body as well. The autonomic nervous system sends output to every major organ, which has impact on inflammation, on the immune system and others. So, fields that are involved in these include the new field of health neuroscience, neuroimmmunology, psychoneuroimmunology and recent work on the brain-gut axis or the microbiome. So MRI is one of the tools that's helping us put all the pieces of this together into integrated models of the person. And that's what we want to understand, how the system works together. One of the great things about fMRI and MRI is that we can take this complicated system, and we can include multiple measures. We can put somebody in the scanner for about one hour and we can get measures of brain structure and brain function. And those structural measures include measures of anatomy, like you see here, grey matter or T1 image. Measures of white matter, tractography, diffusion tensor imaging, or diffusion weighted imaging. Measures of vasculature, time of flight imaging, or MR angiography. Functional measures include measures of task related activity across the brain or in particular regions, measures of brain connectivity, which are functional relationships across regions. And measures of relationships between the brain and the body, for example, physiological connectivity. To understand all these relationships requires a multidisciplinary community. Our vision is one in which people from many fields work together to understand different pieces of the elephant and thereby, particular picture of how it all works. So we need experts in each of these disciplines working together. We also need individuals who have multiple types of expertise who can bridge these traditional disciplinary boundaries. [LAUGH] >> Hi, so I'm going to talk a little about image basics here. And I want to try to put fRMI and MRI into its appropriate context compared to other imaging without these. So brain imaging can be roughly separated into two major categories. We have structural brain imaging on the one hand and functional brain imaging. And there exists a number of different modalities to perform each category. So structural brain imaging, as aforementioned, deals with the study of brain structure, but also with the diagnosis of disease and injury. So for example, if you were in an accident or you believe that you had a stroke or something like that, you might get a structural image to study the effects. Modalities for performing structural imaging include computed axial tomography or CAT, magnetic resonance imaging or MRI, and positron emission tomography or PET. Here's an example of different types of MRI images, so even though MRI is a single modality, we can have MRI images that are focused on different aspects of the underlying tissue. So here's an example of what's called a proton density, a T1 weighted and a T2 weighted image. And as you see, although they all represent the same underlying brain structure, they do it in different ways and we'll talk about this as we progress along this class. Functional brain imaging can be used to study both cognitive and affective processes. And here, modalities again include PET, but also functional magnetic resonance imaging or fMRI, which is the functional analog of MRI. And this is going to be the main focus of this class. Also, and we have EEG and MEG, which are two other modalities. Here's an example of a fMRI experiment, so the difference between fMRI and MRI is here we take a sequence of images acquired over time and study how things change across time. Now each brain imaging modality provides a different type of measurement of the brain. And they also have the pros and cons with respect to things like spatial resolution, temporal resolution, and invasiveness. And so functional MRI provides a nice balance between these properties and has really become the dominant functional imaging modality in the past decade. It's also going to be the focus of this class. Here's an example showing a little bit about the spatial and temporal resolutions for different types of imaging modality. So on the X axis, we have the temporal resolution from milliseconds to days and in the Y axis, we have the spatial resolution from microseconds to centimeters. As you see, MEG and EEG, and PET, and also what's called ASL fMRI and BOLD fMRI, all cover spatial resolutions in the centimeters scale. And here, these can be used to study large scale networks of the brain. One thing that you see that is kind of unique to BOLD fMRI, which is going to be the focus of this class and we'll define it in coming lectures, is that it can also be used to start studying functional maps. In addition, it gives us the promise of studying even lower organization and columns and whatnot. So, BOLD fMRI really promises to be able to look at kind of the nitty-gritty of what's going on inside the brain and it's a very promising technique. Okay, so that's the end of this module. We attempted to sort of just put together some of the important aspects involved in functional MRI and kind of put it into its context. So I hope to see you in the next module where we'll continue talking about fMRI. [LAUGH] >> Bye [LAUGH].
