So actually the techniques in neuroscience, or techniques in any biosciences, or in any sciences if I may say, could be composed of two parts. One is just to establish the correlation. That is to observe. Let's put it this way. To observe, it means that [FOREIGN]. To obtain a correlation mechanism. The other one is to perturb. To establish the causality. So in any biosciences, you're going to have a ways to first to observe how the system works, to establish the correlation you know. For example when action potential comes, somehow the transmitter release. Does that really mean that action potential directly leads to the transmitter release? Probably not, but it always correlates. And the other is perturb. Well, for example, you perturb action potential. There's no transmitter release. This is so important. But it does not established, in your condition, it's required. But it does not establish that they are direct. So all the neuro techniques are compose of I think this part, these precategories. And then in this observing part, you can artificially separate them into different parts. For example, observe their structure. And this is critical for neuroscience because anatomy is so complicated. And there are ways to observe the structure, for example, how a neuron looks like. And real And Golgi, more than 100 years ago, using the special method to stain a single neuron. So it's a way to look at the neuron's morphology. So the observed could be morphology and neuronal structure. Or you can observe how a neuron fire. And that conventionally people used electrophysiology recordings, and now using calcium imaging or imaging to observe that. You can observe how the transmitter can release, and believe it or not, it's very difficult. Neural Circuits, well neural circuits can be seen in a static condition, that a group of cells that are connected that will be neural circuits. It can also be in a functional state. How a neural circuit that interact with each other with their dynamics. But at a more global view, one can also observe behavior. Because people believe that it's the neuronal connections processing information, eventually lead to the consequence of the behavior. The sensory input get converted into the motile output eventually so you can observe the behavior. They have many, many categories as I said. Could be the static cells morphology. Morphology, dynamics behaviour, and the morphology could be at a different levels. For example I said could be a single cell, could be assembly of cells of connecting cells. Again the connecting cells is especially challenging because we believe that enough cells need to have specific connections, were to form during the development to mediate, to process those information. So how to observe not just randomly the cell but observe the cell, so there has connection to each. Again, this is also one of the challenges then in neuroscience for example, so called connectomics. The people are trying to achieve that. And again the morphology has different level. The cell, assembly of cell, and the subcell of the information. For example the synapse. The chemical synapse or natural synapse, they are beyond the current optical resolution. And one needs to use super resolution mass or using electron microscopy methods to observe that. In the cell, also they have some teeny tiny structures, for example if you want to have detailed structures, you want to observe them. The dynamics, again, there are many could be the wattage And that will be using the electrophysiology method to couple with the glass electrode or some other extracellular electrode using the electrical amplifier to amplify the signals. And then you can observe that. The wattage, and that will lead to the synaptic potential or to action potential and the transmitter release, the dynamical transmitter release. And for example, the noninvasive imaging for the whole brain, the blood flow. For example, in the functional MRI, the contrast agent allows people to observe locally the blood flow's speed of the oxygen concentration in certain blood. And that is correlated with the total activity of the brain, of the neurons. And that actually are helping a lot psychologist to understand which brain region is involved, which tasks especially in human in a noninvasive manner. So the dynamics there, also different level. And the behavior can also be observed. Again the behavior, the different kind of behavior, so often the behaviors are the innate behavior, meaning that it does not require to learn. A duckling seeking for her mother. It does not require it to be learned. It's a hardwired behavior. And there'll be learned behavior, meaning that at the beginning it doesn't have those behavior, but after learning, training, for example, some zebra finch, some bird, they need to learn from their parents how to sing. And people have do experiments for that, for those, for zebra finches. You can replay their parents' song, and then they will learn in a critical period. And then, you can swap, you can change the species. For example, a different species, a different song, and some zebra finch will learn a different one. So, the behavior can also be classified into different parts and the behavior can also be from different model organisms invertebrate, humans. So that can also be separate. And likewise the perturbation, Can target both the morphology, the dynamics, and the behavior, okay? The perturbation, for example, how do you perturb the cell assembly? Well if you have wish to perturb how a cell make synapse, you are actually helping to understand the principle controls of neural development, which molecule is important for the axonal guidance, which molecule is important for the synapse formation. And if you perturb those cell assembly, or some special synaptic assembly you understand you, could help understanding in a disease condition how certain disease forr example, neural lichen is a dehision molecule, and it was implicated in the autism disorders. And that could be related to the neuro assembly and development. And likewise, one can dynamically perturb the synapses region by controlling the voltage, perturbing the voltage. The transmitter release or in a disease condition, the blood flow will cause ischemia and that can lead to the brain damage. We want to obtain all of that information. Let's take five minutes break. So now we are going to have fast overview of 154 slides that our TA dedicatedly translated, mainly based on the summary work from Dr. Liqun Luo's new book, Principles of Neurobiology.
