Critically evaluate the use of animal models in the study of human brain structural connectivity.
The animal model is the animal experimental objects that are established in biomedical scientific research with human-simulating properties. The use of animal models is an extremely important experimental approach in modern biological research, which contributes to a more convenient and effective understanding of human brain connectivity research. Much of our knowledge about advanced cognitive functions and complex behaviours come from the use of animal models. Research on the structural connectivity of the human brain could lead to a new understanding of the connectome.
Network analysis of animal brains can bring us closer to the reality of how the human brain really works. Undoubtedly, animal models are of great help to the study of human brain structural connectivity, and they greatly facilitate such studies. First, the risks associated with direct experiments on humans are avoided in this way. For example, Brenner et. al construct a model of Caenorhabditis elegans and Larry et. al found a model of mice. Second, some commonly seen diseases in clinics that we want to study with the connectome can be replicated with animal models at any time. Moreover, this type of research can overcome the shortcomings of long incubation periods, duration and low morbidity. The experimental conditions can be strictly controlled to enhance the comparability of experimental materials. Finally, it also helps to understand the essence of the human brain. If only through clinical research, its performance may have its own characteristics. Through the comparative study of the map of neural connections between humans and animals, we can understand the various effects of the same condition on different organisms. Therefore, in a sense, the research work can be sublimated to a three-dimensional level to reveal the essence of certain connectivity, which is more conducive to explaining all the changes that have occurred in the human body. The use of animal models also allows us to observe the impact of environmental or genetic factors on the development in detail, which is impossible in clinical practice.
One example is that using animal models, the animal brain is serially sliced into many slices, each slice is imaged at high resolution with an electron microscope, and each neuron's branches and synaptic connections to other neurons are traced. Meanwhile, research on human brain structural connectivity can be classified into the connectomics discipline, deciphering vast neural systems with automatization and computer-assisted collaboration.
In this case, what is the significance of a large-scale animal model for whole-brain structural connectivity to address closer to our own nervous system?
The emergence of large-scale connectomic data in animal models, including complete reconstructions of neurons in the adult central brain, has great importance. Comparing non-invasive connectome maps of the same animal model brain will enhance our understanding of the structural basis of signals measured by current non-invasive techniques widely used in the human brain.
The mouse is an excellent animal model for studying brain connectivity, as there are many mouse models involving a variety of brain diseases, well-established experimental methods and theories. Mammalian brains all contain lots of the same cortical and subcortical regions, interregional projections, and intraregional connectivity. The mice have many organizational features that are also present in the human nervous system. Importantly, once the connectomic infrastructure at the scale required to connect the entire mouse brain is established, it will also be useful in animal models of diseases. Many other connectomic studies will be possible.
However, the use of animal models in the study of human brain structural connectivity is not perfect. First and foremost, the advanced level of animal evolution does not mean that all organs and functions are close to the human level. The unique structure and function are difficult to reproduce in animal models, so blindly using animal models to explain the mechanism of the human brain will undoubtedly be far from the truth. Moreover, with the development of big data science, the demand for non-biological thinking systems for the study of human brain structural connectivity is increasing day by day. In some way, those models can explain mechanisms better.
However, everything has its pros and cons. For the application of human brain connectivity research in big data science, the revelation of animal models to its engineering and computers is of great significance. For sure living animals have higher learning intelligence than computer programs. In terms of cognitive learning, animal models are more effective. One example is that inductive learning can be performed through a small number of samples, which AI systems cannot yet have. Besides, our research using mammalian brains is more resource efficient.
Due to the limitations of technology, it is still difficult for us to understand the connected group, and it is largely unexplainable. The connectome will generate entirely unexpected questions about the nervous system and may allow us to understand the principles.
