The brain in made of nerve cells and its function depends on how they work. This module examines current views/models of neuronal function, intercommunication, and nervous system development, based upon anatomical, genetic, molecular, cellular and advanced physiological techniques. Comparisons of what goes wrong in brain diseases are also drawn, as this tells us how the brain normally works, and we explore state-of-the-art means used to treat brain damage and diseases.
Nerve cells (neurons) are biochemically and physiologically very similar to all other cell types. However, the function of the nervous system (to provide rapid collection and integration of signals and to generate immediate and appropriate responses) requires characteristics that are largely absent or poorly developed in other cells types. The second-by-second functioning of a neuron exploits the electrical characteristics of the lipid bilayer membrane and the proteins embedded within it. Transient signals are encoded either in absolute electrical potential or in patterns of electrical activity. At cell junctions the electrical signals are converted to chemical signals and then reconverted back. In many ways a mature neuron can be viewed as an electrically-active membrane system, the cytoplasmic components being required to maintain it in a functional state. This is a simplification (particularly in developing neuronal systems) but is still a useful concept. The physiology, biophysics and molecular biology of neurons, is examined, paying particular attention to (1) ion channels/transmitter receptors and their regulation, including the cloning and expression of recombinant proteins and (2) synaptic function. Synaptic plasticity in vertebrates is used to illustrate successful characterisation of a complex, multi-cellular system at the molecular level.
Nervous system function is tightly interwoven with its structure and by studying development we will look at: how genes control brain development, including the formation of different brain modules; how the thousands of different types of neurons and glia acquire their unique features; how neural networks emerge as the organism develops and how they are modified with experience; how sensory systems enable us to identify features of the world (rather than seeing voices or hearing colours); how the brain knows how many neurons it needs and when to start killing the surplus; how all these genetic, cellular and physiological elements determine how we respond to our environment, how we behave, how we learn and how we remember. Finally, we will look at what goes wrong in diseases or upon injury and what research is doing to repair the nervous system, including cutting-edge techniques such as using stem cells, deep-brain stimulation and bionic limbs.