We all have a genetic blueprint for development, but we know there are other factors that influence our development.
Consider identical twins. These individuals share the same genetic make-up but they are not 100% identical in phenotype. They are recognisable from one another due to small observable differences. From the very beginning of their development in the womb, these twins experience different conditions that can result in differences in their phenotype.
Dr Christine Jasoni from the Department of Anatomy at the University of Otago is fascinated by the development of a particular organ – the brain. Her research interest is in understanding how brain wiring occurs during development and how environmental factors influence this development.
Central nervous system
The brain and spinal cord make up our central nervous system. This enables us to detect, process, communicate and respond to information from our surrounding environment. This incredible system works via a complex network of billions of specialised nerve cells called neurons.
There are a number of different types of neurons. Typically, they all consist of a cell body (containing the nucleusdendrites and an axon. Neurons communicate with each other through electrochemical messages.
During foetal development, neurons move to their final positions in the brain and start to send out axons. Axons are like wires that transmit information from one cell to the next. They may reach lengths of over a metre, and they act like a communication network for our bodies. This process is called ‘brain wiring’. It is largely determined by your genes, but environmental factors also play a role. For example, the stress levels and nutrition of the mother can actually alter the development of her foetus’s brain.
Tracing axon development
Christine and her colleagues are very interested in understanding the detail of how this wiring occurs during development. The work of past scientists means that they have a good understanding of the adult brain and how it functions.
With this background in place, their investigations focus on working backwards to find out more about what happens to the neurons during development to make the human brain. They are interested in how the neurons use different molecules within the body as cues to get their axons to the right place. They call this the ‘molecular map’. Christine’s research aims to learn more about this map for particular groups of neurons that need to be wired correctly for normal cognition to occur.
Results from neurology and psychology research help pinpoint cells that might be important in a particular neurological disorder, for example, a learning disability. Christine then uses in vitro models to look at those particular cells.
Techniques that allow the researchers to visualise the cells within the brain are used to visualise the cell body itself and to visualise the axon extending out of the neuron. They are able to trace the route of a single axon as it leaves the cell body and goes to some distant location within the brain. Combined with other tools such as magnetic resonance imaging (MRI) scans, Christine and her colleagues begin to better understand wiring pathways. This forms the basis for them to start investigating what factors affect these pathways during development.
The importance of understanding brain development
Christine is fascinated by the brain and its complex processes. Her research into the brain and its wiring is driven by a desire to improve people’s lives through understanding brain development. If she can help to predict brain-wiring problems, it may be possible to ensure early treatment for a number of neurological conditions, including learning disabilities and degenerative diseases like Alzheimer’s.
It also has important implications for treating brain injuries. By understanding how axons get to the right place by creating a molecular map, Christine and her colleagues are hoping to develop therapies to regenerate axons that have been damaged and re-establish connections after a brain injury.
Nature of Science
Christine Jasoni’s work builds on the research of past scientists – much of what is possible today was unthinkable 50 years ago. In addition to learning from past scientists, Christine collaborates with scientists in other fields such as neurology and psychology and liaises with organisations such as Autism New Zealand.
Visit the Laboratory of Developmental Neuroendocrinology for more information about Christine’s research.