Jack studies how nerve cells, or neurons, communicate with one another in the nervous system. He is also interested in understanding how chemical and electrical signals move through neural networks, such as the spinal cord or cerebral cortex.[4] Although neurons form large networks, these cells do not actually touch each other. Instead, when the end of a nerve is activated it releases ions or chemicals known as neurotransmitters.[4] Subsequently, these move across the gap, or synapse, between the neuron and the adjacent cell in the network, activating its receptors and perpetuating the signal.[4] Jack applies theoretical and experimental approaches to research this process of synaptic transmission.[4] This includes the use of neurophysiology methods to record bioelectrical activity and mathematical models to analyse the central and peripheral nervous systems. His work on neurotransmission is offering insight into disorders of the nervous system, such as Alzheimer's disease and multiple sclerosis, and has the potential to improve their diagnosis.[4]