Glutamate receptors are amongst the most important signalling molecules in the brain. Activation of receptors by the neurotransmitter glutamate is required for nervous system function, underlying cognition, learning, memory and sensation. Despite advances in the study of their structural biology and physiology, how glutamate receptor complexes are activated remains unclear. With this proposal, we aim to determine how receptor activation and desensitisation are driven by glutamate binding. Our central approach is to map the motions of glutamate receptors during synaptic-like activity, in order to grab the frames needed to produce the movie of receptor activation. We aim to detect motion within the receptor on the angstrom scale by trapping conformational states during activation with artificial metal ion binding sites and disulfide bonds. Trapped receptors will be examined using biochemical measures of subunit association, biophysical reports of receptor activity and by structural biology. The results we obtain will be useful to rationally interfere with excitatory synapses in the brain and may therefore help the development of therapies.