Mounting evidence suggests that many common neurological and psychiatric disorders, such as schizophrenia, autism, and epilepsy, originate from abnormal brain circuit formation and neuron (nerve cell) growth during early development. An increasing number of studies show that in addition to genes, conditions in our surroundings can influence neuron development during early life and in later years. One important contributor to abnormal neuron growth may be altered levels of glutamate (the primary neurotransmitter that nerve cells use to send signals across synapses) and its neurotransmitting capabilities – called glutamatergic synaptic transmission. For example, a reduced glutamatergic transmission has been associated with schizophrenia and an increased level with neonatal seizures. Derek Dunfield is investigating how neurons connect with each other and how activity influences those connections during development. Specifically he is measuring the influence of glutamatergic transmission on dynamic brain circuit growth. Derek is examining real-time imaging of neurons during development using a relatively new imaging technique called two-photon microscopy and a labeling technique called single-cell electroporation. This allows him to label single neurons with different colours and watch how they interact together as they grow. Derek hopes this research will lead to better treatment and diagnosis for disabling brain disorders.