Neurons (nerve cells) need a regular supply of oxygen and nutrients to survive. When neurons are deprived of these essential factors for more than a few minutes, such as during a stroke or cardiac arrest, they undergo changes that lead to cell death. Intracellular concentrations of ions (e.g. sodium ions, calcium ions and protons) show dramatic changes during and following periods of anoxia or ischemia (oxygen deprivation). These changes play an important role in determining subsequent neuronal damage or death. Claire Sheldon is characterizing these anoxia-evoked changes in sodium ions, calcium ions and protons in hippocampal neurons and hopes to identify the mechanisms which contribute to their production. Her research focuses on the role(s) of intracellular pH regulating mechanisms to the changes observed, with particular emphasis on the Na+/H+ exchanger, an acid-extruding mechanism present in hippocampal neurons. Claire hopes her research will lead to new strategies to prevent or limit neuron death and the debilitating effects that stroke or cardiac arrest have on the central nervous system.