Devices and methods of use thereof for determining the presence and concentration of chemicals in a cell, tissue, organ or organism involve semiderivative voltammetric measurements and chronoamperometric measurements of chemicals, e.g. neurotransmitters, precursors, and metabolites. Methods o f diagnosing and/or treating a subject with abnormal levels of neurotransmitte rs includes those having or at risk of developing epilepsy, diseases of the bas al ganglia, athtoid, dystonic diseases, neoplasms, Parkinson's disease, brain injuries, spinal cord injuries, and cancer. Microvoltammetry methods may be performed in vitro, in vivo, or in situ to differentiate white matter from grey matter, diagnose brain tumors, for cancer diagnosis and treatment, and to locate a tumor's position. Broderick probes are used to determine the concentration of the material, e.g. dopamine, norepinephrine, and serotonin, in the brains of patients having epilepsy. In some embodiments of the invention, regions of the brain to be resected or to be targeted for pharmaceutical therapy are identified using Broderick probes. The invention further provides methods of measuring the neurotoxicity of a material by comparing Broderick probe microvoltammograms of a neural tissue in the presence and absence of the material.
DIAGNOSIS AND TREATMENT OF NEURAL DISEASE AND INJURY USING MICROVOLTAMMETRY