Simultaneous glutamate recordings in the frontal cortex network with multisite biomorphic microelectrodes: New tools for ADHD research

Background: The aberrant regulation of glutamate has been implicated in numerous psychiatric disorders including drug addiction and attention-deficit/hyperactivity disorder. To understand glutamate signaling and its role in facilitating disease, tools to directly measure glutamate in a complex, neural network are needed. New method: The development of a ceramic-based, dual-sided, biomorphic microelectrode array with four recording sites on each side to facilitate a more detailed measurement of glutamate in awake, behaving rodents. Results: In vitro calibrations of these biosensors showed selective and specific responses to glutamate. In awake rats, these biomorphic electrode arrays enabled the concurrent evaluation of glutamate in a network, the frontal cortex: including the cingulate, prelimbic, infralimbic and dorsal peduncle regions. Regions within the frontal cortex exhibited varying phasic glutamate patterns in awake animals.Comparison with existing method: Existing methodologies to measure glutamate neurotransmission employ single-sided biosensors or biosensors capable of measuring neurochemicals at only one location in space. Conclusions: Multi-site, biomorphic neurochemical biosensors provide a method for simultaneously measuring glutamate in multiple areas of a neural network in the brain.