2, Center for Sensorimotor Neural Engineering, Seattle, Washington, United States
3, University of California San Diego, La Jolla, San Diego, California, United States
4, University of California San Diego, La Jolla, San Diego, California, United States
Several psychiatric and neurological disorders - ranging from Alzheimer's and Parkinson’s diseases to schizophrenia and deep depressed mood - are attributable to alterations in the structure and function of the synapse, engendered by neurotransmitter imbalances. For this reason, a deeply understanding of the basic neurotransmission mechanism and its involvement in the pathogenesis is acquiring an ever-increasing scientific significance. The broad impact of this basically fundamental understanding is evident since it will lead to the possibility to treat neurological diseases, now representing a dramatic social and economic burdens worldwide.
In our previous investigations, we validated the ability of glassy carbon (GC) microelectrodes in detecting Dopamine release and recording neural activity in vivo in the Striatum and Caudomedial Neostriatum auditory area of European Starling songbirds. The GC microelectrode arrays were made of 4 recording-detection sites with an area of 1500 µm2 and a vertical distance of 220 µm.
In this study, we are presenting an improved version of the GC microelectrode arrays with an higher spatial resolution (8 microelectrodes with 110µm vertical space) and with different recording-detection site areas ranging from 500 µm2 to 2000 µm2. Such device allowed to evaluate how the electrode size influences (i) the Dopamine (DA) sensing capability in terms of lower detection limit, selectivity and sensitivity (ii) the neural signal recording quality. Indeed, the electrode impedance is one of main factor that determines the signal to noise ratio as well as the spike sorting performance.
The new GC microelectrode arrays were tested in vivo in the Striatum and Caudomedial Neostriatum auditory area of European Starling songbirds for the validation of (i) detection of spontaneous and electrically stimulated DA through fast scan cyclic voltammetry and (ii) neural signal recording performance. Preliminary interpretations of the in-vivo results are reported.
This kind of evaluation leads to the identification to the optimum parameters in order to implement a multiplatform able to simultaneously record neural activity and detect neurotransmitters at the synaptic site, essential to obtain a deeper comprehension of the neurotransmission mechanisms.