Effect of Dopamine in Enhancement of SNR of Cortico-Striatal-Thalamo-Cortical Loop Spiking

Abstract: In this work, the effects of dopamine neurotransmitter within the Cortico-Striatal-Thalamo-Cortical (CSTC) loop. Simulations confirmed dopamine facilitates movement via thalamic disinhibition. Analysis of its impact on the signal-to-noise ratio (SNR) revealed a complex, region-specific outcome: SNR increased in some regions (e.g., D2 Striatum: 3.41 dB to 6.25 dB), decreased in others (e.g., Thalamus VL: 6.24 dB to 3.93 dB), and remained stable elsewhere (e.g., M1: 3.16 dB to 3.13 dB). This heterogeneity stems from dopamine increasing the excitability of D1-receptor-expressing neurons, which amplifies channel conductance noise and reduces SNR in specific circuits. Thus, dopamine acts not as a uniform signal enhancer, but as a complex modulator that critically balances facilitation and noise within the CSTC loop.