Dopamine modulation of prefrontal delay activity-reverberatory activity and sharpness of tuning curves
This addresses mechanisms for working memory in neuroscience, but is incremental as it builds on known dopamine effects.
The study investigated how dopamine D1 modulation affects prefrontal cortex networks, finding that it enables robust bistability for selective reverberation and sharpens tuning curves, increasing signal-to-noise ratio.
Recent electrophysiological experiments have shown that dopamine (D1) modulation of pyramidal cells in prefrontal cortex reduces spike frequency adaptation and enhances NMDA transmission. Using four models, from multicompartmental to integrate and fire, we examine the effects of these modulations on sustained (delay) activity in a reverberatory network. We find that D1 modulation may enable robust network bistability yielding selective reverberation among cells that code for a particular item or location. We further show that the tuning curve of such cells is sharpened, and that signal-to-noise ratio is increased. We postulate that D1 modulation affects the tuning of "memory fields" and yield efficient distributed dynamic representations.