Table 1.
Summary of basic gating mechanisms managing information transfer between two groups of cortical neurons.
| Gating mechanisms | ||||
|---|---|---|---|---|
| Gating types |  |
 |
 |
 |
| Key mechanism | Up/down neurons implementing AND gates | Shunting of excitatory cortical neurons by inhibitory interneurons | “Detailed balance” between excitation and inhibition | Oscillations caused by synchronized firing of inhibitory fast-spiking interneurons |
| Trigger | Gating signal switching state of up/down neurons | Gating signal activating inhibitory interneurons | Gating signal modulating the inhibition in the receiver population | Gating signal modifying the relative phase between the neural populations |
| State of the gate without gating signal | Closed | Open | Closed | Depends on the relative phase between the neural populations |
| Experimental evidence | Preliminary observations in prefrontal cortex (Floresco and Grace, 2003; Valenti and Grace, 2009) | Preliminary observations in prefrontal cortex (Floresco and Grace, 2003) | No direct evidence available for the cortex | Gating observed both in vitro (Burchell et al., 1998) and in vivo (Cardin et al., 2009) |
| Theoretical evidence | Model of network exhibiting up/down states (Parga and Abbott, 2007), model of single up/down neurons (Kepecs and Raghavachari, 2007) | Models of visual attention and processing (Anderson and Van Essen, 1987; Olshausen et al., 1993), logic gates for neural information propagation (Vogels and Abbott, 2005) | Large-scale neural network model of gating (Vogels and Abbott, 2009) | Models of working memory (Lisman and Idiart, 1995), sequence generation (Fukai, 1999), goal-directed behavior (Koene and Hasselmo, 2005) and V1 innervation by thalamic input (Paik and Glaser, 2010) |
| Neurotransmitters and neuroreceptors involved | Glutamate: NMDA and AMPA dopamine: D1 (Lewis and O'Donnell, 2000; Kepecs and Raghavachari, 2007) | Glutamate, GABA (Borg-Graham et al., 1998) | Acetylcholine, glutamate, GABA (Vogels and Abbott, 2009) | Glutamate, GABA (Cardin et al., 2009) |
| Time scale of the mechanism | Rapid (tens of ms) (Kepecs and Raghavachari, 2007) | No estimation published so far | No estimation published so far | No estimation published so far |