Centrala begrepp
Cholinergic input to mouse visual cortex signals a locomotion state and acutely enhances the responsiveness of layer 5 neurons to both bottom-up and top-down inputs.
Sammanfattning
The study investigated the signals conveyed by the basal forebrain cholinergic system to the mouse visual cortex and the consequent changes in the activity of layer 2/3 and layer 5 neurons.
Key findings:
- Cholinergic axons in the visual cortex provide a binary locomotion state signal, with no evidence of responses to visual stimuli or visuomotor prediction errors.
- Optogenetic activation of cholinergic axons in the visual cortex increased the amplitude and decreased the latency of responses in layer 5 neurons to both top-down and bottom-up inputs, but did not affect layer 2/3 neurons.
- Cholinergic activity underlies the locomotion-associated decorrelation of activity between neurons in both layer 2/3 and layer 5.
- The authors speculate that acetylcholine augments the responsiveness of layer 5 neurons to inputs from outside the local network, possibly enabling faster switching between internal representations during locomotion.
Statistik
"Acetylcholine is released in visual cortex by axonal projections from the basal forebrain."
"Cholinergic activity in visual cortex is closely related to movement, but whether movement is the primary determinant of cholinergic activity and how movement related activity compares to sensory driven activity is less clear."
"Neurons responsive to iontophoretic application of acetylcholine are preferentially found in deep cortical layers."
"Optogenetic stimulation of cholinergic axons in visual cortex resulted in firing rate increases in layers 4, 5, and 6, but decreased firing rates in layer 2/3."
Citat
"Acetylcholine is one of the key neuromodulators involved in cortical function and plasticity."
"Likely the primary functional effect of increased levels of acetylcholine in cortex is increased sensory responsiveness."
"A second functional effect of acetylcholine is a decorrelation of cortical activity."