However, it is still not clear which mechanisms are actually used by ipRGCs, or when they might use them. There are at least two mechanisms that ipRGCs may use to relay information to the brain: one uses a protein called PACAP, while the other involves a molecule called glutamate. These cells receive information from other light-sensitive cells in the retina called rods and cones. For example, retinal cells called intrinsically photosensitive retinal ganglion cells (or ipRGCs for short) rapidly respond to the intensity of background light and regulate the size of the pupils to control how much light enters the eyes.
There are several different types of light-sensitive cell in the retina that perform different roles. The retina is the part of our eye that detects light and sends visual information to the brain. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day.
Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate, but adapt within minutes. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters.
Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear.
0 kommentar(er)
