Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Neuron. 2023 Mar 1;111(5):711-726.e11. doi: 10.1016/j.neuron.2022.12.006. Epub 2022 Dec 29.
Retinal ganglion cell (RGC) types relay parallel streams of visual feature information. We hypothesized that neuromodulators might efficiently control which visual information streams reach the cortex by selectively gating transmission from specific RGC axons in the thalamus. Using fiber photometry recordings, we found that optogenetic stimulation of serotonergic axons in primary visual thalamus of awake mice suppressed ongoing and visually evoked calcium activity and glutamate release from RGC boutons. Two-photon calcium imaging revealed that serotonin axon stimulation suppressed RGC boutons that responded strongly to global changes in luminance more than those responding only to local visual stimuli, while the converse was true for suppression induced by increases in arousal. Converging evidence suggests that differential expression of the 5-HT1B receptor on RGC presynaptic terminals, but not differential density of nearby serotonin axons, may contribute to the selective serotonergic gating of specific visual information streams before they can activate thalamocortical neurons.
视网膜神经节细胞（RGC）类型传递平行的视觉特征信息流。我们假设神经调质可能通过选择性地从丘脑特定的 RGC 轴突中传递来有效地控制哪些视觉信息流到达皮层。使用光纤光度记录，我们发现，在清醒小鼠的初级视丘脑，光遗传学刺激 5-羟色胺能轴突，抑制了持续的和视觉诱发的钙活动，以及从 RGC 末梢释放谷氨酸。双光子钙成像显示，5-羟色胺能轴突刺激抑制了对亮度整体变化反应强烈的 RGC 末梢，而对仅对局部视觉刺激反应的末梢则相反，而在由觉醒增加引起的抑制中则相反。有证据表明，5-HT1B 受体在 RGC 突触前末梢的差异表达，而不是附近 5-羟色胺能轴突的密度差异，可能有助于在特定的视觉信息流激活丘脑皮层神经元之前对其进行选择性的 5-羟色胺能门控。
