Sensory processing is influenced by neuromodulators such as serotonin, thought to relay behavioural state. Recent work has shown that the modulatory effect of serotonin itself differs with the animal's behavioural state. In primates, including humans, the serotonin system is anatomically important in the primary visual cortex (V1). We previously reported that in awake fixating macaques, serotonin reduces the spiking activity by decreasing response gain in V1. But the effect of serotonin on the local network is unknown. Here, we simultaneously recorded single-unit activity and local field potentials (LFPs) while iontophoretically applying serotonin in V1 of alert monkeys fixating on a video screen for juice rewards. The reduction in spiking response we observed previously is the opposite of the known increase of spiking activity with spatial attention. Conversely, in the local network (LFP), the application of serotonin resulted in changes mirroring the local network effects of previous reports in macaques directing spatial attention to the receptive field. It reduced the LFP power and the spike-field coherence, and the LFP became less predictive of spiking activity, consistent with reduced functional connectivity. We speculate that together, these effects may reflect the sensory side of a serotonergic contribution to quiet vigilance: The lower gain reduces the salience of stimuli to suppress an orienting reflex to novel stimuli, whereas at the network level, visual processing is in a state comparable to that of spatial attention.

• MeSH
• akční potenciály fyziologie   MeSH
• lidé MeSH
• Macaca mulatta MeSH
• serotonin MeSH
• světelná stimulace MeSH
• zraková percepce fyziologie   MeSH
• zrakové evokované potenciály * MeSH
• zrakové korové centrum * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH

This work presents a quick clinical protocol for dark-adapted chromatic (DAC) perimetry as well as a novel clinical tool, scotopic chromatic pupil campimetry (CPC). The goal of the study was to explore the applicability of these methods in a clinical setting, their test-retest repeatability, and the congruence of the results. Local rod sensitivity was assessed at 36 locations within 30° eccentricity of the visual field in 15 healthy subjects (mean age 43 ± 16 years; 7 females and 8 males) with DAC perimetry (red and cyan stimuli) and CPC 2 times in repeated measurements. The duration of individual measurements was 370 ± 5 s for CPC and 366 ± 62 s for DAC perimetry. The intraclass correlation (ICC) coefficient was 0.53 for DAC perimetry cyan stimuli, 0.67 for red stimuli, and 0.93 for CPC. However, the spatial resolution of CPC was substantially smaller than in DAC perimetry. We did not find a correlation of DAC perimetry and CPC measurements on the global or the local level. In comparison to DAC perimetry, CPC shows a superior intervisit repeatability in detecting functional changes in the rod population in an objective way with lower spatial resolution. Our results also indicate that these 2 methods measure the rod function in different ways and could thus constitute complementary scotopic functional diagnostics.

• MeSH
• adaptace na tmu MeSH
• dospělí MeSH
• klinické protokoly MeSH
• lidé středního věku MeSH
• lidé MeSH
• testy zrakového pole * MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• zraková pole * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH