Due to interhuman differences in the perception of color, visual shade assessment human teeth is lacking standardization that may be improved by use a spectrophotometer. In this study, we tested hypothesis spectrophotometric tooth color comparable with determination. On 30 patients, three operators unreported deficiency independently selected best match middle third unrestored maxillary central incisors, using Vita Classical Shade Guide. The same were measured means reflectance group, all 3...

The integration of direct bottom-up inputs with contextual information is a core feature neocortical circuits. In area V1, neurons may reduce their firing rates when receptive field input can be predicted by spatial context. Gamma-synchronized (30–80 Hz) provide complementary signal to rates, reflecting stronger synchronization between neuronal populations receiving mutually predictable inputs. We show that large uniform surfaces, which have high predictability, strongly suppressed yet...

Abstract Circuits of excitatory and inhibitory neurons generate gamma-rhythmic activity (30–80 Hz). Gamma-cycles show spontaneous variability in amplitude duration. To investigate the mechanisms underlying this variability, we recorded local-field-potentials (LFPs) spikes from awake macaque V1. We developed a noise-robust method to detect gamma-cycle amplitudes durations, which showed weak but positive correlation. This correlation, joint amplitude-duration distribution, is well reproduced...

Predictive coding is an important candidate theory of self-supervised learning in the brain. Its central idea that sensory responses result from comparisons between bottom-up inputs and contextual predictions, a process which rates synchronization may play distinct roles. We recorded awake macaque V1 developed technique to quantify stimulus predictability for natural images based on self-supervised, generative neural networks. find neuronal firing were mainly modulated by higher-order image...

Fine-scale temporal organization of cortical activity in the gamma range (∼25–80Hz) may play a significant role information processing, for example by neural grouping ('binding') and phase coding. Recent experimental studies have shown that precise frequency oscillations varies with input drive (e.g. visual contrast) it can differ among nearby locations. This has challenged theories assuming widespread synchronization at fixed common frequency. In present study, we investigated which...

Gamma-band synchronization coordinates brief periods of excitability in oscillating neuronal populations to optimize information transmission during sensation and cognition. Commonly, a stable, shared frequency over time is considered condition for functional neural synchronization. Here, we demonstrate the opposite: instantaneous modulations are critical regulate phase relations In monkey visual area V1, nearby local driven by different stimulation showed gamma frequencies. When similar...

When a visual stimulus is repeated, average neuronal responses typically decrease, yet they might maintain or even increase their impact through increased synchronization. Previous work has found that many repetitions of grating lead to increasing gamma-band Here, we show in awake macaque area V1 both repetition-related reductions firing rate and increases gamma are specific the repeated stimulus. These effects some persistence on timescale minutes. Gamma presented location. Further,...

Under natural conditions, the visual system often sees a given input repeatedly. This provides an opportunity to optimize processing of repeated stimuli. Stimulus repetition has been shown strongly modulate neuronal-gamma band synchronization, yet crucial questions remained open. Here we used magnetoencephalography in 30 human subjects and find that gamma decreases across ≈10 repetitions then increases further repetitions, revealing plastic changes activated neuronal circuits. Crucially,...

Abstract Neurons in the human amygdala and hippocampus that are selective for identity of specific people classically thought to encode a person’s invariant visual features (e.g., skin tone, eye shape). However, it remains largely unknown how information from higher cortical areas is translated into such semantic representation an individual person. Here, we show some hippocampal neurons multiple different unrelated face identities based on shared features. The encoded form clusters deep...

Abstract Parallel multisite recordings in the visual cortex of trained monkeys revealed that responses spatially distributed neurons to natural scenes are ordered sequences. The rank order these sequences is stimulus-specific and maintained even if absolute timing modified by manipulating stimulus parameters. specificity was highest when they were evoked stimuli deteriorated for versions which certain statistical regularities removed. This suggests response result from a matching operation...

Strong gamma-band oscillations in primate early visual cortex can be induced by homogeneous color surfaces (Peter et al., 2019; Shirhatti and Ray, 2018). Compared to other hues, particularly strong gamma have been reported for red stimuli. However, precortical processing the resultant strength of input V1 often not fully controlled for. Therefore, stronger responses might due differences strength. We presented stimuli that had equal luminance cone contrast levels a coordinate system based on...

SUMMARY Circuits of excitatory and inhibitory neurons can generate rhythmic activity in the gamma frequency-range (30-80Hz). Individual gamma-cycles show spontaneous variability amplitude duration. The mechanisms underlying this are not fully understood. We recorded local-field-potentials (LFPs) spikes from awake macaque V1, developed a noise-robust method to detect gamma-cycle amplitudes durations. Amplitudes durations showed weak but positive correlation. This correlation, joint...

Abstract Predictive coding is an important candidate theory of self-supervised learning in the brain. Its central idea that neural activity results from integration and comparison bottom-up inputs with contextual predictions, a process which firing rates synchronization may play distinct roles. Here, we quantified stimulus predictability for natural images based on self-supervised, generative networks. When precise pixel structure falling into V1 receptive field (RF) was predicted by spatial...

Planar intra-cortical electrode (Utah) arrays provide a unique window into the spatial organization of cortical activity. Reconstruction current source density (CSD) underlying such recordings, however, requires “inverting” Poisson’s equation. For inter-laminar this is commonly done by CSD method, which consists in taking second-order derivative recorded local field potentials (LFPs). Although method has been tremendously successful mapping generators LFPs, its application to planar...

When a visual stimulus is repeated, average neuronal responses typically decrease, yet they might maintain or even increase their impact through increased synchronization. Previous work has found that many repetitions of grating lead to increasing gamma-band Here we show in awake macaque area V1 both, repetition-related reductions firing rate and increases gamma are specific the repeated stimulus. These effects showed some persistence on timescale minutes. Further, were presented location....

Curing dentine bonding agents create a film thickness on the surface of teeth which are prepared for all-ceramic crowns. The aim this study was to investigate if (DBAs) is acceptable with fit definitive restorations 50-100 microm. AllBond 2, Syntac, ART Bond, P-Bond (an experimental DBA), and Primer 2 were applied onto standardized crown preparations. DBAs tooth surfaces according manufacturers' instructions under simulation intrapulpal pressure. After curing DBAs, cut mesiodistally...

Under natural conditions, the visual system often sees a given input repeatedly. This provides an opportunity to optimize processing of repeated stimuli. Stimulus repetition has been shown strongly modulate neuronal-gamma band synchronization, yet crucial questions remained open. Here we used magnetoencephalography in 30 human subjects and find that gamma decreases across ~10 repetitions then increases further repetitions, revealing plastic changes activated neuronal circuits. Crucially,...

When a visual stimulus is repeated, average neuronal responses typically decrease, yet they might maintain or even increase their impact through increased synchronization. Previous work has found that many repetitions of grating lead to increasing gamma-band Here we show in awake macaque area V1 both, repetition-related reductions firing rate and increases gamma are specific the repeated stimulus. These effects showed some persistence on timescale minutes. Further, were presented location....