Similar neural and perceptual masking effects of low-power optogenetic stimulation in primate V1

Can direct stimulation of primate V1 substitute for a visual stimulus and mimic its perceptual effect? To address this question, we developed an optical-genetic toolkit to 'read' neural population responses using widefield calcium imaging, while simultaneously using optogenetics to 'write' neural responses into V1 of behaving macaques. We focused on the phenomenon of visual masking, where detection of a dim target is significantly reduced by a co-localized medium-brightness mask [1, 2]. Using our toolkit, we tested whether V1 optogenetic stimulation can recapitulate the perceptual masking effect of a visual mask. We find that, similar to a visual mask, low-power optostimulation can significantly reduce visual detection sensitivity, that a sublinear interaction between visual and optogenetic evoked V1 responses could account for this perceptual effect, and that these neural and behavioral effects are spatially selective. Our toolkit and results open the door for further exploration of perceptual substitutions by direct stimulation of sensory cortex.

Musical Mix Clarity Prediction Using Decomposition and Perceptual Masking Thresholds

Objective measurement of perceptually motivated music attributes has application in both target-driven mixing and mastering methodologies and music information retrieval. This work proposes a perceptual model of mix clarity which decomposes a mixed input signal into transient, steady-state, and residual components. Masking thresholds are calculated for each component and their relative relationship is used to determine an overall masking score as the model’s output. Three variants of the model were tested against subjective mix clarity scores gathered from a controlled listening test. The best performing variant achieved a Spearman’s rank correlation of rho = 0.8382 (p < 0.01). Furthermore, the model output was analysed using an independent dataset generated by progressively applying degradation effects to the test stimuli. Analysis of the model suggested a close relationship between the proposed model and the subjective mix clarity scores particularly when masking was measured using linearly spaced analysis bands. Moreover, the presence of noise-like residual signals was shown to have a negative effect on the perceived mix clarity.

Similar neural and perceptual masking effects of low-power optogenetic stimulation in primate V1

Can direct stimulation of primate V1 substitute for a visual stimulus and mimic its perceptual effect? To address this question, we developed an optical-genetic toolkit to “read” neural population responses using widefield calcium imaging, while simultaneously using optogenetics to “write” neural responses into V1 of behaving macaques. We focused on the phenomenon of visual masking, where detection of a dim target is significantly reduced by a co-localized medium-brightness pedestal. Using our toolkit, we tested whether V1 optogenetic stimulation can recapitulate the perceptual masking effect of a visual pedestal. We find that, similar to a visual pedestal, low-power optostimulation can significantly reduce visual detection sensitivity, that a sublinear interaction between visual and optogenetic evoked V1 responses could account for this perceptual effect, and that these neural and behavioral effects are spatially selective. Our toolkit and results open the door for further exploration of perceptual substitutions by direct stimulation of sensory cortex.

Harsh and Sweet Sensations Predict Acute Liking of Electronic Cigarettes, but Flavor Does Not Affect Acute Nicotine Intake: A Pilot Laboratory Study in Men

Introduction Electronic cigarette use is increasing in popularity, and thousands of flavors are available. Adolescent vaping rates in the United States have nearly doubled in the past year. Unlike combustible tobacco, added flavors are not currently regulated for some types of electronic cigarette products. Here, we investigated the role of flavor in electronic cigarette liking and acute intake. Methods Men (n = 39) aged 18–45 vaped in a controlled laboratory setting after being randomized to one of four e-liquids: 6 mg nicotine/mL cherry, 18 mg/mL cherry, 6 mg/mL chocolate, or 18 mg/mL chocolate. They completed several questionnaires, and vaped ad libitum for 10 minutes. After the first puff, participants rated sensations (sweetness, bitterness, coolness, harshness/irritation) on general labeled magnitude scales (gLMS) and rated overall liking on a generalized hedonic scale. Once the 10-minute session ended, participants made another set of ratings. Results Liking was generally stable across the vaping session and liking varied substantially across the four conditions. Across all conditions, sensory ratings predicted liking: harshness/irritation was negatively associated with first puff liking, whereas perceived sweetness was positively associated with first puff liking. First puff liking associated with increased amount of e-liquid vaped, but not total nicotine intake. Participants appeared to titrate their nicotine intake regardless of assigned condition. Conclusion Flavored e-liquids affect acute liking ratings, but not acute nicotine intake. Implications These data suggest individuals who regularly vape may titrate their nicotine intake, regardless of flavor, and contrary to expectations, acute liking did not predict total nicotine intake. However, more-liked flavors may potentially make higher nicotine levels more tolerable by adding pleasant sensations directly, rather than by perceptual masking that reduces aversive sensations.

An overview on informational masking

Background and Aim: In noisy environments, two types of masking including energetic mask­ing (EM) and informational masking (IM) occur. EM results from the spectral overlap of the target and maskers on the basilar membrane, while IM occurs at higher level. This paper aimed to rev­iew the concept of IM in terms of historical perspective and definitions, the important cues for releasing from it, age-related effects and its neural basis. Recent Findings: The data from psychoacoustic, behavioral, and neuro-imaging studies were revi­ewed and discussed in order to provide an overall image of IM. According to these studies, it seems that perceptual segregation between the target and maskers is the most important cues for relea­sing from IM. This process takes place simply and without any effort in adults with normal hearing; however, it does not occur easily in chil­dren, elderly people and those with impaired hearing. Moreover, it seems that both top-down and bottom-up processing are involved in IM for­mation. Conclusion: Since IM leads to failure in selec­tion of auditory objects and prevents the indivi­dual from auditory scene analysis, understanding the IM concept leads to a better knowledge of speech perception in noise. Keywords: Informational masking; perceptual masking; energetic masking

Harsh and sweet sensations predict acute liking of electronic cigarettes, but flavor does not affect acute nicotine intake: a pilot laboratory study in men

Introduction: Electronic cigarette (eCig) use is increasing in popularity, and thousands of flavors are available. Adolescent vaping rates in the United States have nearly doubled in the past year. Unlike combustible tobacco, added flavors are not currently regulated for electronic cigarette products. Here, we investigated the role of flavor in eCig liking and acute intake. Methods: Men (n=39) aged 18-45 vaped in a controlled laboratory setting after being randomized to one of four e-liquids: 6mg nicotine/ml Cherry, 18mg/ml Cherry, 6mg/ml Chocolate, or 18mg/ml Chocolate. They completed several questionnaires, and vaped ad libitum for 10 minutes. After the first puff, participants rated sensations (sweetness, bitterness, coolness, harshness/irritation) on general labeled magnitude scales (gLMS) and rated overall liking on a generalized hedonic scale. Once the 10-minute session ended, participants made another set of ratings. Results: Liking was generally stable across the vaping session and liking varied substantially across the 4 conditions. Across all conditions, sensory ratings predicted liking: harshness/irritation was negatively associated with first puff liking while perceived sweetness was positively associated with first puff liking. First puff liking associated with increased amount of e-liquid vaped, but not total nicotine intake. Participants appeared to titrate their nicotine intake regardless of assigned condition.Conclusion: Flavored eLiquids affect acute rated liking, but not acute nicotine intake. These data suggest individuals who regularly vape may titrate their nicotine intake, regardless of flavor, and contrary to expectations, acute liking did not predict total intake. However, more-liked flavors may potentially make higher nicotine levels more tolerable by adding pleasant sensations directly, rather than by perceptual masking that reduce aversive sensations.