耳鸣掩蔽治疗条件的测定

目的 寻找耳鸣掩蔽治疗较为合适的掩蔽时间、掩蔽声类型的组合。方法 受试的２７名耳蜗性耳鸣患者,平均分别来自于三个治疗点,并定为甲、乙、丙三组。按析因试验设计原理将掩蔽声设定为窄带噪声（ｎａｒ－ｒｏｗ ｂａｎｄ ｎｏｉｓｅ,ＮＢＮ）、宽带噪声（ｗｉｄｅ ｂａｎｄ ｎｏｉｓｅ,ＷＢＮ）和言语噪声（ｓｐｅｃｈ ｎｏｉｓｒｅ,ＳＮ）三个因素,掩蔽时间设定为１５、３０、４５ｍｉｎ三个水平共九种组合,每组内患     

Sensitivity to masked conditioned stimuli predicts conditioned response magnitude under masked conditions

Expression of conditioned fear has been reported to be independent of perceptual awareness of conditioned stimuli (CSs). Previous studies have been criticized, however, for not adequately assessing perceptual awareness. We fear-conditioned participants to one of two symbols and measured skin conductance responses to dichoptically masked and unmasked CSs. Participants also performed a target detection task and sensitivity (d') to the masked conditioned stimuli (CS+, CS-) was measured. Results showed that sensitivity under masking conditions was related to conditioned responses to masked CSs but not unmasked CSs. Thus, a strong relationship between expression of conditioned fear and awareness of the CS+ emerges when the latter is assessed by signal detection methods. Without consensus on how awareness should be defined, these findings bring balance to previous studies that have typically used less sensitive assessments of awareness.     

“I want to fit in… but I don’t want to change myself fundamentally”: A qualitative exploration of the relationship between masking and mental health for autistic teenagers

BackgroundPrevious research has identified an association between masking and mental health for autistic people. However, the direction of causality and mechanisms involved in this relationship are not well understood. This qualitative study aimed to investigate autistic teenagers’ experiences of masking, mental health and how the two develop and interact.MethodsTwenty autistic teenagers took part in a semi-structured interview. The interviews were analysed using Reflexive Thematic Analysis.ResultsFrom the analysis, one theme was identified to conceptualise masking as described by participants. Five more inter-related themes were identified, each involved both in the relationship between masking and mental health and conversely in the relationship between authenticity and mental health. Participants described how masking and mental health both influence each other, and both are influenced by social and environmental factors.ConclusionsThe findings are consistent with previous research indicating that masking is associated with mental health difficulties. Our analysis presents a broader conceptualisation of masking than previously defined in the literature, placing social oppression of autistic people at the heart of the relationship between masking and mental health. The findings have implications for diagnostic services, post-diagnostic support and therapeutic interventions, highlighting the need to challenge deficit-based narratives of autism.     

Nonconscious formation and reactivation of semantic associations by way of the medial temporal lobe

A successful strategy to memorize unrelated items is to associate them semantically. This learning method is typical for declarative memory and depends on the medial temporal lobe (MTL). Yet, only a small fraction of perceived items emerge into conscious awareness and receive the status of representations in declarative memory. This functional magnetic resonance imaging (fMRI) study tackled the mnemonic fate of unrelated item pairs processed without conscious awareness. Stimuli consisted of a face and a written profession (experimental condition) or of a face (control condition) exposed very briefly between pattern masks. Although the participants were unaware of the stimuli, activity in the hippocampus and perirhinal cortex was changed in the experimental versus the control condition; perirhinal activity changes correlated with the reaction time measure of the later nonconscious retrieval. For retrieval, the previously presented faces were shown again, this time for conscious inspection. The task was to guess the professional category of each face. This task was to induce a nonconscious retrieval of previously formed face-profession associations. Remarkably, activity in the hippocampus and perirhinal cortex was enhanced when subjects were confronted with faces from the experimental versus the control condition. The degree of hippocampal and perirhinal activation changes correlated with the reaction time measure of nonconscious retrieval. Together, our findings suggest that new semantic associations can be formed and retrieved by way of the medial temporal lobe without awareness of the associations or its components at encoding or any awareness that one is remembering at retrieval.     

Temporal tuning characteristics of the perceptual template and endogenous cuing of spatial attention

External noise presented in temporal contiguity with a target impairs perceptual performance, reflecting the temporal tuning of the perceptual template. Deriving the temporal characteristics of the perceptual template, however, requires an observer model that segregates the impact of non-linearities and intrinsic inefficiencies of the observer in order to account for the impact of external noise in various temporal configurations. In Experiment 1, we showed that the perceptual template model successfully accounts for temporal masking functions in foveal Gabor orientation identification masked by external noise with a wide range of temporal configurations, and estimates the temporal characteristics of the perceptual template. In Experiment 2, we extended the paradigm and the model to compare the temporal tuning characteristics of the perceptual template in central pre- and simultaneous cuing of endogenous spatial attention in a Gabor orientation identification task in visual periphery. We found that endogenous spatial attention excludes external noise by both sharpening the temporal window of the perceptual template and (mostly) reducing the impact of external noise uniformly across the entire temporal window.     

Preparation of various solid-lipid beads for drug delivery of enrofloxacin

Solid-lipid beads were prepared to retard the release rate of enrofloxacin and to mask its bitter taste using carrageenan or sodium alginate as a shell material and either cacao butter or Witepsol W-35 as a solid lipid core. Sodium alginate was a better shell material than carrageenan and the highest loading efficiency was obtained using 2% sodium alginate. The alginate beads had a spherical morphology and a sturdy shell structure. The enrofloxacin release rate at room temperature was greatly reduced. Solid-lipid beads have the potential to mask the bitter taste of enrofloxacin and extend its release rate.     

Neural fine tuning during Vernier acuity training?

A superposition masking and summation to threshold paradigm was employed before and after unmasked Vernier acuity training to measure sensory changes of offset analysing mechanisms.Masking functions show a uniform downward translation after training and detection data reveal higher sensitivities to compound Gabor gratings in the post-test.These findings confirm the existence of learning related changes at early levels of information processing, but the results cannot be explained by neural fine tuning of offset analysing mechanisms. The data are consistent with the idea of task dependent broadening of orientation tuned mechanisms responsible for detecting small Vernier offsets.     

The horizontal effect in suppression: Anisotropic overlay and surround suppression at high and low speeds

When a pattern of broad spatial content is viewed by an observer, the multiple spatial components in the pattern stimulate detecting-mechanisms that suppress each other. This suppression is anisotropic, being relatively greater at horizontal, and least at obliques (the “horizontal effect”). Here, suppression of a grating by a naturalistic (1/f) broadband mask is shown to be larger when the broadband masks are temporally similar to the target’s temporal properties, and generally anisotropic, with the anisotropy present across all spatio-temporal parings tested. We also show that both suppression from within the region of the test pattern (overlay suppression) and from outside of this region (surround suppression) show the horizontal-effect anisotropy. We conclude that these suppression effects stem from locally-tuned and anisotropically-weighted gain-control pools.     

Object‐substitution masking modulates spatial attention deployment and the encoding of information in visual short‐term memory: Insights from occipito‐parietal ERP components

If object‐substitution masking (OSM) arises from mask representations replacing target representations, OSM should impede the formation of representations in visual short‐term memory (VSTM). We utilized event‐related potentials to examine the effect of OSM on target processing. An N2pc was observed on trials with delayed‐offset masks, indicating that focused attention was directed to the target. The sustained posterior contralateral negativity (SPCN), an index of VSTM storage, was observed in delayed‐offset trials only on trials with correct responses. This supports the hypothesis that inaccurate performance on delayed‐offset trials arises from a failure to encode the target in VSTM. On co‐termination trials, accuracy was high and neither the N2pc nor SPCN was observed. This indicates that, in the absence of masking, the task was accomplished by maintaining a diffuse attentional state that enabled the joint encoding of the potential target items.