No description available.

In the present study, it was examined whether the spatiotemporal dynamics of transitions towards target dominance in motion-induced blindness (MIB) were wave-like, similar to those in binocular rivalry. The spatiotemporal dynamics of transitions towards dominance in MIB were further compared with those in binocular rivalry to reveal a potential neural locus of MIB. Across a series of experiments, the relationship between target length, stimulus structure, presentation location and the latency for circular arc segment-shaped targets to reappear was examined, respectively. It was found that target reappearance durations increase with target length, as if they reappear in a gradual, wavelike fashion. Target reappearance durations were decreased for collinear compared to radial targets, but they were not influenced by the location of target presentation. The results suggest MIB target reappearances are associated with traveling waves of dominance, and early visual cortex is a likely neural substrate in which these wave-like transitions occur. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Olfactory sensing is ubiquitous across animals and important for survival. Yet, its characteristics, mechanisms, and functions in humans remain not well understood. In this dissertation, I present four studies on human olfactory perception. Study I investigates the impact of short-term exposures to an odorant on long-term olfactory learning and habituation, while Study II examines human ability to localize smells; Study III probes visual-olfactory integration of object representations, and Study IV explores the role of olfaction in sensing nutrients. Several conclusions are drawn from these studies. First, brief intermittent exposures to even a barely detectable odorant lead to long-term incremental odorant-specific habituation. Second, humans localize smells based on gradient cues between the nostrils. Third, there is a within-hemispheric advantage in the integration of visual-olfactory object representations. Fourth, olfaction partakes in nutrient-sensing and facilitates the detection of food. Some broader implications of our findings are discussed.

The dissertation examines the problem of temporally uneven information processing in the nervous system. We chose binocular rivalry and ambiguous figure perception for our research, as these phenomena are pronounced examples of cyclical processes in perception. Binocular rivalry and ambiguous figure perception are cases in perception, when the subjective perception every few seconds vacillates between alternative interpretations, while the physical stimulation remains constant. Our research examines the relationship between these perception alterations and millisecond-order cycles of information processing in the nervous system. We created special equipment to present visual stimuli intermittently (flickering) and examined, whether the flickering rate of the stimuli influences the temporal characteristics (mean dominance duration) of binocular rivalry and ambiguous figure perception. The results confirmed the relationship, but also highlighted the temporal instability of binocular rivalry dominance durations. / Disertacijoje nagrinėjama informacijos apdorojimo procesų nervų sistemoje laikinio netolygumo problema. Tyrimui pasirinkti akių konkurencijos ir dviprasmių figūrų suvokimo reiškiniai, ryškiai atspindintys suvokimo procesų cikliškumą. Akių konkurencija ir dviprasmių figūrų suvokimas yra reiškiniai, kuomet fiziniam stimului nesikeičiant, subjektyvus suvokimas kas kelias sekundes kaitaliojasi tarp alternatyvių interpretacijų. Tyrime nagrinėjamas šių sekundinių suvokimo ciklų ryšys su milisekundžių eilės informacijos apdorojimo ciklais. Sukurta speciali aparatūra, kuria stimulai į akis buvo pateikti mirksintys nustatytu dažniu, ir tikrinta, ar stimulų mirksėjimo dažnis lemia akių konkurencijos ir dviprasmių figūrų suvokimo laikines savybes (vidutinę dominavimo trukmę). Rezultatai patvirtino šį ryšį, tačiau taip pat nustatyta, kad akių konkurencijos vidutinei dominavimo trukmei yra būdingas laikinis nestabilumas – dominavimo trukmė gana didele amplitude kinta kelių minučių, valandos ir kelių parų eigoje.

Disertacijoje nagrinėjama informacijos apdorojimo procesų nervų sistemoje laikinio netolygumo problema. Tyrimui pasirinkti akių konkurencijos ir dviprasmių figūrų suvokimo reiškiniai, ryškiai atspindintys suvokimo procesų cikliškumą. Akių konkurencija ir dviprasmių figūrų suvokimas yra reiškiniai, kuomet fiziniam stimului nesikeičiant, subjektyvus suvokimas kas kelias sekundes kaitaliojasi tarp alternatyvių interpretacijų. Tyrime nagrinėjamas šių sekundinių suvokimo ciklų ryšys su milisekundžių eilės informacijos apdorojimo ciklais. Sukurta speciali aparatūra, kuria stimulai į akis buvo pateikti mirksintys nustatytu dažniu, ir tikrinta, ar stimulų mirksėjimo dažnis lemia akių konkurencijos ir dviprasmių figūrų suvokimo laikines savybes (vidutinę dominavimo trukmę). Rezultatai patvirtino šį ryšį, tačiau taip pat nustatyta, kad akių konkurencijos vidutinei dominavimo trukmei yra būdingas laikinis nestabilumas – dominavimo trukmė gana didele amplitude kinta kelių minučių, valandos ir kelių parų eigoje. / The dissertation examines the problem of temporally uneven information processing in the nervous system. We chose binocular rivalry and ambiguous figure perception for our research, as these phenomena are pronounced examples of cyclical processes in perception. Binocular rivalry and ambiguous figure perception are cases in perception, when the subjective perception every few seconds vacillates between alternative interpretations, while the physical stimulation remains constant. Our research examines the relationship between these perception alterations and millisecond-order cycles of information processing in the nervous system. We created special equipment to present visual stimuli intermittently (flickering) and examined, whether the flickering rate of the stimuli influences the temporal characteristics (mean dominance duration) of binocular rivalry and ambiguous figure perception. The results confirmed the relationship, but also highlighted the temporal instability of binocular rivalry dominance durations.

No description available.

In binocular rivalry, paradigms have been proposed for unobtrusive moment-by-moment readout of observers' perceptual experience (“no-report paradigms”). Here, we take a first step to extend this concept to auditory multistability. Observers continuously reported which of two concurrent tone sequences they perceived in the foreground: high-pitch (1008 Hz) or low-pitch (400 Hz) tones. Interstimulus intervals were either fixed per sequence (Experiments 1 and 2) or random with tones alternating (Experiment 3). A horizontally drifting grating was presented to each eye; to induce binocular rivalry, gratings had distinct colors and motion directions. To associate each grating with one tone sequence, a pattern on the grating jumped vertically whenever the respective tone occurred. We found that the direction of the optokinetic nystagmus (OKN)—induced by the visually dominant grating—could be used to decode the tone (high/low) that was perceived in the foreground well above chance. This OKN-based readout improved after observers had gained experience with the auditory task (Experiments 1 and 2) and for simpler auditory tasks (Experiment 3). We found no evidence that the visual stimulus affected auditory multistability. Although decoding performance is still far from perfect, our paradigm may eventually provide a continuous estimate of the currently dominant percept in auditory multistability.

In binocular rivalry, paradigms have been proposed for unobtrusive moment-by-moment readout of observers' perceptual experience (“no-report paradigms”). Here, we take a first step to extend this concept to auditory multistability. Observers continuously reported which of two concurrent tone sequences they perceived in the foreground: high-pitch (1008 Hz) or low-pitch (400 Hz) tones. Interstimulus intervals were either fixed per sequence (Experiments 1 and 2) or random with tones alternating (Experiment 3). A horizontally drifting grating was presented to each eye; to induce binocular rivalry, gratings had distinct colors and motion directions. To associate each grating with one tone sequence, a pattern on the grating jumped vertically whenever the respective tone occurred. We found that the direction of the optokinetic nystagmus (OKN)—induced by the visually dominant grating—could be used to decode the tone (high/low) that was perceived in the foreground well above chance. This OKN-based readout improved after observers had gained experience with the auditory task (Experiments 1 and 2) and for simpler auditory tasks (Experiment 3). We found no evidence that the visual stimulus affected auditory multistability. Although decoding performance is still far from perfect, our paradigm may eventually provide a continuous estimate of the currently dominant percept in auditory multistability.