Current Search: Intersensory effects (x)
View All Items
(1 - 9 of 9)
- Title
- Functional consequences of top-down anticipatory modulation of primary visual cortex.
- Creator
- Richter, Craig G., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
It is well established that anticipation of the arrival of an expected stimulus is accompanied by rich ongoing oscillatory neurodynamics, which span and link large areas of cortex. An intriguing possibility is that these dynamic interactions may convey knowledge that is embodied by large-scale neurocognitive networks from higher level regions of multi-model cortex to lower level primary sensory areas. In the current study, using autoregressive spectral analysis, we establish that during the...
Show moreIt is well established that anticipation of the arrival of an expected stimulus is accompanied by rich ongoing oscillatory neurodynamics, which span and link large areas of cortex. An intriguing possibility is that these dynamic interactions may convey knowledge that is embodied by large-scale neurocognitive networks from higher level regions of multi-model cortex to lower level primary sensory areas. In the current study, using autoregressive spectral analysis, we establish that during the anticipatory phase of a visual discrimination task there are rich patterns of coherent interaction between various levels of the ventral visual hierarchy across the frequency spectrum of 8 - 90 Hz. Using spectral Granger causality we determined that a subset of these interactions carry beta frequency (14 - 30 Hz) top-down influences from higher level visual regions V4 and TEO to primary visual cortex. We investigated the functional significance of these top-down interactions by correlating the magnitude of the anticipatory signals with the amplitude of the visual evoked potential that was elicited by stimulus processing. We found that in one third of the extrastriate-striate pairs, tested in three monkeys, the amplitude of the visual evoked response is well predicted by the magnitude of pre-stimulus coherent top-down anticipatory influences. To investigate the dynamics of the coherent and topdown Granger causal interactions, we analyzed the relationship between coherence and top-down Granger causality with stimulus onset asynchrony. This analysis revealed that in an abundance of cases the magnitudes of the coherent interactions and top-down directional influences scaled with the length of time that had elapsed before stimulus onset., Together these results reveal a complex network of coherent and top-down directional interactions that predict the amplitude of early components of the visual evoked potential in primary visual cortex and vary in strength on the basis of the length of the stimulus onset.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/369200
- Subject Headings
- Cognitive neuroscience, Brain mapping, Visual perception, Testing, Intersensory effects
- Format
- Document (PDF)
- Title
- Exploiting audiovisual attention for visual coding.
- Creator
- Torres, Freddy., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Perceptual video coding has been a promising area during the last years. Increases in compression ratios have been reported by applying foveated video coding techniques where the region of interest (ROI) is selected by using a computational attention model. However, most of the approaches for perceptual video coding only use visual features ignoring the auditory component. In recent physiological studies, it has been demonstrated that auditory stimuli affects our visual perception. In this...
Show morePerceptual video coding has been a promising area during the last years. Increases in compression ratios have been reported by applying foveated video coding techniques where the region of interest (ROI) is selected by using a computational attention model. However, most of the approaches for perceptual video coding only use visual features ignoring the auditory component. In recent physiological studies, it has been demonstrated that auditory stimuli affects our visual perception. In this work, we validate some of those physiological tests using complex video sequence. We designed and developed a web-based tool for video quality measurement. After conducting different experiments, we observed that in the general reaction time to detect video artifacts was higher when video was presented with the audio information. We observed that emotional information in audio guide human attention to particular ROI. We also observed that sound frequency change spatial frequency perception in still images.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3361251
- Subject Headings
- Digital video, Image processing, Digital techniques, Visual perception, Coding theory, Human-computer interaction, Intersensory effects
- Format
- Document (PDF)
- Title
- Infants' perception of synthetic-like multisensory relations.
- Creator
- Minar, Nicholas J., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Studies have shown that human infants can integrate the multisensory attributes of their world and, thus, have coherent perceptual experiences. Multisensory attributes can either specify non-arbitrary (e.g., amodal stimulus/event properties and typical relations) or arbitrary properties (e.g., visuospatial height and pitch). The goal of the current study was to expand on Walker et al.'s (2010) finding that 4-month-old infants looked longer at rising/falling objects when accompanied by rising...
Show moreStudies have shown that human infants can integrate the multisensory attributes of their world and, thus, have coherent perceptual experiences. Multisensory attributes can either specify non-arbitrary (e.g., amodal stimulus/event properties and typical relations) or arbitrary properties (e.g., visuospatial height and pitch). The goal of the current study was to expand on Walker et al.'s (2010) finding that 4-month-old infants looked longer at rising/falling objects when accompanied by rising/falling pitch than when accompanied by falling/rising pitch. We did so by conducting two experiments. In Experiment 1, our procedure matched Walker et al.'s (2010) single screen presentation while in Experiment 2 we used a multisensory paired-preference procedure. Additionally, we examined infants' responsiveness to these synesthetic-like events at multiple ages throughout development (four, six, and 12 months of age). ... In sum, our findings indicate that the ability to match changing visuospatial height with rising/falling pitch does not emerge until the end of the first year of life and throw into doubt Walker et al.'s (2010) claim that 4-month-old infants perceive audiovisual synesthetic relations in a manner similar to adults.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3362552
- Subject Headings
- Cognition in children, Individual differences in children, Infant psychology, Infants, Development, Perception in infants, Intersensory effects
- Format
- Document (PDF)
- Title
- Learning to match faces and voices.
- Creator
- Davidson, Meredith., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
This study examines whether forming a single identity is crucial to learning to bind faces and voices, or if people are equally able to do so without tying this information to an identity. To test this, individuals learned paired faces and voices that were in one of three different conditions: True voice, Gender Matched, or Gender Mismatched conditions. Performance was measured in a training phase as well as a test phase, and results show that participants were able to learn more quickly and...
Show moreThis study examines whether forming a single identity is crucial to learning to bind faces and voices, or if people are equally able to do so without tying this information to an identity. To test this, individuals learned paired faces and voices that were in one of three different conditions: True voice, Gender Matched, or Gender Mismatched conditions. Performance was measured in a training phase as well as a test phase, and results show that participants were able to learn more quickly and have higher overall performance for learning in the True Voice and Gender Matched conditions. During the test phase, performance was almost at chance in the Gender Mismatched condition which may mean that learning in the training phase was simply memorization of the pairings for this condition. Results support the hypothesis that learning to bind faces and voices is a process that involves forming a supramodal identity from multisensory learning.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2683140
- Subject Headings
- Sensorimotor integration, Senses and sensation, Intersensory effects, Perceptual learning, Pattern recognition systems
- Format
- Document (PDF)
- Title
- Spatiotemporal brain dynamics of the resting state.
- Creator
- Rho, Young-Ah., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
Traditionally brain function is studied through measuring physiological responses in controlled sensory, motor, and cognitive paradigms. However, even at rest, in the absence of overt goal-directed behavior, collections of cortical regions consistently show temporally coherent activity. In humans, these resting state networks have been shown to greatly overlap with functional architectures present during consciously directed activity, which motivates the interpretation of rest activity as day...
Show moreTraditionally brain function is studied through measuring physiological responses in controlled sensory, motor, and cognitive paradigms. However, even at rest, in the absence of overt goal-directed behavior, collections of cortical regions consistently show temporally coherent activity. In humans, these resting state networks have been shown to greatly overlap with functional architectures present during consciously directed activity, which motivates the interpretation of rest activity as day dreaming, free association, stream of consciousness, and inner rehearsal. In monkeys, it has been shown though that similar coherent fluctuations are present during deep anesthesia when there is no consciousness. These coherent fluctuations have also been characterized on multiple temporal scales ranging from the fast frequency regimes, 1-100 Hz, commonly observed in EEG and MEG recordings, to the ultra-slow regimes, < 0.1 Hz, observed in the Blood Oxygen Level Dependent (BOLD) signal of functi onal magnetic resonance imaging (fMRI). However, the mechanism for their genesis and the origin of the ultra-slow frequency oscillations has not been well understood. Here, we show that comparable resting state networks emerge from a stability analysis of the network dynamics using biologically realistic primate brain connectivity, although anatomical information alone does not identify the network. We specifically demonstrate that noise and time delays via propagation along connecting fibres are essential for the emergence of the coherent fluctuations of the default network. The combination of anatomical structure and time delays creates a spacetime structure in which the neural noise enables the brain to explore various functional configurations representing its dynamic repertoire., Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the generation o f the slow coherent fluctuations. We find that these fluctuations in the BOLD signal are significantly correlated with the level of neural synchrony implicating that transient interareal synchronizations are the mechanism causing the emergence of the ultra slow coherent fluctuations in the BOLD signal.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/367762
- Subject Headings
- Brain mapping, Sensorimotor integration, Perceptual-motor processes, Intersensory effects, Movement sequences
- Format
- Document (PDF)
- Title
- Neural Correlates of Auditory Perception, Attention and Expectation.
- Creator
- Zanto, Theodore P., Florida Atlantic University, Large, Edward W., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
This dissertation examined the neural correlates of auditory perception, attention and expectation in three experiments. Experiment 1 analyzed neural correlates of auditory perception and expectation in an electroencephalography (EEG) experiment using a temporally perturbed metronome to establish an expectation for auditory events, then violate and reestablish that expectation. High frequency evoked (phase-locked) gamma band activity (GBA) was observed to follow the onset of tones whereas...
Show moreThis dissertation examined the neural correlates of auditory perception, attention and expectation in three experiments. Experiment 1 analyzed neural correlates of auditory perception and expectation in an electroencephalography (EEG) experiment using a temporally perturbed metronome to establish an expectation for auditory events, then violate and reestablish that expectation. High frequency evoked (phase-locked) gamma band activity (GBA) was observed to follow the onset of tones whereas induced (nonphase- locked) GBA reached maximum power simultaneously with the occurrence oftone onset. Moreover, the latency of induced GBA was perturbed after an expectancy violation and relaxed back into synchrony as the expectation was reestablished. Experiment 2 was a methodological study to compare two functional magnetic resonance imaging (fMRJ) scanning techniques and assess their influence on auditory processing. Subjects passively listened to isochronous tone sequences at three rates while sparse or continuous scanning was employed. Sparse and continuous scanning was observed to yield comparable fMRI data, however, continuous scanner notse was observed to perturb known EEG evoked response potentials. Moreover, high frequency evoked activity, as identified by spectral analysis, was attenuated in the presence of continuous fMRl noise. Experiment 3 was conducted to study auditory expectancy and attention. First, subjects were tested behaviorally to determine their ability to tap the beat of ten highly syncopated patterns. Subjects were asked to return for one EEG and one fMRl session. In these sessions, they were instructed to attend to a syncopated pattern, mentally rehearse the pattern, and then reproduce the pattern. During the control condition, subjects heard the auditory patterns, however, they were instructed to study a list of words, remember the words during the retention interval, and then recall as many words as possible. Brain activity was localized to frontal and auditory regions when attending to the patterns and occipital-auditory areas when attending to the words. Evoked activity was shown to reflect the subject's anticipation of the beat and was attenuated when ignoring the auditory stimulus. Taken together, these results suggest that GBA indexes auditory perception, attention and expectation. The current results suggest that attention and task engagement may elicit stronger neural phase locking.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fau/fd/FA00000885
- Subject Headings
- Electrophysiology, Auditory evoked response, Electroencephalography, Auditory perception, Intersensory effects, Auditory pathways
- Format
- Document (PDF)
- Title
- Time, space, and Shakespeare: Temporal and spatial disturbances at the point of cultural contact.
- Creator
- Murray, Jessica L., Florida Atlantic University, Low, Jennifer A.
- Abstract/Description
-
Cultural geographic theory uses dramatic language (place ballets , time-space routines, temporal rhythms , etc.) to describe how humans sense and dwell in places. Because the theory contemplates human behavior enacted upon a stage, it is applicable to theater studies. This thesis asserts that Hamlet's, Othello's, and Antony's treacherous lifeworlds undermine their spatiotemporal senses and initiate quests similar to those described by Anne Buttimer as searches "for order, predictability, and...
Show moreCultural geographic theory uses dramatic language (place ballets , time-space routines, temporal rhythms , etc.) to describe how humans sense and dwell in places. Because the theory contemplates human behavior enacted upon a stage, it is applicable to theater studies. This thesis asserts that Hamlet's, Othello's, and Antony's treacherous lifeworlds undermine their spatiotemporal senses and initiate quests similar to those described by Anne Buttimer as searches "for order, predictability, and routine, as well as [...] for adventure and change" ("Grasping" 285). Hamlet's revenge plot is a pursuit of order and reclamation of his identity at Elsinore. Desdemona's murder is Othello's attempt to salvage his character, which he believed sullied by infidelity. Alexandria offers Antony a life opposite Rome's and sets him on a course of indecisiveness. These plays demonstrate that, at the point of cultural contact, routines are interrupted and identities destabilize. Tragically, the characters lose themselves in the turmoil.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/13141
- Subject Headings
- Human geography, Psychology, Comparative, Cognitive science, Time perception, Shakespeare, William,--1564-1616--Plays, Intersensory effects
- Format
- Document (PDF)
- Title
- Theoretical and experimental studies of multisensory integration as a coupled dynamical system.
- Creator
- Assisi, Collins G., Florida Atlantic University, Kelso, J. A. Scott, Jirsa, Viktor K.
- Abstract/Description
-
Perception and behavior are mediated by a widely distributed network of brain areas. Our main concern is, how do the components of the network interact in order to give us a variety of complex coordinated behavior? We first define the nodes of the network, termed functional units, as a strongly coupled ensemble of non-identical neurons and demonstrate that the dynamics of such an ensemble may be approximated by a low dimensional set of equations. The dynamics is studied in two different...
Show morePerception and behavior are mediated by a widely distributed network of brain areas. Our main concern is, how do the components of the network interact in order to give us a variety of complex coordinated behavior? We first define the nodes of the network, termed functional units, as a strongly coupled ensemble of non-identical neurons and demonstrate that the dynamics of such an ensemble may be approximated by a low dimensional set of equations. The dynamics is studied in two different contexts, sensorimotor coordination and multisensory integration. First, we treat movement coupled to the environment as a driven functional unit. Our central hypothesis is that this coupling must be minimally parametric. We demonstrate the experimental validity of this hypothesis and propose a theoretical model that explains the results of our experiment. A second example of the dynamics of functional units is evident in the domain of multisensory integration. We employ a novel rhythmic multisensory paradigm designed to capture the temporal features of multisensory integration parametrically. The relevant parameters of our experiment are the inter-onset interval between pairs of rhythmically presented stimuli and the frequency of presentation. We partition the two dimensional parameter space using subjects perception of the stimulus sequence. The general features of the partitioning are modality independent suggesting that these features depend on the coupling between the unisensory subsystems. We develop a model with coupled functional units and suggest a candidate coupling scheme. In subsequent chapters we probe the neural correlates of multisensory integration using fMRI and EEG. The results of our fMRI experiment demonstrate that multisensory integration is mediated by a network consisting of primary sensory areas, inferior parietal lobule, prefrontal areas and the posterior midbrain. Different percepts lead to the recruitment of different areas and their disengagement for other percepts. In analyzing the EEG data, we first develop a mathematical framework that allows us to differentiate between sources activated for both unisensory and multisensory stimulation from those sources activated only for multisensory stimulation. Using this methodology we show that the influences of multisensory processing may be seen at an early (40--60 ms) stage of sensory processing.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/12167
- Subject Headings
- Intersensory effects, Perceptual-motor processes, Sensorimotor integration, Psychology, Comparative, Developmental neurobiology
- Format
- Document (PDF)
- Title
- Multisensory Cues Facilitate Infants’ Ability to Discriminate Other-Race Faces.
- Creator
- Minar, Nicholas J., Bjorklund, David F., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Our everyday world consists of people and objects that are usually specified by dynamic and concurrent auditory and visual attributes, which is known to increase perceptual salience and, therefore, facilitate learning and discrimination in infancy. Interestingly, early experience with faces and vocalizations has two seemingly opposite effects during the first year of life, 1) it enables infants to gradually acquire perceptual expertise for the faces and vocalizations of their own race and, 2)...
Show moreOur everyday world consists of people and objects that are usually specified by dynamic and concurrent auditory and visual attributes, which is known to increase perceptual salience and, therefore, facilitate learning and discrimination in infancy. Interestingly, early experience with faces and vocalizations has two seemingly opposite effects during the first year of life, 1) it enables infants to gradually acquire perceptual expertise for the faces and vocalizations of their own race and, 2) it narrows their ability to discriminate the faces of other-race faces (Kelly et al., 2007). It is not known whether multisensory redundancy might help older infants overcome the other-race effect reported in previous studies. The current project investigated infant discrimination of dynamic and vocalizing other-race faces in younger and older infants using habituation and eye-tracking methodologies. Experiment 1 examined 4-6 and 10-12-month-old infants' ability to discriminate either a native or non-native face articulating the syllable /a/. Results showed that both the 4-6- and the 10-12-month-olds successfully discriminated the faces,regardless of whether they were same- or other-race faces. Experiment 2 investigated the contribution of auditory speech cues by repeating Experiment 1 but in silence. Results showed that only the 10-12-month-olds tested with native-race faces successfully discriminated them. Experiment 3 investigated whether it was speech per se or sound in general that facilitated discrimination of the other-race faces in Experiment 1 by presenting a synchronous, computer-generated "boing" sound instead of audible speech cues. Results indicated that the 4-6-month olds discriminated both types of faces but that 10-12-month-olds only discriminated own-race faces. These results indicate that auditory cues, along with dynamic visual cues, can help infants overcome the effects of previously reported narrowing and facilitate discrimination of other-race static, silent faces. Critically, our results show that older infants can overcome the other race-effect when dynamic faces are accompanied by speech but not when they are accompanied by non- speech cues. Overall, a generalized auditory facilitation effect was found as a result of multisensory speech. Moreover, our findings suggest that infants' ability to process other- race faces following perceptual narrowing is more plastic than previously thought.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004525
- Subject Headings
- Cognition in children, Individual differences in children, Infant psychology, Infants -- Development, Intersensory effects, Perception in infants
- Format
- Document (PDF)
