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Title: A theory for the visual perception of object motion.
Creator: Norman, Joseph W., Barenholtz, Elan, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: The perception of visual motion is an integral aspect of many organisms' engagement with the world. In this dissertation, a theory for the perception of visual object-motion is developed. Object-motion perception is distinguished from objectless-motion perception both experimentally and theoretically. A continuoustime dynamical neural model is developed in order to generalize the ndings and provide a theoretical framework for continued re nement of a theory for object-motion perception....
Show moreThe perception of visual motion is an integral aspect of many organisms' engagement with the world. In this dissertation, a theory for the perception of visual object-motion is developed. Object-motion perception is distinguished from objectless-motion perception both experimentally and theoretically. A continuoustime dynamical neural model is developed in order to generalize the ndings and provide a theoretical framework for continued re nement of a theory for object-motion perception. Theoretical implications as well as testable predictions of the model are discussed.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004221, http://purl.flvc.org/fau/fd/FA00004221
Subject Headings: Human information processing, Neurophysiology, Perceptual motor processes, Visual perception
Format: Document (PDF)

Title: Detecting the spatiotemporal dynamics of neural activity on the cortical surface: applying anatomically constrained beamforming to EEG.
Creator: Murzin, Vyacheslav., Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The neurophysiological signals that are recorded in EEG (electroencephalography) and MEG (magnetoencephalography) originate from current flow perpendicular to the cortical surface due to the columnar organization of pyramidal cells in the cortical gray matter. These locations and directions have been used as anatomical constraints for dipolar sources in estimations of neural activity from MEG recordings. Here we extend anatomically constrained beamforming to EEG, which requires a more...
Show moreThe neurophysiological signals that are recorded in EEG (electroencephalography) and MEG (magnetoencephalography) originate from current flow perpendicular to the cortical surface due to the columnar organization of pyramidal cells in the cortical gray matter. These locations and directions have been used as anatomical constraints for dipolar sources in estimations of neural activity from MEG recordings. Here we extend anatomically constrained beamforming to EEG, which requires a more sophisticated forward model than MEG due to the blurring of the electric potential at tissue boundaries, but in contrast to MEG, EEG can account for both tangential and radial sources. Using computed tomography (CT) scans we create a realistic three-layer head model consisting of tessellated surfaces representing the tissue boundaries cerebrospinal fluid-skull, skull-scalp and scalp-air. The cortical gray matter surface, the anatomical constraint for the source dipoles, is extracted from magnetic resonance imaging (MRI) scans. EEG beamforming is implemented in a set of simulated data and compared for three different head models: single sphere, multi-shell sphere and realistic geometry multi-shell model that employs a boundary element method. Beamformer performance is also analyzed and evaluated for multiple dipoles and extended sources (patches). We show that using anatomical constraints with the beamforming algorithm greatly reduces computation time while increasing the spatial accuracy of the reconstructed sources of neural activity. Using the spatial Laplacian instead of the electric potential in combination with beamforming further improves the spatial resolution and allows for the detection of highly correlated sources.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1930497
Subject Headings: Sensorimotor integration, Brain mapping, Perceptual-motor processes
Format: Document (PDF)

Title: Competing mechanisms in the perception of apparent motion: Effects of zero-hertz and time-varying energy.
Creator: Kogan, Kristine Marie, Florida Atlantic University, Hock, Howard S., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Anstis, et al. (1985) have reported that under certain conditions the visual system adapts and the perception of apparent motion breaks down. The present research indicates that breakdown is actually a result of same-place mechanisms successfully competing with motion-detecting mechanisms. Thus, the perception of stationarity (with flicker) can occur at the start of a trial and spontaneously switch to the perception of motion, or vice versa. The response of same-place mechanisms depends on...
Show moreAnstis, et al. (1985) have reported that under certain conditions the visual system adapts and the perception of apparent motion breaks down. The present research indicates that breakdown is actually a result of same-place mechanisms successfully competing with motion-detecting mechanisms. Thus, the perception of stationarity (with flicker) can occur at the start of a trial and spontaneously switch to the perception of motion, or vice versa. The response of same-place mechanisms depends on the zero-hertz energy at each location of an apparent motion stimulus, whereas the response of motion mechanisms depends on the time-varying energy. Average luminance, luminance contrast, the temporal symmetry of the apparent motion display, and relative phase are manipulated to investigate competition between same-place and motion-detecting mechanisms.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15234
Subject Headings: Motion perception (Vision), Perceptual-motor processes, Visual perception
Format: Document (PDF)

Title: Potential stimulus contributions to counterchange determined motion perception.
Creator: Park, Cynthia Louise Smith, Hock, Howard S., Barenholtz, Elan, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Prior research has explored the counterchange model of motion detection in terms of counterchanging information that originates in the stimulus foreground (or objects). These experiments explore counterchange apparent motion with regard to a new apparent motion stimulus where the necessary counterchanging information required for apparent motion is provided by altering the luminance of the background. It was found that apparent motion produced by background-counterchange requires longer frame...
Show morePrior research has explored the counterchange model of motion detection in terms of counterchanging information that originates in the stimulus foreground (or objects). These experiments explore counterchange apparent motion with regard to a new apparent motion stimulus where the necessary counterchanging information required for apparent motion is provided by altering the luminance of the background. It was found that apparent motion produced by background-counterchange requires longer frame durations and lower levels of average stimulus contrast compared to foreground-counterchange. Furthermore, inter-object distance does not influence apparent motion produced by background-counterchange to the degree it influences apparent motion produced by foreground-counterchange.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004313
Subject Headings: Motion perception (Vision), Perceptual motor processes, Visual analysis, Visual discrimination, Visual pathways, Visual perception
Format: Document (PDF)

Title: The Effects of Dichoptic and Isoluminant-Chromatic Stimuli on the Perception of Object and Objectless Motion.
Creator: Seifert, Matthew S., Hong, Sang Wook, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Visual motion can be conveyed by a variety of information sources in the environment, and those types of information may be detected at various levels by different motion-perceiving mechanisms in the visual system. High-level visual information has been demonstrated to have 3rd order, or salience-based properties (Lu & Sperling, 1995). The perceptual system they describe that computes motion from these types of information shares several characteristics with Hock and colleagues' counterchange...
Show moreVisual motion can be conveyed by a variety of information sources in the environment, and those types of information may be detected at various levels by different motion-perceiving mechanisms in the visual system. High-level visual information has been demonstrated to have 3rd order, or salience-based properties (Lu & Sperling, 1995). The perceptual system they describe that computes motion from these types of information shares several characteristics with Hock and colleagues' counterchange detection system, notably flexibility with respect to types of input from which motion can be computed, which comes at the cost of diminished processing speed. The mechanism of counterchange detection is well suited to processing visual features often present in environmental scenes, e.g., objects and surfaces, and may be a mechanism of 3rd order motion. Consistent with reported properties of 3rd order motion, the current experiments tested count erchange-, luminance-, and color-based motion stimuli with 3 objectives: to identify whether the 3 systems framework generalizes beyond the stimulus type with which it was defined, to test whether counterchange shares similarities with the 3rd order system with respect to dichoptic integration, and perception of isoluminant color-based motion, and to test subjectively objectless sources of motion-defining information (spreading luminance and hue) to see if they display properties of the 1st order system derived from sine wave gratings. Results indicate that counterchange-based stimuli displayed predicted properties of dichoptic integration, and perception at isoluminance, but putative 1st order (spreading) stimuli also displayed these properties. This may suggest that object-like surfaces, even when not directly the source of motion information, can contribute to computation of motion. Further, these results highlight the difficulty of generalizing from one theoretical framework to another, and specifically, of psychophysically testing high-level information while isolating contributions from low level information upon which high level visual stimuli are built.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004545, http://purl.flvc.org/fau/fd/FA00004545
Subject Headings: Movement, Psychology of, Perceptual motor processes, Physiological optics, Space and time, Visual perception
Format: Document (PDF)

Title: Segregating stimululs information for counterchange and motion energy-determined motion perception.
Creator: Seifert, Matthew S., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: It has been argued that the perception of apparent motion is based on the detection of counterchange (oppositely signed changes in luminance contrast at pairs of spatial locations) rather than motion energy (spatiotemporal changes in luminance). A constraint in furthering this distinction is that both counterchange and motion energy are present for most motion stimuli. Three experiments used illusory-contour and luminance-based stimuli to segregate (experiments 1 and 2) and combine ...
Show moreIt has been argued that the perception of apparent motion is based on the detection of counterchange (oppositely signed changes in luminance contrast at pairs of spatial locations) rather than motion energy (spatiotemporal changes in luminance). A constraint in furthering this distinction is that both counterchange and motion energy are present for most motion stimuli. Three experiments used illusory-contour and luminance-based stimuli to segregate (experiments 1 and 2) and combine (experiment 3) counterchange and motion energy information. Motion specified by counterchange was perceived for translating illusory squares over a wide range of frame durations, and preferentially for short motion paths. Motion specified by motion energy was diminished by relatively long frame durations, but was not affected by the length of the motion path. Results for the combined stimulus were consistent with counterchange as the basis for apparent motion perception, despite the presence of motion energy.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362563
Subject Headings: Perceptual-motor processes, Movement, Psychology of, Space and time, Visual perception
Format: Document (PDF)

Title: Spatiotemporal beanformer analysis of neuromagnetic activity in sensorimotor cortex: rhythmic perception, production and sensorimotor coordination.
Creator: Ferrari, Paul., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Research presented in this dissertation has the central aim of applying a novel method of source localization called beamforming to neuromagnetic recordings for characterizing dynamic spatiotemporal activity of sensorimotor brain processes in subjects during rhythmic auditory stimulation, self-paced movement, and two sensorimotor coordination (synchronization and syncopation) tasks known to differentiate on the basis of behavioral stability. Each experimental condition was performed at...
Show moreResearch presented in this dissertation has the central aim of applying a novel method of source localization called beamforming to neuromagnetic recordings for characterizing dynamic spatiotemporal activity of sensorimotor brain processes in subjects during rhythmic auditory stimulation, self-paced movement, and two sensorimotor coordination (synchronization and syncopation) tasks known to differentiate on the basis of behavioral stability. Each experimental condition was performed at different rates resulting in 26 experimental runs per subject. Event-related neural responses were recorded with a whole-head MEG system and characterized in terms of their phase-locked (evoked) and non-phase-locked (induced) activity within the brain using both whole-brain analysis and region of interest (ROI) analysis. The analysis of the auditory conditions revealed that neural activity within extraauditory areas throughout the brain, including sensorimotor cortex, is modulated by rhythmic auditory stimulation. Additionally, the temporal profile of this activity was markedly different between sensorimotor and auditory cortex, possibly revealing different physiological processes, entrained within a common network for representing isochronic auditory events. During self-paced movements cycle-by-cycle dynamics of induced neural activity was measured and consistent neuro-modulation in the form of event-related desynchronization (ERD) and synchronization (ERS) was observed at all rates investigated (0.25 - 1.75Hz). ERD and ERS modulations exhibited dynamic scaling properties on a cycle-by-cycle basis that depended on the period of movement. Activity in the beta- and mu-bands also exhibited patterns of phase locking between sensorimotor locations. Phase locking patterns exhibited abrupt decreases with increases in movement rate., During sensorimotor coordination tasks, the effect of temporal positioning of the auditory stimulus was apparent within sensorimotor cortical sites. This finding offers direct source level support for previous sensor level analysis revealing a differentiation of functional specificity for mu- and beta-band activity (Chen, Ding, Kelso, 2003; Jantzen, Fuchs, Mayville et al., 2001; Mayville, Fuchs, Ding et al., 2001), and may be reflective of specific coupling mechanisms between auditory and sensorimotor networks. The beamformer analysis applied within this dissertation successfully characterized large-scale neural networks during a variety of rhythmic perceptual, motor, and sensorimotor tasks resulting in the general message that information processes across disparate parts of the brain from different sensory, motor, and cognitive modalities appear to have the ability for widespread integration.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/228770
Subject Headings: Sensorimotor integration, Perceptual-motor processes, Auditory provoked response, Brain mapping
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.
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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: 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.
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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: Eye Fixations of the Face Are Modulated by Perception of a Bidirectional Social Interaction.
Creator: Kleiman, Michael J., Barenholtz, Elan, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Eye fixations of the face are normally directed towards either the eyes or the mouth, however the proportions of gaze to either of these regions are dependent on context. Previous studies of gaze behavior demonstrate a tendency to stare into a target’s eyes, however no studies investigate the differences between when participants believe they are engaging in a live interaction compared to knowingly watching a pre-recorded video, a distinction that may contribute to studies of memory encoding....
Show moreEye fixations of the face are normally directed towards either the eyes or the mouth, however the proportions of gaze to either of these regions are dependent on context. Previous studies of gaze behavior demonstrate a tendency to stare into a target’s eyes, however no studies investigate the differences between when participants believe they are engaging in a live interaction compared to knowingly watching a pre-recorded video, a distinction that may contribute to studies of memory encoding. This study examined differences in fixation behavior for when participants falsely believed they were engaging in a real-time interaction over the internet (“Real-time stimulus”) compared to when they knew they were watching a pre-recorded video (“Pre-recorded stimulus”). Results indicated that participants fixated significantly longer towards the eyes for the pre-recorded stimulus than for the real-time stimulus, suggesting that previous studies which utilize pre-recorded videos may lack ecological validity.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004701, http://purl.flvc.org/fau/fd/FA00004701
Subject Headings: Eye -- Movements, Eye tracking, Gaze -- Psychological aspects, Nonverbal communication, Optical pattern recognition, Perceptual motor processes, Visual perception
Format: Document (PDF)

Title: Afferent projections to rhomboid nucleus of thalamus.
Creator: Owens, Michelle Ann, Florida Atlantic University, Vertes, Robert P.
Abstract/Description: The midline thalamus of rats is anatomically and functionally part of the "limbic" thalamus. The midline thalamic rhomboid nucleus (RH) has not been well characterized. The rhomboid nucleus is located just dorsal to the reuniens nucleus (RE), and just ventral to the central medial nucleus (CeM) of the thalamus. Using the retrograde tracer fluorogold (FG) and anti-FG antibody, we examined afferent projections to RH in the rat. Control injections were also made in CeM and the submedial nucleus...
Show moreThe midline thalamus of rats is anatomically and functionally part of the "limbic" thalamus. The midline thalamic rhomboid nucleus (RH) has not been well characterized. The rhomboid nucleus is located just dorsal to the reuniens nucleus (RE), and just ventral to the central medial nucleus (CeM) of the thalamus. Using the retrograde tracer fluorogold (FG) and anti-FG antibody, we examined afferent projections to RH in the rat. Control injections were also made in CeM and the submedial nucleus of thalamus (SMT). The main sources of input to RH were from the anterior cingulate, agranular insular, orbital, and somatosensory cortices; the claustrum; the reticular nucleus of the thalamus; the posterior hypothalamus; and various brainstem structures. Based on patterns of the afferent projections, the role of RH in arousal, attention, and mnemonic functions is discussed.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13220
Subject Headings: Rats as laboratory animals, Rats--Nervous system, Thalamus--Research, Rats--Embryology, Afferent pathways, Perceptual-motor processes, Sensorimotor integration
Format: Document (PDF)

Perceptual-motor processes (7)	+ -
Sensorimotor integration (5)	+ -
Visual perception (5)	+ -
Perceptual motor processes (4)	+ -
Brain mapping (3)	+ -

Intersensory effects (2)	+ -
Motion perception (Vision) (2)	+ -
Space and time (2)	+ -
Afferent pathways (1)	+ -
Auditory provoked response (1)	+ -
Developmental neurobiology (1)	+ -
Eye -- Movements (1)	+ -
Eye tracking (1)	+ -
Gaze -- Psychological aspects (1)	+ -
Human information processing (1)	+ -
Movement sequences (1)	+ -
Movement, Psychology of (1)	+ -
Movement, Psychology of (1)	+ -
Neurophysiology (1)	+ -
Nonverbal communication (1)	+ -
Optical pattern recognition (1)	+ -
Physiological optics (1)	+ -
Psychology, Comparative (1)	+ -
Rats as laboratory animals (1)	+ -
Rats--Embryology (1)	+ -
Rats--Nervous system (1)	+ -
Thalamus--Research (1)	+ -
Visual analysis (1)	+ -
Visual discrimination (1)	+ -
Visual pathways (1)	+ -

Charles E. Schmidt College of Science (9)	+ -
Florida Atlantic University (7)	+ -
Department of Psychology (5)	+ -
Barenholtz, Elan (3)	+ -
Center for Complex Systems and Brain Sciences (3)	+ -

Hock, Howard S. (2)	+ -
Seifert, Matthew S. (2)	+ -
Assisi, Collins G. (1)	+ -
Department of Physics (1)	+ -
Ferrari, Paul. (1)	+ -
Hong, Sang Wook (1)	+ -
Jirsa, Viktor K. (1)	+ -
Kelso, J. A. Scott (1)	+ -
Kleiman, Michael J. (1)	+ -
Kogan, Kristine Marie (1)	+ -
Murzin, Vyacheslav. (1)	+ -
Norman, Joseph W. (1)	+ -
Owens, Michelle Ann (1)	+ -
Park, Cynthia Louise Smith (1)	+ -
Rho, Young-Ah. (1)	+ -
Vertes, Robert P. (1)	+ -

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