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Traveling Waves of Dominance in Motion-Induced Blindness
Title
Traveling Waves of Dominance in Motion-Induced Blindness.
Creator
Cox, Dustin, Hong, Sang Wook, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
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...
Show moreIn 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.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004704, http://purl.flvc.org/fau/fd/FA00004704
Subject Headings
Binocular rivalry, Binocular vision, Visual pathways, Visual perception
Format
Document (PDF)
effect of spatial attention on pupil dynamics
Title
The effect of spatial attention on pupil dynamics.
Creator
Daniels, Lori B., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
Although it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the...
Show moreAlthough it is well known that the pupil responds dynamically to changes in ambient light levels, the results from this dissertation show for the first time that the pupil also responds dynamically to changes in spatially distributed attention. Using a variety of orientating tasks, subjects alternated between focusing attention on a central stimulus and spreading attention over a larger area. Fourier analysis of the fluctuating pupil diameter indicated that: 1) pupil diameter changed at the rate of attention variation, dilating with broadly spread attention and contracting with narrowly focused attention, and 2) pupillary differences required changes in attentional spread; there were no differences in pupil diameter between sustained broad and sustained spread attention. Given that broadly spread attention increases the relative activation of large receptive fields and narrowly focused attention increases the relative activation of small receptive fields (Balz & Hock, 1997), the results of this study indicate that these attentional effects on receptive field activation can be mediated by changes in pupil diameter. That is, under broad attention, the corresponding pupillary dilation observed would increase spherical aberration, blurring the image thereby reducing high spatial frequency information and decreasing the activation of relatively small cortical receptive fields compared to relatively large receptive fields. This increased perception of low spatial frequencies would be beneficial in cases where attention is spread over a large area. Alternatively, under narrow attention the resulting pupillary constriction reduces spherical aberration sharpening the image and preserving high spatial frequency information resulting in a relatively increased response of small receptive fields.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/1870692
Subject Headings
Visual perception, Eye, Physiology, Optics, Adaptive, Visual pathways
Format
Document (PDF)
Potential stimulus contributions to counterchange determined motion perception
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)
Function of glycinergic interplexiform cells in rod synaptic transmission
Title
Function of glycinergic interplexiform cells in rod synaptic transmission.
Creator
Jiang, Zheng., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
The interplexiform cells(IP cells) are the most recently discovered neurons in the retina and their function is to provide centrifugal feedback in retina. The anatomical structure of the IP cells has been well studied, but the function of these neurons is largely unknown. I systematically studied the excitatory and inhibitory inputs from IP cells in salamander retina. I found that L-EPSCs in IP cells are mediated by AMPA and NMDA receptors; in addition, L-IPSCs are mediated by glycine...
Show moreThe interplexiform cells(IP cells) are the most recently discovered neurons in the retina and their function is to provide centrifugal feedback in retina. The anatomical structure of the IP cells has been well studied, but the function of these neurons is largely unknown. I systematically studied the excitatory and inhibitory inputs from IP cells in salamander retina. I found that L-EPSCs in IP cells are mediated by AMPA and NMDA receptors; in addition, L-IPSCs are mediated by glycine receptors and GABAC receptors. In response to light, IP cells reaction potentials transiently at the onset and onset of light stimulation. The major neural transmitter of IP cells in salamander retina is glycine. We also studied the distribution and function of glycine transporters. Our result indicates that GlyT1- and GlyT2-like transporters were present in Muller cells and neurons. The glycine feedback at outer plexiform layer (OPL) has effects on both the bipolar cell dendrites and rod photoreceptor terminals. At bipolar cell dendrites, glycine selectively depolarizes rod-dominant On-bipolar cells, and hyperpolarizes Off- bipolar cells. At rod photoreceptor terminals, 10 M glycine activates voltage-gated Ca2+ channels. These effects facilitated glutamate vesicle release in photoreceptors. It increases the sEPSC in OFF bipolar cells. The combined effect of glycine at rod terminals and bipolar cell dendrites leads to enhanced dim light signal transduction in the rod photoreceptor to ganglion cell pathway. This study provides a model that displays the function of centrifugal feedback through IP cells in the retina.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/2708369
Subject Headings
Cellular signal transduction, Neurochemistry, Neuroplasticity, Synapses, Retina, Cytology, Visual pathways
Format
Document (PDF)
Efficient Representation of Natural Visual Input in the Thalamus
Title
Efficient Representation of Natural Visual Input in the Thalamus.
Creator
Dastjerdi, Mohammad, Dong, Dawei, Florida Atlantic University
Abstract/Description
In this dissertat ion, the early visual system is used to explore the role of efficiency in the general organization of the nervous system. Efficient representation theory predicts that neurons dynamically change their responses to changes in the environment in order to maintain their efficiency. To directly test the predication of this theory, a computational model and a neurophysiological experiment are used. Using a computational model, we investigate the sparseness of the response of...
Show moreIn this dissertat ion, the early visual system is used to explore the role of efficiency in the general organization of the nervous system. Efficient representation theory predicts that neurons dynamically change their responses to changes in the environment in order to maintain their efficiency. To directly test the predication of this theory, a computational model and a neurophysiological experiment are used. Using a computational model, we investigate the sparseness of the response of filters at each stage of the model of the visual pathway. We find that the temporal bandpass filter and the rectification in each stage improves the efficiency of the response representation. Moreover, we find that ON/nonlagged responses carry more information than OFF/ lagged responses in signals with low signal-to-noise ratios. In the neurophysiological experiment, the response of LGN cells is measured and compared to their input from the retina in awake cats during free-viewing of natural time-varying images using quasi-intracellular recording technique. We find that the neural responses in the retina and the LGN are efficient. However, the LGN response is more efficient, sparser and less correlated than the retina's response, and it carries less information about eye movements than the retina's. As a result the LGN represents the visual world with fewer spikes. The LGN response changes with the variation of visual input. The temporal correlation of the visual input changes with saccade timing. Accordingly, the temporal receptive field of the LGN also changes in order to maintain the decorrelation of the LGN response regardless of the saccade. The retina-thalamic transmission changes during and after a saccade in order to transmit useful information to the visual cortex and decreases during a saccade in order to eliminate the variation of the visual input during a saccade. However, the transmission increases after a saccade to facilitate the transmission of new information due to the new gaze direction in the visual environment. The temporal receptive field of the LGN, derived from the efficacy of the thalamic transmission, is causal and bimodal. Such a receptive field decorrelates the visual input and improves the sparseness of the LGN response representation.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000851
Subject Headings
Thalamus--Physiology, Neurotransmitter receptors, Developmental neurobiology, Visual pathways
Format
Document (PDF)
Global feedback in hierarchical motion pattern formation
Title
Global feedback in hierarchical motion pattern formation.
Creator
Brownlow, Stacey W., Florida Atlantic University, Hock, Howard S., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
An array of four motion quartets (stimuli for which either horizontal or vertical motion is perceived depending on quartet aspect ratio) is arranged in a diamond configuration such that two global motion patterns are formed: (1) Rotation---alternating counterclockwise and clockwise motion is perceived, and (2) Parallel path motion---the perceived motions of all the elements are simultaneously horizontal or simultaneously vertical. The perception of rotation resulted in global feedback that...
Show moreAn array of four motion quartets (stimuli for which either horizontal or vertical motion is perceived depending on quartet aspect ratio) is arranged in a diamond configuration such that two global motion patterns are formed: (1) Rotation---alternating counterclockwise and clockwise motion is perceived, and (2) Parallel path motion---the perceived motions of all the elements are simultaneously horizontal or simultaneously vertical. The perception of rotation resulted in global feedback that biases the motion perceived for an individual component motion quartet to be more consistent with rotation than aspect ratio. Stronger rotation produced greater bias. Under certain conditions, the feedback-induced bias occurred even though global rotation was not perceived. The results were interpreted in the context of neurophysiological evidence regarding neurons in Areas MT and MSTd, and a dynamical theory of motion pattern formation (Hock, Schoner & Giese, 2003; Nichols, Hock & Schoner, 2006).
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Date Issued
2006
PURL
http://purl.flvc.org/fcla/dt/13371
Subject Headings
Motion perception (Vision)--Mathematical models, Visual pathways, Neurophysiology, Nonlinear chemical kinetics
Format
Document (PDF)