Top-Down Versus Bottom-Up Control
... perisaccadic period, beginning 150 ms before saccade to 50 ms afterward) and compared to a baseline, an intertrial interval (ITI) epoch (a 200-ms window starting 500 ms before trial onset). Shaded regions are 95% confidence intervals around average coherence. Frequencies below 10 Hz are not meaningf ...
... perisaccadic period, beginning 150 ms before saccade to 50 ms afterward) and compared to a baseline, an intertrial interval (ITI) epoch (a 200-ms window starting 500 ms before trial onset). Shaded regions are 95% confidence intervals around average coherence. Frequencies below 10 Hz are not meaningf ...
Perception of Motion, Depth, and Form
... N vISIoN,AS IN orHERmental oPerations, we exPerrence the world as a whole. Independent attributesmotion, depth, form, and color-are coordinated into a single visual image. In the two Previous chapters we began to consider how two parallel Pathways-the magnocellular and parvocellular pathways, that e ...
... N vISIoN,AS IN orHERmental oPerations, we exPerrence the world as a whole. Independent attributesmotion, depth, form, and color-are coordinated into a single visual image. In the two Previous chapters we began to consider how two parallel Pathways-the magnocellular and parvocellular pathways, that e ...
Changes in the N1-P2 Complex after Speech
... reflects training-induced changes in perception, there is tremendous potential for clinical application. The N1-P2 complex could be used to monitor neurophysiologic changes during speech-sound acquisition after cochlear implantation, hearing aid use, or any other form of auditory learning. More impo ...
... reflects training-induced changes in perception, there is tremendous potential for clinical application. The N1-P2 complex could be used to monitor neurophysiologic changes during speech-sound acquisition after cochlear implantation, hearing aid use, or any other form of auditory learning. More impo ...
Evidence of Basal Temporo-occipital Cortex
... correlation from uncorrelation, and they show a longer latency than responses found in the pericalcarine cortex. Our findings indicate that the fusiform area is involved in the processing of the stereoscopic information and shows responses that suggest a high level of stereoscopic processing. ...
... correlation from uncorrelation, and they show a longer latency than responses found in the pericalcarine cortex. Our findings indicate that the fusiform area is involved in the processing of the stereoscopic information and shows responses that suggest a high level of stereoscopic processing. ...
Beyond the classical receptive field: The effect of contextual stimuli
... (1959–1968). In these experiments, simple stimuli, such as dots, lines, and bars, were used to explore RF properties. In this paper, we extend the history of RF research to experiments in striate and extrastriate cortex, using contextual stimuli, including movie clips and natural scenes. Over the ye ...
... (1959–1968). In these experiments, simple stimuli, such as dots, lines, and bars, were used to explore RF properties. In this paper, we extend the history of RF research to experiments in striate and extrastriate cortex, using contextual stimuli, including movie clips and natural scenes. Over the ye ...
Visual signals in the dorsolateral pontine nucleus of the alert
... the fovea (CNT) in the preferred direction (right), a burst of discharges was observed with a 150 ms delay (Fig. 1A and B). The magnitude of the transient response was related to the size of the test spot stimulus. For a 1.7 deg test spot moving at about 0.4 Hz + 10 deg, the amplitude of the burst w ...
... the fovea (CNT) in the preferred direction (right), a burst of discharges was observed with a 150 ms delay (Fig. 1A and B). The magnitude of the transient response was related to the size of the test spot stimulus. For a 1.7 deg test spot moving at about 0.4 Hz + 10 deg, the amplitude of the burst w ...
Chapter 5 Learning to attend in primary visual cortex
... searched increase their activity at an early point in time during the trial whereas neurons that represented the curve to be traced enhanced their activity after a delay. Thus it is possible to monitor the precise time-course of a sequence of cognitive operations in area V1. The modulation of neuron ...
... searched increase their activity at an early point in time during the trial whereas neurons that represented the curve to be traced enhanced their activity after a delay. Thus it is possible to monitor the precise time-course of a sequence of cognitive operations in area V1. The modulation of neuron ...
- Neuro-Optometric Rehabilitation Association
... Visual and nonvisual processing affects many sensory, motor, cognitive and emotional systems. Dysfunctional processing or linkages can cause a distortion in spatial or temporal orientation and an overall diminution in the patient’s ability to perform even simple everyday tasks. More than 30% of the h ...
... Visual and nonvisual processing affects many sensory, motor, cognitive and emotional systems. Dysfunctional processing or linkages can cause a distortion in spatial or temporal orientation and an overall diminution in the patient’s ability to perform even simple everyday tasks. More than 30% of the h ...
KliperEtAl CIP2010
... B. Learning a single cell’s invariant space Motivated by the view that different neurons impose different partitions of stimulus space which are not necessarily simply related to the simple feature structure of the stimuli [12], we attempt instead to learn the structure of the stimulus space by lear ...
... B. Learning a single cell’s invariant space Motivated by the view that different neurons impose different partitions of stimulus space which are not necessarily simply related to the simple feature structure of the stimuli [12], we attempt instead to learn the structure of the stimulus space by lear ...
Mechanisms of Visual Attention in the Human Cortex
... The competition among multiple objects in visual cortex can be biased by both bottom-up sensory-driven mechanisms and top-down influences, such as selective attention. Functional brain imaging studies reveal that, both in the absence and in the presence of visual stimulation, biasing signals due to ...
... The competition among multiple objects in visual cortex can be biased by both bottom-up sensory-driven mechanisms and top-down influences, such as selective attention. Functional brain imaging studies reveal that, both in the absence and in the presence of visual stimulation, biasing signals due to ...
Negative BOLD in Sensory Cortices During
... Abstract People tend to close their eyes when trying to retrieve an event or a visual image from memory. However the brain mechanisms behind this phenomenon remain poorly understood. Recently, we showed that during visual mental imagery, auditory areas show a much more robust deactivation than durin ...
... Abstract People tend to close their eyes when trying to retrieve an event or a visual image from memory. However the brain mechanisms behind this phenomenon remain poorly understood. Recently, we showed that during visual mental imagery, auditory areas show a much more robust deactivation than durin ...
attention - CMU Graphics
... whose receptive field overlaps the current attentional focus, creating an enhanced representation at that location that is akin to a local increase in contrast ...
... whose receptive field overlaps the current attentional focus, creating an enhanced representation at that location that is akin to a local increase in contrast ...
Implications on visual apperception: energy, duration
... neurons. However, the highest density of neurons in neocortex (number of neurons per degree of visual angle) devoted to representing the visual field is found in retinotopic V1. It means that the highest mitochondrial (energetic) activity can be achieved in mitochondrial cytochrome oxidase-rich V1 a ...
... neurons. However, the highest density of neurons in neocortex (number of neurons per degree of visual angle) devoted to representing the visual field is found in retinotopic V1. It means that the highest mitochondrial (energetic) activity can be achieved in mitochondrial cytochrome oxidase-rich V1 a ...
Primary Visual Pathway
... of on and off zones • Length cells - respond to length of a bar that was moved across a receptive field • Direction cells - respond to direction of a bar moving across the receptive field. ...
... of on and off zones • Length cells - respond to length of a bar that was moved across a receptive field • Direction cells - respond to direction of a bar moving across the receptive field. ...
Impact on Perception, Attention, and Memory
... emotional stimuli. This was demonstrated using an attentional cuing paradigm (Posner, 1980) in which fearful or neutral faces were used to cue the location of a subsequent target (Phelps, Ling, & Carrasco, 2006). The target was a simple gabor patch that varied in its visibility from trial to trial b ...
... emotional stimuli. This was demonstrated using an attentional cuing paradigm (Posner, 1980) in which fearful or neutral faces were used to cue the location of a subsequent target (Phelps, Ling, & Carrasco, 2006). The target was a simple gabor patch that varied in its visibility from trial to trial b ...
Interactions between attention, context and learning in primary
... C. Gilbert et al. / Vision Research 40 (2000) 1217–1226 ...
... C. Gilbert et al. / Vision Research 40 (2000) 1217–1226 ...
Contextual modulation of primary visual cortex by auditory signals
... been suggested that crossmodal interactions in auditory and visual cortices are driven by projections from the opposite sensory cortex, with conduction delays of up to 35 ms [21]. Time-resolved multisensory interactions can be studied using electrophysiological techniques that reveal early effects i ...
... been suggested that crossmodal interactions in auditory and visual cortices are driven by projections from the opposite sensory cortex, with conduction delays of up to 35 ms [21]. Time-resolved multisensory interactions can be studied using electrophysiological techniques that reveal early effects i ...
Examples of well-written lab reports, by section
... explanation for the results is that the greater complexity of a visual signal trumps all other factors and causes a slower brain processing time when compared to an audio signal. On the other hand, the data suggests that in the case of audio signals, neither prompts nor priming contributed to signif ...
... explanation for the results is that the greater complexity of a visual signal trumps all other factors and causes a slower brain processing time when compared to an audio signal. On the other hand, the data suggests that in the case of audio signals, neither prompts nor priming contributed to signif ...
Stimuluslocked responses on human arm muscles reveal a rapid
... Previous studies have demonstrated that humans are sometimes capable of initiating arm movements towards visual stimuli at extremely short latencies, implying the presence of a short-latency neural pathway linking visual input to limb motor output. However, little is known about the neural mechanism ...
... Previous studies have demonstrated that humans are sometimes capable of initiating arm movements towards visual stimuli at extremely short latencies, implying the presence of a short-latency neural pathway linking visual input to limb motor output. However, little is known about the neural mechanism ...
David Hunter Hubel. 27 February 1926 — 22 September 2013
... when Mike suggested placing wires in the cortex of cats and recording from them while they were awake. The attempt was a failure, but the idea captured David’s imagination. He began developing techniques for recording from animals while they were awake. He first developed a tough tungsten microelect ...
... when Mike suggested placing wires in the cortex of cats and recording from them while they were awake. The attempt was a failure, but the idea captured David’s imagination. He began developing techniques for recording from animals while they were awake. He first developed a tough tungsten microelect ...
text of chapter 2
... One important distinction that neuroscientists make is that early and later encoding in the visual system can differ. Early on, light is encoded into neural impulses by neural cells at the back of our eyes (step 1). The coded message is then passed on to other more central, but specific, parts of th ...
... One important distinction that neuroscientists make is that early and later encoding in the visual system can differ. Early on, light is encoded into neural impulses by neural cells at the back of our eyes (step 1). The coded message is then passed on to other more central, but specific, parts of th ...
Uncomfortable images produce non-sparse responses in a model of
... generate sparse responses to natural image samples produce units with receptive fields that are strikingly similar to those found in the visual cortex [5]. This suggests that sparse coding might, indeed, be a strategy used by the human visual system to maximize information transfer with minimum meta ...
... generate sparse responses to natural image samples produce units with receptive fields that are strikingly similar to those found in the visual cortex [5]. This suggests that sparse coding might, indeed, be a strategy used by the human visual system to maximize information transfer with minimum meta ...
Creating Visual Thinking Tools - National Science Teachers
... quickly and are especially useful in the creative/development phase of a project where many ideas can be generated without evaluation or critique. Although they do present a model of organizing the information, their physical appearance tends to be unstructured and randomly constructed. This “chaoti ...
... quickly and are especially useful in the creative/development phase of a project where many ideas can be generated without evaluation or critique. Although they do present a model of organizing the information, their physical appearance tends to be unstructured and randomly constructed. This “chaoti ...
mechanisms of visual attention in the human cortex
... The competition among multiple objects in visual cortex can be biased by both bottom-up sensory-driven mechanisms and top-down influences, such as selective attention. Functional brain imaging studies reveal that, both in the absence and in the presence of visual stimulation, biasing signals due to ...
... The competition among multiple objects in visual cortex can be biased by both bottom-up sensory-driven mechanisms and top-down influences, such as selective attention. Functional brain imaging studies reveal that, both in the absence and in the presence of visual stimulation, biasing signals due to ...
REVIEW Time Course of Auditory Processing, Visual Processing
... Bottom-up process is to take the heard sounds from bottom to up for processing. The process of first the auditory input, such as speech depends of ağabeylity to discriminate changes in the intensity, frequency, and duration of the sounds or-in psychological terms, changes in loudness, pitch and timi ...
... Bottom-up process is to take the heard sounds from bottom to up for processing. The process of first the auditory input, such as speech depends of ağabeylity to discriminate changes in the intensity, frequency, and duration of the sounds or-in psychological terms, changes in loudness, pitch and timi ...
P200
In neuroscience, the visual P200 or P2 is a waveform component or feature of the event-related potential (ERP) measured at the human scalp. Like other potential changes measurable from the scalp, this effect is believed to reflect the post-synaptic activity of a specific neural process. The P2 component, also known as the P200, is so named because it is a positive going electrical potential that peaks at about 200 milliseconds (varying between about 150 and 275 ms) after the onset of some external stimulus . The distribution of this component in the brain, as measured by electrodes placed across the scalp, is located around the centro-frontal and the parieto-occipital region. It is generally found to be maximal around the vertex (frontal region) of the scalp, however there have been some topographical differences noted in ERP studies of the P2 in different experimental conditions.Research on the visual P2 is at an early stage compared to other more established ERP components and there is much that we still do not know about it. Part of the difficulty of clearly characterizing this component is that it appears to be modulated by a large and diverse number of cognitive tasks. Functionally, there seems to be partial agreement amongst researchers in the field of cognitive neuroscience that the P2 represents some aspect of higher-order perceptual processing, modulated by attention. It is known that the P2 is typically elicited as part of the normal response to visual stimuli and has been studied in relation to visual search and attention, language context information, and memory and repetition effects. The amplitude of the peak of the waveform may be modulated by many different aspects of visual stimuli, which allow it to be used for studies of visual cognition and disease. In general, the P2 may be a part of cognitive matching system that compares sensory inputs with stored memory.