The Visual System: From Eye to Cortex - U
... • We all have a blind spot at the optic disk, due to the exit of axons from the retinal ganglion cells • We are normally unaware of our blind spots, even when looking through one stationary eye because of completion; the visual system is able to use visual information gathered from receptors around ...
... • We all have a blind spot at the optic disk, due to the exit of axons from the retinal ganglion cells • We are normally unaware of our blind spots, even when looking through one stationary eye because of completion; the visual system is able to use visual information gathered from receptors around ...
The Neural Fate of Consciously Perceived and Missed Events in the
... by the subjects (Miss) still activated the PPA more than when no scenes were presented (CR) [Miss ⬎ CR, t(18) ⫽ 2.19, p ⬍ 0.05], suggesting that the PPA responds to scenes even when they are not consciously perceived. Moreover, this subliminal PPA activation was enhanced when subjects consciously pe ...
... by the subjects (Miss) still activated the PPA more than when no scenes were presented (CR) [Miss ⬎ CR, t(18) ⫽ 2.19, p ⬍ 0.05], suggesting that the PPA responds to scenes even when they are not consciously perceived. Moreover, this subliminal PPA activation was enhanced when subjects consciously pe ...
Lecture 1 - Gabriel Kreiman
... cry from the complexity of the real visual input. If each pixel can take 256 possible grayscale values, then even for such a simple patch, there is a large number of possible images. For only one pixel, there are 256 possible one-pixel images. For two pixels, there are 256x256 possible two-pixel ima ...
... cry from the complexity of the real visual input. If each pixel can take 256 possible grayscale values, then even for such a simple patch, there is a large number of possible images. For only one pixel, there are 256 possible one-pixel images. For two pixels, there are 256x256 possible two-pixel ima ...
TalkHumaine_grandjean
... The responses of neurons are higher when multimodal spatial stimuli occur compared to unimodal stimulus or the sum of unimodal stimuli. When the spatial occurrence of stimuli are disparate these neurons do not discharge or show a decrease of spontaneous activity. The temporal rule: Apparently time i ...
... The responses of neurons are higher when multimodal spatial stimuli occur compared to unimodal stimulus or the sum of unimodal stimuli. When the spatial occurrence of stimuli are disparate these neurons do not discharge or show a decrease of spontaneous activity. The temporal rule: Apparently time i ...
VL_CHAPTER_4
... cortex clearly. This movie shows the response measured by fMRI in the visual cortex of a human who was viewing a stimulus. The stimulus shown is a flickering ring with a checkerboard pattern that slowly expanded, moving from the center of vision (the foveal region) to the periphery. Notice that the ...
... cortex clearly. This movie shows the response measured by fMRI in the visual cortex of a human who was viewing a stimulus. The stimulus shown is a flickering ring with a checkerboard pattern that slowly expanded, moving from the center of vision (the foveal region) to the periphery. Notice that the ...
LISC-322 Neuroscience Cortical Organization Primary Visual Cortex
... Neurons in the dorsal stream exhibit properties that are related to the spatial relationships of objects. At the highest levels in this pathway, visual neurons in the monkey posterior parietal cortex respond preferentially to optic flow. ...
... Neurons in the dorsal stream exhibit properties that are related to the spatial relationships of objects. At the highest levels in this pathway, visual neurons in the monkey posterior parietal cortex respond preferentially to optic flow. ...
Attention and Consciousness
... improves the accuracy and speed of detecting target at this location. Attention can be based on internal goals (finding a friend in the crowd) or external environment (alarm sound, bright colors) ...
... improves the accuracy and speed of detecting target at this location. Attention can be based on internal goals (finding a friend in the crowd) or external environment (alarm sound, bright colors) ...
Slide 1 - Elsevier Store
... CCD camera while the anesthetized, paralyzed animal is viewing a visual stimulus. These images are stored on a second computer for further analysis. (B) Individual image (9 by 6 mm) of a region of V1 and a portion of V2 taken with a special filter so that blood vessels stand out. (C) Ocular dominanc ...
... CCD camera while the anesthetized, paralyzed animal is viewing a visual stimulus. These images are stored on a second computer for further analysis. (B) Individual image (9 by 6 mm) of a region of V1 and a portion of V2 taken with a special filter so that blood vessels stand out. (C) Ocular dominanc ...
Document
... that guides navigation and skilled movements directed toward objects, and that of the ventral stream is to provide visual information about the size, shape, color, and texture of objects (including, as we shall see, other people). (See Figure 6.34 .) ...
... that guides navigation and skilled movements directed toward objects, and that of the ventral stream is to provide visual information about the size, shape, color, and texture of objects (including, as we shall see, other people). (See Figure 6.34 .) ...
Visual Coding and the Retinal Receptors
... in space from which light strikes it. • For other visual cells, receptive fields are derived from the visual field of cells that either excite or inhibit. – Example: ganglion cells converge to form the receptive field of the next level of cells. ...
... in space from which light strikes it. • For other visual cells, receptive fields are derived from the visual field of cells that either excite or inhibit. – Example: ganglion cells converge to form the receptive field of the next level of cells. ...
Viktor`s Notes * Visual Pathways and Cortex
... PRIMARY VISUAL CORTEX (V1, area 17, striate cortex) visual cortex has six layers (like rest of neocortex). there are many nerve cells associated with each fiber. magnocellular and parvocellular pathways end in layer 4 (in its deepest part, layer 4C). thick, light-colored layer 4 is visible to ...
... PRIMARY VISUAL CORTEX (V1, area 17, striate cortex) visual cortex has six layers (like rest of neocortex). there are many nerve cells associated with each fiber. magnocellular and parvocellular pathways end in layer 4 (in its deepest part, layer 4C). thick, light-colored layer 4 is visible to ...
CHAPTER 15 THE CENTRAL VISUAL PATHWAYS
... Figure 15-10. Example of a neuron in visual cortex that responds best to a bar in a specific orientation, moving at a specific speed. Many cortical neurons are also selective for the direction of motion. ...
... Figure 15-10. Example of a neuron in visual cortex that responds best to a bar in a specific orientation, moving at a specific speed. Many cortical neurons are also selective for the direction of motion. ...
Modeling Visual Cognition
... validity in relation to both their structure and parameters. The latter determines whether the models are valid in terms of their direct link to psychologically meaningful concepts such as the rate of encoding of stimulus information and the amount of information that can be retained in memory. An a ...
... validity in relation to both their structure and parameters. The latter determines whether the models are valid in terms of their direct link to psychologically meaningful concepts such as the rate of encoding of stimulus information and the amount of information that can be retained in memory. An a ...
Neuro-ophthalmology
... Test the function of the extraocular muscles Evaluate the visual fields Inspect the optic nerve head ...
... Test the function of the extraocular muscles Evaluate the visual fields Inspect the optic nerve head ...
Visual7
... Images in the nasal hemiretina from both sides cross over (temporal stay ipsilateral). This allows for complete cross-over of each visual field (see Fig. 7-3C). ...
... Images in the nasal hemiretina from both sides cross over (temporal stay ipsilateral). This allows for complete cross-over of each visual field (see Fig. 7-3C). ...
Neural coding of behavioral relevance in parietal cortex
... in neuronal responses in MT were generally too small to account for the behavioral changes, whereas the changes in VIP responses were generally stronger than expected to explain the behavioral effect. These results suggest that comparing the neuronal and behavioral effects of attention may be a reas ...
... in neuronal responses in MT were generally too small to account for the behavioral changes, whereas the changes in VIP responses were generally stronger than expected to explain the behavioral effect. These results suggest that comparing the neuronal and behavioral effects of attention may be a reas ...
Visual Field Defects - Northwestern Medical Review
... Normally damage to the brain cortex causes contralateral deficits in the extremities. This is not, however, true of the visual system. Unilateral damage to the visual cortex is manifested by characteristic partial loss of vision in both eyes. Neither of the eyes is able to see the contralateral visu ...
... Normally damage to the brain cortex causes contralateral deficits in the extremities. This is not, however, true of the visual system. Unilateral damage to the visual cortex is manifested by characteristic partial loss of vision in both eyes. Neither of the eyes is able to see the contralateral visu ...
Perception - Vision
... strongly to faces than to just about any other category of objects. This region responds more to human, animal and cartoon faces than to a variety of non-face stimuli. Neurons in this area specialize in facial expression, particular identity or ...
... strongly to faces than to just about any other category of objects. This region responds more to human, animal and cartoon faces than to a variety of non-face stimuli. Neurons in this area specialize in facial expression, particular identity or ...
Why light
... Registration refers to the fact that the projections of activity in layers 3 and 4 are at the same place in their respective layers, even though the stimulation is from different eyes. That is, the activity generated by stimulus A is at the same end of both LGN layers. The activity generated by stim ...
... Registration refers to the fact that the projections of activity in layers 3 and 4 are at the same place in their respective layers, even though the stimulation is from different eyes. That is, the activity generated by stimulus A is at the same end of both LGN layers. The activity generated by stim ...
attention - CMU Graphics
... -- homogeneous, if only space attention an attention map. Such a representation of behaviorally relevant locations might be activated by knowledge of the environment ...
... -- homogeneous, if only space attention an attention map. Such a representation of behaviorally relevant locations might be activated by knowledge of the environment ...
19. Visual (2)
... terminate in the visual cortex above the calcarine sulcus . Those which represent the upper part of the visual field sweep into the temporal lobe ( Meyer’s loop ) then below the calcarine sulcus . Surrounding the primary visual cortex , the rest of the occipital lobe constitutes the visual associati ...
... terminate in the visual cortex above the calcarine sulcus . Those which represent the upper part of the visual field sweep into the temporal lobe ( Meyer’s loop ) then below the calcarine sulcus . Surrounding the primary visual cortex , the rest of the occipital lobe constitutes the visual associati ...
Interactions between attention, context and learning in primary
... Lamme & Schiller, 1996; Kastner, Nothdurft & Pigarev, 1997; Levitt & Lund, 1997; Kapadia, Westheimer & Gilbert, 1998, 1999). An important source of contextual influences is a plexus of long range horizontal connections that link cells with widely separated receptive fields. This is a network of conn ...
... Lamme & Schiller, 1996; Kastner, Nothdurft & Pigarev, 1997; Levitt & Lund, 1997; Kapadia, Westheimer & Gilbert, 1998, 1999). An important source of contextual influences is a plexus of long range horizontal connections that link cells with widely separated receptive fields. This is a network of conn ...
A multi-level account of selective attention
... between the competing models. While studies on dichotic listening remained prominent (e.g. Corteen and Wook 1972), many researchers turned to investigating early and late selection in the visual domain. The prototypical approach was to infer the locus of selection based on behavioural measures such ...
... between the competing models. While studies on dichotic listening remained prominent (e.g. Corteen and Wook 1972), many researchers turned to investigating early and late selection in the visual domain. The prototypical approach was to infer the locus of selection based on behavioural measures such ...
CVI
... Movement cues, especially in the peripheral fields can often stimulate a visual response. Visual interpretation may be improved for some children when they are actually moving as opposed to standing still. Color vision does not seem to be affected. ...
... Movement cues, especially in the peripheral fields can often stimulate a visual response. Visual interpretation may be improved for some children when they are actually moving as opposed to standing still. Color vision does not seem to be affected. ...
Visual N1
The visual N1 is a visual evoked potential, a type of event-related electrical potential (ERP), that is produced in the brain and recorded on the scalp. The N1 is so named to reflect the polarity and typical timing of the component. The ""N"" indicates that the polarity of the component is negative with respect to an average mastoid reference. The ""1"" originally indicated that it was the first negative-going component, but it now better indexes the typical peak of this component, which is around 150 to 200 milliseconds post-stimulus. The N1 deflection may be detected at most recording sites, including the occipital, parietal, central, and frontal electrode sites. Although, the visual N1 is widely distributed over the entire scalp, it peaks earlier over frontal than posterior regions of the scalp, suggestive of distinct neural and/or cognitive correlates. The N1 is elicited by visual stimuli, and is part of the visual evoked potential – a series of voltage deflections observed in response to visual onsets, offsets, and changes. Both the right and left hemispheres generate an N1, but the laterality of the N1 depends on whether a stimulus is presented centrally, laterally, or bilaterally. When a stimulus is presented centrally, the N1 is bilateral. When presented laterally, the N1 is larger, earlier, and contralateral to the visual field of the stimulus. When two visual stimuli are presented, one in each visual field, the N1 is bilateral. In the latter case, the N1’s asymmetrical skewedness is modulated by attention. Additionally, its amplitude is influenced by selective attention, and thus it has been used to study a variety of attentional processes.