Reduced BOLD response to periodic visual stimulation
... 10 s was calculated for each condition (seven frequencies, periodic and aperiodic), starting 10 s after the onset of stimulation. Baseline was taken as the mean signal during 30 s of rest preceding the stimulus. The results were averaged over the two trials of each condition. For each subject, the p ...
... 10 s was calculated for each condition (seven frequencies, periodic and aperiodic), starting 10 s after the onset of stimulation. Baseline was taken as the mean signal during 30 s of rest preceding the stimulus. The results were averaged over the two trials of each condition. For each subject, the p ...
Chapter 29 - krigolson teaching
... ision requires eye movements. Small eye movements are essential for maintaining the contrast of objects that we are examining. Without these movements the perception of an object rapidly fades to a field of gray, a phenomenon correlated with the decreased response of neurons in area V1 (see Chapter ...
... ision requires eye movements. Small eye movements are essential for maintaining the contrast of objects that we are examining. Without these movements the perception of an object rapidly fades to a field of gray, a phenomenon correlated with the decreased response of neurons in area V1 (see Chapter ...
Visual signals in the dorsolateral pontine nucleus of the alert
... pontine nucleus (DLPN) cells were studied in two alert monkeys. In 41 cells, presentation of a moving random dot background pattern, while the monkeys fixated a stationary spot, elicited modulations in discharge rate that were related either to (i) the velocity of background motion in a specific dir ...
... pontine nucleus (DLPN) cells were studied in two alert monkeys. In 41 cells, presentation of a moving random dot background pattern, while the monkeys fixated a stationary spot, elicited modulations in discharge rate that were related either to (i) the velocity of background motion in a specific dir ...
Visual Perception: Objects and Scenes
... According to the figural simplicity theory, visual completion is done in the way that results in the “simplest” perceived figures. This theory successfully explains the first case of Figure 2; the arbitrary shape occluded by the black square is completed just by smoothly connecting two points at the ...
... According to the figural simplicity theory, visual completion is done in the way that results in the “simplest” perceived figures. This theory successfully explains the first case of Figure 2; the arbitrary shape occluded by the black square is completed just by smoothly connecting two points at the ...
The Constructive Nature of Visual Processing
... from background (see Chapter 27). The highest level involves object recognition (see Chapter 28). Once a scene has been parsed by the brain and objects recognized, the objects can be matched with memories of shapes and their associated meanings. Vision also has an important role in guiding body move ...
... from background (see Chapter 27). The highest level involves object recognition (see Chapter 28). Once a scene has been parsed by the brain and objects recognized, the objects can be matched with memories of shapes and their associated meanings. Vision also has an important role in guiding body move ...
The Emergence of Selective Attention through - laral
... target, presented among others, the distracters, by pressing alternative buttons or by verbally reporting the observed items. Usually in these experiments the target is defined on the basis of its features, such as the colour or the shape. Subjects’ response is very fast and accurate when the target ...
... target, presented among others, the distracters, by pressing alternative buttons or by verbally reporting the observed items. Usually in these experiments the target is defined on the basis of its features, such as the colour or the shape. Subjects’ response is very fast and accurate when the target ...
Features of Neuronal Synchrony in Mouse Visual Cortex
... adult C57BL/6J mouse. The figure shows traces from a single trial at compressed time scale (a) and at an expanded time scale (b). Arrows in a indicate the onset and offset of visual stimulation, respectively. Note the presence of rhythmic oscillations (approximately 40 Hz) in the local field potenti ...
... adult C57BL/6J mouse. The figure shows traces from a single trial at compressed time scale (a) and at an expanded time scale (b). Arrows in a indicate the onset and offset of visual stimulation, respectively. Note the presence of rhythmic oscillations (approximately 40 Hz) in the local field potenti ...
Basic principles of attention and decision
... • Do not mistake with the ‘where’ (old) pathway: SC and pulvinar • Parietal cortex represents potential targets to reach with respect to body, and is involved in motor control (see Ramachandran, Balint’s syndrom) • Lateral Intraparietal cortex (LIP): highest-order area in the visual hierarchy of t ...
... • Do not mistake with the ‘where’ (old) pathway: SC and pulvinar • Parietal cortex represents potential targets to reach with respect to body, and is involved in motor control (see Ramachandran, Balint’s syndrom) • Lateral Intraparietal cortex (LIP): highest-order area in the visual hierarchy of t ...
Stimuluslocked responses on human arm muscles reveal a rapid
... target appearance (immediate task) or central marker disappearance (delayed task) to the point of reach initiation, when tangential hand velocity exceeded 5% of its peak value. Movements were considered to be in the correct direction if the direction of hand movement at 100 ms after manual reaction ...
... target appearance (immediate task) or central marker disappearance (delayed task) to the point of reach initiation, when tangential hand velocity exceeded 5% of its peak value. Movements were considered to be in the correct direction if the direction of hand movement at 100 ms after manual reaction ...
Comparison of Quantities: Core and Format
... et al. 2010). Whereas in an analogue stimulus the magnitude is a perceptually accessible aspect of the stimulus, in a symbolic stimulus the magnitude being coded is independent from physical characteristics. For example, 3 dots and the Arabic digit ‘‘3’’ both implement the notion of 3 but the visual ...
... et al. 2010). Whereas in an analogue stimulus the magnitude is a perceptually accessible aspect of the stimulus, in a symbolic stimulus the magnitude being coded is independent from physical characteristics. For example, 3 dots and the Arabic digit ‘‘3’’ both implement the notion of 3 but the visual ...
Simulating the Fröhlich Effect of Motion Misperception as a Result... Attentional Modulation in the Visual System
... of each trial. When the stimulus appears, attention is shifted towards the onset location. On its way attention may either have to “catch up” with the stimulus or the stimulus moves toward the focus of attention. Thus, a stimulus that moves away from the fixation point “costs” the attention shift so ...
... of each trial. When the stimulus appears, attention is shifted towards the onset location. On its way attention may either have to “catch up” with the stimulus or the stimulus moves toward the focus of attention. Thus, a stimulus that moves away from the fixation point “costs” the attention shift so ...
Cortical mechanisms of sensory learning and object recognition
... In the olfactory systems of locusts, precisely such a mechanism has been observed (figure 1g ; Stopfer & Laurent 1999). It remains to be seen whether neurons in IT show any timing effects with learning, or if any oscillations develop. Though inconclusive, it is perhaps of interest that the activatio ...
... In the olfactory systems of locusts, precisely such a mechanism has been observed (figure 1g ; Stopfer & Laurent 1999). It remains to be seen whether neurons in IT show any timing effects with learning, or if any oscillations develop. Though inconclusive, it is perhaps of interest that the activatio ...
Attention - Biology Courses Server
... environment and daydreaming. • Attention confers behavioral flexibility. – We use attention to focus mental resources. – Network of brain areas, priority maps – Allocation of attention followed by selective enhanced processing in sensory cortex • Many mysteries remain about consciousness of informat ...
... environment and daydreaming. • Attention confers behavioral flexibility. – We use attention to focus mental resources. – Network of brain areas, priority maps – Allocation of attention followed by selective enhanced processing in sensory cortex • Many mysteries remain about consciousness of informat ...
- Stem-cell and Brain Research Institute
... monkeys (Macaca fascicularis). Some of the results from these injections have already been reported in another article (Falchier et al., 2002). Central area 17 injections were in the cortex subserving 0º–2º in the lower visual field (M85RHDY and M85RHFsB). Injections aimed at the peripheral represen ...
... monkeys (Macaca fascicularis). Some of the results from these injections have already been reported in another article (Falchier et al., 2002). Central area 17 injections were in the cortex subserving 0º–2º in the lower visual field (M85RHDY and M85RHFsB). Injections aimed at the peripheral represen ...
David Hunter Hubel. 27 February 1926 — 22 September 2013
... that moved the electrode to record from isolated neurons. Both inventions required multiple versions. The advancer required so many versions that he decided to make new ones himself, so he learned to operate a lathe. David recorded from freely moving cats during sleep and wakefulness and noted that ...
... that moved the electrode to record from isolated neurons. Both inventions required multiple versions. The advancer required so many versions that he decided to make new ones himself, so he learned to operate a lathe. David recorded from freely moving cats during sleep and wakefulness and noted that ...
Within-hemifield perceptual averaging of facial expressions
... those that respond to faces, have large receptive fields often encompassing substantial regions of the contralateral visual field (e.g., Boussaoud et al., 1991; Chelazzi et al., 1998; Desimone & Gross, 1979; Niemeier et al., 2005; Op De Beeck & Vogels, 2000). Thus, when a pair of faces is presented ...
... those that respond to faces, have large receptive fields often encompassing substantial regions of the contralateral visual field (e.g., Boussaoud et al., 1991; Chelazzi et al., 1998; Desimone & Gross, 1979; Niemeier et al., 2005; Op De Beeck & Vogels, 2000). Thus, when a pair of faces is presented ...
the clinical role of evoked potentials
... VEPs provide a sensitive indication of abnormal conduction in the visual pathway. Increases in retino-striate conduction time caused by processes such as demyelination can be detected by measuring the latency of this cortical response. Abnormalities in the amplitude and waveform of the VEPs may also ...
... VEPs provide a sensitive indication of abnormal conduction in the visual pathway. Increases in retino-striate conduction time caused by processes such as demyelination can be detected by measuring the latency of this cortical response. Abnormalities in the amplitude and waveform of the VEPs may also ...
Specialization within the ventral stream: The case for the visual word
... “sight”. We are immediately aware of their radically different meanings and pronunciation, but it takes some time to realize that visually speaking, those words differ only by a very small amount. Our visual system is attuned to the minute difference between “eight” and “sight”, which it amplifies s ...
... “sight”. We are immediately aware of their radically different meanings and pronunciation, but it takes some time to realize that visually speaking, those words differ only by a very small amount. Our visual system is attuned to the minute difference between “eight” and “sight”, which it amplifies s ...
PDF file
... The primate visual pathways have been extensively investigated in neuroscience: branching primarily from V2, two primary pathways exist, called the dorsal pathway and the ventral pathway, respectively. The dorsal stream begins with V1, through V2, the dorsomedial area and MT (also known as V5), to t ...
... The primate visual pathways have been extensively investigated in neuroscience: branching primarily from V2, two primary pathways exist, called the dorsal pathway and the ventral pathway, respectively. The dorsal stream begins with V1, through V2, the dorsomedial area and MT (also known as V5), to t ...
ppt - UC Davis Imaging Research Center
... across studies No studies have been run assessing whether behavioral effects vary according to the type of switch required Only recently have attempts been made to dissociate neural activity in regard to different types of shifts (Wager, et al., 2005). We focus on two types of shifts: Percep ...
... across studies No studies have been run assessing whether behavioral effects vary according to the type of switch required Only recently have attempts been made to dissociate neural activity in regard to different types of shifts (Wager, et al., 2005). We focus on two types of shifts: Percep ...
Neuronal mechanisms for the perception of ambiguous stimuli
... suppressed. Neuronal responses to suppressed stimuli have been studied with a specific paradigm of flash suppression as well as with binocular rivalry. In both paradigms, suppressed stimuli provide one index of whether or not neuronal firing is directly linked with conscious perception of objects. I ...
... suppressed. Neuronal responses to suppressed stimuli have been studied with a specific paradigm of flash suppression as well as with binocular rivalry. In both paradigms, suppressed stimuli provide one index of whether or not neuronal firing is directly linked with conscious perception of objects. I ...
Saccadic Suppression of Retinotopically Localized Blood Oxygen
... of scripts written in Matlab (MathWorks, Natick, MA) that contained a more sensitive algorithm that included information about the slope of the main sequence obtained from each run. For purposes of quality control, all detected saccadic onsets from all trials were visually inspected by plotting them ...
... of scripts written in Matlab (MathWorks, Natick, MA) that contained a more sensitive algorithm that included information about the slope of the main sequence obtained from each run. For purposes of quality control, all detected saccadic onsets from all trials were visually inspected by plotting them ...
Creating Visual Thinking Tools - National Science Teachers
... Types of Visual Thinking Tools By developing visual thinking tools, such as charts and diagrams, students acquire formats for recalling, retelling, or making meaning from written text. As adults, we tend to create such mental pictures intuitively as we read information. Creating these mental picture ...
... Types of Visual Thinking Tools By developing visual thinking tools, such as charts and diagrams, students acquire formats for recalling, retelling, or making meaning from written text. As adults, we tend to create such mental pictures intuitively as we read information. Creating these mental picture ...
Chapter 5 Learning to attend in primary visual cortex
... window centered on a red fixation point (FP in Fig. 1a). After an interval of 300 ms, the stimulus appeared on the screen. It consisted of two curves starting at two different small icons. The monkey was presented with a new pair of icons each day, one of which was relevant and the other was to be i ...
... window centered on a red fixation point (FP in Fig. 1a). After an interval of 300 ms, the stimulus appeared on the screen. It consisted of two curves starting at two different small icons. The monkey was presented with a new pair of icons each day, one of which was relevant and the other was to be i ...
- 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 ...
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.