Horizontal line bisections in upper and lower body space

2000 ◽  
Vol 6 (4) ◽  
pp. 455-459 ◽  
Author(s):  
ANNA M. BARRETT ◽  
J. BRENT CROSSON ◽  
GREGORY P. CRUCIAN ◽  
KENNETH M. HEILMAN
Keyword(s):  
Object Recognition ◽  
Left Hemisphere ◽  
Visual Processing ◽  
Right Hemisphere ◽  
Dorsal Stream ◽  
Spatial Localization ◽  
Upper Body ◽  
Horizontal Line ◽  
Lower Body ◽  
Visual Stream

Whereas the ventral cortical visual stream is important in object recognition, the dorsal stream is specialized for spatial localization. In humans there are also right and left hemisphere asymmetries in visual processing: the left hemisphere being more important in object recognition and the right in specifying spatial locations. Based on these dorsal–ventral and right–left where–what dichotomies, one would expect that the dorsal right hemisphere systems would be most activated during spatial localization tasks, and this activation may induce a leftward spatial bias in lower space. To determine if visual stimuli in upper and lower body space evoke different hemispheric activation, we had 12 normal participants bisect horizontal lines above and below eye level. Participants erred leftward in lower body space relative to upper body space (M = 1.3345 mm and 0.4225 mm, respectively; p = .011). In upper body space, bisection errors did not differ from zero, but in lower body space, errors tended to deviate leftward (M = 1.3345 mm, differs from null hypotheses at p = .0755). Our results are consistent with dorsal stream/right hemisphere activation when performing a spatial localization task in lower versus upper body space. (JINS, 2000, 6, 455–459.)

Two Categorical Stages of Object Recognition

Perception ◽  
1978 ◽  
Vol 7 (6) ◽  
pp. 695-705 ◽  
Author(s):  
Elizabeth K Warrington ◽  
Angela M Taylor
Keyword(s):  
Object Recognition ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Perceptual Categorization ◽  
Categorization Task ◽  
Semantic Categorization ◽  
Tentative Model ◽  
The Right

Visual object recognition was investigated in a group of eighty-one patients with right- or left-hemisphere lesions. Two tasks were used, one maximizing perceptual categorization by physical identity, the other maximizing semantic categorization by functional identity. The right-hemisphere group showed impairment on the perceptual categorization task and the left-hemisphere group were impaired on the semantic categorization task. The findings are discussed in terms of categorical stages of object recognition. A tentative model of their cerebral organization is suggested.

Lateral Differences for Person Perception: Effects of Task on Visual Processing of Handwriting

1983 ◽  
Vol 57 (3_suppl) ◽  
pp. 1023-1035 ◽  
Author(s):  
R. Bruyer ◽  
K. Secq
Keyword(s):  
Left Hemisphere ◽  
Visual Processing ◽  
Person Perception ◽  
Right Hemisphere ◽  
Important Variable ◽  
Experimental Conditions ◽  
Push Button ◽  
The Right ◽  
Normal Adults

Sergent and Bindra suggested that identification of faces using few different stimuli engages mainly the left hemisphere and, conversely, that discrimination of faces using more stimuli engages mainly the right hemisphere. The present study examined whether this suggestion holds for the perception of handwriting which, like faces, authorizes the perception of “persons”. Normal adults were presented stimuli consisting of a word written in various hands, laterally displayed for 180 msec. Exp. 1 (identification) was conducted with 8 subjects, who were asked to identify (push-button) four different stimuli by means of an associated first name. Exp. 2 (discrimination) was conducted with 16 subjects who were asked to make same/different judgments between a central stimulus and a lateral one under three experimental conditions, normal, mirror-reversed, and inverted presentations of both members of the pair. The results suggest that the direction of asymmetry depends more on the amount of stimuli than on the task and that familiarity with the stimuli is an important variable.

scholarly journals CORnet: Modeling the Neural Mechanisms of Core Object Recognition

2018 ◽  
Author(s):  
Jonas Kubilius ◽  
Martin Schrimpf ◽  
Aran Nayebi ◽  
Daniel Bear ◽  
Daniel L. K. Yamins ◽  
...  
Keyword(s):  
Object Recognition ◽  
Visual Processing ◽  
State Of The Art ◽  
Recognition Performance ◽  
Explanatory Power ◽  
Large Body ◽  
Response Dynamics ◽  
Visual Stream ◽  
Current State ◽  
Ventral Visual Stream

AbstractDeep artificial neural networks with spatially repeated processing (a.k.a., deep convolutional ANNs) have been established as the best class of candidate models of visual processing in primate ventral visual processing stream. Over the past five years, these ANNs have evolved from a simple feedforward eight-layer architecture in AlexNet to extremely deep and branching NAS-Net architectures, demonstrating increasingly better object categorization performance and increasingly better explanatory power of both neural and behavioral responses. However, from the neuroscientist’s point of view, the relationship between such very deep architectures and the ventral visual pathway is incomplete in at least two ways. On the one hand, current state-of-the-art ANNs appear to be too complex (e.g., now over 100 levels) compared with the relatively shallow cortical hierarchy (4-8 levels), which makes it difficult to map their elements to those in the ventral visual stream and to understand what they are doing. On the other hand, current state-of-the-art ANNs appear to be not complex enough in that they lack recurrent connections and the resulting neural response dynamics that are commonplace in the ventral visual stream. Here we describe our ongoing efforts to resolve both of these issues by developing a “CORnet” family of deep neural network architectures. Rather than just seeking high object recognition performance (as the state-of-the-art ANNs above), we instead try to reduce the model family to its most important elements and then gradually build new ANNs with recurrent and skip connections while monitoring both performance and the match between each new CORnet model and a large body of primate brain and behavioral data. We report here that our current best ANN model derived from this approach (CORnet-S) is among the top models on Brain-Score, a composite benchmark for comparing models to the brain, but is simpler than other deep ANNs in terms of the number of convolutions performed along the longest path of information processing in the model. All CORnet models are available at github.com/dicarlolab/CORnet, and we plan to up-date this manuscript and the available models in this family as they are produced.

Separable Mechanisms in Face Processing: Evidence from Hemispheric Specialization

1991 ◽  
Vol 3 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Lynn A. Hillger ◽  
Olivier Koenig
Keyword(s):  
Left Hemisphere ◽  
Face Processing ◽  
Visual Processing ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Facial Feature ◽  
General Purpose ◽  
Facial Features ◽  
Left And Right ◽  
The Right

This article addresses three issues in face processing: First, is face processing primarily accomplished by the right hemisphere, or do both left- and right-hemisphere mechanisms play important roles? Second, are the mechanisms the same as those involved in general visual processing, or are they dedicated to face processing? Third, how can the mechanisms be characterized more precisely in terms of processes such as visual parsing? We explored these issues using the divided visual field methodology in four experiments. Experiments 1 and 2 provided evidence that both left- and right-hemisphere mechanisms are involved in face processing. In Experiment 1, a right-hemisphere advantage was found for both Same and Different trials when Same faces were identical and Different faces differed on all three internal facial features. Experiment 2 replicated the right-hemisphere advantage for Same trials but showed a left-hemisphere advantage for Different trials when one of three facial features differed between the target and the probe faces. Experiment 3 showed that the right-hemisphere advantage obtained with upright faces in Experiment 2 disappeared when the faces were inverted. This result suggests that there are right-hemisphere mechanisms specialized for processing upright faces, although it could not be determined whether these mechanisms are completely face-specific. Experiment 3 also provided evidence that the left-hemisphere mechanisms utilized in face processing tasks are general-purpose visual mechanisms not restricted to particular classes of visual stimuli. In Experiment 4, a left-hemisphere advantage was obtained when the task was to find one facial feature that was the same between the target and the probe faces. We suggest that left-hemisphere advantages shown in face processing are due to the parsing and analysis of the local elements of a face.

scholarly journals Multiple adjoining word and face selective regions in ventral temporal cortex exhibit distinct dynamics

2020 ◽  
Author(s):  
Matthew J. Boring ◽  
Edward H. Silson ◽  
Michael J. Ward ◽  
R. Mark Richardson ◽  
Julie A. Fiez ◽  
...  
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Visual Processing ◽  
Word Processing ◽  
Right Hemisphere ◽  
Temporal Dynamics ◽  
Temporal Cortex ◽  
7 Tesla ◽  
Important Principle ◽  
Ventral Temporal Cortex

AbstractThe map of category-selectivity in human ventral temporal cortex (VTC) provides organizational constraints to models of object recognition. One important principle is lateral-medial response biases to stimuli that are typically viewed in the center or periphery of the visual field. However, little is known about the relative temporal dynamics and location of regions that respond preferentially to stimulus classes that are centrally viewed, like the face and word processing networks. Here, word- and face-selective regions within VTC were mapped using intracranial recordings from 36 patients. Partially overlapping, but also anatomically dissociable patches of face and word selectivity were found in ventral temporal cortex. In addition to canonical word-selective regions along the left posterior occipitotemporal sulcus, selectivity was also located medial and anterior to face-selective regions on the fusiform gyrus at the group level and within individual subjects. These regions were replicated using 7-Tesla fMRI in healthy subjects. Left hemisphere word-selective regions preceded right hemisphere responses by 125 ms, potentially reflecting the left hemisphere bias for language; with no hemispheric difference in face-selective response latency. Word-selective regions along the posterior fusiform responded first, then spread medially and laterally, then anteriorally. Face-selective responses were first seen in posterior fusiform regions bilaterally, then proceeded anteriorally from there. For both words and faces, the relative delay between regions was longer than would be predicted by purely feedforward models of visual processing. The distinct time-courses of responses across these regions, and between hemispheres, suggest a complex and dynamic functional circuit supports face and word perception.Significance StatementRepresentations of visual objects in the human brain have been shown to be organized by several principles, including whether those objects tend to be viewed centrally or in the periphery of the visual field. However, it remains unclear how regions that process objects that are viewed centrally, like words and faces, are organized relative to one another. Here, direct neural recordings and 7T fMRI demonstrate that several intermingled regions in ventral temporal cortex participate in word and face processing. These regions display differences in their temporal dynamics and response characteristics, both within and between brain hemispheres, suggesting they play different roles in perception. These results illuminate extended, bilateral, and dynamic brain pathways that support face perception and reading.

What Does the Brain Do When You Fake It? An fMRI Study of Pantomimed and Real Grasping

2007 ◽  
Vol 97 (3) ◽  
pp. 2410-2422 ◽  
Author(s):  
G. Króliczak ◽  
C. Cavina-Pratesi ◽  
D. A. Goodman ◽  
J. C. Culham
Keyword(s):  
Visual Processing ◽  
Right Hemisphere ◽  
Statistical Significance ◽  
Three Dimensional ◽  
Dorsal Stream ◽  
Occipital Cortex ◽  
Ventral Stream ◽  
Underlying Assumption ◽  
Neuropsychological Evidence ◽  
The Right

Given that studying neural bases of actions is very challenging with fMRI, numerous experiments have used pantomimed actions as a proxy to studying neural circuits of real actions. However, the underlying assumption that the same neural mechanisms mediate real and pantomimed actions has never been directly tested. Moreover, the assumption is called into question by neuropsychological evidence suggesting that real actions depend on the dorsal stream of visual processing whereas pretend actions also recruit the ventral stream. Here, we directly tested these ideas in neurologically intact subjects. Ten right-handed participants performed four tasks: 1) grasping real three-dimensional objects, 2) reaching toward the objects and touching them with the knuckle without hand preshaping, 3) pantomimed grasping in an adjacent location where no object was present, and 4) pantomimed reaching toward an adjacent location. As expected, in the anterior intraparietal area, there was significantly higher activation during real grasping than that during real reaching. However, the activation difference between pantomimed grasping and pantomimed reaching did not reach statistical significance. There was also no effect of pantomimed grasping within the ventral stream, including an object-selective area in the lateral occipital cortex. Instead, we found that pantomimed grasping was mediated by right-hemisphere activation, particularly the right parietal cortex. These results suggest that areas typically invoked by real actions may not necessarily be driven by “fake” actions. Moreover, pantomimed grasping may not tap object-related areas within the ventral stream, but rather may rely on mechanisms within the right hemisphere that are recruited by artificial and less practiced actions.

Decoding conjunctions of direction-of-motion and binocular disparity from human visual cortex

2012 ◽  
Vol 107 (9) ◽  
pp. 2335-2341 ◽  
Author(s):  
Kiley J. Seymour ◽  
Colin W. G. Clifford
Keyword(s):  
Visual Processing ◽  
Binocular Disparity ◽  
Dorsal Stream ◽  
Visual Stream ◽  
Activation Patterns ◽  
Independent Information ◽  
Uncrossed Disparity ◽  
Multivariate Pattern ◽  
Joint Encoding ◽  
Dorsal Visual Stream

Motion and binocular disparity are two features in our environment that share a common correspondence problem. Decades of psychophysical research dedicated to understanding stereopsis suggest that these features interact early in human visual processing to disambiguate depth. Single-unit recordings in the monkey also provide evidence for the joint encoding of motion and disparity across much of the dorsal visual stream. Here, we used functional MRI and multivariate pattern analysis to examine where in the human brain conjunctions of motion and disparity are encoded. Subjects sequentially viewed two stimuli that could be distinguished only by their conjunctions of motion and disparity. Specifically, each stimulus contained the same feature information (leftward and rightward motion and crossed and uncrossed disparity) but differed exclusively in the way these features were paired. Our results revealed that a linear classifier could accurately decode which stimulus a subject was viewing based on voxel activation patterns throughout the dorsal visual areas and as early as V2. This decoding success was conditional on some voxels being individually sensitive to the unique conjunctions comprising each stimulus, thus a classifier could not rely on independent information about motion and binocular disparity to distinguish these conjunctions. This study expands on evidence that disparity and motion interact at many levels of human visual processing, particularly within the dorsal stream. It also lends support to the idea that stereopsis is subserved by early mechanisms also tuned to direction of motion.

The study of cerebral lateralization of global-local visual processing inobsessive-compulsive patients

2011 ◽  
Vol 26 (S2) ◽  
pp. 966-966
Author(s):  
N. Fath ◽  
M.A. Goodarzi
Keyword(s):  
Left Hemisphere ◽  
Visual Processing ◽  
Right Hemisphere ◽  
Repeated Measure ◽  
Repeated Measure Design ◽  
Obsessive Compulsive ◽  
Cerebral Lateralization ◽  
Measure Design ◽  
Local Interference ◽  
The Right

IntroductionObsessive-compulsive patients have many problems in their processing.ObjectivesThey have a local processing than global processing. They focoused on the local aspect of world.AimsThe purpose of this study was to examine cerebral lateralization of global-local visual processing in obsessive-compulsive patients.MethodsAll participants were right handed. Participants completed Edinburgh, the padua, Beck Depression and the Anxiety Inventories and computer task. The repeated measure design of 2(2×3×2) was used to analyze the reaction time data, and the repeated measure design of 2(2×2) was used to analyze the interference data.ResultsResults indicated that OC patients were generally faster in local stimuli processing than global stimuli processing. Also in patient’s group, global stimuli (incongruent) processing contrary to local stimuli (incongruent) processing in the right hemisphere was faster than that of the left hemisphere, a result consistent with previous literature for normal people. In patient’s group, global-to-local interference contrary to local-to-global interference in the right hemisphere was greater than that of the left hemisphere, but in normal’s group, interference pattern in two hemispheres showed no significant differences. In addition, local to global interference in the left hemisphere of normal’s group was greater than that of the patient’s group, but these differences was not significant. Also results showed similar global-to-local interference in normal and patient’s group.ConclusionsIn general, the results of this study show that OC patients are faster in processing of local stimuli than global stimuli. However, this can not be attributed to a dysfunctional hemisphere.

Investigation of the Effect of Mode and Tempo on Emotional Responses to Music Using EEG Power Asymmetry

2013 ◽  
Vol 27 (3) ◽  
pp. 142-148 ◽  
Author(s):  
Konstantinos Trochidis ◽  
Emmanuel Bigand
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Emotional Responses ◽  
Interactive Effects ◽  
Eeg Activity ◽  
Musical Excerpt ◽  
Major Mode ◽  
Musical Modes ◽  
Slow Tempo ◽  
The Right

The combined interactions of mode and tempo on emotional responses to music were investigated using both self-reports and electroencephalogram (EEG) activity. A musical excerpt was performed in three different modes and tempi. Participants rated the emotional content of the resulting nine stimuli and their EEG activity was recorded. Musical modes influence the valence of emotion with major mode being evaluated happier and more serene, than minor and locrian modes. In EEG frontal activity, major mode was associated with an increased alpha activation in the left hemisphere compared to minor and locrian modes, which, in turn, induced increased activation in the right hemisphere. The tempo modulates the arousal value of emotion with faster tempi associated with stronger feeling of happiness and anger and this effect is associated in EEG with an increase of frontal activation in the left hemisphere. By contrast, slow tempo induced decreased frontal activation in the left hemisphere. Some interactive effects were found between mode and tempo: An increase of tempo modulated the emotion differently depending on the mode of the piece.

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