A comparison of blocked and mixed‐trial methods for teaching auditory–visual discriminations

2018 ◽  
Vol 52 (2) ◽  
pp. 534-540
Author(s):  
Stephanie N. Bentham ◽  
Stephen F. Walker ◽  
Maria E. Vander Pluym ◽  
Kristina N. Tejeda
Keyword(s):  
Visual Discriminations

Deficits in Complex Visual Perception Following Unilateral Temporal Lobectomy

1998 ◽  
Vol 10 (3) ◽  
pp. 395-407 ◽  
Author(s):  
Krystel R. Huxlin ◽  
William H. Merigan
Keyword(s):  
Visual Field ◽  
Visual Perception ◽  
Temporal Cortex ◽  
Stimulus Presentation ◽  
Texture Segmentation ◽  
Temporal Lobectomy ◽  
Long Term Memory ◽  
Additional Control ◽  
Short And Long Term ◽  
Visual Discriminations

Although human temporal cortex is known to be important for short- and long-term memory, its role in visual perception is not well understood. In this study, we compared the performance of three patients with unilateral temporal lobectomies to that of normal controls on both fisimplefl and ficomplexfl visual discriminations that did not involve explicit memory components. Two types of complex tasks were tested that involved discriminations secondary to texture segmentation. These were contrasted with simple discriminations using luminance-defined stimuli. Patients showed impaired thresholds only on tasks involving texture segmentation, performing as well as controls when the targets were defined by luminance rather than texture. The minimum stimulus presentation times for threshold performance were also measured for all tasks and found to be elevated in temporal lobectomy patients relative to controls. Although the magnitude of the deficits observed was substantial, loss was equivalent in ipsi- and contra-lesional regions of the visual field. Additional control experiments showed that the patients' perceptual deficits were not due, even in part, to disturbances of basic visual capacities such as acuity and contrast sensitivity. Our results indicate that temporal lobe damage disrupts complex, but not simple, visual discriminations throughout the visual field.

Visual Discriminations of a Subject with Acquired Unilateral Tritanopia

Science ◽  
1963 ◽  
Vol 140 (3565) ◽  
pp. 381-382 ◽  
Author(s):  
C. H. Graham ◽  
Y. Hsia ◽  
F. F. Stephan
Keyword(s):  
Visual Discriminations

Human Brain Regions Involved in Visual Discriminations

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 298-298
Author(s):  
G A Orban
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Brain Regions ◽  
Orientation Discrimination ◽  
National Academy Of Sciences ◽  
Temporal Comparison ◽  
Dot Motion ◽  
Speed Discrimination ◽  
Academy Of Sciences ◽  
Visual Discriminations

We have used simple visual discriminations as a tool to investigate the human visual system with PET and fMRI. In discrimination tasks, stimuli in which an attribute is defined by a cue are presented in a position in the visual field and the subjects compare the stimuli with each other or with a standard. We have manipulated each of these four aspects. Manipulation of stimulus position engages visuo-spatial attention mechanisms in parietal and frontal cortex (Vandenberghe et al, 1996 Brain119 1263 – 1276; 1997 Journal of Neuroscience in press). Manipulation of the cue has revealed the kinetic occipital (KO) region involved in the processing of kinetic contours (Orban et al, 1995 Proceedings of the National Academy of Sciences of the USA92 993 – 997; Dupont et al, 1997 Cerebral Cortex in press). Using luminance-defined patterns presented centrally and contrasting successive orientation discrimination with identification we have demonstrated the involvement of right fusiform cortex in temporal comparison of orientation (Orban et al, 1997 European Journal of Neurosciences9 246 – 259). The same region is involved in spatial comparison of orientation as well as in temporal comparison of speed and direction of random-dot motion. This set of experiments shows that processing in the human visual system depends not only on the attribute used but also on the nature of the task to be performed. The direction and speed discrimination experiments also reveal the involvement of the lingual motion area in these tasks, but surprisingly very little involvement of human MT/V5.

Visual discriminations of a subject with acquired unilateral tritanopia

1967 ◽  
Vol 7 (5-6) ◽  
pp. 469-479 ◽  
Author(s):  
C.H. Graham ◽  
Yun Hsia ◽  
F.F. Stephan
Keyword(s):  
Visual Discriminations
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