Vision in a Monkey without Striate Cortex: A Case Study

Perception ◽  
1974 ◽  
Vol 3 (3) ◽  
pp. 241-255 ◽  
Author(s):  
N K Humphrey
Keyword(s):  
Rhesus Monkey ◽  
Striate Cortex ◽  
Visually Guided ◽  
Permanent Loss ◽  
Limited Degree ◽  
Ambient Vision

A rhesus monkey, Helen, from whom the striate cortex was almost totally removed, was studied intensively over a period of 8 years. During this time she regained an effective, though limited, degree of visually guided behaviour. The evidence suggests that while Helen suffered a permanent loss of ‘focal vision’ she retained (initially unexpressed) the capacity for ‘ambient vision’.

scholarly journals Collicular Vision Guides Nonconscious Behavior

2010 ◽  
Vol 22 (5) ◽  
pp. 888-902 ◽  
Author(s):  
Marco Tamietto ◽  
Franco Cauda ◽  
Luca Latini Corazzini ◽  
Silvia Savazzi ◽  
Carlo A. Marzi ◽  
...  
Keyword(s):  
Visual Experience ◽  
Striate Cortex ◽  
Visual Signals ◽  
Visually Guided ◽  
Visuomotor Integration ◽  
Motor Processing ◽  
Pupillary Responses ◽  
Cortex Area ◽  
Extrastriate Areas

Following destruction or deafferentation of primary visual cortex (area V1, striate cortex), clinical blindness ensues, but residual visual functions may, nevertheless, persist without perceptual consciousness (a condition termed blindsight). The study of patients with such lesions thus offers a unique opportunity to investigate what visual capacities are mediated by the extrastriate pathways that bypass V1. Here we provide evidence for a crucial role of the collicular–extrastriate pathway in nonconscious visuomotor integration by showing that, in the absence of V1, the superior colliculus (SC) is essential to translate visual signals that cannot be consciously perceived into motor outputs. We found that a gray stimulus presented in the blind field of a patient with unilateral V1 loss, although not consciously seen, can influence his behavioral and pupillary responses to consciously perceived stimuli in the intact field (implicit bilateral summation). Notably, this effect was accompanied by selective activations in the SC and in occipito-temporal extrastriate areas. However, when instead of gray stimuli we presented purple stimuli, which predominantly draw on S-cones and are thus invisible to the SC, any evidence of implicit visuomotor integration disappeared and activations in the SC dropped significantly. The present findings show that the SC acts as an interface between sensory and motor processing in the human brain, thereby providing a contribution to visually guided behavior that may remain functionally and anatomically segregated from the geniculo-striate pathway and entirely outside conscious visual experience.

scholarly journals Contrasting effects of strabismic amblyopia on metabolic activity in superficial and deep layers of striate cortex

2015 ◽  
Vol 113 (9) ◽  
pp. 3337-3344 ◽  
Author(s):  
Daniel L. Adams ◽  
John R. Economides ◽  
Jonathan C. Horton
Keyword(s):  
Metabolic Activity ◽  
Striate Cortex ◽  
Optokinetic Nystagmus ◽  
Rectus Muscle ◽  
Visually Guided ◽  
Experimental Intervention ◽  
Deep Layers ◽  
Unusual Occurrence ◽  
Fixation Preference ◽  
The Right

To probe the mechanism of visual suppression, we have raised macaques with strabismus by disinserting the medial rectus muscle in each eye at 1 mo of age. Typically, this operation produces a comitant, alternating exotropia with normal acuity in each eye. Here we describe an unusual occurrence: the development of severe amblyopia in one eye of a monkey after induction of exotropia. Shortly after surgery, the animal demonstrated a strong fixation preference for the left eye, with apparent suppression of the right eye. Later, behavioral testing showed inability to track or to saccade to targets with the right eye. With the left eye occluded, the animal demonstrated no visually guided behavior. Optokinetic nystagmus was absent in the right eye. Metabolic activity in striate cortex was assessed by processing the tissue for cytochrome oxidase (CO). Amblyopia caused loss of CO in one eye's rows of patches, presumably those serving the blind eye. Layers 4A and 4B showed columns of reduced CO, in register with pale rows of patches in layer 2/3. Layers 4C, 5, and 6 also showed columns of CO activity, but remarkably, comparison with more superficial layers showed a reversal in contrast. In other words, pale CO staining in layers 2/3, 4A, and 4B was aligned with dark CO staining in layers 4C, 5, and 6. No experimental intervention or deprivation paradigm has been reported previously to produce opposite effects on metabolic activity in layers 2/3, 4A, and 4B vs. layers 4C, 5, and 6 within a given eye's columns.

Visually Guided Acquisition of Contact Dynamics and Case Study in Data-Driven Haptic Texture Modeling

2020 ◽  
Vol 13 (3) ◽  
pp. 611-627 ◽  
Author(s):  
Arsen Abdulali ◽  
Ibragim R. Atadjanov ◽  
Seokhee Jeon
Keyword(s):  
Contact Dynamics ◽  
Data Driven ◽  
Visually Guided ◽  
Texture Modeling

Visual aftereffects and the consequences of visual system lesions on their perception in the rhesus monkey

1994 ◽  
Vol 11 (4) ◽  
pp. 643-665 ◽  
Author(s):  
Peter H. Schiller ◽  
Robert P. Dolan
Keyword(s):  
Rhesus Monkey ◽  
Visual System ◽  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Luminance Contrast ◽  
Repeated Exposure ◽  
Lateral Geniculate ◽  
Central Factors

AbstractThis study examined the consequences of visual system lesions on visual aftereffects produced by achromatic stimuli of various luminance contrasts and chromatic stimuli of various wavelength compositions. The effects of repeated exposure to such adapting stimuli were assessed using probes whose luminance contrast and wavelength composition were systematically varied using both detection and discrimination paradigms. Interocular tests revealed that both peripheral and central mechanisms contribute to the visual aftereffects produced by the adapting stimulus arrays used in this study. Contrary to the hypothesis according to which the midget system of the retina is the conveyor of visual afterimages, we found that blocking this system with lesions of parvocellular lateral geniculate nucleus, through which the midget cells make their way to the striate cortex in primates, did not eliminate the visual aftereffects. It appears therefore that the parasol system of the retina, which courses through the magnocellular layers of the lateral geniculate nucleus to cortex, can convey the necessary signals for the generation of visual aftereffects. Lesions of areas V4 and MT did not have significant effects on the visual aftereffects studied suggesting that the central factors that contribute to the visual aftereffects occur either already in area VI or are conveyed to higher centers through regions other than areas V4 and MT.

scholarly journals “Die Muttersprache vergisst man nicht” – or do you? A case study in L1 attrition and its (partial) reversal,

2009 ◽  
Vol 13 (1) ◽  
pp. 19-31 ◽  
Author(s):  
DORIS STOLBERG ◽  
ALEXANDRA MÜNCH
Keyword(s):  
Language Skills ◽  
Research Interest ◽  
Language Attrition ◽  
Primary Research ◽  
Permanent Change ◽  
L1 Attrition ◽  
Permanent Loss ◽  
Primary Research Interest ◽  
Partial Reversal

Is it possible to undo or reverse language attrition? In other words, has there been, in the case of attrition, a permanent change with respect to the speaker's L1 knowledge, or do we only see temporary effects on the control of that knowledge? It is proposed here that the concept of attrition should include the temporary loss of language skills since it is, so far, not clear whether or to what extent once-acquired linguistic abilities can be permanently lost at all, particularly with respect to an L1. A reversal in the development of attrition after renewed contact with the L1 can support the claim that a decrease in L1 proficiency can be temporary, and that it is the accessibility of items and structures that is affected by attrition rather than the L1 knowledge (competence) itself. Our primary research interest in the present study is to analyze what skills and features are recoverable and what phenomena persist, (possibly) indicating permanent loss.

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