The primitive retino-tecto-reticular pathway is functional in hemidecorticate patients

Savina, Olga; Guitton, Daniel

doi:10.1016/j.cub.2018.09.006

Cited by 10 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In terms of the brain regions responsible for blindsight, the observation with extensive ablation of the cortical tissue suggests the totally subcortical processing for some visuomotor functions (Tomaiuolo et al, 1997;Savina and Guitton, 2018); but other studies suggest the involvement of cortical visual processing for goal-directed movements in the blindsight subjects (monkeys: Schmid et al, 2010;Bridge et al, 2019;humans: Ajina et al, 2015;Ajina and Bridge, 2018). As for the visual pathway to the cortex, the earlier studies focused on the role of the superior colliculus (SC)-pulvinar-extrastriate pathway to bypass the V1 (Diamond and Hall, 1969;Bender, 1983Bender, , 1988Warner et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Contribution of the Pulvinar and Lateral Geniculate Nucleus to the Control of Visually Guided Saccades in Blindsight Monkeys

et al. 2020

View full text Add to dashboard Cite

After damage to the primary visual cortex (V1), conscious vision is impaired. However, some patients can respond to visual stimuli presented in their lesion-affected visual field using residual visual pathways bypassing V1. This phenomenon is called "blindsight." Many studies have tried to identify the brain regions responsible for blindsight, and the pulvinar and/or lateral geniculate nucleus (LGN) are suggested to play key roles as the thalamic relay of visual signals. However, there are critical problems regarding these preceding studies in that subjects with different sized lesions and periods of time after lesioning were investigated; furthermore, the ability of blindsight was assessed with different measures. In this study, we used double dissociation to clarify the roles of the pulvinar and LGN by pharmacological inactivation of each region and investigated the effects in a simple task with visually guided saccades (VGSs) using monkeys with a unilateral V1 lesion, by which nearly all of the contralesional visual field was affected. Inactivating either the ipsilesional pulvinar or LGN impaired VGS toward a visual stimulus in the affected field. In contrast, inactivation of the contralesional pulvinar had no clear effect, but inactivation of the contralesional LGN impaired VGS to the intact visual field. These results suggest that the pulvinar and LGN play key roles in performing the simple VGS task after V1 lesioning, and that the visuomotor functions of blindsight monkeys were supported by plastic changes in the visual pathway involving the pulvinar, which emerged after V1 lesioning.

show abstract

Section: Introductionmentioning

confidence: 99%

Contribution of the Pulvinar and Lateral Geniculate Nucleus to the Control of Visually Guided Saccades in Blindsight Monkeys

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Schiller, Stryker, Cynader, and Berman (1974) demonstrated that a 0.3° flash produced strong activation in monkey SC (stimulus duration = 1 s) when the V1 activity was suppressed by cooling. Furthermore, monkeys with V1 lesions manifest blindsight-like behavior in response to small and briefly presented stimuli (Mohler & Wurtz, 1977), and human patients with blindsight can unconsciously process small and brief stimuli (e.g., Savina & Guitton [2018] used a 0.5° stimulus with an 86-ms duration). We have also previously shown that RTE can be observed when similar small and brief achromatic contrast stimuli were suppressed by TMS of V1 at a 90 ms SOA (Hurme et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Neuronavigated TMS of early visual cortex eliminates unconscious processing of chromatic stimuli

et al. 2020

View full text Add to dashboard Cite

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

show abstract

“…Schiller, Stryker, Cynader, and Berman (1974) demonstrated that a 0.3° flash produced strong activation in monkey SC (stimulus duration = 1 s) when the V1 activity was suppressed by cooling. Furthermore, monkeys with V1 lesions manifest blindsight-like behavior in response to small and briefly presented stimuli (Mohler & Wurtz, 1977), and human patients with blindsight can unconsciously process small and brief stimuli (e.g., Savina & Guitton [2018] used a 0.5° stimulus with an 86-ms duration). We also previously showed that the RTE could be observed when similar small and brief achromatic contrast stimuli were suppressed by the TMS of the V1 at a 90-ms SOA (Hurme et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

TMS of V1 eliminates unconscious processing of chromatic stimuli

Hurme

Koivisto

Henriksson

et al. 2019

Preprint

View full text Add to dashboard Cite

Some of the neurological patients with primary visual cortex (V1) lesions can guide their behavior based on stimuli presented to their blind visual field. One example of this phenomenon is the ability to discriminate colors in the absence of awareness. These so-called patients with blindsight must have a neural pathway that bypasses the V1, explaining their ability to unconsciously process stimuli. To test if similar pathways function in neurologically healthy individuals or if unconscious processing depends on the V1, we disturbed the visibility of a chromatic stimulus with metacontrast masking (Experiment 1) or transcranial magnetic stimulation (TMS) of the V1 (Experiment 2). We measured unconscious processing using the redundant target effect (RTE), which is the speeding up of reaction times in response to dual stimuli compared with one stimulus, when the task is to respond to any number of stimuli. An unconscious chromatic RTE was found when the visibility of the redundant chromatic stimulus was suppressed with a visual mask. When TMS was applied to the V1 to disturb the perception of the redundant chromatic stimulus, the RTE was eliminated. Based on our results and converging evidence from previous studies, we conclude that the unconscious processing of chromatic information depends on the V1 in neurologically healthy participants.

show abstract

The primitive retino-tecto-reticular pathway is functional in hemidecorticate patients

Cited by 10 publications

References 11 publications

Contribution of the Pulvinar and Lateral Geniculate Nucleus to the Control of Visually Guided Saccades in Blindsight Monkeys

Contribution of the Pulvinar and Lateral Geniculate Nucleus to the Control of Visually Guided Saccades in Blindsight Monkeys

Neuronavigated TMS of early visual cortex eliminates unconscious processing of chromatic stimuli

TMS of V1 eliminates unconscious processing of chromatic stimuli

Contact Info

Product

Resources

About