Task 7- Own article: FOX: THE AGE-DEPENDENT NEURAL SUBSTRATES OF BLINDSIGHT Flashcards
What is Blindsight?
show spared visually driven behaviour in their scotoma, despite denial of any conscious visual experience –> unconscious vision
What is type 1 blindsight?
whereby spared visual abilities are unaccompanied by any conscious experience
What is type 2 blindsight?
patient reports some form of awareness, but the experience is merely a feeling rather than visual
What is action blindsight?
involves being able to pre-shape and orient hands in flight to match dimensions and orientation of target object when they reach out to grasp it despite not being able to report object’s shape, dimensions, or orientation
What is attention blindsight?
refers to covert shifts of attention and aspects of spatial orienting in the absence of visual experience
What does blindsight likely reflect?
reflects the engagement of multiple pathways from the eye to the brain, many of which do not project towards V1
Where do two pathways from eye to brain lead to?
V5 (MT) area
What can V5 (MT) help facilitating?
facilitates visual input when V1 absent
What happens in the developing brain after lesions of V1?
MT neurons show vigorous activity after lesions of V1
What happens if a V1 injury occurs later in life?
typical MT neural responses: more attenuated and their activity for motion and contrast sensitivity resembles response patterns observed in healthy patient’s V1
What happens in the first pathway?
- koniocellular layers ( k-layers) of LGN receive visual information from layers of SC (superior colliculus)
- LGN neurons can survive V1 lesions
- surviving neurons maintain connections w/ extra-striate cortex
What happens in the second pathway?
- Pulvinar nuclei (thalamus) receives direct retinal input
- explains how MT could receive instructive subcortical input during development (=strenghtens dorsal stream activity to visual Stimuli before V1 Input to MT is fully established)
