Chapter 5 Perception & Sensation Flashcards
What does each sensory system do?
Collect, filter and amplify information
What happens at the pontomedullary junction?
Facial nerves enter the brain
What region do all sensory nerves terminate?
Different parts of the Thalamus
What do rods and cones lack when compared to other neurones?
They do not fire action potentials
What are the two types of protein photo pigments found in the eye?
Rhodopsin in the rods and photospin in the cones
How think is the retina and what is it made up of?
0.5mm thick and is made up of 10 layers of neutrons
What is the main function of rod photoreceptors?
They enable us to see better in the dark as rhodopsin splits and destabilises in low levels of light
How many types of photospin are there and what are their corresponding wavelengths?
Three:
Short wavelengths that respond to blue colours
Medium wavelengths that respond to green
Long wavelengths that respond to red
What is the fovea?
An area of the retina that contains densely packed cone photoreceptors
BONUS less cones are found in the periphery of the eye which is why we can’t make out colours that well unless we look directly at an object
What are ganglion cells and how many do we have?
They are interneuro a connecting photoreceptors to the optic nerve
We have approximately 2 million ganglion cells and about 260 million photoreceptors in our eye
What are the two visual fields and how are they perceived by the eyes?
Left and right visual fields which are broken down into temporal (lateral) and nasal (medial) pathways; all information from the right visual field is processed in the left hemisphere and all information from the left is processed in the right
What is an example of a sensory system?
Outer ear, ear canal, and the inner ear; eye muscles, cornea, pupil, lens, and retina
What is the optic chiasm?
Where the two optic nerve parts crossover in the brain
90% of axons of the optic nerve follow which pathway?
The retino geniculate pathway
Where do the other 10% of neurons go?
Innervate subcortical structures
What does LGN stand for?
Lateral geniculate nucleus
What are the main components of the subcortical structures associated with vision?
Pulvinar nucleus (thalamus) and the superior colliculus (midbrain)
What is the edge of darkness?
A great name for a band and where a concentric centre-surround organisation cell is most active
What types of cells are concentric centre- surround organisation cells?
LGN cells, ganglion cells and primary visual cortex cells
What is the fundamental principle of perception?
The nervous system is primarily interested in change
Describe how a concentric centre-surround organisation cells works?
It is activated or excited when light encompasses the centre, inhibited when light is positioned on the surround and shows no change when light crosses both sections
What is the hallmark of cells in the PVC?
Orientation selectivity
What is the hierarchical theory of visual processing?
Each area is responsible for a different part of visual processing which builds on the last EG V1 identifies edges, V2 corners and edge terminations, V3 shapes and V4 matching to shapes stored on memory etc
What theory can be described as the divide and conquer approach to visual processing?
The analytic process theory
What is the optic chiasm?
Where the two optic nerve parts crossover in the brain
90% of axons of the optic nerve follow which pathway?
The retino geniculate pathway
Where do the other 10% of neurons go?
Innervate subcortical structures
What does LGN stand for?
Lateral geniculate nucleus
What are the main components of the subcortical structures associated with vision?
Pulvinar nucleus (thalamus) and the superior colliculus (midbrain)
What is the edge of darkness?
A great name for a band and where a concentric centre-surround organisation cell is most active
What types of cells are concentric centre- surround organisation cells?
LGN cells, ganglion cells and primary visual cortex cells
What is the fundamental principle of perception?
The nervous system is primarily interested in change
Describe how a concentric centre-surround organisation cells works?
It is activated or excited when light encompasses the centre, inhibited when light is positioned on the surround and shows no change when light crosses both sections
What is the hallmark of cells in the PVC?
Orientation selectivity
What is the hierarchical theory of visual processing?
Each area is responsible for a different part of visual processing which builds on the last EG V1 identifies edges, V2 corners and edge terminations, V3 shapes and V4 matching to shapes stored on memory etc
What theory can be described as the divide and conquer approach to visual processing?
The analytic process theory
