Vision Flashcards
What is the initial activation of the nervous system?
Sensation
What is the translation of stimulus into patterns of neural activity called?
Transduction
What is the construction of a mental representation?
Perception
Sensory systems require specialised ________ cells for transduction of the stimuli to neural impulses
Receptor
What structure of the eye forms the image that focuses light at on the retina at the back of the eye?
Cornea
What structure of the eye adjusts the shape of the image; and can change to focus on near or more distant objects, before focusing light on the retina on the back of the eye?
Lens
The _______ receives an inverted image from the cornea and lens, and converts light to electric signals
Retina
What nerve transmits electric signals to the brain?
Optic
What part of the retina is specialised for vision with fine detail?
Fovea
What area of the eye contains no photo receptors?
The Blind spot
Name two types of photoreceptors in the eye
Rods and Cones
What type of photoreceptor is sensitive to dim light, not colour?
Rods
What type of photoreceptor is sensitive to colour, and contains different types of photopigment which determines the colour (ie light wavelengths), to which they are sensitive?
Cones
If you are closer to the Fovea, would more cones or rods be predominant?
Cones
Towards the periphery of the fovea, you would you find a higher percentage of __________
Rods
Do rods or cones require higher light stimulation?
Cones
What type of photoreceptor helps us see in low light?
Rods
Name the three types of cones: ______, ______, and ______
Blue, Red and Green
There are approximately 260,000,000 _____________ cells, in comparison to 2,000,000 _________ cells in the eye
Photoreceptor, Ganglion
From the retina, information is transferred on via the ________ nerve
Optic
Optic nerve fibers cross at the optic _________
Chiasm
The left visual hemifield is “viewed” by the ________ hemisphere
Right (and vice versa)
Between the optic nerve and the primary visual cortex, where does information travel through?
The Lateral Geniculate Nucleus (LGN), which is part of the thalamus
Name the Brodmann’s area in which you would find the Primary Visual Cortex
BA 17, or V1, or Striate Cortex
A neuron will only respond to a stimulus, if it occurs in that neurons ________ ________
Receptive Field
Near what fissure would you find the Primary Visual Cortex?
Calcarine Fissure
The __________ of a visual stimulus in the receptive field will influence the degree of cell discharge (and if it discharges at all)
Orientation
The Hierarchical Coding Hypothesis suggests that regions are successively sensitive to more _______ feature combinations
Complex
There are two cortical pathways in the Visual system, one enables the brain to locate ________ an object is, and the other enables the brain to locate ________ the object is
Where, What
The “Where” pathway can be found in the _________ are of the brain
Dorsal
The “What” pathway can be found in the _________ area of the brain
Ventral
In the hierarchical organisation, when the complexity increases, the receptive field size _______ and increases in ________
Increases, Latency
__________ is the initial activation of the nervous system
Sensation
Photoreceptors contain _____________, protein molecules sensitive to light
Photopigments
Blue coloured cones respond to _________ wavelengths
Shorter
Green coloured cones respond to ________
Medium
Red coloured cones respond to ________ wavelengths
Longer
White light activates all three cone receptors because it contains all __________
wavelengths
The _________ pathway contains more than 90% if the axons in the optic nerve
Retinogeniculate
The ____________ pathway is the projection from the retina to the lateral geniculate nucleus (LGN) of the thalamus
Retinogeniculate
The LGN is made up of how many layers?
Six
The _______ Ganglion cell projects to the bottom two layers of the LGN, while the ________ Ganglion cell projects to the top for layers of the LGN
M, P
The Superior Colliculus and Pulvinar Nucleus play a large role in Visual ________
Attention
Light reflected off an object to the right of someone’s gaze will activate photoreceptors on the medial, or nasal, side of the _________ retina, and the lateral, or temporal side of the __________ retina
Right, Left
The receptive fields of cells in the LGN are _________ shape
Circular
LGN cells are ideal for signalling changes in __________
Illumination
