GE CLST 73A Lecture Notes - Lecture 12: Primary Olfactory Cortex, Olfactory Bulb, Illusory Contours
23 Feb 2017
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Transduction in the Olfactory System
● Olfactory bulb nerves synapses STRAIGHT to the primary olfactory cortex
● Thalamus (Mediodorsal Nucleus)
● Orbitofrontal Cortex (Conscious Perception)
● Amygdala
● Hypothalamus
Role of the visual system
● To use light energy to identify objects and layout of physical world
○ Creates representation, not an accurate picture
● Mach bands
○ Our perception in the visual system
■ Edges are particularly important
■ Visual system accentuates edges
■ We perceive the white part as lighter than the grey one
● Kanizsa triangle
○ Illusory contours
○ We perceive a triangle because our brain constructs the triangle
■ If we are confronted with this pattern of light in the real world, it is very
likely that this will occur
● Therefore the brain constructs the triangle this way
Light -a stimulus
● visual system responds to a band of electromagnetic radiation
○ Has a wavelength, we are only sensitive to certain wavelengths (only a very
narrow range of wavelengths)
■ We perceive these as color
○ We are sensitive to a huge range of brightness (amount of energy)
● Frequency & amplitude
● ROYGBIV
● Bees can see UV light
○ Flowers have a center region that reflects UV light
○ Helps bees locate the center of the flower
The Eye
● Cornea (covers outside of the eye) and lens focus light
● Amount of light entering the eye is controlled by the pupil, an opening in the iris
○ Pupil dilation and constriction regulates amount of light entering
● The transduction takes place in the retina
○ Contains rods and cones, where transduction takes place
○ Bipolar cells receive input from photoreceptors and synapse on ganglion cells
whose axons form the optic nerve
● Transduction in the rods and cones
○ When light shines on retina, a cascade of events produces a hyper polarization
of rods or cones
■ The photoreceptors are depolarized?
■ Any change is information
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Document Summary
Olfactory bulb nerves synapses straight to the primary olfactory cortex. To use light energy to identify objects and layout of physical world. We perceive the white part as lighter than the grey one. We perceive a triangle because our brain constructs the triangle. If we are confronted with this pattern of light in the real world, it is very likely that this will occur. Therefore the brain constructs the triangle this way. Visual system responds to a band of electromagnetic radiation. Has a wavelength, we are only sensitive to certain wavelengths (only a very narrow range of wavelengths) We are sensitive to a huge range of brightness (amount of energy) Flowers have a center region that reflects uv light. Helps bees locate the center of the flower. Cornea (covers outside of the eye) and lens focus light. Amount of light entering the eye is controlled by the pupil, an opening in the iris.
