CH 5 Sensation & Perception (TERMS) Flashcards
Light
Electromagnetic radiation
Transduction (1,1)
Convert environmental energy into neural activity with sensory receptors
- radiant energy ⇨ sensory code
Anatomical coding (+ doctrine of specific nerve energies) (1, 2)
Specific neural circuits signify particular sensory experiences
- Doctrine of specific nerve energies: What we perceive is not the external world directly, but rather the activity of our sensory nerves
ex. Pressing on your eye can cause you to see flashes of light because the optic nerve is being stimulated, even though there is no actual light present.
Temporal coding
Rate of neural firing signifies stimulus intensity (Intensity of neuron firing determines the intensity of colour)
Retina
Screen of photoreceptors extending over most of the interior
Choroid/Pigment epithelium
Nourishes photoreceptors and absorbs excess light
Fovea
Region around axis or centre, point of focus for fixated objects
Blind spot
Point of exit of ganglion cell axons
Cornea
Transparent bulge in sclera, fixed lens
Pupil
Black hole where light enters the eye, capable of 16 fold change in area (pupil can become 16 times larger or smaller in diameter)
Iris
Coloured membrane, controls amount of light entering eye
Lens
Focuses image on retina through process of accommodation or bending to focus near objects (less than 6m)
Bipolar & Ganglion
Neurons that transmit information from the rods and cones to the brain
Horizontal
Connect receptors to receptors
Amacrine
Connect spatially adjacent bipolar and ganglion neurons
Cones (3)
shorter, thicker, tapered
photopic vision (day); high acuity, poor low-light vision
responsible for colour vision
Rods (3)
long, cylindrical
scotopic vision (night) poor acuity, excellent low-light vision
more sensitive to light
