Chapter 2: Sensation and Perception

conversion or transduction of physical, electromagnetic, auditory, and other information from the internal and external environment into electrical signals.
processing of sensation to make sense of it
Sensory receptors include:
photoreceptors, hair cells, nociceptors, thermoreceptors, osmoreceptors, olfactory receptors, and taste receptors
Sensory ganglia
Regions that received receptors that are not connected to the CNS.
Absolute threshold
minimum of stimulus needed to activate a sensory a sensory system
Threshold of conscious perception
minimum stimulus needed to activate a sensory system large enough to bring conscious awareness
Difference threshold (or just-noticeable difference)
minimum difference in magnitude that a signal will be noticed.
Weber's law
The JND and magnitude of a signal are proportional. Keep in mind this is proportion, not a set difference. So if it is 50% then .5 of 100hz is 50hz difference, and .5 of 1000hz means a difference of 500hz.
Signal Detection Theory
effects of non-sensory factors (such as experiences, motives, and expectations) on perceptions of stimuli. For example, it may affect response bias ( hits, misses, false alarms, and correct negatives)
gathers and filters incoming light
muscular structure that controls the amount of light entering the pupil. It has a dilator and constrictor pupillae that do this.
refracts incoming light to focus it on the retina and is held in place by suspensory ligaments.
Ciliary body
creates aqueous humor that drains into the canal of Schlemm
Visual pathway
rods/cones -> bipolar cells -> ganglion cells -> optic nerves -> optic chiasm -> optic tracts -> Lateral geniculate nucleus (LGN)
LGN (lateral geniculate nucleus)
Receives visual information LGN (for "looking")
Parvocellula cells
Visually detect shape (high resolution, low temporal resolution)
Magnocelllar cells
Visually detect motion (low resolution, high temporal resolution)
Middle ear components
Malleus, incus, and stapes
Inner ear components
bony labyrinth, membranous layrinth
Filled with perilymph and endolymph
saccule and utricle (lateral acceleration)
semicircular canals (detect rotational acceleration)
Medial geniculate nucleus (MGN)
area of the thalamus that is the auditory cortex
Smell pathway
nares -> olfactory nerves -> olfactory bulb --> olfactory tract
four touch modalities, pressure, vibration, pain, and temperature.
Pacinian Corpuscles (Nerves)
respond to deep pressure and vibration
Meissner corpuscles (nerves)
respond to light touch
Merkle cells (nerves)
respond to deep pressure and texture
Ruffini endings (nerves)
respond to stretch
free nerve endings (nerves)
respond to pain and temperature
Gestalt principles
The brain can infer the missing parts of a picture when a picture is incomplete