Sensation and Perception Flashcards
What is sensation?
Simple stimulation of a sense organ, basic registration of sensory stimuli, detection of physical energy by sense organs
What is perception?
Organization, identification, and interpretation of a sensation in order to form a mental representation
What is transduction?
When many sensors in the body convert physical signals from the environment into encoded neural signals sent to the CNS
Sensory adaptation
Tendency to pay less attention to a non-changing source of information
Paying less attention to a stimuli over time
What does length of light wave correlate to?
Hue or what we perceive as color
What does amplitude of light wave correlate to?
Brightness
What does purity of light wave correlate to?
Saturation or richness of color
Describe
The path of light sensation
- Eye
- Lens inverts and focuses
- Retina (photoreceptors)
- Light causes changes in photopigments
- Electural current -> neural signal
- Bipolar and ganglion cells
- Retinal ganglion cells fire action potentials
- Optic nerve
- Optic chiasm (crossover)
- Thalamus
- Optic radiation
- Primary visual cortex (V1)
- Secondary areas (V2, V3, etc.
Cones
Detect color, operate under normal daylight conditions, focus on fine detail, concentrated in fovea, red, green, and blue
Rods
Active under low-light conditions for night vision, basic shape and form, involved in dark adaptation
Receptive field
Area of external space within which a stimulus must be present to activate the cell
Fundamental principle of perception
The brain cares about change
V1
Oriented lines, as you move an electrode across the cortex, neurons respond to differently oriented lines
V4
Color, shapes, attention
V5
Motion-activated, movement, speed
Dorsal vs. Ventral visual pathways
D: where
V: what
Describe the
Auditory pathway
Stimulus = sound wave
1. Outer ear (air) - pressure
2. Middle ear (bones) - vibrate
3. Inner ear (fluid) - waves
4. Cochlea (hair cells)
a. hair cells move
b. neurotransmitters enter
c. action potentials
5. Auditory nerve
6. Midbrain relays (cochlear nucleus, inferior colliculus)
7. Thalamus MGN
8. Primary auditory cortex A1
9. Secondary auditory cortex A2
Interaural time and intensity differences
Sound reaches the closer ear first and is louder in the closer ear
Merkel’s corpuscles
Regular touch
Meissner’s corpuscles
Light touch
Pacinian corpuscles
Deep pressure
Ruffini corpuscles
For temperature
Nociceptors
Signal pain via both myelinated AND unmyelinated fibers
Proprioceptors
At linkages of muscles and tendons, provide physical state
Describe the
Somatosensory pathway
- Spinal nerve
- Spinal cord
- Brainstem/midbrain relays (cross)
- Thalamus
- Primary somatosensory cortex S1
- Secondary somatosensory cortex S2
- Cerebellum, etc.
S1
Contains representation of the body (homunculus)
S2
Builds more complex representations, texture and size
Recieves info from both hemispheres, forming integrated representations
Describe the path of olfaction
- Nose
- Nasal cavity (odor receptors)
- Odorant binds to bipolar neuron
- Signaling cascade > action potential
- Signal sent to olfactory bulb
- Olfactory nerve
- Primary olfactory cortex
- Orbitofrontal cortex
Describe
Nostril asymmetry
Nostril size changes every few hours, one is always larger and has greater input airflow than the other
Describe the pathway of gustation
- Papilla
- Tastebuds & taste receptor cells
- Nerves
- Nucleus of the solitary tract
- Thalamus
- Taste zone of cortex
