Week 4: Sensory and Motor Function Flashcards
Perception
interpretation at the higher order; one sensation can produce multiple perceptions
Sensation
Early processing of energy
Similarity of sensory pathways
All 5 senses begin with a specialized organ and receptor cells, involve the PNS, synapse with the brain, interact with the thalamus (all except smell), and have dedicated cortical areas (primary and secondary)
Role of the thalamus
To direct AND modify sensory stimuli
Sense organs
Eyes = vision
Ears = hearing
Nose = olfaction/smell
Tongue = gustation/taste
Skin = touch
Rate adaptation
When exposed to prolonged stimulus, sensory neurons will adapt their firing rate (either increase or decrease)
Sensory Nerves
Cranial nerves = related to the face
Spinal/peripheral nerves = relate to touch/the body
All nerves stop in the thalamus before moving to cortex (except smell)
Sensory nerve - Smell
Nerve I - olfactory
Sensory nerve - Vision
Nerve II - optic nerve
Sensory nerve - Hearing
Nerve VIII - vestibulocochlear nerve; does two jobs of balance and hearing
Sensory nerve - Taste
Nerves 7, 9, 10 - Facial nerve, glossopharyngeal nerve, vagus nerve
Sensory nerve - Touch
Many peripheral nerves used to detect touch
Cortex for Smell
Primary = pyriform
Secondary = orbitofrontal
Cortex for Taste
Primary = insula
Secondary = orbitofrontal
Cortex for Hearing
Temporal (primary and secondary)
Cortex for Touch
Parietal (primary and secondary)
Cortex for Vision
Occipital (primary and secondary)
Sensory Cortexes
Follows hierarchical processing (always processed in the primary cortex before the secondary); has segregated representation; plastic and adaptable to change
Segregated representation
Different cells for different stimuli are organized together (ex: groups of cells for high and low frequencies); disproportionate compared to the body due to adaptive utility
Adaptive utility
When the representation of a sense is adapted to be bigger or smaller than the bodily representation based on amount of use
Smell/Olfaction
Uses: detection of threats (poison, smoke, etc.) and social behavior
Pathway: bipolar receptors -> glomerulus -> olfactory nerve -> primary Cortex (pyriform) -> secondary cortex (orbitofrontal); chemical sense that does NOT pass through the thalamus
Shape/docking theory of smell
Key-and-lock model. Suggests that specific odorants body with specific shaped sensory neurons/receptors