Exam 1 • Monday, Tuesday, Wednesday next week • WebCT testing centre • Covers everything up to and including hearing (i.e. the previous lecture)
Exam 1
• Monday, Tuesday, Wednesday next week
• WebCT testing centre• Covers everything up to and including
hearing (i.e. the previous lecture)
Exam 1
• Karla will host a review session – PE250– 3:00 to 4:00 Friday February 4– Bring specific questions to ask
A quick peek at all the other sensory systems we don’t
have time to considerTouch, Taste, Smell,
Proprioception, Thermoception and Balance
Vestibular System (Balance)
• movement of the cupula is detected by hair cells
• hair cells in the vestibular system are more sensitive than hair cells on the basilar membrane!
Vestibular, Visual, and Proprioceptive Systems Work Together
• Balance is a multimodal sense and is an example of cross-modal integration
• Try standing on one foot with your eyes closed!
Fun Facts about The Vestibular System
• Seasickness arises when the vestibular system and the visual system send conflicting information
Fun Facts about The Vestibular System
• Seasickness arises when the vestibular system and the visual system send conflicting information
• People can be knocked down by moving walls!
Fun Facts about The Vestibular System
• Seasickness arises when the vestibular system and the visual system send conflicting information
• People can be knocked down by moving walls!
• Alcohol causes the spins by (among other things) changing the density of the fluid in the semicircular canals
• Touch receptors send signals to the somatosensory cortex via long axons in the spinal cord
• Signals are sent to the opposite (contralateral) side of the brain
• Wilder Penfield - Montreal Neurological Institue - 1940’s
• Found somatotopic map by stimulating brain during surgery
The Homunculus
• Multi-dimensional scaling reveals several “varieties” of tastes:– sweet– salt– bitter– sour– umami (MSG) - possibly a protein
receptor– there may also be a lipid (fat) receptor
Taste
• Olfactory receptors use a “lock-and-key” mechanism - only specific molecules will bind with a given receptor
Smell
Receptor
Odor Molecules
• Odor recognition is excellent in humans• but odor identification (naming) is very
poor• Women tend to be (slightly) better than
men at naming smells
Smell
• Smell is strongly influenced by “top-down” processes such as what you are expecting to smell
Smell
• Pheromones are not smells• Pheromones are chemical signals sent
from one animal to another
Pheromones
• Pheromones either induce a behavior in another animal or cause some physiological change
• Very common in insects...not so common in mammals...unclear role in humans
Pheromones
• For example: Androstenone, found in male pig saliva, causes a female pig to allow the male to mate with her
Fun Facts about Pheromones
• androstenone is also found in the sweat of human males!
• Does androstenone (or pheromones in general) affect humans?
• Design an (ethical) experiment…
Fun Facts about Pheromones
• Kirk-Smith & Booth (1980) sprayed some of the seats in a dentist’s waiting room with androstenone
• Compared to a control condition, more women used the androstenone seat
Fun Facts about Pheromones
• Other possible ways in which pheromones influence humans:– synchronization of menstrual cycles– mate selection - attraction to opposite
major histocompatibility complex
Pheromones
• Pheromones do not control behavior!• Human behavior is largely under top-
down influences, but may be affected subtly by pheromones
• It is unclear whether molecules such as androstenone even qualify as pheromones - they may be just like other odour molecules
Pheromones