Unit: Sensation

10/26/12 - Formatting change (no content change)
10/22/12 - Clarified readings for Chapter 6
10/18/12 - Added Terms section
10/16/12 - More comments in Reading/Resources section
10/14/12 - Added comments to Reading/Resources section
10/3/12 - original version

Readings/Resources

To give you an idea of where to focus, we will spend 3 days of class on vision, 1 day on hearing and 1 day on olfactory/smell

We'll be talking about pathways of information through the brain, which begin to use anatomical terms such as: dorsal, posterior, medial, parietal, cortex, etc. We'll cover this in more detail in Unit 3: Organization, but you might find it helpful to briefly look over or reference:
    Section 3.3 Neuro Techniques > "Directions in the Vertebrate Nervous System"
        (specifically diagram on P62 in 8th Ed)
    Section 3.5 Five Major Divisions of the Brain > Telencephalon
        (specifically diagram on P68 in 8th Ed)

Chapter 6-- The Visual System
    All sections except the following might be covered briefly in class or not all, so you may want to skim or hold off:
    All sections of Chapter 6 will be covered except:
        In 6.4, from "Receptive Fields: Complex Cortical Cells"
            you will be tested on the material presented in Brad's lecture
        6.5 "Seeing Color" - stick to what was covered in class on Oct 22nd
            you don't need to know all the color constancy/theory in the book

Chapter 7-- Mechanisms of Perception
    This chapter will not be covered in as much detail as vision (see comment at beginning of this section)
    All sections except:
        Section 7.5 will be covered in Unit 4: Cognition

Optional resources:
    Vision research Hubel & Weisel: Intro & long version
    Olfactation fun facts: APA's Sense and Sensibility, 2011

Study Questions

Eye
    How is light turned into a neural signal?
    What are the physical (as in relating to physics) characteristics of light that the retina is sensitive to?
    What can the eye do to tailor the image that is reaching the retina?
    What are the cells in the retina that support vision?
Visual pathway
    What is the pathway from the retina to the visual cortex?
    How are the left/right sides of vision organized? (by eye, by visual field, by cortical hemisphere)
    What is retinotopic organization?
Visual processing
    What are receptive fields and how do they perform?
    How does lateral inhibition affect the way we see edges?
    How is color processed by the visual system?
    Where can the visual system be damaged and what are the corresponding deficits?
Visual Cortex
    What are the areas of the cortex that process visual information?
    What is the difference between the dorsal and ventral stream?
    How is motion processed by the visual system?
    How are faces special to the visual system?
Principles of the Visual System
    What is an example of hierarchical organization?
    What is an example of functional segregation?
    What is an example of parallel processing?
Hearing
    How is sound turned into a neural signal?
    What are the physical (as in related to physics) characteristics of sound that the cochlea is sensitive to?
    What is the pathway from the cochlea to the auditory cortex?
    How is sound localized?
    What is known about cortical processing of auditory information?
    How can the auditory system be damaged?
Somatosensory system
    What physical/tactile characteristics are somatosensory receptors sensitive to?
    What are the pathways for somatosensory information?
    How is somatosensory processing organized in the cortex?
    How is physical pain processed in the brain?
Chemical senses
    How are olfactory signals turned into a neural signal?
    How is the olfactory pathway different form other senses?
    How are taste signals turned into a neural signal?
    Which has more distinct categories that can be detected, the olfactory or taste system?

Terms

accommodation amacrine cell analgesic anterolateral system asomatognosia astereognosia bimodel binocular disparity bipolar cell blind spot center-surround cochlea cochlear implant conductive deafness cones contralateral convergence dermatome dorsal-column medial-lemniscus system dorsal/ventral stream electromagnetic spectrum flavor fovea frequency functional segregation gustation hierarchical processing homunculus

horizontal cell iodopsin iris lateral inhibition lens LGN loudness M & P channels mechanoreceptors medial geniculate nucleus nerve deafness neurogenesis neuropathic pain nociceptors olfaction olfactory bulb optic chiasm optic nerve optic tract organ of Corti parallel processing perception periaqueductal gray pheromones photoreceptor piriform cortex pitch primary auditory cortex

primary visual cortex prosopagnosia pupil receptive field retina retinal ganglion cell retinotopic rhodopsin rods saccade sensation somatosensory somatosensory cortex somatotopic organization striate cortex taste bud taste receptor thermoreceptors timbre tinnitus tonotopic organization transduction tympanic membrane unami vestibular system visual field wavelength

Clicker Questions

Monday, Oct 15

1. Based on the rod/cone connection diagram, which will provide better spatial resolution?
(meaning which provides more specific information on where the photon hit the retina)

1. a retinal ganglion cell attached to ONE CONE
   
2. a retinal ganglion cell attached to MANY RODS
   

2. A single neuron is post-synaptic to a rod photoreceptor. When light hits the rod:

1. the post-synaptic receptors will receive MORE glutamate
   
2. the post-synaptic receptors will receive LESS glutamate

Wednesday, Oct 17

1. Why is it easier to see something in the dark if you don't look directly at it?

1. Because of the blind spot
   
2. Because you have few rods in your fovea
3. Because the lens focuses peripheral objects more clearly
   

2. The visual information entering your right eye goes to...

1. The left hemisphere of your brain
2. The right hemisphere of your brain
3. Both hemispheres of your brain

3. What part of the visual system processes simple information like edges and patterns?

1. Retina
2. LGN
3. Primary visual cortex
4. Secondary visual cortex

Friday, Oct 19

1. Why would the white area within the receptive field of “A” be perceived as less bright than “B”?

1. More on-center rods are being activated in “A”
2. more off-surround rods are being activated in “A”
3. there is less total light hitting “A”
   

Monday, Oct 22

1. (Based on the "Relative Absorption" graph in the Color section)
If the "middle" cones are being stimulated to 60%, what wavelength is the light?

1. Indigo
   
2. Green
3. Red
4. Either Indigo or Green
5. Either Red or Green

2. The organ of Corti in the ear is analogous to the _________ of the eye

1. Lens
   
2. Pupil
3. Retina
4. Optic nerve

3. How is the auditory system similar to the visual system?

1. Stimuli (sounds) from the right side of space are only processed in the left hemisphere and vice versa
   
2. Information is relayed through the thalamus before getting to the cortex
   
3. Like retinotopic organization, sounds from adjacent areas in space will activate adjacent areas on the cochlea
4. More than 1 of these is true

Wednesday, Oct 24

1. How does a cochlear implant work?

1. Electrodes stimulate areas of the cochlea based on what frequencies are being presented
   
2. Amplified sound is targeted at the cochlea
   
3. Electrical stimulation increases the sensitivity of the cochlea
   

2. Which is true of the somatotopic organization (in the primary somatosensory cortex)?

1. Sensation from the right side is processed by the left cortex
   
2. Adjacent regions of the body are represented in adjacent regions of the cortex
   
3. Large body regions have large cortical representations
4. 2 out of 3 of these are true
5. 3 out of 3 of these are true

I didn't have time to get to this question:

3. The olfactory system is unique among the sensory systems in that 

A) it is constantly growing new neurons
B) its signals are relayed to the cortex by the thalamus.
C) its signals reach cortical tissue before reaching the thalamus
D) A & B are true
E) A & C are true