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59 Cards in this Set
- Front
- Back
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What is the main principle of sensory processing?
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Converting forms of energy in the environment into activation of neurons using sensory receptor organs that filter and code the incoming information into a usable form.
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What does "adequate stimulus" mean?
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Adequate stimulus is the right KIND of stimulus - e.g. photons for retina, sound waves for cochlea.
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What are the five types of sensory systems?
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Mechanical
Photic Thermal Chemical Electrical |
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What are some examples of mechanical sensory systems?
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Touch, Hearing, Vestibular, Joint, Muscle
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What is an example of photic sensory systems
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seeing
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What is an example of thermal sensory systems?
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Cold
Warmth |
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What are some examples of chemical systems
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Smell
Taste CO2 concentration (breathing) pH sensing osmotic pressure Vomeronasal (pheromones) |
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What species has an electrical sensing system?
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Sharks
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What are labeled lines?
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Particular cells that are, at the outset, labeled for distinctive sensory experience.
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What are the three stages of sensory processing?
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1. Energy of the proper type ("adequate stimulus") impinges on receptor cells
2. Receptor transduces energy into a change in electrical potential in the cell membrane ("generator potentials") (example - pacinian corpuscle deformation physically opens Na gates) 3. Stimulus characteristics are encoded |
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What information is encoded in a stimulus?
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1. Intensity (By rate of fire)
2. Source (by linked lines) 3. Location a. location of receptor(somatosensory, vision) b. intensity differences (audition, olfaction) 4. Identity (higher processing) |
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What are the two general types of receptors?
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tonic
phasic |
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If we are initially aware of a continuing stimulus but then cease to continue the same level of awareness, what is that called?
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Adaptation
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How does adaptation happen?
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Direct reduction of stimulus (tonic vs. phasic) and the brain modulation of pathways (attention)
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Name all the levels at which sensory processing occurs.
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receptors
spinal cord brain stem thalamus midbrain primary sensory cortex secondary sensory cortex |
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Why are receptive fields useful?
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It allows us to distinguish edges and discontinuities.
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What is the typical receptor style of receptive field?
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Center surround.
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What types of receptor fields exist in the cortex?
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center-surround
unimodal (one sense) polymodal (integration of multiple senses) |
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What does the property of "plasticity" mean in reference to cortical fields?
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Regions of the brain adapt. The loss of a hand does not mean the loss of the cortex used to process that information. The unused portion gets innervated by neighboring fields.
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What cortical region is especially important in attention?
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posterior parietal lobe (polymodal cells)
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What part of the brain is associated with the motivational aspect of attention?
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Posterior cingulate gyrus
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What are the parts of the skin?
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epidermis
dermis-contains most receptors subcutaneous tissue |
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Name the large touch/skin receptors
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Pacinian corpuscles & Ruffini endings
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Name the small touch/skin receptors
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Meissner's corpuscle & Merkel's discs
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Name the phasic touch/skin receptors
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Pacinian corpuscles & Meissner's corpuscle
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Name the tonic touch/skin receptors
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Ruffini endings & Merkel's discs
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Name the response type, size, and sensing function of Pacinian corpuscles
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Phasic
Large Vibration, deep pressure |
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Name the response type, size, and sensing function of Ruffini endings
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Tonic
Large Stretching |
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Name the response type, size, and sensing function of Meissner's corpuscle
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Phasic
Small Spatial discrimination |
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Name the response type, size, and sensing function of Merkel's discs
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Tonic
Small Touch |
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What are the four main types of receptor axon (mylanation?
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A-alpha
A-beta A-gamma C |
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What are the receptor types, diameter, and conduction speed of A-alpha axons?
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Muscle Spindle
13-20um 80-120 m/s |
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What are the receptor types, diameter, and conduction speed of A-beta axons?
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Pacinian corpuscles,Ruffmi endings, Meissner's corpuscle,
Merkel's discs 6-12um 35-75 m/s |
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What are the receptor types, diameter, and conduction speed of A-gamma axons?
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Free nerve endings (VRL1: pain, temp)
1-5um 5-30 m/s |
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What are the receptor types, diameter, and conduction speed of C axons?
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Free nerve endings (VR1, CMR1: temp, itch, pain)
0.02-1.5um 0.5-2 m/s |
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How far do sensory axons travel in the dorsal column system?
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All the way to the medulla.
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Where do sensory axons "cross over"
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Between the medulla and the thalamus.
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What are the four dermatomes?
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Cervical
Thorasic Lumbar Sacral |
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What is the location of the somatosensory cortex?
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The area between the central sulcus and the postcentral sulcus.
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Give examples of somatosensory cortex plasticity
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The removal of the middle finger (D3) causes the expansion of the surrounding digits (D2&D4) into the D3 area.
The association of stimulating D2&D3 digits with food causes an expansion of those areas, encroaching on D1 & D4. |
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What is needed to be done to objects for them to be accurately represented in the brain?
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Active manipulation
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What are some behavioral responses to pain?
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withdrawing
engaging in recuperative behaviors social signaling |
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What are three typical pain aspects measured?
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sensory-discriminative
motivational-affective cognitive |
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When is pain usually triggered?
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destruction or injury to tissue
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How do nerves detect pain?
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free nerve endings have receptors for chemicals or temperature changes
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What chemicals have been peripherally associated with pain detection by free nerve endings?
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Serotonin
K+ Prostaglandins Leukotrienes |
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What are the four main types of pain receptors?
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VR1 (vanilloid receptor 1)
VRL1 (vanilloid receptor-like 1) CMR1 (cool menthol receptor 1) Nociceptive |
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What does VR1 respond to and what nerve fibers does it use?
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heat (capssaicin works too)
C fibers |
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What does VRL1 respond to and what nerve fibers does it use?
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high-temp heat
A-gamma fibers |
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What does CMR1 respond to and what nerve fibers does it use?
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cool temps
C fibers |
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What system transmits temp and pain signals?
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Spinothalamic (anterolateral) pathway
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What are the four stages of Spinothalamic processing?
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a. Afferent fibers use glutamate as a neurotransmitter, with Substance P as a modulator.
b.Postsynaptic neurons in dorsal horn take up the Substance P and show plasticity of dendrites that eventually affects perception of pain c.Pain information crosses over spinal cord at the entry point d. Pain information integrated in cingulate cortex |
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What are seven ways to control pain?
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a. Opiate drugs
b. Skin stimulation c. Placebos d. Acupuncture e. Stress f. Aspirin, acetaminophen, NSAIDS g. Hypnosis |
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How do opiates control pain?
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stimulation of the periaqueductal gray matter sends signals that shut the "pain gate"
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How does skin stimulation control pain?
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affects "pain gate"
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How does a placebo control pain?
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most likely stimulates "natural" opioids
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How does a accupuncture control pain?
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most likely like opiates.
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How do NSAIDS control pain?
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block release of substances peripherally
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How does hypnosis control pain?
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cognitive/ motivational
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