Chapter 7 Flashcards
_________________ cortex is a cortical area that receives input from more than one sensory system.
Association
Most input to areas of _________________ cortex comes via areas of _________________ cortex.
association; secondary sensory
The hierarchical organization of sensory systems is apparent from a comparison of the effects of damage to various levels. In general:
the higher the level of damage, the more specific and complex the deficit.
Research reveals that sensory systems are characterized by functional _____ and _____ processing.
segregation; parallel
________________ processing refers to the simultaneous analysis of a signal in different ways by the multiple parallel pathways of a neural network.
Parallel
A mixture of pure tones with frequencies of 200, 300, and 400 Hz would be perceived as having the same pitch as a pure tone of 100 Hz. This important aspect of pitch perception is called the:
missing fundamental.
The cochlea is a long, coiled tube containing the auditory receptor organ, which runs almost to its tip. This auditory receptor organ is called the:
organ of Corti.
As compared to their visual counterparts, the subcortical pathways in the auditory system seem:
more complex.
Primate auditory cortex is organized:
tonotopically
________________ bypass damage to the auditory hair cells by converting sounds picked up by a microphone on the patient’s ear to electrical signals, which are then conducted directly to the cochlea.
Cochlear implants
The largest and deepest cutaneous receptors are the:
Pacinian corpuscles.
________________ neurons that respond to both visual and somatosensory stimulation are found in the ________________ parietal cortex.
Bimodal; posterior
The inability to recognize objects by touch is called:
astereognosia
Somatosensory signals are conducted to areas of association cortex in ________________ cortex.
both prefrontal and posterior parietal
Neuropathic pain is believed to be caused by:
abnormal activity in the CNS.
Compare/contrast the pathways from sensory neuron to brain for visual vs. auditory vs. somatosensory systems. Is the somatosensory system “crossed” (i.e., does information from one side of the body get sent to the opposite side of the brain)?
Somatosensory:
Somatosensory. Nerves → Thalamus (VPN) → primary somatosensory cortex (anterior p. lobe) → secondary somatosensory cortex → assoc. Cortex (p.p. Cortex, PFC)
Visual:
Retina → Thalamus (LGN) → primary visual cortex → secondary visual cortex → assoc. Cortex (ventral and dorsal streams)
Audition:
Inner ear → hindbrain → inferior colliculi → thalamus (MGN) → primary auditory cortex → secondary auditory cortex → assoc. Cortex (p.p. Cortex, PFC)
Yes the somatosensory system is crossed
Somatosensation is composed of what 3 sub-types of somatosensory systems? Where are the sensory nerve endings in each sub-system, and what does each of these sub-systems enable you to detect? (come up with some of your own examples)
Exteroceptive System: nerve endings in the skin, detect touch, temp and pain. (touching a hot stove)
Proprioceptive System: nerve endings in muscles, tendons, and joints, provide body position/ balance info ( → cerebellum, largely unconscious) (when you are playing sports and you keep your balance even though there is a lot of jostling)
Interoceptive System: Nerve endings in organs (gut, lungs, heart, bladder) (when you are hungry you feel it)
What types of sensory nerves (named for their specialized nerve endings, “receptors”) are there in the exteroceptive somatosensory system, and what type of physical stimulus causes each of them to fire?
Mechanoreceptors respond to pressure
Thermoreceptors; respond to temperature change
Explain how mechanoreceptors vs. thermoreceptors transduce physical stimuli (e.g., pressure vs. temperature) into electrochemical signals. In other words, what causes these nerve endings to depolarize?
Mechanoreceptors: the deformation of nerve endings open Na+ channels → depolarization
Rapid adaption to constant pressure. Which is why you no longer feel your clothes on you after dressing
Thermoreceptors: fire in response to cold or heat; have cation channels that are temp- sensitive.
Explain how the number of somatosensory nerve endings and number of primary somatosensory (S1) neurons relate to how sensitive different parts of your body are to touch. How is the primary somatosensory cortex organized?
Homunculus, more nerve ending on the mouth and tongue, hands, feet, genitals than the rest of the body.
Describe how limited vs. extensive damage to somatosensory nerve endings in skin, vs. spinal cord damage at different levels, vs. single vs. dual hemisphere damage to VPN or primary somatosensory cortex might affect one’s somatosensory experiences and abilities.
Damage to Sensory nerve endings: your brain would do completion when you see someone touch you.
Damage Spinal cord: the higher the damage the more conscious perception you lose, the more loss you will have in the body., also loss of feeling
Damage to VPN on one side: you would not feel things coming from the opposite side
Damage to primary somatosensory cortex: distorted or changed sensation from the other side, they can tell they have something in their hand but can’t tell what it is Restricted → mostly touch discrimination. More extensive → cannot identify objects by touch w/ opposite hand
Describe what substantial damage to the right posterior parietal lobe causes. Contrast this syndrome with what happens when a person sustains damage to their left posterior parietal lobe (see Ch. 8 lecture notes).
Asomatoagnosia: failure to percieve/ recognize left side or self and world. A somatosensory and visual deficit
