Univ. of Illinois, Urbana-Champaign Bio/Neuro 303 Chapter 10 - Study Questions *** LAST UPDATED - 01 OCTOBER 2002*** 47. Coding in sensory systems means a. the way the energy of the stimulus is transformed to changes in nerve membrane potential. *b. the way information about the stimulus is conveyed to sensory centers. c. the control of a sense organ's output by coded signals from the central nervous system. d. the system by which sense organs are protected from adaptation. 50. In sensory neurons, stimulus intensity is usually coded by a. absolutely labeled lines for each intensity. b. topographical organization. c. across fiber patterning. *d. variations in spike frequency. 54. The frequency of action potential in a sensory neuron can encode *a. the strength of a stimulus. b. the modality of a stimulus. c. the type of stimulus energy impinging on the cell. d. all of the above. 55. Frequency coding in a tonic hair mechanoreceptor is for stimulus a. duration. b. quality. c. source. *d. strength. 57. Activity in a sensory neuron using an absolutely labeled line code means to the brain that *a. a stimulus with some particular quality or at some specific location has been detected. b. if the activity is from a phasic receptor, it is signaling position. c. in conjunction with activity in other neurons from a sense organ showing range fractionation, stimulus quality can be determined. d. it can be absolutely certain as to the TYPE of stimulus that excited the receptor (i.e., only one type of stimulus can excite the neuron). 58. In a sense organ using range fractionation, coding of the stimulus parameter that is fractionated is by *a. across fiber patterning. b. labeled lines. c. intensity. d. frequency. 59. An across-fiber patterning or code is frequently found in association with a. adaptation. b. phasic properties. *c. range fractionation. d. topographical projection to the brain. 60. Across-fiber coding a. is the easiest way of coding the strength of a stimulus. b. refers to the information transmitted in an axo-axonal synapse. c. is found in the lateral inhibition in the eyes of arthropods. *d. refers to information transfer via the profile of response of several cells to a single stimulus. 64. The control of a peripheral sense organ by the CNS is called ______ control. a. reflex *b. efferent c. afferent d. reafferent 65. One reason that efferent control might be useful in a sensory system is to a. ensure smooth movement of muscles. b. compensate for reafference. c. protect the system against strong stimuli. *d. all of the above. 67. Efferent control is NOT used to *a. lower the excitability of rod cells. b. protect the ear against strong sounds. c. compensate for reafference in swimming fish. d. generate smooth muscular movements. 70. Alpha efferents are a. sensory neurons from a muscle spindle. b. motor neurons innervating intrafusal muscle fibers. c. sensory neurons from Golgi tendon organs. *d. motor neurons innervating extrafusal muscle fibers. 71. Gamma efferents are a. sensory neurons from a muscle spindle. *b. motor neurons innervating intrafusal muscle fibers. c. sensory neurons from Golgi tendon organs. d. motor neurons innervating extrafusal muscle fibers. 72. Group Ia and II afferents are *a. sensory neurons from a muscle spindle. b. motor neurons innervating intrafusal muscle fibers. c. sensory neurons from Golgi tendon organs. d. motor neurons innervating extrafusal muscle fibers. 73. An intrafusal muscle fiber is part of *a. a muscle spindle organ. b. a Golgi tendon organ. c. the group of muscles that control the eye. d. a system of rhythmically contracting muscles. 74. Intrafusal muscle fibers are a. part of the load-bearing bulk of vertebrate skeletal muscles. b. innervated by alpha motor neurons. c. under peripheral control. *d. part of vertebrate muscle spindle organs. 75. You are using your right biceps (upper arm) muscle to hold a bucket of water when someone drops a brick into the bucket. The first thing that happens is a. a decrease in the rate of firing of the group I and II afferents in your biceps muscle. *b. an increase in the rate of firing of the group I and II afferents in your biceps muscle. c. no difference in the rate of firing of the group I and II afferents in your biceps muscle. d. an increase in the rate of firing of the gamma motor neurons in your biceps muscle. 76. The function of the mammalian muscle spindle organ is to report to the CNS a. the absolute tension of the muscle with which it is associated. *b. the length of the muscle with which it is associated relative to its desired length. c. the absolute length of the muscle with which it is associated. d. the tension of the muscle with which it is associated relative to that of an antagonist muscle. 78. Reafference is *a. the sensory stimulation an animal obtains as a result of its own movements. b. the reaction an animal has to sensory stimulation that arises from its own movement. c. control of sense organs so an animal will not be confused by sensory stimulation arising from its own movement. d. none of the above. 79. The fact that a goldfish will not initiate a tail-flip escape response when its lateral line organ is stimulated by its own slow swimming is due to *a. efferent inhibition of the neuromast organs of the lateral line. b. afferent inhibition of the neuromast organs of the lateral line. c. its ability to distinguish between two stimuli of equal strength. d. efferent control over the swimming muscles. 80. An example of reafference is a. the stimulus you receive if you fail to duck from a snowball. b. the pain from a thumbtack you step on. *c. the wind you feel blowing on your face as you run. d. the wind you feel on a windy day while you are standing still. 81. In a swimming fish, an example of re-afference is the *a. sensory signals that result from stimulation of its lateral line organs by its movement through the water. b. efferent signals that suppress the response of the lateral line organs to water pressure as it swims. c. sensory signals that result from stimulation of its lateral line organs by a large predator fish that attacks it. d. afferent signals that suppress the response of the lateral line organs to water pressure as it swims. 83. Protection of a sense organ against strong stimuli is one suggested function of a. reafference control. b. lateral inhibition. *c. efferent control. d. phasic responses. 84. By reducing the sensitivity of a sense organ during extremely strong stimulation, an animal may protect the sense organ from a. fatigue. b. corollary discharge. *c. physical damage. d. premature inhibition.