Chapter 18 Answer Key 278. The selection and timing of individual muscles to be used in a rhythmic behavior is carried out by the a. executive functions of the CNS. *b. execution functions of the CNS. c. both the executive and the execution functions. d. neither the executive nor the execution functions. 279. In motor control systems, the so-called executive functions differ from the functions of execution in that the former include a. selection of muscles to be used in the behavior. b. timing of activation of muscles to be used. *c. vigor or speed of execution of the behavior. d. control of muscular tension in individual muscles. 280. An IDENTIFIABLE neuron is a neuron that is a. only morphologically unique. b. only physiologically unique. *c. both morphologically and physiologically unique. d. none of the above. 281. The original work that led to the concept of a command neuron (done on crayfish) demonstrated neurons that, when stimulated at different frequencies, caused a. beating of only some of the swimmerets. b. beating of all the swimmerets, but at frequencies that included only a small part of their natural range. c. freezing of the swimmerets at one particular stage of their movements. *d. beating of all swimmerets at frequencies throughout their entire natural range. 282. The idea of command neurons is closely tied to the idea of a. nonspiking neurons. b. local (intrinsic) neurons. *c. identifiable neurons. d. none of the above. 283. "Command" neurons were thought to control *a. executive functions. b. execution functions. c. timing of muscle activation. d. muscle tension. 284. The originators of the concept of command neurons were a. Wiersma and Ikeido. b. Weisman and Ikeda. c. Weisman and Ikeido. *d. Wiersma and Ikeda. 285. The originator(s) of the idea of command neurons was (were) *a. Wiersma and Ikeda. b. Wilson. c. Wilson and Ikeda. d. Wiersma. 286. A command neuron was first defined as a neuron that a. controlled a behavior. b. determined the onset of a behavior. c. determined the strength (vigor) of a behavior. *d. all of the above. 287. Command neurons are a a. type of motor neuron. *b. type of interneuron. c. type of sensory neuron. d. special type of neuron that does not fall into the normal sensory neuron-interneuron-motor neuron classification system. 288. Stimulation of a single "command" neuron for swimmeret beating in a crayfish AT DIFFERENT FREQUENCIES caused *a. the swimmerets to beat at different frequencies. b. different groups of swimmerets to beat at the same frequency. c. different groups of swimmerets to beat at different frequencies. d. no effect (other than to cause beating of the swimmerets). 289. A current redefinition of the term command neuron requires primarily that *a. stimulation of the neuron be both necessary and sufficient for evoking a behavior. b. the neuron be anatomically identifiable. c. stimulation of the neuron evokes a behavior. d. the fiber not be a sensory neuron. 290. Joe Premed is studying the nervous system of the cockroach and has isolated an axon in a nerve connective. He is very excited because he notices that when he stimulates the single axon, the animal walks. Previously, Joe developed a technique enabling him to destroy this axon in live animals. He found that after applying this technique, the animal could not walk. Joe has established a. that this is an identified neuron. b. that this is a command neuron. c. that there are no higher command centers in this system. *d. the necessary and sufficient conditions for a command neuron. 291. The current view of behavioral control in invertebrates suggests that behaviors like walking are initiated via a. activity in one or a few classical "command" neurons. *b. the summed action of all "recommendations" originating from higher centers. c. identified, non-spiking interneurons. d. reflex effects from specific stimuli. 292. The main brain stem nuclei involved with motor control include the *a. red, vestibular and reticular nuclei. b. red. vestibular and dentine nuclei. c. red, reticular and bulbar nuclei. d. vestibular, reticular and dentine nuclei. 293. The brain stem nuclei for motor control receive input from all of the sources listed below except one. Which one does NOT provide input to these nuclei? a. Afferent inputs. *b. Basal ganglia. c. Cerebellum. d. Cerebral cortex. 294. The cerebellum does NOT have DIRECT anatomical connections (inputs or outputs) with the a. motor cortex. b. thalamus. *c. spinal motor neurons. d. brain stem. 295. In the mammalian motor system, the alpha motor neurons receive input from a. the motor cortex. b. certain sensory neurons. c. brain stem nuclei. *d. all of the above. 296. Transecting a mammalian brain above (anterior to) the red nucleus in the brain stem produces an animal that has a. no deficits in voluntary or reflex movements. b. lost the ability to stand upright relatively normally. c. lost all motor responses, including simple reflexes. *d. lost the ability to make voluntary movements, but has not lost most simple reflexes. 297. The brain region(s) that seem(s) to be especially important in the control of postural muscles is(are) a. the medullary reticular nucleus. b. the pontine reticular nucleus. c. the vestibular nucleus. *d. all of the above. 298. The pyramidal system refers to bundles of axons traveling from the a. basal ganglia to the hypothalamus. b. thalamus to the basal ganglia. c. cerebral cortex to the cerebellum. *d. cerebral cortex to the spinal motor centers. 299. Experiments in which the activity of individual monkey motor cortex cells was recorded while the monkey moved its arm in different directions showed that the direction of movement was strongly correlated with a. the activity of only a few of all the neurons that responded during the movement. *b. the vector sum of the activity and peak directional sensitivity of all of the neurons active during each particular movement. c. the force exerted by the monkey to move its arm. d. nothing -- the researchers could find no correlation between neuron activity and direction of movement. 300. Neurons in the motor cortex of an awake monkey free to move a lever in different directions a. become active after the movement is initiated, indicating that they are involved in reafference. b. show no activity, since movement of a lever involves planning that takes place in deeper brain structures such as the basal ganglia. c. become active before the movement is initiated, showing that they are involved in planning, not just execution. *d. become active before the movement is initiated, but are tuned to the movement, so that not all cells are active for a movement in each different direction. 301. Which of the following structures is NOT generally considered to contribute to planning and programming of a motor sequence? *a. Brain stem. b. Cerebellum. c. Motor cortex. d. Thalamus. 302. An important function of the motor circuit involving the basal ganglia seems to be to *a. plan and program a sequence of movements before the movement starts. b. select the specific muscles to be used in a movement. c. determine the precise timing of muscle activities during movement. d. evaluate the appropriateness of a movement as it is carried out. 303. In Parkinson's disease, *a. the basal ganglia can not participate in the planning of movements as they normally do. b. the loss of proprioceptive input renders coordinated movements difficult. c. an anomaly of the muscle gap junction explains the rigidity of the limbs. d. the cerebellum can no longer program the execution of movements for the cerebral cortex.