Exam 8: Motor and Regulatory Systems

What do you predict will happen to the circadian rhythms of wild-type golden hamsters when their suprachiasmatic nucleus (SCN) is replace with a SCN from a hamster with a longer circadian rhythm of about 26-28 hours?

There is considerable redundancy in the mechanisms involved in the regulation of eating. Why would the nervous system invest so much energy in creating and maintaining these apparent redundancies? How Are Circadian Rhythms and Sleep Regulated?

Electroencephalography (EEG) has been used to characterize different patterns of sleep. Stage 1 and 2 of sleep is characterized by high frequency activity. What causes the EEG signal?

Leptin inhibits AgRP neurons and excites POMC neurons. AgRP neurons release GABA and neuropeptide Y (NPY) on POMC neurons in the arcuate nucleus (Figure Q8-35). Figure Q8-35 A. Describe the basic idea of an experiment that would show that agouti-related protein (AgRP) neurons are (1) necessary and (2) sufficient for food intake. B. What are the two major ways that the AgRP neurons inhibit the activity and actions of the POMC neurons? C. Based on the circuitry shown above, how does leptin inhibit eating?

In the experiment illustrated in Figure Q8-1, five fluorescently labeled actin filaments on a myosin-coated glass slide were tracked over the course of 38 s, and their positions were tracked at successive short intervals as they appeared on a video monitor. Figure Q8-1 If you could make an ATP molecule that could not be hydrolyzed to ADP and performed the same experiment, what would happen to the fluorescent actin and why?

Similar network activity can be produced by distinct circuit parameters. Give one example from Figure Q8-11 that demonstrates this idea. Figure Q8-11

What does the visceral motor system control? Choose all that apply.

What is the net output of the direct pathway of the basal ganglia?

You record from a nerve innervating your bicep muscle while your friend slowly adds more weight for you to hold up, which means you have to slowly contract your muscle more and more. What is the order of recruitment of motor neurons? A) Small diameter axon B) Large diameter axon C) Medium diameter axon

It is thought that one function of the cerebellum is to correct for motor errors-for example, if you put a small external weight on your arm and tried to throw a baseball to a particular target. Initially, you would probably miss the target, but with repeated training, you would improve and hit the target with the weight on. Based on the description of the vestibulo-ocular reflex, how does the cerebellar circuitry change the arm movement?

If SCN neurons are dissociated from each other and put in cell culture, what happens to the timing of Per expression? Choose all that apply.

In the pyloric circuit of the stomatogastric ganglion (Figure Q8-12), what would happen to the triphasic pattern if the PD neuron was stimulated so that it was briefly depolarized for a longer period of time and produced more action potentials? Figure Q8-12

What is the function of the pacemaker neuron in a central pattern generator?

What are three properties of the SCN that contribute to it being the master regulator of circadian rhythms?

In Figure Q8-4, label the 'motor unit' of one of the motor neurons, the 'motor pool' for muscle B and state the 'the motor unit size' of the one of the neurons being sure to identify which neuron you are describing. Figure Q8-4

What is one proposed function of sleep and what is one piece of evidence supporting this??

Which of the following describe a central pattern generator? Choose all that apply.

Figure Q8-24A shows an experiment that measured the activity of a single neuron when a monkey moved his arm in eight different directions. How did this neuron respond and what does this tell you about how this neuron is tuned? (A) (B) (C) Figure Q8-24 B. The experiment in Figure Q8-24B was repeated for many neurons. What did they find and what does this tell you about how movements are coded in the motor cortex? C. The neuron shown was from a multi-electrode array, which records the activity of a large number of neurons. How would the response in this area of the motor cortex differ when the arm movement was in a different direction?

If ATP is present, why do actin and myosin not spontaneously interact with each other in the absence of nerve stimulation? Select all that apply.

Neural prosthetics are promising technology to aid paralyzed people regain some independence. Based on the tuning properties of neurons in motor cortex, how can multi-unit recordings from the motor cortex produce movement of a prosthetic arm or other device? How Does the Brain Regulate the Functions of Internal Organs?