Chapter 7

Question 1

Why do we have a brain

Answer 1

to control our behavior. If we were stationary like a plant, we would not need a brain (like a plant)

Question 2

three types of muscles

Answer 2

smooth muscles: for organs
skeletal or striated muscles: control of body movement
cardiac muscles: control the heart

Question 3

muscle fiber - axon ratio

Answer 3

one muscle fiber can only have one axon, but one axon can control many fibers

Question 4

neuromuscular junction

Answer 4

synapse between motor neuron and muscle fiber. For all skeletal muscles acetylcholine is the neurotransmitter. It excites the muscle to contract

Question 5

antagonistic muscles

Answer 5

each muscle can only make one movement: contraction. relaxation is a lack of contraction. to move a limb in more than one direction requires antagonistic muscles, which work in opposite directions. The flexor for example brings your hand towards your shoulder, while the extensor straightens the arm.

Question 6

fast twitch and slow twitch fibers

Answer 6

fast twitch: fast contraction but also rapid fatigue

slow twitch: slower contraction but no fatigue

Question 7

aerobic

anaerobic

Answer 7

slow twitch fibers are aerobic because they continually use oxygen.
fast twitch fibers are anaerobic because they don’t need oxygen to function, but need it to recover from functioning (oxygen debt)

Question 8

proprioceptor

Answer 8

receptor that detects the position of movement of a part of the body

Question 9

stretch reflex

Answer 9

reflex caused by stretching of a muscle. It contracts back to its original position

Question 10

muscle spindle

Answer 10

Is a kind of proprioceptor.
Whenever the muscle spindle is stretched, its sensory nerve sends a message to a motor neuron in the spinal cord, which in turn sends a message back to the muscles surrounding the spindle, causing a contraction.

Question 11

Golgi tendon organs

Answer 11

also proprioceptors, respond to increases in muscle tension. Located at opposite ends of a muscle.
In short, a vigorous muscle contraction inhibits further contraction by activating the Golgi tendon organs

Question 12

Reflexes

Answer 12

Reflexes are consistent automatic responses to stimuli

Question 13

ballistic movements

Answer 13

ballistic movement, such as a reflex, is executed as a whole: Once initiated, it cannot be altered. However, most behaviors are subject to feedback correction

Question 14

central pattern generators

Answer 14

neural mechanisms in the spinal cord that generate rhythmic patterns of motor output.

Question 15

motor program

Answer 15

behavioral sequence that once begun, is fixed from beginning to end

Question 16

primary motor cortex

Answer 16

we know it already but again: anterior gyrus just anterior to the central sulcus. We can map our body on it, and it matches up nice with the sensory cortex, right on the other side of the central sulcus

Question 17

hierarchy for execution of movements

Answer 17

The motor cortex orders an outcome and leaves it to the spinal cord and other areas to find the right combination of muscles

Question 18

posterior parietal cortex

Answer 18

monitors the position of the body relative to the world. also important for planning movements

Question 19

supplementary cortex

Answer 19

inhibits habituated motor responses

Question 20

premotor cortex

Answer 20

most active directly before a movement

Question 21

prefrontal cortex

Answer 21

considers possible outcomes and thereby organizes our movements.

Question 22

antisaccade task

Answer 22

our eyes get naturally attracted to stimuli. In this task you have to look in the opposite direction, thereby inhibiting your reflex. Activates the prefrontal cortex and the basal ganglia

Question 23

mirror neurons

Answer 23

do not explain autism.

they get active when we see, imagine, or act out a movement. They are not essential for imitation.

Question 24

corticospinal tracts

Answer 24

there are two tracks, and they transport nearly all information between brain and spinal cord

Question 25

lateral corticospinal tract

Answer 25

primary motor cortex –> red nucleus (in midbrain) –> crosses to contralateral side
controls movements in peripheral areas such as hand and feet. The axons from the primary cortex directly project into the spinal cord. New axons join the tract at the red nucleus

Question 26

medial corticospinal tract

Answer 26

many cerebral cortex areas –> midbrain (vestibular nucleus) –> both sides of the spinal cord
controls bilateral movements such as walking, or banding

Question 27

the crebellum

Answer 27

for rapid movements that require timing

sensory perception of timing and rhythm of stimuli

Question 28

cerebellar cortex

Answer 28

the surface of the cerebellum

The cells are arranged in a regular pattern that enables them to produce outputs of precisely controlled duration

Question 29

purkinje cells

Answer 29

cells in sequential planes parallel to each other

send inhibitory messages down to the nuclei of the cerebellum

Question 30

parallel fibers

Answer 30

axons parallel to each other and perpendicular to the planes of purkinje cells. The excite one purkinje cell after another. The stronger the signal, the more purkinje cells get excited, the longer the duration of response in the purkinje cells. this is used to control the timing of movement

Question 31

nuclei of the cerebellum

Answer 31

clusters of cell bodies in the interior of the cerbellum

Question 32

direct and indirect pathway of the basal ganglia

Answer 32

in the book is complicated description of the details, which I will leave out here
direct: enhances selected movements
indirect: inhibits inappropriate competing movements
working of the indirect pathway is essential for learning

Question 33

basal ganglia

Answer 33

The term basal ganglia applies collectively to a group of large subcortical structures in the forebrain. It is crucial for the learning and initiating of new behavior.
It controls the vigor of movement based on input from the cortex, that tells the ganglia how rewarding an action is going to be

Question 34

readiness potential

Answer 34

a preparation for voluntary movements that occurs 500ms before your movement, and that occurs before the point in time where you notice a conscious decision. This does not mean that our decisions are not voluntary

Question 35

Parkinson’s disease

Answer 35

main symptoms: rigidity, muscle tremors, slow movements, difficulty initiating physical and mental activity
more common as people age, striking 1 percent to 2 percent of people over age 65

Question 36

neurological causes of parkinson

Answer 36

loss of neurons at the substantia nigra which leads to less dopamine releasing axons at the basal ganglia. This leads to an inhibition of the thalamus, which in turn leads to less vigorous voluntary movements.

Question 37

environmental and genetic causes of parkinson

Answer 37

genetics play a role for early onset of Parkinson, but this causation is not very clear. toxic chemical can also cause Parkinson, as well as head injury.
Coffee and cigarettes surprisingly decrease the risk for parkinson

Question 38

L-dopa treatment

Answer 38

is a treatment against Parkinson increasing dopamine in the brain. It works but not well, because the disease continues getting worse, only the symptoms get less. Furthermore it stimulates the whole brain creating unpleasant side effects

Question 39

other treatments for Parkinson

Answer 39

brain transplants: did not work well
stem cells: not ready yet
neurotrophin: promising but not ready yet

Question 40

Huntington’s disease

Answer 40

severe neurological disorder that strikes about 1 person in 10,000 in
Motor symptoms usually begin with arm jerks and facial twitches. Then tremors spread to other parts of
the body and develop into writhing
Gradually, the tremors interfere more and more with
walking, speech, and other voluntary movements
a lot of psychological disorders result out of it too
occurs at any age, but mostly 30-50

Question 41

huntington neurological cause

Answer 41

The disorder is associated with gradual, extensive
brain damage, especially in the basal ganglia but also in the cerebral cortex
Because the output from the basal ganglia is inhibitory to the thalamus, damage to the basal ganglia leads to increased activity in motor areas of the thalamus. That increase produces the involuntary jerky movements.

Question 42

heredity of huntington

Answer 42

is a dominant gene, the gene has been located and we can give a precise risk assessment. the wrong genes lead to a mutation of a protein called “huntingtin”