task 5 - senses

Question 1

reflex

Answer 1

a rapid motor response through neural connections located within the spinal cord

Question 2

steps of the

Question 2

monosynaptic strech reflex

Answer 2

a reflex, whose neural circuit consists of only 1 synapse along the route from receptor to effector

Question 3

what does the monosynaptic stretch reflex do?

Answer 3

this reflex performs in the forearm muscle and also helps maintain an upright posture

Question 4

patellar tendon (knee-jerk) reflex

Answer 4

a sudden stretch in the quadriceps muscle after tapping of the patellar tendon

Question 5

polysynaptic reflex

Answer 5

there are 2 populations of afferent axons from the golgi tendon organ, with different sensitivities to stretch

Question 6

the move sensitive afferent axons….

Answer 6

tell the brain how hard the muscle is pulling

Question 7

the less sensitive have..

Answer 7

their terminal buttons synapse on spinal cord interneurons (neurons that reside entirely within the gray matter of the spinal cord and serve to interconnect other spinal neurons) these interneurons synapse on the alpa neurons serving the same muscle. the TB release glycine and produce IPSPs on the motor neurons

Question 8

inhibitory golgi tendon organ reflex

Answer 8

decreases the strength of muscular contraction when there is danger/damage to the tendons or bones to which the muscles are attached

Question 9

motor cortex

Answer 9

hierarchically organized (commands cascade down from the cortex to the muscles → higher levels of the hierarchy are left free to preform more complex functions)

functionally segregated

Question 10

primary motor cortex (M1)

Answer 10

most involved in the control of movement

→ lies on the percental gyrus. it shows somatotopic organization (activation of particular parts of it cause movements of particular parts of the body) referred to as the motor homunculus

→ organized in terms of particular movements of parts of the body

→ movement accomplished by the contraction of several muscles, complex neural circuitry is located between

Question 11

motor association cortex

Answer 11

at the top of the sensorsorimotor hierarchy

contains: posterior parietal cortex, dorsolateral prefrontal cortex

Question 12

posterior parietal cortex

Answer 12

→ integrates information about body part locations and the locations external objects that the body is going to interact with

• directs behavior by providing spatial info. and directing attention

→ output goes to the dorsolateral prefrontal cortex and to the frontal eye field (controls eye movements and shifts in attention)

Question 13

dorsolateral prefrontal cortex

Answer 13

→ receives projection from the posterior parietal cortex and it sends projections to areas of secondary motor cortex, primary motor cortex and to the frontal eye field

→ decisions to initiate voluntary movements may be made in this area of cortex but that depends on interactions with the posterior parietal cortex and other areas of the frontal cortex

Question 14

the secondary motor cortex

Answer 14

→ includes supplementary motor area and premotor cortex (scientists say other areas too) receive most of their input from association cortex and send most of their output to primary motor cortex

→ neurons in this area often become more active just before the initiation of a voluntary movement and continue to be active throughout the movement

Question 15

pre-supplementary motor area

Answer 15

involved in the perception of control of spontaneous movements

Question 16

premotor cortex

Answer 16

involved in using arbitrary stimuli to indicate what movement should be made

Question 17

arbitrary information

Answer 17

info. that is not directly related to the movement that signals (e.g. pointing to a particular object when somebody says its name)

• the associations between arbitrary stimuli and the movements they designate are arbitrary and must be learned

Question 18

nonarbitrary information

Answer 18

info. that specifies just what movement should be done (e.g. visual information of object location specifies where to target reaching object is)

Question 19

sensory association cortex

Answer 19

→ every primary sensory area of the cerebral cortex sends information to adjacent regions

→ receive and information from more than 1 sensory system

Question 20

reticular formation

Answer 20

controls the activity of the gamma motor system and hence regulates muscle tonus, also helps in control of posture and locomotion

Question 21

medulla

Answer 21

respiration, sneezing, coughing, and vomiting

Question 22

cerebellum

Answer 22

the lateral zone of the cerebellum is involved in the control of independent limb movements, especially rapid, skilled movements.

when the cerebellum receives info that the motor cortex has begun to initiate a movement, it computes the contribution that various muscles will have to make to perform it

when damaged movements become jerky, erratic and uncoordinated

Question 23

basal ganglia senses function

Answer 23

→ can monitor somatosensory information and are informed of movements being planned and executed by the motor cortex

→ responsible for movement vigor; the control of speed and amplitude of movement based on motivational factors

Question 24

descending motor pathways

Answer 24

neurons in the primary motor cortex control movements by 2 groups of descending tracts: the dorsolateral (lateral) group and the ventromedial group

Question 25

dorsolateral group

Answer 25

involved in the control of independent limb movements (particularly of the hands and fingers, contralateral and distal)

• dorsolateral (direct)
• dorsolateral rubro (indirect)

Question 26

ventromedial group

Answer 26

→ originates in the brain stem and consists of different tracts, these tracts cause automatic movements: gross movements of muscles of the trunk and coordinated trunk and limb movements involved in posture and locomotion (ventral, medial, proximal)

• ventromedial (direct)
• ventromedial brainstem (indirect)

Question 27

central sensorimotor programs

Answer 27

patterns of activity programmed into all levels but the highest of levels of the sensorimotor system, complex movements produced by activating the appropriate combinations of these programs

• some behaviors can be established by practicing but the programs for many species-typical behaviors are established without explicit practice

Question 29

motor equivalence

Answer 29

the same basic movement can be carried out in different ways involving different muscles (shows the plasticity in the sensorimotor system)

Question 30

response-chunking hypothesis

Answer 30

practice combines the central sensorimotor programs that control individual responses into programs that control sequences (chunks) of behavior

Question 31

mirror neurons

Answer 31

→ neurons located in the ventral premotor cortex and the rostral part of the inferior parietal lobe

→ the system is activated when preforming an action, seeing someone else performing an action and by sounds that indicate the occurrence of a familiar action