Final - Lecture 16

Front 1

Are rhythms considered unconscious or subconscious?

Back 1

Unconscious

Front 2

Are drives considered unconscious or subconscious?

Back 2

Subconscious

Front 3

What is the difference between unconscious and subconscious?

Back 3

With subconscious, you can sense it, but you do not have to be an actual participant.

Front 4

Describe how homeostasis is like a thermostat.

Back 4

- Compare external (incentive) stimuli with set point signal; the difference (error signal) causes controlling elements, such as endocrine, behavioral motor pathways, and autonomic symp/parasymp pathways to take place; controlled system (varaible) leads to feedback detectors

Front 5

What 3 basic concepts underlie drives?

Back 5

1. Homeostasis
2. Diffuse signaling
3. Hypothalamus as master regulator

Front 6

Describe point-to-point vs. diffuse signaling.

Back 6

Point-to-point is synaptic signaling (temporal and spatial specificity; meaning from locaiton and firing patterns of synapses),whereas diffuse signaling is endocrine signaling (less temporal almost no spatial speficity; meaning form the molecule/hormone)

Front 7

What are hormone receptors molecularly simiilar to?

Back 7

Post-synaptic receptors

Front 8

Describe the 'identity' difference in point-to-point vs. diffuse signaling.

Back 8

In point-to-point, glutamate and GABA, for example, are used for most excitatory inhibitory responses respectively in the brain, because info. is based on connectivity; in diffuse signaling, hormones have identity

Front 9

What is modulatory signaling?

Back 9

Intermediate between synaptic and hormonal signaling

Front 10

What are 3 types of modulatory signaling?

Back 10

1. Autonomic nervous system (wide synaptic cleft, work through GPCRs, which have slow, long-lasting responses)
2. Diffuse modulatory systems (coordinate motivated behaviour; 1:100,000 divergence; serotonin, dopamine, acetylcholine, norepinephrine also work through GPCRs)
3. Neuroendocrine systems consist of hormones secreted from the brain to affect the body

Front 11

What is the 3-part response coordinated by the hypothalamus?

Back 11

1. Commands to brain stema nd spinal cord that activate autonomic preganglionic neurons and sympathetic/arasympathetic responses
2. Commands that activate diffuse modulatory systems and therefore basal ganglia (motor center) and cortex
3. Release of hormones into the bloodstream via the pituitary

Front 12

What do magnocellular cells in teh hypothalamus do?

Back 12

Sne daxons to the posterior pituitary where they secrete hormones directly into the blood stream

Front 13

What are two hormones secreted by magnocellular cells?

Back 13

1. Oxtocin, which acts on uterus durin ghcildbirth and mammary glands during lactation
2. Vasopressin: Acts on kidney to control salt balance and blood volume

Front 14

What do parvocellular cells do?

Back 14

Secrete "releasing" hormones into a local capillary bed connected to the anterior pituitary; trigger o r inhibit the release of hormones from secretory cells in the anterior pituitary into the blood stream

Front 15

Give 3 examples of hormones released by parvocellular cells.

Back 15

LHRH, GHRH, and TRH

Front 16

What do the 3 hormones secreted by the parvocellular cells cause the anterior pituitary to release (and in turn what do those hormones do)?

Back 16

- LHRH - LH (lutenizing) - ovary (ovulation)
- GHRH - GH (growth) - many cells
- TRH - TSH (thyroid) - thyroid (release thyroxin which affects metabolism)

Front 17

What are the 3 places the hypothalamus can send signals to?

Back 17

1. Release hormones from pituitary ~ endocrine response
2. Commands to autonomic system (symp/parasymp)
3. Diffuse modulatory signals to other parts of the brain, which causes motivation and awareness

Front 18

Describe how certain tastes can elicit temperature.

Back 18

Temperature sensors are members of the TRP channel family; menthol activate the cold-sensitive Trpm8; capscaicin of the hot pepper activates the heat-sensitive Trpv1

Front 19

How many types of TRPs are there?

Back 19

About 30 types

Front 20

How are TRP channels controlled?

Back 20

cation-selective (Depolarizing), voltage-independent, gated by temperature, mechanical deformation

Front 21

What is the most important goal temperature-wise?

Back 21

To keep the brain temperature constant

Front 22

In response to temperature change, what are the responses coordinated by the hypothalamus?

Back 22

1. Motor response (shiver if cold and pant if hot)
2. Autonomic response: vasoconstrict if cold and vasodilate if hot)
3. Endocrine response (hypothalamus releases TRH to comma

Front 23

What percent of female teenagers are anorexic or bulemic?

Back 23

1%

Front 24

What percent of the US is overweight today?

Back 24

60%

Front 25

What is the difference between anabolism and catabolism?

Back 25

Anabolism uses energy to build molecules; catabolism breaks down stores of molecules to obtain energy

Front 26

How many calories does it take to gain a pound?

Back 26

3000-4000 "excess" calories, but generally we keep our weight constant within 2-3 pounds per year

Front 27

Describe the difference in influence on eating between the lateral and the ventromedial hypothalamus?

Back 27

Lateral hypothalamus encourages eating; ventromedial hypothalamus represses eating

Front 28

Describe the ob/ob mutant mouse

Back 28

"Obese" mutant house; mutation in gene encoding leptin, which keeps weight under control

Front 29

Describe the db/db mutant mouse

Back 29

Obese; mutation in the gene encoding the leptin receptor (GPCR)

Front 30

Describe leptin.

Back 30

Made and released by fat cells; travels to the hypothalamus where it activates leptin receptors; essentially indicates fat reserves, so the hypothalamus can adjust activities to promote or discourage deposition of more fat

Front 31

What happens when there is too much leptin?

Back 31

Stimulates the release of "anorectic pepties" which:
1. (Neuroendocrine) stimulate ACTH and thyrotropin release from the pituitary, increasing metaboslim
2. (Autonomic) activate sympathetic neurons in the brainstem that stimulate sympathetic neuronsalso increasing metabolism
3. (Behavioral) activate lateral hypothalamus neurons that activate motor feeding centers

Front 32

What happens when there is too little leptin?

Back 32

Causes secretion of "orexigenic pepties" from NPY/AgRP neurons of arcuate nucleus. These pepties, along with the lack of anorectic peptides:
1. (Neuroendocrine) Inhibit the edocrine responses that lead to catabolism
2. (Autonomic) Stimulate autonomic parasympathetic activity
3. (Behavioral) Stimulate motor feeding behavior, such as foraging

Front 33

Are "orexigenic" signals hunger or satiety signals?

Back 33

Hunger signals

Front 34

What are the 3 components of feeding regulation

Back 34

1. Sensory input
2. Satiety signal
3. Hunger signal

Front 35

What are the long-term and short-term effects of the 3 types of feeding regulation

Back 35

1. Sensory input: Fat levels (long-term) and carbohydrate levels/distension of stomach (short-term)
2. Satiety signal: increased leptin (long-term); CCK, inslin, sensory n's (short-term)
3. Hunger signal : decreased leptin (long-term); Ghrelin (short-term)

Front 36

What's CCK?

Back 36

Cholecytokinin; released when food reaches intestine

Front 37

Describe Ghrelin.

Back 37

Hunger signal ;a neuropeptide that is released form the stomach when it is empty; acts on ghrelin receptors in the hypothalamus, which stimulates appetite

Front 38

How does gastic bypass surgery function?

Back 38

Decreases ghrelin secretion, which may be the main reason it leads to weigh loss

Front 39

Outline the difference in the 5-step pathways for conscious and subconscious behavior.

Back 39

Conscious: Sensation - Perception - Thought - Planning - Action
Subconscious: Same intermediate steps, except only aware of sensation to action
In both, memory bridges perception and thought

Front 40

Who said "To move things is all that mankind can do...for such the sole executant is muscle, whether whispering a syllable or in felling a forest"

Back 40

Charles Sherrington, who pioneered English neurophysiology

Front 41

Who was Charles Sherrington?

Back 41

Pioneering English neurophysiologist; said motor system gives rise to all behavior

Front 42

Why has it historically been harder to understand motr systems than sensory systems?

Back 42

Motor systems are more complicated than sensory, becuase you can locate the starting point for sensory systems

Front 43

What are the 3 classes of skeletal muscles?

Back 43

1. Axial (trunk)
2. Proximal (arms) and girdle (legs)
3. Distal (fingers for dexterity)

Front 44

Where do the lower motor neurons come out of the spinal cord?

Back 44

Ventral horn of the spinal cord (alpha and gamma)

Front 45

What are 3 maps of the lower motor neuron?

Back 45

1. Segmental (rostrocaudal) with cervical enlargement (C3-T1) for arms and lumber enlargement (L1-S3) for legs
2. Medial to Lateral (inside to outside) Axial to proximal to distal (such as along arm)
3. Dorsal to ventral for flexors to extensors

Front 46

What are 3 sources of input to alpha motor neurons?

Back 46

1. Upper motor neurons in the brain
2. Spinal interneurons (excitatory & inhibitory)
3. DRG cells; sensory input form muscle spindles

Front 47

What is the myotatic stretch reflex?

Back 47

Knee-jerk reflex; 1a afferent sensory neurons take information to the spinal cord, where alpha motor neurons then relay information back to the muscle spindle, causes quadriceps to contract

Front 48

What is the reverse myotatic reflex?

Back 48

Causes collapse during arm wrestling match; if muscle is contrasting, have you prevent yourself from tearing it in half ~ golgi tendon organ sends 1b afferent to spinal cord, where it synapses on inhibitory interneuron, which then leads to alpha motor neuron which leads to muscle

Front 49

WHat does reciprocal inhibition do?

Back 49

Shuts off antagonistic muscle; for ex., if flexor is activate, makes sure extensor is inhibited; activate muscle sends 1a afferetnt to sipnal cord, where synapses on inhibitory interneuron, which sends alpha motor neuron to antagonistic muscle; 1a afferent neuron also directly synapse with alpha motor neuron, which sends directly to activate muscle

Front 50

What is the flexor reflex?

Back 50

Flexor motor neurons are activated by pain sensors; pain afferent sensory neuron sends to spinal cord, where synapses on excitatory interneurons, which then send alpha motor neurons to flexor muscles

Front 51

What is the cross-extensor reflex?

Back 51

Allows extension on one side and distension on the other, such as if step on tac and one foot extends, other food needs to extend

Front 52

What are 5 reflexes?

Back 52

1. Myotatic stretch reflex
2. Reverse myotatic reflex
3. Reciprocal inhibition
4. Flexor reflex
5. Cross extensor reflex

Front 53

What was the name of the headless chicken?

Back 53

Mike

Front 54

What do cats iwth high cervical spinal cord transection and the headless chicken show about central pattern generators?

Back 54

The central pattern generator is in the spinal cord

Front 55

What happens if cats with high cervical spinal cord transection are "tonically" stimulated?

Back 55

Even with this chronic depolarization, cat can still walk (central pattern generator when stimulated has inherent rhythmic activity)

Front 56

What are pacemaker neurons?

Back 56

Simplest rhythmic activity generators whose membrane properties endow them with pacemaker properties to repeat the sequences: rest, fire action potentials, rest, fire action potentials...

Front 57

Describe in detail how pacemaker neurons work.

Back 57

When Glu is applied, the Glu activates NMDA receptors, which let in Ca2+, which hyperpolarizes the neuron, which causes Mg2+ to block the NMDA receptor, which causes K+ to leave out of the calcium-activated K+ channel

Front 58

Describe the CPG for walking.

Back 58

Upper motor neuron input excites two excitatory interneurons, one leading to the flexor motor neurona nd the other leading to the extensor motor neuron; when the one leading to the extensor is excited, the extensor is excited and the excitator interneuron sends a signal to an inhibitory interneuron, which inhibits the excitatory interneuron leading to the flexor motor neuron; however, this inhibitory interneuron also inhibits itself, so that it shuts off and the other excitatory interneuron leading to the flexor motor neuron then fires.

Front 59

Which require the most brain control of movement, in order form lost to highest: reflexive, rhythmic (central pattern generators) and voluntary

Back 59

Reflexive is lowest, then rhythmic, then voluntary

Front 60

What are the 2 parallel descending pathways?

Back 60

1. Lateral path for voluntary movement of distal muscles (direct cortical control; fine motor control)
2. Ventromedial path for posture and locomotion (brainstem controls some axial movement)

Front 61

What do lesions to the lateral path cause?

Back 61

1. Lose fine motor control; fingers don't work independently; posture completeyl spared

Front 62

What did Wilder Penfield do?

Back 62

Canadian neurosurgeon, who stimulated cortex and found that the weakest stimulation strengths could give muscle twitches (contralaterally) only if the stimulation was localized just anterior to the central sulcus in an area now known as "M1" or area 4; area 6 could also elicit movements, but these were more complex and requirecd more stimulation; the posterior parietal area is also essential in planning movements but does not provide direct input to the spinal cord (ccordinates movements in space)

Front 63

What are upper motor neurons essential for?

Back 63

Initiation of voluntary movmeents, complex temporal sequences of movements (such as piano playing); descend oto synapse on interneurons and lower motor neurosn

Front 64

What is more complex, the spinal cord or the brain stem?

Back 64

Brain stem

Front 65

How do we know that the cerebellum and basal ganglia provide feedback?

Back 65

Evidence by the defects in movement in their absence; Basal ganglia absence in Parkinson's and Huntington's; Cerebellar damage causes "ataxias"

Front 66

Describe the high level of voluntary movements and where they take place.

Back 66

Goal or general strategy; take place in association areas of the neocortex and basal ganglia

Front 67

Describe the middle level of voluntary movements and where they take place.

Back 67

Tactics; take place in the motor cortex and cerebellum

Front 68

Describe the low level of voluntary movements and where they take place.

Back 68

Execution; takes place int eh brain stem, spinal cord

Front 69

Sensory systems generate an internal representation of the actual world; what do voluntary movements do?

Back 69

Reverse the task and begin with an internal representation of the actual world

Front 70

What is one important law about the voluntary movement's internal representation?

Back 70

Brain represents the outcome of motor actions in a way that is independent of hte specific muscles used or the way the goal is achieved; the goal is set with little carea bout the particular way the goal is executed (as seen with video games and driving); if we can get access to the cortical neurons responsible for planning and initiating movements, we can get robotic movements just by thinking about them.

Front 71

Describe what happened with Jesse SUllivan.

Back 71

SUffered 7200 volt burns to shoulders bilaterally; Underwent surgery to graft nerve endings from his shoulders onto the pectoral muscle on his chest. Those nerves grew into the muscle in about six months; electrodes in the muscle on the ragt can pick up thought-generated nerve impulses to the absent limbs and transmit them instead to the prosthesis, controlling the movements of the arm

Front 72

Where are diffuse modulatory systems?

Back 72

Brain; believed to reulgate, among other things, the level of arousal and mood

Front 73

WHat is the perientricular zone?

Back 73

Layer of the ypothalamus above laterala nd medial (closest to third ventricle space), which has 3 types of complex cells:
1. Superchiasmatic nucleus (SCN): receive retinal innervation and function to synchronize circadian rhythms ((because closest to optic chiasm)
2. Cells that regulate outflow of sympathetic and parasympathetic nervous system
3. Neurosecretory neurons: release neurohormones

Front 74

Describe the communication between the kidneys and the brain.

Back 74

Kidneys release vasopressin (ADH) causes kidneys to release renin, which converts angiotensinogen from liver to angiotensin I then angiotensin II which has direct effect of increasing blood pressure; angiotensin II is detected by teh subfornical organ which suppresses release from the hypothalamus)

Front 75

What are 6 hormones released by the anterior pituitary and what are their targets?

Back 75

1. FSH: gonads for ovulation, erpmatogenesis
2. LH: gonds for ovulation, sperm maturation
3. TSH: thyroid to stimulate metabolism
4. ACTH: adrenal cortex to secrete cortisol
5. GH: all cells to stimulate protein synthesis
6. Prolactin: mammary glands for growth and milk secretion

Front 76

Describe the stress response.

Back 76

Hypothalamus releases CRH, which causes anterior pituitary to release CTH, which stimulates cortisol release

Front 77

What happens if a genetically obese ob/ob mouse is surgically fused with a nromal house?

Back 77

Bloodborne signals are shared, so the obestity of hte ob/ob mouse is geratly moderated

Front 78

What does the ob gene encode?

Back 78

Leptin

Front 79

How does leptin function?

Back 79

Released directly from the adipocytes Z(fat clles), reulgating body mass bya cting directly on neurons of arcuate nucleus in the hypothalamus which:
1. Cause paraventricular nucleus to stimulate release of ACTH and thyrotropin
2. Activate brain stem and preganglionic neurons of sympathetic ANS
3. Inhibits lateral hypothalamic area to inhibit feading behaviour

Front 80

What do lesions of the lateral hypothalamus cause?

Back 80

Anorexia

Front 81

What do lesions of the ventromedial hypothalamus cause?

Back 81

Obesity

Front 82

What are anorectic peptides?

Back 82

alphaMSH and CART, which the arcuate nucleus releases in response to leptin

Front 83

Describe the response to decreased leptin.

Back 83

NPY and AgRP neurons of arcuate nucleus are stimualted which:
1. Inhibit secretion of ACTH and TSH by parvocellular cells
2. Stimulate lateral hypothalamic area to stimulate feeding behavior by releasing MCH and Orexin

Front 84

What is the MC4 receptor?

Back 84

Receptor on lateral hypothalamic area for alphaMSH (stimulating) and AgRP (repressing); these peptides compete for the activation of this receptor

Front 85

What causes satiety?

Back 85

Fastric distension and CCk stimulate vagus nerve which causes feeling of satiety by stimulating nucleus of ht esolitary tract

Front 86

What is the ventral tegmental area?

Back 86

Animal sare motivated in ways that stimulat ethe release of dopamin in the basal forebraina rea; along the pathway to the basal forebrain area is ventral tegemental area; at first, when animals are learning to assicate a sensory atimulus with a reward, the neurons in the ventral tegemntal area are strongly activated by arrival of reward; after learn, they area activated by presentation of stimulus, as if to say "yes!"

Front 87

Describe the two pathways to volumetric thirst.

Back 87

1. Decreasedblood flow to the kidneys activates release of angiotensin II, which activates neurons in the subfornical organ
2. Drop in blood pressure is detected by mechanoreceptors in walls of major blood vessles & heart walls, sosent to vagues nerve which stimulates nucleus to solitary tract
- Subfornical organ and nucleus of solitary tract relay information to hypothalamus

Front 88

Describe the pathway to osmometric thirst.

Back 88

Blood hypertonicity is sensed by neurons OVLT, which activate vasopressin-secreting magnocellular neurosecretory cells and cells in the lateral hypothalamus (which trigger osmometric thirst)

Front 89

Thirs is a response to which to factors?

Back 89

- Hypervolemia (volumetric thrist): decrease in blood voulume
- Hypertonicity (osmometric thirst): increase in concentration of dissolved substances in the blood

Front 90

WHat does decreased insulin do

Back 90

Activates arcuate nucleus to decrease ACTH and decrease TSH to increase parasympathetic activity (feeding)

Front 91

Hormonally, what doe sincreased temperature cause?

Back 91

Causes medial preoptic area to decrease TSH to increasea parasympathetic activity (panting, seeking cold)

Front 92

Is panting and seekingc old parasympathetic or sympathetic

Back 92

Parasympathetic

Front 93

How many axons is each muslce fiber innervated by?

Back 93

One

Front 94

Describe the difference between upper motor neurons and lower motor neurons.

Back 94

Upper motor neurons are motor neurons that originate in motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway. These neurons connect the brain to the appropriate level in the spinal cord, from which point nerve signals continue to the muscles by means of the lower motor neurons. Upper releases the neurotransmitter, glutamate, to lower

Front 95

What are the cervical and lumbar enlargeuemtns?"

Back 95

Enlargemetns of the spinal cord that contain the motor neurons that innerve ath arm and leg muscles, respectively

Front 96

Describe the dorsal/ventral distribution of motor neurons.

Back 96

Motor neurons controlling flexors (muslces on top of arm) lie dorsal to those contrllling extensors.

Front 97

Describe the meial/lateral distribution of motor neurons.

Back 97

Motor neuron controlling axial muscles (closest to chest) lie medial to those controlling distal muscles

Front 98

Wha tis a motor unit?

Back 98

An alpha motor neuron and all the muslce fibers it innervates

Front 99

What is a motor neuron pool?

Back 99

All the alpha motor neurons that innervate one muscle

Front 100

What are the 3 sources of input to alpha motor neurons

Back 100

1. Input from spinal interneurons
2. Sensory input from muslcle spindles
3. Input from upper motor neurons int he brain

Front 101

Describe reverse myotatic reflex.

Back 101

Goli tendon organ stimulates sensory neuron, which ynapses on inhibitotry neuron, which stops the same muslce tha twas sensed from contracting; as muscle tension falls, the inhibition of th ealpha motor neuron is reduced and muscle contraction increases; thought to play a role in the manipulation of fragile objects with the hands

Front 102

Describe the polysynaptic flexor reflex.

Back 102

Pain axon synapses on excitatory interneurons that activate flexor muscles

Front 103

Describe how the rhythmic activity of the spinal interneuron is accomplished.

Back 103

Glutamate causes NMDA receptor to open and Ca2+ to enter & depolarize the cell; the rise on Ca2+ activates K+ channels, which causes K+ to leave and hyperpolarize the cell; hyperpolarization allows Mg2+ to enter through NMDA, which clogs NMDA and prevents further Ca2+ from entering; as Ca2+ falls, the K+ channels close, restting the membrane for another oscillation

Front 104

What is ap opulation vector?

Back 104

For any direction, teh direction vectors of individaul cells ar averaged to yield a population vector, reflecting the strength of hte response of both cells during this movement