Lecture 11 Limbic System

Question 1

What are the 4 major functions of the limbic system?

Answer 1

Homeostasis
Olfaction
Memory
Emotions and Drive

Question 2

What is the primary limbic structure involved with homeostasis?

Answer 2

hypothalamus

Question 3

What are the major anatomical landmarks of the hypothalamus and where can they be found?

Answer 3

• tuber cinereum - bulge of gray matter on ventral surface of hypothalamus behind the optic chiasm
• mamillary bodies - under optic chiasm
• infundibulum - stock that gives rise to pituitary stock

Question 4

What are the 2 major functions of the hypothalamus?

Answer 4

2 H’s - Homeostasis and Hormons

• regulation of homeostatic mechanisms
• regulates release of hormones via pituitary gland

Question 5

What are the major afferent inputs to the hypothalamus for homeostasis?

Answer 5

• solitary nucleus
• reticular formation and spinal cord
• retinal pathways
• limbic system
• circumventricular organs

Question 6

What information does the solitary nucleus bring to the hypothalamus?

Answer 6

visceral info from Vagus nerve on BP and gut distention

Question 7

What information does the reticular formation and spinal cord bring to the hypothalamus?

Answer 7

general info re: skin temperature (thermoregulation)

Question 8

What information does the retinal pathways bring to the hypothalamus?

Answer 8

input on day/night input - circadian rhythm

Question 9

What information does the limbic system bring to the hypothalamus?

Answer 9

eating, reproduction

Question 10

What information does the circumventricular organs bring to the hypothalamus?

Answer 10

changes in osmolarity and toxins

Question 11

What are circadian rhythms?

Answer 11

• physical, mental, and behavioral changes that follows a 24-hour cycle of our day

Question 12

How does our hypothalamus get involved with circadian rhythms during the day?

Answer 12

During the day, posterior hypothalamic nuclei contain glutamatergic, histaminergic and orexin neurons that contribute to arousal

Question 13

How does our hypothalamus get involved with circadian rhythms at night?

Answer 13

Retinal ganglion cells convey photosensitivity info re: day/night directly to suprachiasmatic nucleus of hypothalamus

• SCN projects to other hypothalamic nuclei and pineal gland to modulate body temp and produce sleep hormones
• inhibitory projects from neurons in ventral lateral preoptic area of anterior hypothalamus inhibit ascending activity of reticular formation

Question 14

Where is the “shut off” switch for wakefulness?

Answer 14

suprachiasmatic nucleus (SCN)

Question 15

What are the major outputs of the hypothalamus to help regulate homeostatic control?

Answer 15

• autonomic system (para and sympathetic systems to control HR, vasoconstriction, digesting, sweating, etc)
• endocrine gland - pituitary gland
• limbic system - when we need to attach memory or emotion to these changes in homeostasis

Question 16

What is the major memory center?

Answer 16

hippocampal formation

Question 17

What is the major emotional center?

Answer 17

amygdala

Question 18

Why is the pituitary gland referred to as the master gland?

Answer 18

it controls itself and controls others through its own secretion of hormones

Question 19

What does the anterior pituitary contain?

Answer 19

glandular cells that synthesize and release hormones into circulation

Question 20

What does the posterior pituitary contain?

Answer 20

axons and terminals of neurons whose cell bodies are located in the hypothalamus
- then hypothalamus releases hormones into circulation

Question 21

What are the 6 hormones secreted by the anterior pituitary gland?

Answer 21

• Adrenocorticotropic hormone (ACTH)
• Growth Hormone
• Prolactin
• Thyroid-Stimulating Hormone (TSH)
• Luteinizing Hormone (LH)
• Follicle-Stimulating Hormone (FSH)

Question 22

What does ACTCH do?

Answer 22

stimulates adrenal cortex to create corticosteroid hormones that maintain BP, control electrolyte balance, promote glucose mobilization into bloodstream

Question 23

What does GH do?

Answer 23

causes liver, kidneys, and other organs to produce somatomedins or insulin-like growth factors to promote increased growth of long bones and other tissues

Question 24

What does Prolactin do?

Answer 24

stimulates mammillary glands on breasts to produce milk

Question 25

What does TSH do?

Answer 25

stimulates thyroid gland to produce T3 and T4 to promote cellular metabolism

Question 26

What does LH do?

Answer 26

regulate ovarian hormones responsible for menstruation and oogenesis in females

Question 27

What does FSH do?

Answer 27

Regulate testicular hormones and spermatogenesis in males

Question 28

What are the 2 hormones released by the posterior pituitary?

Answer 28

Oxytocin and Vasopressin

Question 29

How does the hypothalamus modulate pituitary function?

Answer 29

hypothalamus controls the release of the hormones that the pituitary gland synthesizes

Question 30

Where can the primary olfactory cortex be found?

Answer 30

medial and rostral tip of temporal lobe

Question 31

What secondary areas of the brain does the primary olfactory cortex project to?

Answer 31

- entorhinal cortex - orbitofrontal olfactory area - amygdala

Question 32

What is the entorhinal cortex's role in olfaction?

Answer 32

smell and memory

Question 33

What is the orbitofrontal olfactory area's role in olfaction?

Answer 33

smell discrination

Question 34

What is the amygdala's role in olfaction?

Answer 34

smell + emotion and motivation

Question 35

What are the two major regions in which we find limbic structures that are involved with memory?

Answer 35

- medial temporal lobe memory areas | - medial diencephalic memory areas

Question 36

What structures are in the medial temporal lobe memory areas?

Answer 36

- hippocampal formation (primary memory structure) - parahippocampal gyrus - perirhinal cortex

Question 37

What structures are in the medial diencephalic memory areas?

Answer 37

- mediodorsal and anterior nuclei of thalamus | - mammillary bodies of hypothalamus

Question 38

What is the primary limbic structure associated with memory?

Answer 38

hippocampal formation

Question 39

What is the major role of the medial diencephalic memory areas?

Answer 39

crucial relay stations of efferent memory signals coming from our medial temporal lobes and then going up to other areas of the cortex and some cortical regions

Question 40

What are the major anatomical structures that make up the hippocampal formation?

Answer 40

- dentate gyrus - hippocampus - subiculum

Question 41

What is the hippocampal formation most involved with when it comes to memory?

Answer 41

long-term memory

Question 42

Where is the Parahippocampal gyrus in relation to the hippocampal formation?

Answer 42

medial and slightly inferior

Question 43

What are the major anatomical structures that make up the Parahippocampal gyrus?

Answer 43

- entorhinal cortex | - parahippocampal cortex

Question 44

What is the Parahippocampal gyrus most involved with when it comes to memory?

Answer 44

object identity and object configuration memory

Question 45

Where is the perirhinal cortex in relationship to the Parahippocampal gyrus?

Answer 45

lateral and slightly inferior

Question 46

What is the perirhinal cortex most involved with when it comes to memory?

Answer 46

recognition and ID of environmental stimuli | - visual or depth perception of our surrounding environment

Question 47

Where does the hippocampal formation receive input from?

Answer 47

- most from heteromodal association cortex via entorhinal cortex - contralateral hippocampus via hippocampal commissure - basal forebrain and Septal nuclei send cholinergic (AcH) projections

Question 48

Where does the hippocampal formation project to?

Answer 48

- heteromodal association cortex via entorhinal cortex | - subcortical structures (thalamus, hypothalamus, etc.) through fornix

Question 49

What is the fornix? Where can it be found?

Answer 49

- connects hippocampal formation with variety of subcortical regions - found in medial aspect of cerebral hemispheres surrounding the thalamus

Question 50

What are the main targets of the fornix?

Answer 50

- mamillary bodies of hypothalamus - Septal nuclei - anterior nucleus of thalamus

Question 51

The limbic system is not the only system involved in memory storage and consolidation. Where do limbic structures’ function fall in the continuum of memory?

Answer 51

minutes to years

Question 52

What is the function of the temporal poles?

Answer 52

left - semantic memory (meanings, names, general impersonal facts) right - personal and episodic memories (closely associated with emotion and socially relevant memories)

Question 53

What is the major limbic structure associated with emotions and drive?

Answer 53

amygdala

Question 54

What are the major connections seen with the amygdala?

Answer 54

- olfactory system and hypothalamus - hypothalamus and brainstem - mediodorsal nucleus of thalamus - limbic cortex and hypothalamus - hippocampal formation - Septal nuclei, basal forebrain - medial orbitofrontal cortex

Question 55

What does the olfactory system and hypothalamus offer with regards to our emotions?

Answer 55

- appetitive states | - emotional and motivational aspects of smell

Question 56

What does the hypothalamus and brainstem offer with regards to our emotions?

Answer 56

- autonomic and breathing control

Question 57

What does the mediodorsal nucleus of thalamus offer with regards to our emotions?

Answer 57

- fear reflex | - emotional learning

Question 58

What does the limbic cortex and hypothalamus offer with regards to our emotions?

Answer 58

- neuroendocrinological modulation - modulates release of certain hormones in response to emotion - prominent pathway in motherhood

Question 59

What does the hippocampal formation offer with regards to our emotions?

Answer 59

- emotional aspects of memory | - important with forming memories that are associated with fear-inducing events

Question 60

What does the Spetal nuclei and basal forebrain offer with regards to our emotions?

Answer 60

- processing of rewarding events | - synthesize AcH

Question 61

What does the medial orbitofrontal cortex offer with regards to our emotions?

Answer 61

decision-making and emotion | - modulation of bodily changes associated with emotion in fight or flight - as we are making decisions

Question 62

What is the function of the anterior cingulate cortex?

Answer 62

Regulates autonomic and endocrine responses, pain perception, and selection and initiation of motor movements

Question 63

What is the function of the posterior cingulate cortex?

Answer 63

- recall of autobiographical memories - more when they have an emotional quality to them