Limbic System Overview

Question 1

what are the major functions of the limbic system? (HOME)

Answer 1

homeostasis, olfaction, memory, emotions and drive

Question 2

what are the 2 main functions of the hypothalamus?

Answer 2

homeostasis and hormones

Question 3

how does the hypothalamus regulate homeostatic mechanisms?

Answer 3

• Regulation of vital functions (temp, HR, BP, blood osmolality, food/water intake, sexual behavior, emotions)
• Endocrine control, autonomic control, and limbic mechanisms

Question 4

how is the hypothalamus involved with hormonal regulation?

Answer 4

Regulates release of hormones via pituitary gland

Question 5

what info does the solitary nucleus input to the hypothalamus?

Answer 5

Visceral info from vagus n. on BP and gut distention

Question 6

what info do the reticular formation and SC input to the hypothalamus?

Answer 6

General info re: skin temp (thermoregulation)

Question 7

what info does the limbic system input to the hypothalamus?

Answer 7

eating and reproduction

Question 8

what info do the circumventricular organs input to the hypothalamus?

Answer 8

• Changes in osmolarity

- Toxins

Question 9

what info do the retinal pathways input to the hypothalamus?

Answer 9

input on day/night for circadian rhythms

Question 10

what are circadian rhythms?

Answer 10

physical, mental, and behavioral changes that follow a 24-hour cycle

Question 11

what is significant about the retinal pathways sending inputs directly to the SCN of the hypothalamus?

Answer 11

This is an example of the hypothalamus contributing to homeostasis without the need of a stressor

Question 12

autonomic output from hypothalamus goes where?

Answer 12

multiple ANS nuclei in medulla → parasympathetic and sympathetic systems to control HR, vasoconstriction, digestion, sweating, etc.

Question 13

the limbic system gets involved with autonomic and endocrine systems when we need to attach ____ or ____ to changes in homeostasis

Answer 13

• memory

- emotion

Question 14

why is the pituitary gland called the “master gland”?

Answer 14

• Synthesizes and distributes many important hormones

- Regulates activity of other endocrine glands

Question 15

the anterior pituitary contains….

Answer 15

glandular cells that synthesize and then release a variety of hormones into circulation

Question 16

the posterior pituitary contains….

Answer 16

axons and terminals of neurons (cell bodies located in hypothal) that carry hormones secreted by the hypothalamus so the posterior pituitary can release them into circulation

Question 17

hormones secreted by anterior pituitary

Answer 17

• ACTH
• GH
• Prolactin
• TSH
• LH
• FSH

Question 18

hormones secreted by posterior pituitary

Answer 18

• oxytocin

- vasopressin

Question 19

the primary olfactory cortex is the only sensory cortex that….

Answer 19

receives input without a need for relay through the thalamus

Question 20

smell is the only sense that does not….

Answer 20

go to the limbic system’s major memory structure, the hippocampal formation

Question 21

what structure is responsible for smell and memory?

Answer 21

entorhinal cortex (plus perirhinal cortex and parahippocampal cortex)

Question 22

what structure is responsible for smell discrimination?

Answer 22

orbitofrontal olfactory area

Question 23

what structure is responsible for smell + emotion and motivation?

Answer 23

amygdala

Question 24

medial temporal lobe memory areas

Answer 24

• hippocampal formation
• parahippocampal gyrus
• perirhinal cortex

Question 25

what makes up the hippocampal formation?

Answer 25

dentate gyrus, hippocampus, and subiculum

Question 26

the hippocampal formation is a major center for components of ____ memory

Answer 26

long-term

Question 27

what makes up the parahippocampal gyrus?

Answer 27

Entorhinal cortex + parahippocampal cortex

Question 28

functions of the parahippocampal gyrus

Answer 28

• object identity

- object configuration memory

Question 29

functions of the perirhinal cortex

Answer 29

• Recognition and identification of environmental stimuli

- Coding of familiarity of recency of objects

Question 30

function of the medial diencephalic memory areas

Answer 30

critical relay stations for primarily efferent memory signals coming from medial temporal lobes and going to other areas of the cortex

Question 31

medial diencephalic memory areas

Answer 31

• mediodorsal and anterior nuclei of thalamus

- mamillary bodies of hypothal

Question 32

minutes to years worth of memories are stored and consolidated by what structures?

Answer 32

• Medial temporal and diencephalic structures

- Unimodal and heteromodal association cortices

Question 33

Temporal poles = some of the strongest connections between ____ and ____

Answer 33

memory, emotion

Question 34

the temporal poles have strong connections with what structures?

Answer 34

hippocampus, amygdala, and orbital prefrontal cortex

Question 35

Hippocampus and amygdala have ____ connections to each other

Answer 35

back and forth

Question 36

the temporal poles are thought to be part of the ____ association cortex

Answer 36

heteromodal

Question 37

semantic memory

Answer 37

• L temporal pole

- Meanings, names, general impersonal facts

Question 38

personal and episodic memories

Answer 38

• R temporal pole

- Closely associated with emotion and socially relevant memories

Question 39

function of basal forebrain and septal nuclei

Answer 39

Secretion and distribution of ACh in the cortex

Question 40

Hippocampal theta rhythm

Answer 40

thought to help us store short-term memory, although not fully understood

Question 41

fornix

Answer 41

major relay center that connects hippocampus with variety of subcortical regions

Question 42

3 main targets of output going through the fornix

Answer 42

• Mamillary bodies of hypothalamus
• Septal nuclei
• Anterior nucleus of thalamus