Limbic System Overview Flashcards
what are the major functions of the limbic system? (HOME)
homeostasis, olfaction, memory, emotions and drive
what are the 2 main functions of the hypothalamus?
homeostasis and hormones
how does the hypothalamus regulate homeostatic mechanisms?
- Regulation of vital functions (temp, HR, BP, blood osmolality, food/water intake, sexual behavior, emotions)
- Endocrine control, autonomic control, and limbic mechanisms
how is the hypothalamus involved with hormonal regulation?
Regulates release of hormones via pituitary gland
what info does the solitary nucleus input to the hypothalamus?
Visceral info from vagus n. on BP and gut distention
what info do the reticular formation and SC input to the hypothalamus?
General info re: skin temp (thermoregulation)
what info does the limbic system input to the hypothalamus?
eating and reproduction
what info do the circumventricular organs input to the hypothalamus?
- Changes in osmolarity
- Toxins
what info do the retinal pathways input to the hypothalamus?
input on day/night for circadian rhythms
what are circadian rhythms?
physical, mental, and behavioral changes that follow a 24-hour cycle
what is significant about the retinal pathways sending inputs directly to the SCN of the hypothalamus?
This is an example of the hypothalamus contributing to homeostasis without the need of a stressor
autonomic output from hypothalamus goes where?
multiple ANS nuclei in medulla → parasympathetic and sympathetic systems to control HR, vasoconstriction, digestion, sweating, etc.
the limbic system gets involved with autonomic and endocrine systems when we need to attach ____ or ____ to changes in homeostasis
- memory
- emotion
why is the pituitary gland called the “master gland”?
- Synthesizes and distributes many important hormones
- Regulates activity of other endocrine glands
the anterior pituitary contains….
glandular cells that synthesize and then release a variety of hormones into circulation
the posterior pituitary contains….
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
hormones secreted by anterior pituitary
- ACTH
- GH
- Prolactin
- TSH
- LH
- FSH
hormones secreted by posterior pituitary
- oxytocin
- vasopressin
the primary olfactory cortex is the only sensory cortex that….
receives input without a need for relay through the thalamus
smell is the only sense that does not….
go to the limbic system’s major memory structure, the hippocampal formation
what structure is responsible for smell and memory?
entorhinal cortex (plus perirhinal cortex and parahippocampal cortex)
what structure is responsible for smell discrimination?
orbitofrontal olfactory area
what structure is responsible for smell + emotion and motivation?
amygdala
medial temporal lobe memory areas
- hippocampal formation
- parahippocampal gyrus
- perirhinal cortex
what makes up the hippocampal formation?
dentate gyrus, hippocampus, and subiculum
the hippocampal formation is a major center for components of ____ memory
long-term
what makes up the parahippocampal gyrus?
Entorhinal cortex + parahippocampal cortex
functions of the parahippocampal gyrus
- object identity
- object configuration memory
functions of the perirhinal cortex
- Recognition and identification of environmental stimuli
- Coding of familiarity of recency of objects
function of the medial diencephalic memory areas
critical relay stations for primarily efferent memory signals coming from medial temporal lobes and going to other areas of the cortex
medial diencephalic memory areas
- mediodorsal and anterior nuclei of thalamus
- mamillary bodies of hypothal
minutes to years worth of memories are stored and consolidated by what structures?
- Medial temporal and diencephalic structures
- Unimodal and heteromodal association cortices
Temporal poles = some of the strongest connections between ____ and ____
memory, emotion
the temporal poles have strong connections with what structures?
hippocampus, amygdala, and orbital prefrontal cortex
Hippocampus and amygdala have ____ connections to each other
back and forth
the temporal poles are thought to be part of the ____ association cortex
heteromodal
semantic memory
- L temporal pole
- Meanings, names, general impersonal facts
personal and episodic memories
- R temporal pole
- Closely associated with emotion and socially relevant memories
function of basal forebrain and septal nuclei
Secretion and distribution of ACh in the cortex
Hippocampal theta rhythm
thought to help us store short-term memory, although not fully understood
fornix
major relay center that connects hippocampus with variety of subcortical regions
3 main targets of output going through the fornix
- Mamillary bodies of hypothalamus
- Septal nuclei
- Anterior nucleus of thalamus
