Limbic Flashcards
Limbic system functions include
Homeostasis
Olfaction
Memory
Emotion and Drive
Where is the hypothalamus
Diencephalon
Forms walls and floor of 3rd ventricle
Components of the hypothalamus
Many important nu
Tuber cinereum
Mammillary bodies
Infundibulum
Function of the hypothalamus
Homeostasis by way of endocrine (pituitary gland) autonomic and limbic control
What structures send information to the hypothalamus for homeostasis
Solitary Nu.
Reticular formation and SC
Retinal pathways
What info does the solitary nu. Send to the hypothalamus
Visceral info from vagus n on BP/HR and gut distention
What information do the reticular formation and sc send to the hypothalamus
Thermoregulation
Damage to the anterior hypothalamus would result in what (in relation to thermoregulation)? Why?
Hyperthermia
Anterior hypothalamus detects increases in body temp to activate mechanisms of heat dissipation
The ____________ hypothalamus detects decreases in body temp and activates mechanisms of heat conservation
Posterior hypothalamus
What type of information do the retinal pathways send to the hypothalamus?
Input of day/night > circadian rhythm
What nucleus of the hypothalamus regulates circadian rhythms? By input of what?
Suprachiasmatic nu (SCN) From retinal ganglion cells (photosensitivity)
When the hypothalamus gets told that it is DAYTIME what does it do?
The posterior hypothalamic nu contain glutamatergic, histaminergic, and orexin neurons that contribute to arousal
Damage to the posterior hypothalamic nu will cause
Hypersomnia
Damage to the SCN (suprachiasmatic nu) will result in
Insomnia
What does the hypothalamus do in response to being told that it is NIGHTTIME
The SCN projects to other nuclei and pineal gland to modulate body temp and release hormones for sleep (cortisol and melatonin)
Anterior hypothalamus sends inhibitory projections to RAS of reticular formation
The limbic system send what information to the hypothalamus
Stimulate/inhibit hunger/thirst
Reproductive behavior
Emotional influence on autonomic pathways (bidirectional)
Homeostatic control on immune regulation (bidirectional)
What information do the circumventricular organs send to the hypothalamus?
changes in osmolarity and when toxins enter the brain
Damage to the lateral hypothalamus will result in what (limbic system)? Why?
Weight loss because lateral hypothalamus stimulates hunger/thirst
Damage to the medial hypothalamus will result in what (limbic system)? Why?
Obesity because it inhibits hunger/thirst
What systems does the hypothalamus send information to?
Autonomic
Endocrine
Limbic
What information does the hypothalamus send to the autonomic system?
Projections to parasympathetic and sympathetic systems to control HR, vasoconstriction, digestion, sweating etc
What information does the hypothalamus send to the limbic system?
Reciprocal connections that further impact autonomic and endocrine function
The hypothalamus communicates with the hippocampus and amygdala to
Attach memory and emotion
Function of the anterior pituitary
It contains glandular cells that synthesize and release a variety of hormones into circulation
Function of the posterior pituitary
Contains axons and terminals of neurons whose cell bodies are in hypothalamus
Also release hormones into circulation
What hormones are secreted by the anterior pituitary
Adrenocorticotropic hormone (ACTH) GH Prolactin TSH LH FSH
Function of the Adrenocorticotropic hormone
Stimulates adrenal cortex for corticosteroid synthesis >maintain BP, electrolyte balance, promote glucose mobilization
Function of GH
Increased growth of long bones and other tissues
Prolactin function
Stimulate mammillary glands for breast milk production
TSH function
Produce T3 and T4 and promote cellular metabolism
LH function
Regulate ovarian hormones
FSH function
Regulate testicular hormones
Release of anterior pituitary hormones is controlled by
Hypothalamus
What hormones are released by the posterior pituitary
Oxytocin and vasopressin
Function of oxytocin
Smooth muscle contraction and plays a roll in compassion and social bonding
Function of vasopressin
Promotes water retention by kidneys
Regulates BP
Hormones released by posterior pituitary are made by
The hypothalamus
Primary olfaction cortex is a combination of
Piriform cortex and periamygdaloid cortex
Where does olfactory information go to integrate smell and memory
Entorhinal cortex
Perirhinal cortex
Parahippocampal cortex
What does the orbitofrontal olfactory area do?
Smell discrimination
What does the amygdala do with olfactory info
Integrate smell with emotion and motivation
Memory lasting a second or less is considered …..
where is it stored
Attention or registration
Brainstem-diencephalon connections
Frontoparietal ass. Cort.
Uni- hetero- modal ass. Cort.
Working memory lasts how long…
Where is it stored
Seconds-minutes
Frontal association Cort.
Uni- hetero- modal ass. Cort.
Consolidation memory lasts how long…..
Where is it stored
Medial temporal and diencephalic structures
Uni-hetero- modal association cortices
Declarative/explicit memory includes
Facts and events
Nondeclarative/implicit memory includes
Skills/habits
Priming
Simple classical conditioning
Nonassociative learning
Medial temporal lobe memory areas include
Hippocampus formation
Parahippocampal gyrus
Perirhinal cortex
Medial diencephalic memory areas include
Mediodorsal and anterior nu of thalamus (additional thalami nu play smaller rolls as well)
Mammillary bodies of hypothalamus
Hippocampus formation is made of
Dentate gyrus
Hippocampus
Subiculum
The hippocampal formation is a major center for components of
Long-term memory
Parahippocampal gyrus includes
Entorhinal cortex (rostral) and Parahippocampal cortex (caudal)
Parahippocampal gyrus function
Memory encoding and retrieval
Perirhinal cortex function
Facilitates the recognition and identification of environmental stimuli
Medial temporal lobe structures receive input from…
Heteromodal association cortex via entorhinal cortex
Contralateral hippocampus via hippocampal commissars
Basal forebrain and septal nu
The basal forebrain and septal nu send cholinergic (ACH) projections to medial temporal lobe memory structures for..
Neuromodulatior effect (neuron excitability and synaptic plasticity) Hippocampal theta rhythm
Medial temporal lobe memory structures send output to
Heteromodal association cortex via entorhinal cortex
Medial diencephalic structures
- mediodorsal nu via inferior thalami peduncle
- thalamus, hypothalamus ext. via fornix
The medial temporal lobe memory structures send into to the mediodorsal nucleus for what functions
Working memory
Executive function and memory
What is working memory
Holding concept briefly in awareness while a mental operation is performed
The fornix connects the hippocampus with variety of subcortical regions, including
Mammillary bodies of hypothalamus
Anterior nu of thalamus
Septal nu (bidirectional)
What effect does the septal nu have
Modulatory
Temporal poles have strong connections with…
Hippocampus, amygdala, and orbital prefrontal cortex
The left temporal pole function
Semantic memory
Meanings, names, general impersonal facts
Overall function of the temporal poles
Social and emotional processing
Right temporal pole function
Personal and episodic memories
Closely associated with emotion and socially relevant memories
Main structure involved with emotion and drive
Amygdala
Amygdala function
Attracting emotional significance to various stimuli perceived by association cortices
The amygdala receives input from
All senses and visceral inputs
The amygdala regulation of emotion and drive is a complex, ____________ connection with __________&_________ areas
Bidirectional
Cortical and subcortical
What structures connect for appetitive states (emotional and motivational aspects of smell)
Amygdala, olfactory system and hypothalamus
What structures process fear to trigger “fight or flight” via autonomic control
Amygdala, hypothalamus and brainstem
Connections between amygdala and the hypothalamus are __________ and between Amygdala and brainstem are ___________
Bidirectional
Efferent from amygdala
Amygdala is connected to the mediodorsal nu of the thalamus for…
“Fear reflex”
Emotional learning > projections to hippocampus
The amygdala is connected to the limbic cortex and hypothalamus for..
Neuroendocrinological modulation (changes in different emotional states)
What connection to the amygdala is involved with olfaction, emotion, and forming new memories?
Uncus
What connection to the amygdala deals with emotional aspects of memory, especially the fear-inducing events
Hippocampal formation
What connections to the amygdala process rewarding/pleasurable experiences
Septal nu and basal forebrain
Function of the connection between amygdala and medial orbitofrontal cortex
Decision making and emotion (identify poor/good choices)
Modulation of bodily changes associated with emotion
Dense interconnections with amygdala and hypothalamus describes
Anterior cingulate cortex
Function of anterior cingulate cortex
Regulation of affect
Assigning emotion to internal and eternal stim/
Making vocalizations associated with expression of states or desires
Regulates autonomic and endocrine responses, pain perception, and selection, and initiation of motor movements
Posterior cingulate cortex function
Recall of autobiographical memories (more involved when memories have emotional quality)
