Limbic System Flashcards
What is the function of the limbic system?
Homeostasis (Hypothalamus), Olfaction (Olfactory Cortex), Memory Drive (Hippocampus), Emotion (Amygdala)
Limbic system is involved with what structures?
Subcortical or Cortical structures (Bidirectional)
What are components of the hypothalamus?
Many nuclei, tuber cinerulum, infundiulum, mamillary body
What is the function of the hypothalamus?
Homeostasis, Endocrine, Autonomic, Limbic Mechanisms
What are the major inputs for the hypothalamus?
Solitary nuclei, Reticular Formation in Spinal Cord, Retinal Pathways
What is the function of the solitary nuclei in regards to the hypothalamus?
Visceral input for HR/BP and gut dissentation
What is the function reticular formation of spinal cord?
Anterior: detects increase in body temperature, activates mechanisms to disspiate heat
Posterior: heat conversation
What happens if their is damage to the anterior reticular formation of the spinal cord?
Hyperthermia
What happens if there is damage to the posterior reticular formation of the spinal cord?
Hypothermia
What is the function of the retinal pathways
Helps detect sleep/wake cycle by the circardian cycle
What is the function of the circardian cycle?
Circardian cycle (located in the suprachiasmic nuclei) is a major input in the hypothalamus. It receives input from retinal ganglion cells about information of photosensitivity.
What happens in regards to homeostasis during the day time?
The posterior hypothalamic nuclei contains histaminergic, glutamatergic, and orexin neurotransmitters for arousal
What happens in regards to homeostasis during the night time?
SCN that projects to the hypothalamic nuclei and pineal gland (which functions for body temperature regulation and produces hormones such as cortisol and melatonin)
Anterior hypothalamic nuclei that sends inhibitory projections to the reticular activating system (RAS) —> which allows you to go to sleep
What are some other functions in regards to homeostasis?
Eating, thirst, reproductive control, emotions, and homeostatic control
For eating and thirst: what is the function of the lateral and medial hypothalamus?
Lateral: stimulate hunger and thirst
Medial: inhibit hunger and thirst
What happens if the medial and lateral aspect of the hypothalamus is damaged?
Lateral: hunger, starvation
Medial: overeating, obesity
What is the function of the reproductive system in regards to the hypothalamus?
Sexual arousal, motivation, and nurturing components
What does the emotional aspect of the hypothalamus influence?
Autonomic System
What does the homeostatic aspect of the hypothalamus influence?
Immune regulation
Emotion control and homeostatic control are both
Bidirectional
What are the major outputs for the hypothalamus?
Endocrine System, Autonomic System, and Limbic System
What are the circumference organs and how do they play a role in the hypothalamus?
The circumference organs do not contain a BBB and play a role in the hypothalamus due to levels of osmoarlity and toxins
What is the pituitary gland known for?
To be the MASTER GLAND
What is the function of the anterior pituitary gland?
Granular cells are going to create (synthesize) and release various hormones into the circulation
What is the function of the posterior pituitary gland?
Contains axons and terminals of the cell bodies in the hypothalamus and also facilitates the release of hormones in the circulation
What is the difference between the hormones in anterior and posterior pituitary gland?
Hormones in the anterior pituitary gland are going to be CONTROLLED by the hypothalamus
Hormones in the posterior pituitary gland are CREATED in the hypothalamus?
List all of the hormones in the anterior pituitary gland?
ACTH, Prolactin, TSH, LH, FSH, Growth hormone
List all of the hormones in the posterior pituitary gland?
Oxycontin and Vapopression
What is unique about the primary olfactory cortex?
Primary olfactory cortex is the only cortex that does not have to relay to the thalamus
What are the primary structures of the olfactory cortex?
Piriform and Periamydgaloid Cortex
What are the secondary cortices for olfaction?
Enteohinal Cortex (Parahippocampus and Perihinal Cortex)
Orbitofrontal Olfactory Cortex
Amydgala
What is the function for the enterohinal cortex?
Smell and memory
What is function of the orbitofrontal olfactory cortex?
Smell discrimination
What is the function of the amydgala in regards to smell?
Smell, motivation, and emotion
What structures of the brain are involved in long term memory?
Mediotemporal and diencephalon structures, and unimodal and heteromodal structures
What is declarative (long term) memory?
Consists of events and facts
For memory: What structures are located in the mediotemporal lobe?
Hippocampus formation, parahippocampus gyrus, and perihinal cortex
What structures of the brain are located in the hippocampus formation and what is the function?
Dentate, hippocampus, and Subiculum
The function is a large storage area for long term memory
What is the function of the parahippocampus gyrus?
Memory encoding or retrieval
What is the function of the perihinal cortex?
Memory identification and recognition
Describe the input for long term memory?
Receives input from the enterohinal cortex (heteromodal cortices) and sends information bilaterally to the hippocampus through the hippocampal commissure. Projects to basal forebrain and septal nuclei which sends chlogenic effects (ACH) –> which produces neuron excitability and synaptic rewiring.
Describe output for long term memory?
Receive output back from the enterohinal cortex (heteromodal cortices)
Medial Diencephalon structures have a direct connection to where?
Direction connection to the mediodorsal nucleus of thalamus by way of the inferior thalamic peduncle
What are functions of the medial diencephalon structure?
Forward memory: Having memory at your forebrain and actively utilizing it (Like right now)
Also executive function and memory
What is the function of the fornix?
Connects the hippocampus to subcortical structures
What are the three main targets for the fornix?
Mamillary bodies of the hypothalamus, anterior nuclei of the thalamus, and septal nuclei (bidrectional)
What are temporal poles?
Temporal poles are strong connections between the amydgala, hippocampus, and orbital prefrontal cortex
What is the difference between left and right temporal poles
Left temporal poles: facts, names, general impersonal information
Right temporal poles: episodic and personal (usually more emotional and socially)
What is the function of the amydgala and what is significant about it?
Emotion and drive connects all emotion to stimuli
Involved in all limbic systems and receives input from all sensory systems (including visceral)
What is a survival mechanism for the amydgala?
Negative emotion: fear, anxiety, and aggression
Amydgala connections projects to
Bidirectional. Projecting to subcortical and cortical structures (Heteromodal Associations)
What are all of the connections regarding the amydgala (emotion and drive)?
Olfactory and hypothalamus Brainstem and hypothalamus Mediodorsal nucleus of thalamus Limbic cortex and hypothalamus Septal nuclei, basal forebrain Uncus Hippocampal formation Medial orbitiofrontal cortex
What is the function of the olfactory and hypothalamus connection?
Appetite state; linking emotional and motivational in regards to sense of smell
Increases or decrease appetite depending on the smell
What is the function of the brainstem and hypothalamus connection?
Autonomic control
What is the trigger proccessor or what starts autonomic control?
The Amydgala
The amydgala sends mainly what type of fibers
Efferent
What is the function of the amydgala connection with mediodorsal nucleus of thalamus?
“Fear reflex”
Takes memory learning and sends it to the hippocampus
What is the function of connection of the limbic cortex and hypothalamus?
Neuroendocringological Modulation
Changes in emotional state
What is the function of the amydgala as it connects with the uncus?
connects olfaction (smell), emotion, and new memories together.
What is the function of the hippocampal formation as it relates to the connection with the amydgala
The function is that it ties emotion and memory together. It usually causes fear-induced memories.
What is the function of the septal nuclei and basal forebrain as it relates to connections with the amydgala?
Function of the septal nuclei and basal forebrain is positive emotions as it relates to rewarding/pleasurable experiences
What is the function of the medial orbitofrontal cortex as it connects to the amydgala?
decision-making and emotion, also lowkey relates to autonomic function as it compares bodily changes to emotion.
What is the anterior cingulate cortex densely interconnected to?
Amydgala and hypothalamus
What are the functions anterior cingulate cortex?
Assigning internal and external stimuli, vocalization of expression states and desires, and regulates the autonomic and endocrine system, pain perception, and initiation and selection of motor movement.
What is the function of the posterior cingulate cortex?
Recall autobiographical memory. Memory that has a quality emotional meaning behind it
