Limbic 1 Flashcards
What are the two main regions of the limbic system?
cortical region and subcortical region
What makes up the cortical region of the limbic system?
prefrontal, cingulate, insula, parahippocampal gyrus
What makes up the subcortical region of the limbic system?
Hippocampus, amygdala, ventral striatum/nucleus accumbens
what does the limbic system provide the basis for?
memory, motivation (dopamine), and emotions, with the help of other CNS structures
Where does planning happen?
frontal cortex and cingulate cortex
Where does cognition happen?
cerebral cortex
Where is stress processed?
HPA axis, hippocampus, amygdala
Where is fear?
amygdala
Where is memory?
hippocampus, and entorhinal cortex
Where is the reticular formation?
In the medulla, pons and midbrain that project to thalamus and cortex
What makes up the reticular formation?
several nuculei
What is the reticular formation send projections to the thalamus and cortex for?
alerting and wakefullness ARAS
Where does sensory info enter the reticular formation?
input enters the raphe and lateral nuclei
Where do the medial nuclei of the reticular formation project?
to brain and spinal cord for general modulation
what are the two views of the reticular formation?
anatomical and physiological
What is the anatimical view of the reticular formation?
reticular neurons with long axons that are modulation wide areas of the brain
What is the physiological view of Reticular formation?
ascending reticular activation system, ARAS for alerting and wakefullness.
What does Norepinephrine do for cortical and limbic system?
attentional selectivity under stress, focus.
where does norepinephrine come from in reticular formation?
Locus cerelus in the pons.
Where does dopamine come from and what does it effect?
From vental tegmentum of the midbrain (substantia niagra and ventral tegmentum area) to the prefrontal cortex and basal ganglia
What does dopamine do for the prefrontal cortex/basal ganglia?
Provides motivation bases behavior
what projects to wider areas of the brain NE or dopamine?
NE from single locus coerules hit wide area of cortex, brain stem, spinal cord and cerebellum, thalamus.
Basically where does dopamine go?
mostly to the front half of brain
Where does seratonin come from?
Raphe nucleus of the medulla going to the cortical areas.
what does seratonin effect?
mood, sleep wake cycles.
Where does acetyl choline come from?
septum, neuceus basalis, and diagnal bane of broca to thalamus and cortical areas.
What does acetylcholine do?
facilitate hippocampal and cortal regions in memory and cognition.
What areas does working memory?
lateral prefrontal cortex
what are the executive control functions of lateral cortex?
formulation, refining, goals to regulate behavior and solve problems.
what can determine course of behavior based on various alternatives?
lateral prefrontal cortex
what does reward, motivation, and emotional decision making?
orbitofrontal cortex
what area will allow you to chose better reward later instead of one now?
orbitofrontal cortex
what does the ventromedial cortex include?
medial prefrontal cortex and anterior cingulate cortex
what does the ventromedial cortex do overall?
generate and regulate emotional responses decleritive memory and habits.
what does the anterior cingulate of ventromedial cortex do?
chose amond complex actions, behaviorly based
What does medial PFC do?
enotinal biasing into decisions,, experience of emotion, meaning to perception,
Where does fear conditioning happen?
medial PFC of the ventromedial cortex
overall, what does the ventral and medial regions of PFC regulate?
emotions
overall, what does the dorsal and lateral regions of PFC regulate?
thought and action
Prefrontal cortex provides top down control over what three things?
attention, emotion, and behavior
how does PFC help regulate decision making and planning for future
via extensive interconnections with other cortices
how can PFC help regulate its own catecholeamine inputs?
it has direct and indirect connections to reticular foramen nuculi
two more places that dopamine comes from?
Substantia niagra and ventral tegmental area.
where is hippocampus?
near surface of medial temporal lobe, bulging into lateral ventricle.
How many layers of cortex in hypocampus?
three layers of cortex. Archicortex?
Direction of afferents to hippocampus?
parahippocampal gyrus, entorhinal cortes to hippocampus.
what parts of cortex project to hippocampus?
sensory, association, cingulate and prefrontal cortex
what is purpose of hippocampal efferents?
consolidate processed info into memory to wide arease of cortex, parietal, prefrontal and temporal
three types of memory developed in limbic system?
declaritive, procedural, and working
Where is declaritive memory?
hippocampus and medial temporal lobe
where is emotional type of procedural memory?
amygdala
where is working memory
prefrontal is associated with working memory
what is declaritive memory?
explicit episodic and semantic memory
what is episodic memory, part of declaritive?
autobigraphial, mental time travel, caused by interconnection of hippocampus and prefrontal cortex
what does hippocampus do to episodic memory?
consolidates and them projects them all around cortex, maybe so you have copies if one gets lost
what is semantic memory?
non contextual, experience or knowledge about world, representations of concepts etc.
what is semantic memory consolidated?
anterior temporal lobe and lateral prefrontal cortex.
is sense of self attached to semantic memory?
no sense of self,
what are the two distinct regions of memory consolidation for declaritive memory?
Anterior temporal system, and the posterior medial system
what does Anterior temporal system do?
relates representations of specific entities to existing concepts, ie, person, noun
What does PM system do?
matches incomming info about contex to interactions with environment during new experience.
What system gives object value or social revelance?
anterior temporal system
what system gives temporal order and place?
posterior medial system
what cordinates many regions for a precise recall of episodic memory?
retrosplenal area of cingulate gyrus
when is memory consolidated?
During sleep, especially if its emotionally significant.
what are the two major stages of sleep?
REM, rapid eye movement and non REM (slow wave)
What distinguises sleep stages?
EEG, electroencephalogram
what stage of sleep is more similar to waking?
REM, with low amplitude and high frequency
what happens to amplitued and frequency as sleep deepens?
when sleep depens, amplitued increases and frequency decreases.
is there more REM near the beginning or end of night?
Near the end of the night there is more REM.
how do sleep stages change with age?
The older you get the less time spent in deep sleep, and the les rem also.
how much REM does average person need?
2 hours of 8 hours sleeping
what pathway facilitate transmission of info from thalamus to cortex?
Cholinergic pontine pathways which are most active during REM and wakeing
What pathways activate the cortex to process info from thalamus?
The monoaminogeric pathways, cholinergic pathway from Basal forebrain and Orexin/hypocretin path
what come from the monoaminergic pathways?
NE, serotonin and dopamine
what area of brain regulates sleep?
the hypothalamus with its VLPO, ventralateral preoptic nuculeus
how does hypothalamus regulate sleep?
by inhibiting nuculei hat participate in arousal to induce drowsiness and during non REM sleep
what nuclues responds to ambient light and dark cycles?
the SCN, superchiasmatic nuculeus. Chercadian rhythem stuff.
how does DMH, dorsal medial nucuei of hypothalamus promote wakefulness?
inhibits the VLPO using gaba neurons and stimulating orexin.
how can we sleep easily during the day when sick?
cytokines disrup circadian sleep cycle TNF, IL
what part of memory is consolidated in early sleep?
declaritive and procedural
what part of memory is consolidated in late sleep?
final consolidation of all memory
what gets excited for waking/cortical arousal?
cholinergic ineurons, Norepinephrine neurons and serotonin 5ht neurons, they all activate cortex.
so, what part of brain stimulates all the neurons for wakefulness?
neurons of the posterolateral hypothalamus.
what inhibits sleep active neurons in the ventrolateral preoptic VLPO?
neurons of the Posterolateral hypothalamus.
what are the neurotransmitter systems tha are effected by the postlateral hypothalamus?
serotonin, norepinephrinergic, acetyocholine, spinal motor neruons
inhibition of what pathways block sensory input to cortex?
inhibition of cholinergic and adrenergic pathways
what is different between hearing sound while awake or during non REM sleep?
when awake auditory activity is stimulated, when asleep, cortical areas get downregulated in a sleep protective mechanism.
during non REM sleep what inhibits serotonin, acetylcholine and norepinephrine of the ascending arousal system?
the Ventrolateral preoptic neurons, VLPO
when the ascending arousal systems are inhibited, what happens?
decrease info to cortex, decreased muscle tone, HR, breathing and metabolic rate. Inactive body in active mind
what is inhibited and excited in REM sleep?
Excitation of cholinergic neurons from LDT, more than when awake, Inhibition of serotonergic neurons.
what does fMRI show is happening during REM?
High brain activity with paralysis.
what are the two types of REM sleep?
Phasic and Tonic
Phasic REM?
rapid eye movement, brain super active, supression of external sounds
Tonic REM?
no rapid eye movement, increased reactivity to sound and outside stimuli
REM characteristics,
Rapid eye movement, paralysis, increased BP, HR, metabolism, dreaming, hallucinations, Active mind in inactive body.
Three brainstem nuclei for wakefullness that are activated
cholinergic of pons, midbrain, locus coeruleus, Raphe nuclei
Three branstem nuclei for non REM sleep that are deactivated
cholinergic of pons midbrain junct, locus coeruleus, Raphe nuclei
Two brainstem nuclei for REM sleep
Cholinergic is active and Raphe nuclei is inactive
one brainstem nuclei for REM off
Locus coeruleus is active
NE comes from what nuclei
locus coeruleus
Serotonin from where?
Raphe nuclei
Acetylcholine from were?
cholinerginic nuclei
4 physiological functions that corelate with REM?
Eye movement, HR, Respiraton, Penile erection
what does the EEG look like for awake and REM?
low voltage and fast which is opposite of non rem sleep of high voltage and slow.
do we have rapid eye movement while awake?
yes
how are memories reactivated and transferred to neocortex?
Decrease in Ach during slow wave sleep increases reactivation in hippocampus
what helps encode sensory input into hippocampus origionally?
increase in ach.
what can stabalize memories after learning?
memory reactivation during slow wave sleep.
what happens if memories are reactivated while awake?
makes memories more lible to be modified
what happens with memories consolidated during REM?
connections can be made between that and other memories helping to facilitate learning and storage of new info.
what structure regulates memory encoding in hippocampus?
The septum, helps avoid mixing new info that is being coded and old info that is being retrieved
what nucleus that helps with memory consolidation is degenerated in alzheimers patients.
nucleus basalis
what may contribute to beta-amyloid plaque patholgy in alzheimers?
impaired cortical cholinergic neurotransmission
description of alzheimers
degeneration of cortex, cholinergic and neuromodulatory tracts, amyloid plaques, neurofibrillary tangles, inability to consolidate short term to long term.
what causes korsakoffs syndrome?
degeneration of thalamic nuculi and mammilary bodies due to alcholism.
what is the papez circuit?
circular route connecting hippo/amygdala to cingulate and prefrontal cortex via mediodorsal thalamus
