18. Limbic System Flashcards
Limbic system functions
H - homeostatic functions, autonomic and neuroendocrine control
O - olfaction
M - memory
E - emotions and drives
Limbic cortex/lobe structures
- Cingulate gyrus
- Parahippocampal gyrus
- Uncus
- Medial orbitofrontal gyrus
- Temporal pole
- Anterior insular cortex
- Hippocampal formation
- Amygdala
What is the route of olfaction?
- Olfactory n receptors
- Olfacotry bulb thru cribiform plate
- Olfactory tract
- Primary olfactory cortex to temporal pole
- Amygdala
- Olfactory tubercle inside anterior perforated susbtance
what are the 3 types of memory?
- working
- declarative
- procedural
which type of memory handles short term storage and handling of information AND is goal relevant?
working memory
which type of memory is needed for language, problem solving, mental wayfinding, and reasoning?
working memory
which type of memory is required for complex mental multi-tasking and is impt for cognition?
working memory
What are the cortical areas for working memory?
- Lateral prefrontal cortex
- Temporoparietal association cortex
*White matter tracts connecting these areas
which type of memory can be verbalized AKA explicit memory?
declarative memory
What lobe recognizes memory for longer term storage BUT doesn’t store these memories?
Medial temporal lobe
for declarative memory
what are the 3 stages of declarative memory?
- Encoding
- Consolidation
- Retrieval
What does stage 1: Encoding consist of? (of declarative memory)
- Processing info
- enhanced by attentiveness, emotional arousal, tying new memory to others, reviewing
What does Stage 2: Consolidation consist of? (of declarative memory)
- Stabilization of memories
synaptic thru long term potentiation (min > hrs)
synaptic thru med temporal lobe (min > decades)
Declarative memory starts in _____ selecting input perceived by ______ and then encoded into _____
Thalamus
Temporoparietal assoc cortex (TPAC)
Medial temporal lobe (MTL)
Medial temporal lobe includes…
- Hippocampus - gray/white matter of gyrus
- Part of fornix - connects hippocampus with mammillary body and thalamus
- Parahippocampal gyrus
What cortical area has voluntary control over Medial Temporal Lobe in processing and organizing info for storage?
Lateral prefrontal cortex
LPFC:
_____ stored info
_____ content of language
Accesses stored info
Analyzes content of language
Note: for retrieval, it searches for and verifies encoded memories in MTL
< 12 years, what brain area is activated during recall of memories?
MTL
medial temporal lobe
13+ years, what brain area is activated during recall of memories?
Prefrontal, parietal, lateral temporal cortices
for longer term memory
What is episodic declarative memory?
Personal events/experiences
e.g. a story
What is semantic declarative memory?
Learned common knowledge not related to personal experiences
e.g. history, science
What type of memory is learning skills or habits, reasoning or logic, perceptual skills AKA implicit or nonconscious memory?
Procedural memory
When skill is _____, then less attention is needed to _____
When skill is learned, then less attention is needed to perform
What are the 3 stages of motor learning?
- Cognitive
- Associative
- Automatic
What parts of the brain does learning a motor sequence include?
Motor and parietal cortices and striatum
Where 2 areas are learned movement sequence memory representations stored in?
- Supplemental motor area
- Putamen/globus pallidus
What do adjustments of movements involve?
Cerebellum
Motor and parietal cortices
What is loss of declarative memory?
Amnesia
What is retrograde amnesia?
Loss of memory of events prior to illness/injury
What is anterograde amnesia?
Loss of memory of events after illness/injury
Note: includes PTA (post-traumatic amnesia)
For patients with impaired memory, it is important to separate _______ from _______. Why?
Declarative
Procedural
To learn things subconsciously even with no conscious awareness of learning them
What is essential for the patient to encode info?
Attention - in order to form memories of new info
Cognitive screens?
Mini-Mental Status Exam (MMSE)
MOntreal Cognitive Assessment (MOCA)
Temporal aspects of cognitive screens
* Encoding registration to ______ recall
* Attention/working memory
* ______ memory (few min - short term memory)
* ______ memory (long term memory)
Temporal aspects of cognitive screens
* Encoding registration to immediate recall
* Attention/working memory
* Recent memory (few min - short term memory)
* Remote memory (long term memory)
What does Goal Directed behavior include?
- Making a goal
- Making a plan for how to reach the goal
- Executing the plan
- Monitoring how plan is working out
What cortical area is responsible for goal directed behavior including working memory, judgment, planning, reasoning, divided attention, and sequencing?
Lateral Prefrontal Cortex
Which cortical area (-) inhibits inappropriate behavior AND formulates ranges of possibilities/alternatives?
Lateral Prefrontal Cortex
Mood vs. Emotion
Mood: enduring subjective ongoing emotional experience
Emotion: short term subjective experience
Emotions influence our _____ and _____
Perceptions
Actions/responses
Note: emotions can trigger immediate physiologic responses or subconscious processing of an experience or situation
What are the 6 structures involved with recognition, generation, and perception of emotions?
- Amygdala
- Area 25
- Anterior insula
- Medial prefrontal cortex
- Ventral striatum
- Thalamus
What does the amygdala do?
- Produces emotions of fear, disgust
- Interprets social signals
- Impt for social behavior and emotional learning
- Decision making
What does Area 25/thalamus do for emotions?
Produces sad/depress
:(
What does Anterior Insula do for emotions?
Awareness of feelings and internal stimuli
What is in the Emotion Loop?
Medial Prefrontal Cortex
VS (ventral striatum)
Thalamus (MPC and VS important for motivation)
Note: for reward seeking behavior, finding pleasure (implicated in addictions)
Automatic regulation of emotions is …
Subconscious, ignoring, leaving
Voluntary regulation of emotions is …
Conscious, choosing to control emotions
Ventral prefrontal cortex includes what cortical area?
Orbital cortex (VM and VL prefrontal cortex)
Social behavior connects with regions regulating ____ and ____
mood and affect
Social behavior utilizes ____ and feelings to steer behaviors, inhibiting (-) _____ behaviors, and activates ____
Social behavior utilizes rewards and feelings to steer behaviors, inhibiting (-) undesirable behaviors, and activates ANS
what loop detects relevant from irrelevant behavior?
social behavior loop
what loop regulates self control
social behavior loop
what loop understands social disapproval
social behavior loop
social behavior loop:
Ventral prefrontal cortex
Head of Caudate
SNr
Thalamus
Somatic marker hypothesis =
“gut feelings”
Emotion and social intelligence requires:
Ventral prefrontal cortex
Amygdala
Anterior insula
What is a disruption of homeostasis from changes in 3 systems: somatic, autonomic, neuroendocrine?
Stress Response
Somatic disruption in stress response
Motor neurons increase muscle tension
Autonomic nervous system in stress response
Sympathetic activity induces blood flow to muscles and reduces it to skin, GI tract, and kidneys
Neuroendocrine system in stress response
Sympathetic activity causes adrenal medulla to release epinephrine into blood to increase HR, BP, metabolic rate, and inhibits intestinal smooth muscle contractions
T/F: Stress response is always unhealthy if too prolonged/chronic
False
can be healthy or unhealthy
Clinical Implications of disorders of Limbic System
- Loss of goal directed behavior and divergent thinking
- Apathy, lack of emotion and insight
- Emotional lability/labile effect
- Impaired voluntary and/or automatic regulation of social behaviors
Signs or symptoms of disorders of limbic system
- Delusions
- Hallucinations
- Mania
- Depression
- Anxiety
Psychiatric Disorders examples
- Personality disorders
- Anxiety disorders
- Depression
- autism spectrum disorders
- bipolar disorder
- schizophrenia
What part of the cortex does extraversion?
ventral prefrontal cortex
What part of the brain does neuroticism?
amygdala
cingulate cortex
medial prefrontal cortex
hippocampus
What part of the brain does agreeableness?
temporoparietal association area
cingulate cortex
What part of the cortex does conscientiousness?
Lateral prefrontal cortex
What is intellect?
the ability to develop concepts and to reason (which involve memory and ability to process mental experiences)
Trisomy 21 = ?
Down Syndrome
if a specific area is affected in developmental disorders of intellect = ?
learning disability
Dementia is ?
Neurodegenerative mental condition with reduced memory, intellect, orientation, and judgment
