Limbic System Flashcards
What an emotional Roller Coaster Ride
Lymbic System Functions
- Emotional aspects of behavior related to survival of the species
- Visceral Responses to accompany these emotions
- Recent Memory brain mechanisms
Ventral Striatum
Where Caudate and Putamen come together
The Limbic pathway/loop is active
when making a decision when the outcome is uncertain–can lead to addictive behavior
Controlling Emotions is part of the
Prefrontal Cortex
Limbic Lobe
cingulate gyrus
parahippocampal gyrus
hippocampus
dentate gyrus
Amygdala Nucleus
within temporal lobe
Limbic System Structural Components
Limbic Lobe Amygadala Nucleus Olfactory Areas Epithalamus Septal Area 25 Mammillary Bodies Anterior Thalamic Nucleus and Medial Dorsal Nucleus
Septal Area 25
Prefrontal Cortex
Frontal area bear Broca
Medial orbital and medial frontal cortex
Mamillary Bodies
Part of the Hypothalamus
Limbic System Pathways
2 major fiber bundles
Fornix
efferrents from temporal lobe hippocampus—diencephalon’s habenula–anterior thalamic mamillary nuclei
Medial Forebrain
connects septal area, amygdala, cingulate gyrus and hypothalamus to –midbrain reticular formation
Amygdala Functional Aspects
- Visceral responses elicited when stimulated
- Electrical stimulation causes feelings of fear and anxiety, confusion and loss of memory of events during stimulation
- Interpretation of facial expressions, body language, and social signals.
- Disgust
- Endocrine ANS responses to stimulation
- ACTH=adrenocorticotropic—growth of adrenal cortex
- LH=luteohoromone (progesterone)
- LTH=luteotrophic, stimulates ovarian luteum
Hippocampal Functional Aspects
Bilateral lesions—recent memory loss
Role in expression of emotions
Role in sexual behavior
-no direct relationship to sense of smell
-Probably no relationship to old memory, personality or general intelligence
Limbic System Output Pathways
Autonomic NS ---Increased heart rate ---Dilations of pupils ---Cessation of digestion Horomonal NS ---Responses to amygdala stimulation Somatic and Reticular NS ---Increased muscle tone/tension
Just when you thought the Basal Ganglia was only devoted to motor control
4 additional separate, parallel cortico-basal ganglia-thalamic systems/loops
- —Oculomotor
- ——body of caudate
- –Executive
- ——Head of caudate
- –Behavioral flexability
- ——head of caudate
- –Limbic;emotion and motivation
- ——ventral striatum and pallidum
KNOW THIS THIS LOOKS VERY TESTABLE
5 Basal Ganglia Loops/Pathways
Executive, social, behavioral, and emotional functions
- -These loops contribute to :
- —-Predicting future events
- —-selecting desired behaviors
- —-preventing undesired behaviors
- —-shifting attention
- —-spatial working memory
Limbic Loop Structure and Function
Includes ventral striatum (n. accumbens), ventral pallidum, and mediodorsal thalamic nucleus
In linking with cognitive and motor systems, the function of the limbic loop is to:
—Identify the value of stimuli
—Be involved in reward-guided behavior
—monitor errors in predictions
—be concerned with seeking pleasure
Function of the Five Basal Loops
Motor Movement selection and action
Occulomotor: Decisions about eye movements and spatial attention; initiation of fast eye movements
Executive: goal-directed behavior, makes perceptual decisions, plans, and decides upon actions in context
Behavioral flexibility and control: recognition of social disapproval self-regulatory control, selecting relevant knowledge from irrelevant, maintaining attention, stimulus-response learning
Limbic: links limbic, cognitive, and motor systems; identifies value of stimuli; involved in reward guided behaviors; monitors errors in predictions; concerned with seeking pleasure
Emotional Structures
Amygdala Hypothalamus Septal area Anterior thalamic nucleus anterior limbic cortex limbic association areas
Memory Structures
Hippocampus Medial thalamic Nuclei Posterior limbic cortex Basal forebrain Mammillary bodies
Emotions Tied into our Behavior
An emotion is a short term and subjective
A mood is a sustained, ongoing emotion
Emotions color our perceptions and influence our actions
—–Happy, positive emotions/moods are tied to our left prefrontal cortex
—–Sad, anxious negative emotions/moods are tied to our right prefrontal cortex
Emotions and Behavior
Five structures recognize emotional stimuli and generate and perceive emotions:
-Amygdala
-Septal Area 25 (cingulate cortex below start of corpus callosum)
-Mediodorsal nucleus of the thalamus
-Ventral Striatum
Anterior Insula (of Reil)
Areas of the brain Involved with emotions…chart chapter 17 page 418-419
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Emotion and Decision Making
- Emotion is intimately ties to decision making
- When making a decision where the outcome is uncertain, the limbic loop is active
- Emotional Signals–“gut feelings”–are based on prior experiences and memories
- —-Ex. Author’s roommate’s date - Theory that emotions are crucial for sound judgement
- —called the “somatic marker hypothesis”
- —-Involves the ventromedial prefrontal cortex, amygdala, and anterior insula of Reil
Kluver-Bucy Syndrome
A Bilateral Temporal Lobe Lesion
A voracious appetite, increased sex drive, docility, and loss of recognition of people(visual agnosia) and memory defect; responses elicited depend upon the extent of the lesion
Kluver-Bucy Syndrome
- Attitude of indifference
- –absence of emotional responses
- –loss of facial expressions - Reversal of behavioral patterns
- –Inappropriate behavior
- –Loss of social morals - Increased tactile impulses
- Strong oral tendencies
- -Hyperorality–indiscriminate mouthing and chewing motions - Lack of sexual inhibitions
- -Perverted auto-hetero-homosexual responses - Unicate fits
- –involves amygadala and uncus (medial parahippocampus)
- –Hallucinations related to hearing a non-existent fearful sound, smelling a non-existent bad odor
