Limbic System: Behavior, Emotions, and Learning Flashcards
Major functions of the limbic system
Emotions and drives (amygdala), memory (hippocampal formation), homeostasis (hypothalamus), olfaction. The Four F’s: Feeding fighting fear fucking
Dorsolateral PFC Function
Executive function, working memory, decision making, cognitive control
ACC Function
Mediates reward anticipation, empathy, emotional processing, motivation
Orbitofrontal Cortex Function
Corrects and inhibits maladaptive emotional responses, mediates socially appropriate behavior.
Limbic system modulated by?
Wide variety of serotonergic, dopaminergic, cholinergic, noradrenergic projections
Processes of Emotion Perception
Stimulus, appraisal (amygdala/insula), affective state (amygdala, ACC, OrbCtx, NAcc), regulation (anterior cingulate, hippocampus, PFC), which also affects appraisal.
Schizophrenia Hypotheses
Major problems with mesolimbic pathway, hyperactivity of dopaminergic neurons cause psychosis, hypoactivity of dopaminergic neurons cause negative symptoms.
Brain abnormalities in schizophrenia
Decreased activity of dorsolateral PFC and ACC. Decreased hippocampal activity during memory task performance. Inability to engage amygdala, anterior cingulate, and hippocampus in processing stimuli with high emotional valence.
Learning
The strengthening of preexisting responses or behaviors, or the formation of new responses to existing stimuli that occurs because of practice or repetition, type of implicit memory.
Habituation
Repeated stimulation results in a decreased response
Sensitization
Repeated stimulation results in an increased response
Classical conditioning
The association of a neutral stimulus with an unconditioned stimulus such that the neutral stimulus comes to bring about a response similar to that originally elicited by the unconditioned stimulus.
Stimulus generalization
The conditioned response occurs when a new stimulus resembles the conditioned stimulus.
Operant conditioning
Trial and error learning that is reinforced.
Positive reinforcement
Introduction of a stimulus that results in an increase in the rate of a behavior
Negative reinforcement
Removal of an aversive stimulus that results in an increase in the rate of behavior
Punishment
Introduction of an aversive stimulus aimed at reducing the rate of unwanted behavior.
What is stronger, fixed or variable ratio reinforcement
Variable ratio, produces slower learning, but more resistant to extinction.
Neurobiology of operant conditioning
Nucleus basalis (ACh) activated after conditioned stimulus or primary reward, synaptic plasticity as mechanism of learning and memory formation.
Dopamine reward system
Reward ->Cortex -> Vta -> Nacc -> Ventral pallidum -> Mediodorsal nucleus of thalamus ->PFC
Kluver Busy Syndrome
Hyperorality, hypersexuality (no modulation of the hypothalamus by the amygdala), tame, no fear
Urbach Wiethe Disease
Rare autosomal recessive disease, causes calcifications of the medial temporal lobes (amygdala) cant recognize fear or rate emotional intensity
Neural pathways of empathy
Insula, ACC (triggers when something is wrong), amygdala/orbitofrontal/VMPFC (empathy and socially acceptable behavior)
Antisocial personality disorder
You know this. Limbic dysfunction: amygdala and orbitofrontal cortex hypoactivity
Limbic encephalitis
Causes acute short term memory loss, group of autoimmune disorders that affect the limbic system. Antibodies may appear in CSF, many different types
Herpes simplex encephalitis
Usually caused by HSV-1, can cause confusion, personality change, seizures, impaired consciousness, impaired memory, can be fatal in 1-2 weeks.
Temporal Lobe Epilepsy
Can cause crazy symptoms like mood changes, hallucinations, hypersexually.
