Exam 6: Limbic System I Flashcards
What does the limbic system control?
mood, emotion, feelings, motivation; critical for memory
Where does the hippocampus project to? Via what?
Mammillary body, septal nuclei; fornix
Where do the mammillary bodies project to? Via what tract?
Anterior thalamic nucleus; mamillothalamic tract
Where does the amygdala project to? via what?
septal nucleus; stria terminalis
Where does the midbrain (via hypothalamus) project to? Via what bundle?
Forebrain; medial forebrain bundle
What neurotransmitter does the locus ceruleus release?
Norepinephrine
Where is the locus ceruleus located?
pons
What neurotransmitter does the raphe nuclei release?
serotonin
Where is the raphe nuclei?
midbrain and pons
What is the locus ceruleus and rephe nucleus responsible for in a humn?
arousal and sleep/wake cycles
What neurotransmitter is involved in the mesolimbic system?
dopamine
Where does the ventral tegmental area (VTA) project to? (4 different areas)
Nucleus accumbens, medial prefrontal cortex, amygdala, septal nuclei
What is the action of cocaine and amphetamines?
blocks DA uptake
Where does a lesion in the brain decrease drug-seeking behavior? How does it work?
VTA and Nucleus accumbens; decreases amount of dopamine in the brain that acts as a reward
What neurotransmitter does the nucleus basalis and septal nucleus release?
Acetylcholine
What role does the amygdala have in the limbic system?
fear conditioning
What do lesions in the amydala lead to?
prevents fear conditioning
what do lesions in the prefrontal lobe lead to?
Impairment in goal directed behavior, lack of emotion in decision-making (Lack of risk aversion), Poor social judgement (antisocial behavior), poor emotional control (increased impulsivity)
What areas are involved with the symptoms of a lesion to the prefrontal lobe?
Dorsolateral PFC and Orbital frontal cortex
What do lesions of the hippocampus lead to?
anterograde amnesia, temporally graded retrograde amnesia, explicit or declarative memory (semantic and episodic)
T/F: motor skills are not lost in a lesion to the hippocampus
True
What are symptoms of Urbach-Wiethe disease?
impaired recognition of emotion in facial expressions, memory loss especially of information with emotional content
What are the symptoms of PTSD?
re-experiencing phenomena in the form of flashbacks, avoidance of situations that parallel initial trauma, hyperarousal/hypervigilence
What is the etiology of PTSD?
increased amygdala activity, decreased medial prefrontal cortex activity (which usually plays a role in inhibiting amygdala)
What are the positive/negative symptoms of schizophrenia?
Positive: delusions, hallucinations. negative: Social withdrawal
What symptoms of schizophrenia are the target of treatment?
Positive symptoms: delusions and hallucination
What are the two main hypotheses of schizophrenia?
Dopamine and glutamate hypotheses
Explain the dopamine hypothesis of schizophrenia?
Increase in dopamine receptor activity
What are the treatments for the dopamine hypothesis of schizophrenia?
haloperidol, clozapine
What is the mechanism of action and side effects of haloperidol?
Blocks dopamine receptors; causes motor dysfunction (Parkinsonian like)
What are the mechanisms of action of clozapine?
Block DA-receptors, block 5HT receptors, block glutamate reuptake
Explain the glutamate hypothesis of schizophrenia? What was the idea that people though of?
Decrease in glutamate in synapse ; PCP blocks NMDA glutamate receptor
What are symptoms of depression?
lethargy, annedonia, loss of sleep
What is the hypothesis behind the cuase of depression?
monoamine hypothesis (depression due to decrease in NE and 5HT activity
What is the monoamine hypothesis?
depression due to decrease in NE and/or decrease in 5HT activity
What are the three main treatments for anti-depression? what are their actions?
monoamine oxidase inhibition, tricyclics (imipramine) (block reuptake of 5HT and NE, SSRI (fluoxetine) (Block reuptake of 5HT)
What are the symptoms of Korsakoff’s syndrome?
Disorder of immediate memory, disorientation, confabulation
What are the causes of Korsakoff’s syndrome?
chronic alcoholism, vitamin deficiency
What is the brain etiology of Korsakoff’s syndrome?
damage to mamillary bodies or to mamilothalamic tract
What are symptoms of Kluver-Bucy syndrome?
Oral tendencies, changes in emotions, hypersexuality, visual agnosias
What are symptoms of alzheimer’s disease?
Loss of memory, mood disorder (anxiety/depression), loss of motor function, complete loss of cognitive function
what is the etiology of Alzheimer’s disease?
loss of cholinergic input to hippocampus (nucleus basalis), loss of neurons in multiple brain areas, present of neurofibrillary tangles and Beta-amyloid plaques
What are the symptoms of chronic traumatic encephalopathy
Cognition: anterograde amnesia, dysfunction in goal-directed behaviors. Mood: depression, apathy. Behavior: decreased impulse control, increased aggressiveness
What is the etiology of chronic traumatic encephalopathy
generalized brain atrophy including prefrontal cortex, temporal lobes (amygdala, hippocampus), and parietal lobes
