% of people treated for mood disorders?
50%
Five functions of Limbic system:
- mood
- emotion
- feelings
- motivation
- critical for memory
4 limbic system pathways:
- hippocampus –> fornix –> mammilary bodies OR septal nuclei
- mammilary bodies –> mammilothalamic tract –> anterior nucleus of the Thalamus
- Amygdala –> stria terminalis –> septal nucleus
- midbrain via hypothalamus –> medial forebrain bundle –> forebrain
NE is produced where?
Locus ceruleus (pons)
seretonin 5HT is produced where?
Raphe nuclei (Ra, midbrain, pons)
NE and 5HT role in Limbic system?
arousal
sleep cycle
Mesolimbic system produces what NT?
dopamine
dopaminergic neurons have cells bodies where? and project where?
ventral tegmental area (VTA)
project to:
nucleus accumbens
medial prefrontal cortex
amygdala
septal nuclei
Two substances that block DA reuptake?
cocaine
amphetamine
Two possible ways to decrease drug seeking behavior:
lesion in VTA or nucleus accumbens
DA receptor blockers
natural rewards associated with dopamine:
sex
food
two areas affected in Alzheimers associated with decreased Ach:
nucleus basalis
septal nucleus
Region of Limbic system involved in fear conditioning:
amygdala
impaired goal directed behavior
lack of emotion in decision making
poor social judgement
poor emotional control
…these are sx of injury to?
Prefrontal lobe
prefrontal lobe syndrome
Prefrontal lobe region involved with working memory and executive function?
Dorsolateral
Prefrontal lobe region sending INHIBITORY projections to amygdala?
Orbital frontal cortex
Amygdala usually stimulates hypothalamus
What happens in BL hippocampal lobectomy?
anterograde amnesia (no new memories) -facts and experiences (semantic and episodic)
***can still learn motor skills (implicit memory)
Disease involving amygdala disfunction with sx of:
- impaired recognition of facial expressions (emotions)
- inability to judge “like” emotions (fear vs anger, surprise vs happiness)
Urbach-Wiethe disease
- flashbacks
- avoidance of situations that parralel initial trauma
- hyperarousal (increased anxiety)
Triad of sx for:
Post Traumatic Stress Disorder
Etiology of PTSD?
INCREASED amygdala activity
DECREASED prefrontal cortex inhibition of amygdala–“take the brakes off”
Fragmentation of mood, thought, and movement are sx of:
Ex: delusions, hallucinations, social withdrawal
Schizophrenia
Neurochemical basis for Schitzophrenia:
Increased DA activity
Anti-psychotic that blocks DA receptors:
Side effects?
haloperidol
motor dysfunction (Parkisonian-like)
Atypical anti-psychotic that blocks DA receptors, 5HT receptors and glutamate reuptake
clozapine
What does PCP do?
blocks NMDA glut receptors
Tx: increase Glut receptor activity
Lethargy, anhedonia, and loss of sleep are sx of:
depression
what is the “monoamine hypothesis” for depression?
decrease in NE and/or 5HT receptor activity
Three tx’s for depression:
- MAO inhibitors
- tricyclics (Imiprine)
- SSRIs (Fluoxitine AKA Prozac)
MOA for MAO inhibitors?
Blocks degredation of NE or 5HT in presynaptic neuron
MOA for tricyclics?
blocks reuptake of NE and 5HT
MOA for SSRIs (Fluoxitine/Prozac)?
blocks reuptake of 5HT
- no new memories
- disorientation in space and time
- confabulation
….this is the triad of sx for:
Karsakoff’s Syndrome
Causes of Karsakoff’s?
Chronic EtOH
Vit B1 (thiamin) deficiency
Area damaged in Karsakoff’s?
mammilary bodies
- Oral tendencies
- changes in emotion (neutral affect due to amygdala damage)
- hypersexuallity (increase in # and variety of sexual activities due to damage to pathways to hypothalamus)
- visual agnosia
…these are sx of which disease?
Kluver-Bucy Syndrome
Temporal lobe damage
Etiology of Alheimer’s disease:
- loss of cholinergic input to hippocampus (nucleus basillis)
- loss of neurons to multiple brain areas
- presence of neurofibrillary tangle (NFTs: phosphorylated TAU proteins) and B-amyloid plaques
Drug used to treat Alzheimer’s that blocks acetylcholinesterase?
Donepezil (Aricept)
Progressive neurodegenerative disease caused by repeated head trauma?
Chronic Traumatic Encephalopathy (CTE)