Motivational Systems And Psychiatry Flashcards
What is schizophrenia a disorder of
Mesolimbic dopamine system and prefrontal cortex
When does schizophrenia emerge
Early adulthood
Positive symptoms of schizophrenia
-hallucinations, paranoid delusions, dissociated from reality. Common type of hallucinations: ‘hearing voices in my head”. Erratic eye movements, related to constantly shifting attention
Negative symptoms of schizophrenia
-impaired attention, executive function, behavioral control, flattening of emotional expression (flat affect)
Neurobiology of schizophrenia
Excessive activity of mesolimbic DA system (opposite of Parkinson’s)
Rx for schizophrenia
Dopamine receptor antagonists, referred as “typical anti-psychotics’ or ‘neuroleptic’ drugs
One potential serious complication of anti-psychotics or neuroleptics
Tardive dyskinesia
- involuntary movements of facial/mastication/tongue muscles.
- can also develop Parkinson’s like signs including cogwheel rigidity
- extra-pyramidal side effects
Role of serotonin in schizophrenia
- some atypical anti-psychotics can also affect serotonin NT
- normal functions of serotonin systems include promoting memory retrieval
- some hallucinogenic act by activating serotonin receptors
- speculative explanation for efficacy of Rx that modulates serotonin: schizophrenia involved excess serotonin signaling which drives hallucinations and delusions
Role of glutamate dysregulation in schizophrenia
- role of dysregulation of glutamate in prefrontal cortex and straitum: excess glutamate release by axon terminals
- dysregulation of glutamate occurs in corticostriatal projections, i.e. Part of the basal nuclei “cognitive loop” or emotive loop
Two major groups of nuclei (multi raphe) of serotonin systems
Ascending/rostral
- caudal midbrain
- rostral pons
Caudal/descending raphe nuclei
-in pons/medulla
Which serotonin system is involved with schizophrenia and how
Rostral/ascending system
- caudal midbrain
- rostral pons
Spritzing serotonin all over cerebrum
Group of nuclei located at the midline in brainstem sections
Nuclei raphe
Early generation diet pills and rostral/ascending system
Act via increasing serotonin in hypothalamus, normally mediates stress-induced interruption of eating
Serotonin levels regulate what
Aggressive behavior, natural reward (eating)
Different raphe nuclei and effects on anxiety
They have opposing affects on anxiety, due to difference in projections targets and receptors types. Ascending serotonin systems have widespread, diffuse projections in cerebrum, but important targets include amygdala, prefrontal cortex, other subcortical sites
What is used for Rx for anxiety/panic/ PTSD, and as anti-depressants
SSRIs
Core symptoms of MMD
- loss of interest, pursuit, and pleasure from usual rewarding activities
- inability/disinterest in performing any daily plan, motivational ‘paralysis’
- feelings of hopelessness/worthlessness
- causes severe dysfunction in daily work/social life
- lasts more than 1 month
Additional diagnostics criteria for MDD
- increases anxiety/agitation
- excessive sleeping or insomnia
- excessive appetite or absence of appetite
- lethargy or high ‘psychomotor’ activity
Crisis point requiring emergency intervention for MDD
Suicidal ideation/planning
Onset of MDD
-chronic/insidious, but often triggered by chronic stress, trauma, grief
Course: may be episodic or chronic state
What do anti depressants target
norepi, serotonin, and dopamine systems
Efectiveness of ant depressant Rx discovery
Through historical/medical accident, not by any pathophysiological understanding of the neurobiology basis of depression
What lead to the monoamine hypothesis of depression
The effectiveness of anti-depressants
What is the monoamine hypothesis of depression
An imbalance of deficiency in monoamines is the cause of depression
