PSYC 110 Study Guide - Final Guide: Substantia Nigra, Nigrostriatal Pathway, Reduced Affect Display
29 Jun 2018
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300-500 releases per second. Neurotransmitters are released from the presynaptic terminal and
diffuse across the synaptic cleft to the postsynaptic membrane.
Neurotransmitter Lifecycle: Bound
Neurotransmitters bind to receptor proteins embedded in the postsynaptic cell's membrane.
Neurotransmitter Lifecycle: Cleared
Neurotransmitters are a) broken down by enzymes in the cleft or b) reused by active reuptake.
Glial cells like astrocytes help clean up neurotransmitters that have diffused outside of the cleft.
Examples of Reuptake Inhibitors
Cocaine, SSRI's and SNRI's, Amphetamines
3 Dopaminergic Circuits:
1- pleasure/reward/goal (VTA to Nucleus Accumbens)
1-mesolimbic pathway
Dopamine Receptors
D1-like = usually
D2-like = usually
D1 = excitatory
D2 = inhibitory
3 dopaminergic circuits:
2-motivational/emotional (VTA to Neocortex)
2-mesocortical pathway
3 dopaminergic circuits
3-coordination of movement (Substantia nigra to caudate-putamen)
3-nigrostriatal pathway
Dopamine Hypothesis of Schizophrenia- Positive Symptoms = added symptoms
VTA to NA, D2.
non-goal directed behavior ("catatonic behavior"), disorganized speech, hallucinations and
delusions
Dopamine Hypothesis of Schizophrenia- Negative Symptoms= lack of symptoms
VTA to Neocortex: D1
lack of expression ("flattened affect") and motivation
Dysregulation of both the mesolimbic and mesocortical circuits
Schizophrenia
Cells in substantia niagra dying•Not enough dopamine in the nigrostriatal pathway
Document Summary
Neurotransmitters are released from the presynaptic terminal and diffuse across the synaptic cleft to the postsynaptic membrane. Neurotransmitters bind to receptor proteins embedded in the postsynaptic cell"s membrane. Neurotransmitters are a) broken down by enzymes in the cleft or b) reused by active reuptake. Glial cells like astrocytes help clean up neurotransmitters that have diffused outside of the cleft. Dopamine hypothesis of schizophrenia- positive symptoms = added symptoms. Vta to na, d2. non-goal directed behavior ("catatonic behavior"), disorganized speech, hallucinations and delusions. Dopamine hypothesis of schizophrenia- negative symptoms= lack of symptoms. Vta to neocortex: d1 lack of expression ("flattened affect") and motivation. Dysregulation of both the mesolimbic and mesocortical circuits.
