Exam 2 Dr Langford Review Flashcards
What are the key causes and mechanisms of depression?
✔ Monoamine Dysfunction: Imbalance in serotonin (5-HT), norepinephrine (NE), dopamine (DA)
✔ HPA Axis Dysregulation: Overactive stress response = excessive cortisol, hippocampal shrinkage
✔ Neuroinflammation: Increased cytokines reduce BDNF & neuroplasticity
✔ Neurodegeneration: Chronic stress leads to neuronal loss & volume reduction in key areas
✔ Genetic & Epigenetic Factors: Genetic predisposition + environmental stress
Mnemonic: “H.I.G.S.” → Hormonal, Inflammatory, Genetic, Stress-related
Why is the Monoamine Hypothesis considered incomplete?
Antidepressants increase neurotransmitters immediately, yet symptom relief takes weeks.
Direct neurotransmitter level changes aren’t consistently found in depressed patients. Neuroplasticity plays a major role in recovery (BDNF & structural changes)
What role does serotonin (5-HT) play in depression?
Regulates mood, anxiety, and impulsivity
Part of the Monoamine Model.
What is the function of norepinephrine (NE) in relation to mood disorders?
Controls alertness, energy, & stress response
Part of the Monoamine Model.
What is the role of dopamine (DA) in mood regulation?
Governs motivation, pleasure, & reward processing
Part of the Monoamine Model.
Which brain regions are commonly affected in depression?
✔ Prefrontal Cortex (PFC)
✔ Amygdala
✔ Nucleus Accumbens
✔ Thalamus
✔ Striatum
Mnemonic: “PANTS” → Prefrontal Cortex, Amygdala, Nucleus Accumbens, Thalamus, Striatum
What happens to the Prefrontal Cortex (PFC) in depression?
Underactive, leading to poor decision-making & executive dysfunction
How does the amygdala change in depression?
Overactive, contributing to increased anxiety & negative emotional bias
What is the effect of a reduced Nucleus Accumbens in depression?
Reduced reward response, leading to anhedonia
What imaging findings are associated with depression?
✔ MRI: Reduced hippocampal volume, prefrontal cortex thinning
✔ fMRI: Overactivity in amygdala, default mode network hyperconnectivity (rumination)
What is the impact of chronic stress on the HPA axis in depression?
Chronic stress leads to an overactive HPA axis, increasing cortisol & damaging the hippocampus
What is the Dexamethasone Suppression Test (DST) used for?
To assess HPA axis function; depressed patients fail to suppress cortisol
It is not specific enough for diagnosis.
What are the effects of antidepressants on neuroplasticity?
✔ Increase BDNF → Supports neurogenesis
✔ Reduce glucocorticoids which restores HPA function by upregulating the glucocorticoid receptors→ Protects hippocampus from stress damage
✔ Restore neurotransmitter balance → 5-HT, NE, DA, Glutamate
Mnemonic: “BIG N” → BDNF, Inflammation, Glucocorticoids, Neurogenesis
What differentiates unipolar depression from bipolar disorder?
✔ Unipolar Depression: Consistent underactivity
✔ Bipolar Disorder: Fluctuating hyper/hypoactivity
Mnemonic: “Bipolar = Rollercoaster Brain”
What are key interventions that can increase BDNF?
✔ Sleep regulation
✔ High-intensity exercise
✔ Electroconvulsive Therapy (ECT)
✔ Social interaction & environmental enrichment
✔ Antidepressants (increase BDNF over time, but this isn’t their primary mechanism of action).
✔ Nutrition (Omega-3s, flavonoids, and curcumin).
✔Lithium may support neuroplasticity but is not a primary BDNF booster.
What are the symptoms associated with the Nucleus Accumbens?
Anhedonia (no pleasure) due to dopamine dysfunction.
What is the role of the hypothalamus in depression?
Appetite and sleep issues caused by regulation disruption.
What occurs in the striatum in depression?
Motor agitation due to hyperactivation.
What are neurobiological changes that occur in Bipolar Disorder?
✔ PFC and Limbic System Dysregulation: Abnormal connectivity between the amygdala & PFC.
✔ Gray Matter Changes:
Increased amygdala volume.
Decreased gray matter volume in PFC.
✔ Mania = Dopamine & Glutamate Excess
✔ Depression Phase = Low Dopamine & Underactive PFC
What is the role of the dorsolateral PFC in depression?
Cognitive impairment due to executive function deficits.
What occurs in the amygdyla during depression?
Anxiety, stress, and suicidality (emotions) are overactivated due to the stress response.
What occurs in the basal forebrain due to depression?
fatigue and low energy due to NE and DA reduction.
How does Ketamine work for depression?
Ketamine (NMDA antagonist) → Immediate effects via glutamate modulation.
How do SSRIs/SNRIs work in depression?
SSRIs/SNRIs → Gradual increase in BDNF & neuroplasticity.
How does the HPA axis release cortisol?
Hypothalamus → Releases CRH
Pituitary → Releases ACTH
Adrenal Gland → Releases cortisol
