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Neurobiology of anxiety

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Page 1: Neurobiology of anxiety
Page 2: Neurobiology of anxiety

I. DefinitionsII. Neuro-anatomical circuitsIII. Neurochemicals

Page 3: Neurobiology of anxiety

Anxiety- Feeling of apprehension caused by anticipation of danger, which may be internal or external.

Fear-Unpleasurable emotional state consisting of psychophysiological changes in response to a realistic threat or danger.

Phobia-Persistent, pathological, unrealistic, intense fear of an object or situation

Obsession- Persistent and recurrent idea, thought, or impulse that cannot be eliminated from consciousness by logic or reasoning; obsessions are involuntary and ego-dystonic.

Page 4: Neurobiology of anxiety
Page 5: Neurobiology of anxiety

all share core symptoms of fear and worry

all basically treated with the same drugs (including many of the same drugs that treat major depression)

what is the difference between major depression and anxiety disorders?

Are all these entities really different disorders?

Page 6: Neurobiology of anxiety

•GAD- persistent and unremitting yet not severe•Panic- intermittent and catastrophic in an unexpected manner•Phobia- intermittent and catastrophic in an expected manner•PTSD-traumatic in origin and conditioned

Page 7: Neurobiology of anxiety
Page 8: Neurobiology of anxiety

Conditioned fear associations

Organising fear responses- rapid and long latency

Innate fear and social behaviour

Organising emotional experience- motor , autonomic,endocrinesystems.

Page 9: Neurobiology of anxiety

Monosynaptic projections from sensory thalamus to lateral nucleus rapid conditioning(vision+sound+somatic). [subcortical]

Long latency response – highly processed complex sensory stimuli and environmental contexts.[higher cognitive processing]

Extinction resistant memory storage

Plasticity

Hippocampus + Amygdala = spatial contextual conditioning (mental map) (emotion)

Page 10: Neurobiology of anxiety

Tachistoscope

Page 11: Neurobiology of anxiety

Facial expression and voice intonation Recall of emotional or arousing memories

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Page 13: Neurobiology of anxiety
Page 14: Neurobiology of anxiety
Page 15: Neurobiology of anxiety

Central nucleus = fear, BNST = anxiety

CRH acts on BNST Anxiogenic effect of very

bright light presented for long time

Bigger in males.(hormone related change)

Red. vol = pedophiles, Inhibition of sexual maturity ; disruption shown to attenuate reinstatement of drug seeking behaviour.

Striaterminalis

AMYGDALA

Page 16: Neurobiology of anxiety
Page 17: Neurobiology of anxiety

WARRIORS WORRIERS

Page 18: Neurobiology of anxiety

Perirhinal cortex(anterior) – conveys visual stimuli to amygdala

Temporopolar cortex – emotional salience of actual or anticipated stimuli

mPFC- critical in attenuating fear response Insular cortex – active during developing/

while experiencing disgust. Significant role in interoceptive function especially heartbeat.

Page 19: Neurobiology of anxiety

GABA Serotonin NE Glutamate Dopamine Voltage gated ion channels NeuropeptideY Galanin CCK

Page 20: Neurobiology of anxiety

GABA-A and GABA-C ligand gated ion channels. GABA-B –G-Protein linked.

GABA-A – critical role in inhibitory neurotransmission + targets of BZD

Functions vary based on the subunits

α1- sleep, α2 α3-anxiety

Page 21: Neurobiology of anxiety

Increased turnover in mPFC, amygdala, nucleus accumbens and hypothalamus.

Sensitive to severity of stress(esp in mPFC) Chronic Learned helplessness – decreased

5HT release BZD and Antidepressants prevent decrease of

5HT and learned helplessness. 5HT1A knockout mice – marked anxiety and

fear behaviours.

Page 22: Neurobiology of anxiety

Fight /flight/freeze response

NE PTSD

Yohimbine – panicogenic

β-blockers and opioids can disrupt reconsolidation of fear memory.

Page 23: Neurobiology of anxiety

Benjamin james sadock.Virginia alcott sadock.Pedro ruiz.,2009.Comrehensive textbook of psychiatry.9th edition. Lippincott Williams & Wilkins.

Stephen.M.Stahl.2013.Stahl’s essential psychopharmacology.4th

edition.Cambridge university press.

Schiltz K, Witzel J, Northoff G, Zierhut K, Gubka U, Fellman H, Kaufmann J, Tempelmann C, Wiebking C, Bogerts B (2007). "Brain pathology in pedophilic offenders: Evidence of volume reduction in the right amygdala and related diencephalic structures". Archives of General Psychiatry 64: 737–746.

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