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Brain Circuits Involved inEmotion processing:Subcortical Regions

BIOS E 232

Sabina Berretta, MD

Harvard Medical School McLean Hospital

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Plan for today’s class

• Journal club presentations and discussion:

Carlin Aloe:Adolphs R, 2010. What does the amygdala contribute to social cognition? Ann N Y Acad Sci 1191, 42-61.

Kameron Sheikh:Berridge KC, Ho CY, Richard JM, DiFeliceantonio AG, 2010. The tempted brain eats: pleasure and desire circuits in obesity and eating disorders. Brain Res 1350, 43-64.

• Brain circuits involved in emotion processing: amygdala, limbic thalamus and cortical circuits

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Hypothalamus

Pituitary gland

Adrenal gland

MidbrainPons

Medulla

DA, 5HT, NE

motor response

Spinal cordBrainstem

glucocorticoidautonomic response

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The Human amygdala

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Orbital and medial prefrontal cortex (OMPFC)

Price, 2007

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The Human amygdala

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Amygdala circuitryModulation of motivated behavior in the context of emotionally/socially significant setting

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Intrinsic amygdalar connections

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The intercalated cell masses of the amygdala

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Amygdala control and modulation of visceral functions

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Modified from Price, 2003

The amygdala receives inputs from all sensory modalities

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Note that all these connections, with the exception of that from the posterior thalamus are reciprocal. They provide sensory information to the amygdala and support amygdaloid modulation on sensory processing

Modified from Price, 2003

The amygdala-forebrain circuit

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Within the forebrain, the amygdala is part of a circuit that includes the orbital and medial prefrontal cortex, medial thalamus, ventromedial striatum and ventral pallidum

Modified from Price, 2003

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Central n.Amygdala

Visceral inputs

Hormonal, autonomic, motor responses

Sensorythalamus

Sensory-related associative Cx areas:Gustatory and Visceral Insular Cx, temporal auditory and visual Cx, parietal and rhinal somatosensory Cx

Basolateralcomplex Orbitofrontal

cxMedial

prefrontal cxAnterior cingulate

gyrusLimbic

thalamus

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AmygdalaAttribution of emotional value

Fear/anxietySocial behavior

OPFCSocial behavior

Representation of reinforcer values

ACGAttention

MotivationResponse selection

DLPFCExecutive cognitive functions

Strategy generationWorking memory

ECxGating of cortical and subcortical

inputs to the HPMemory processing

HPContext-related cognitive

processingEpisodic memory

MDAttention

Decoding of stimulus/significance

relationship

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The amygdala organizes multiple aspects of emotional response:

• Immediate visceral response• Acquisition and response to emotional / arousing stimuli

• Modulation of memory consolidation in response to emotion

• Access to current motivational or affective value predicted by a specific stimulus• Emotional significance of social cues

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Cortico-amygdalo-cortical circuits and emotion-related learning

Berretta S., Stress, 2005

18Hughlings Jackson

1835 - 1911

Jackson reported complex auditory and visual hallucinations, memory flashbacks and emotions in patients with temporal lobe epilepsia.The work of Penfield and collaborators (1955) confirmed these observations and reported that similar phenomena could be elicited in these patients by electrical stimulation of the lateral temporal cortex and from the amygdala (but not from other lobes in the brain).

Evidence for a complex role of the amygdala in emotion processing derives from temporal lobe epilepsy

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Sato et al 2004

The amygdala is activated by emotionally valenced stimuli and tracks their subjective relevance