2:25

• Quiz 3 today, after class until 10 pm
• Exam 3 next Thursday, March 31

• Wrap up on schizophrenia
• Biology of emotion
• Happiness/pleasure and reward
• Fear & stress

• What is emotion?
• What are the types of emotions?
• Biological systems involved in emotion

• Feelings
• Physiological state

https://www.biomotionlab.ca/html5-bml-walker/

“Do we run from a bear because we are afraid or are we afraid because we run? William James posed this question more than a century ago, yet the notion that afferent visceral signals are essential for the unique experiences of distinct emotions remains a key unresolved question at the heart of emotional neuroscience.”

(Harrison, Gray, Gianaros, & Critchley, 2010)

• James-Lange
  • Physiological response -> subjective feelings
• Cannon-Bard
  • Severing CNS (spinal cord & vagus, Xth n) from rest of body leaves emotional expression unchanged
  • Physiological states slow, don’t differentiate among emotions

• Schacter-Singer
  • Physiological arousal + cognitive appraisal -> emotional states

• Vary in valence
  • Positive/negative
• Vary in intensity (arousal)
• Vary in action tendency
  • Approach/avoid

• Ingestion

• Defense

• Reproduction

• Affiliation

• Input
  • Internal states
  • External world
• Processing/evaluation
• Output
  • Internal states
  • External world

Figure 1. Locationist Hypotheses of Brain–Emotion Correspondence. A: Lateral view. B: Sagital view at the midline. C: Ventral view. D: Coronal view. Brain regions hypothesized to be associated with emotion categories are depicted. Here we depict the most popular locationist hypotheses, although other locationist hypotheses of brain–emotion correspondence exist (e.g., Panksepp, Reference Panksepp 1998). Fear: amygdala (yellow); Disgust: insula (green); Anger: OFC (rust); Sadness: ACC (blue). A color version of this image can be viewed in the online version of this target article at http://www.journals.cambridge.org/bbs.

(Lindquist et al., 2012)

A psychological constructionist account of emotion assumes that emotions are psychological events that emerge out of more basic psychological operations that are not specific to emotion. In this view, mental categories such as anger, sadness, fear, et cetera, are not respected by the brain (nor are emotion, perception, or cognition, for that matter).

(Lindquist et al., 2012)

…emotions emerge when people make meaning out of sensory input from the body and from the world using knowledge of prior experiences. Emotions are “situated conceptualizations” (cf. Barsalou 2003) because the emerging meaning is tailored to the immediate environment and prepares the person to respond to sensory input in a way that is tailored to the situation,

(Lindquist et al., 2012)

• Aristotle
• Hedonia
  • Pleasure
• Eudaimonia
  • Life satisfaction
  • Relates to motivation

• Inputs
  • External
  • Internal
• Processing
• Outputs
  • Feelings
  • Actions

• Circuits for signaling pleasure and pain
• Similarities across animal species
  • Behavior & brain
• Dopamine and endogenous opioid neurotransmitter systems involved

• A reward reinforces (makes more prevalent/probable) some behavior
• Milner and Olds (Milner, 1989) discovered ‘rewarding’ power of electrical self-stimulation
• (Heath, 1963) studied effects in human patients.

• Ventral tegmental area (VTA) in midbrain
• Nucleus accumbens (nAcc), ventral striatum
• Hypothalamus (Hyp)
• Amygdala (Amy)
• Hippocampus (HP)
• Dorsal Raphe Nucleus/Locus Coeruleus (DR/LC)
• Prefrontal cortex (PFC)

• Dopamine
• Serotonin, Norepinephrine
• ACh

• Endorphins: Endogenous morphine-like compounds
  • e.g., morphine, heroin, oxycontin (oxycodone) are opioids

“A comparative risk assessment of drugs including alcohol and tobacco using the margin of exposure (MOE) approach was conducted. The MOE is defined as ratio between toxicological threshold (benchmark dose) and estimated human intake. Median lethal dose values from animal experiments were used to derive the benchmark dose. The human intake was calculated for individual scenarios and population-based scenarios…”

(Lachenmeier & Rehm, 2015)

“…For individual exposure the four substances alcohol, nicotine, cocaine and heroin fall into the “high risk” category with MOE < 10, the rest of the compounds except THC fall into the “risk” category with MOE < 100.”

(Lachenmeier & Rehm, 2015)

• Endogenous cannabinoids
  • Cannabinoids == psychoactive compounds found in cannibis
  • Cannabinoid receptors: CB1 in CNS; CB2 in body, immune system

• Types of pleasure activate overlapping areas
• Pleasure/happiness engage a network of brain areas
• Pleasure/happiness signaling involves multiple neuromodulators, but DA especially important
• “Reward” pathways activated by many different inputs
• Some exogenous substances bind to endogenous receptor systems