Neur Ch. 11

  • Emotion is a subjective mental state that is usually accompanied by distinctive behaviors as well as involuntary physiological changes.
  • Sympathetic nervous system—“fight or flight” system; prepares the body for action
  • Parasympathetic nervous system—prepares the body to relax and recuperate
  • James-Lange theory- autonomic reaction triggers feeling
  • Cannon-Bard theory- autonomic reaction and feeling happen simultaneously
  • Schacter’s cognitive theory- stimulus>perception>stimulus/context> stimulus contributes to autonomic arousal and along with context contributes to emotion which gives feedback to the perception.
  • Facial expressions are mediated by facial muscles, cranial nerves, CNS pathways
  • Two categories of facial muscles
    • superficial facial muscles- attach between points of facial skin
    • deep facial muscles- attach to bone, produce larger movement
    • Facial muscles are innervated by two facial nerves, the facial nerve and the trigeminal nerve
  • The facial feedback hypothesis- suggests that sensory feedback from our facial expressions can affect our mood
  • Brain self-stimulation—animals (including humans) will work to receive electrical stimulation to their brains. Brain sites that support self-stimulation have been mapped. Most are subcortical, concentrated in the medial forebrain bundle.
  • Medial forebrain bundle—the tract that rises from the midbrain through the hypothalamus; affected at many self-stimulation sites
  • Nucleus accumbens—an important target for axons of medial forebrain bundle; a major component of the reward circuit; release of dopamine here produces very pleasurable feelings
  • Feeling love can bilaterally increase activity in the insula and anterior cingulate cortex and decrease activity in the posterior cingulate and prefrontal cortices.
  • Aggression is behavior intended to cause pain or harm to others.
  • Intermale aggression is seen between males of the same species.
  • The ventromedial hypothalamus (VMH) is involved in aggressive behavior.
  • The release of serotonin normally inhibits aggression.
  • Maternal aggression—aggression in mothers defending their nest or offspring; controlled by circuits in the VMH, as well as the preoptic area and the pre-mammillary nucleus
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