Do you know what it feels like to be aware of every star, every blade of grass? Yes. You do. You call it 'opening your eyes again.' But you do it for a moment. We have done it for eternity. No sleep, no rest, just endless… endless experience, endless awareness. Of everything. All the time. How we envy you, envy you! Lucky humans, who can close your minds to the endless deeps of space! You have this thing you call… boredom? That is the rarest talent in the universe! We heard a song — it went 'Twinkle twinkle little star….' What power! What wondrous power! You can take a billion trillion tons of flaming matter, a furnace of unimaginable strength, and turn it into a little song for children! You build little worlds, little stories, little shells around your minds, and that keeps infinity at bay and allows you to wake up in the morning without screaming! ~ Terry Pratchett, A Hat Full of Sky

Fibres carrying inputs to the amygdala are in virtually all cases combined with fibres carrying outputs from the amygdala. The amygdala receives inputs from all senses as well as visceral inputs (coming from strong emotions and not from logic or reason).

  • Visceral inputs come from the:
    • hypothalamus (regulates primal drives such as hunger and sex; produces oxytocin; activates pituitary gland).
    • septal area (plays a role in reward and reinforcement along with the nucleus accumbens).
    • orbitofrontal cortex (evokes emotions and bodily states that hypothetical activities would elicit, and facilitates empathy).
    • parabrachial nucleus (important in emotional learning).
  • Olfactory sensory information comes from the olfactory bulb (functions as a filter, as opposed to an associative circuit that has many inputs and many outputs: sensory input via axons from olfactory receptor neurons of the olfactory epithelium and output via mitral cell axons. The bulb also receives “top-down” information from the amygdala, neocortex, hippocampus, locus coeruleus, and substantia nigra).
  • Auditory, visual and somatosensory information comes from the temporal and anterior cingulate cortices (steadies attention and monitors plans; helps integrate thinking and feeling).

  • Ventral amygdalofugal pathway (plays an important role in associative learning, of a conditioned fear, for example. The gratifying or aversive nature of a stimulus is associated by connections of this pathway to the nucleus accumbens, which plays a recognised role in the brain's pleasure circuits).
  • Stria terminalis (a relay site within the hypothalamic-pituitary-adrenal axis, regulating its activity in response to acute stress, and promoting behavioral inhibition in response to unfamiliar individuals, by input from the orbitofrontal cortex).
  • Directly to the hippocampus (forms memories, detects threats, …).
  • Directly to the entorhinal cortex (a hub in a distributed network for memory and navigation, and the main interface between the hippocampus and neocortex).
  • Directly to the dorsomedial nucleus of the thalamus (major relay station for sensory information).