Consciousness is not unique to humans; it likely exists in other animals and varies along a continuum shaped by evolution. To understand consciousness more fully, research should adopt a neuroethological perspective based on Tinbergen's four questions: mechanism, development, adaptive function, and evolutionary origin. This approach moves beyond studying only human adults and can help investigate consciousness in infants, non-human animals, and other entities. Adopting this broader view has important scientific, ethical, and societal implications.
Ketamine anesthesia does not uniformly suppress auditory cortex responses to all sounds. In bats, multifunctional neurons that process both echolocation and communication sounds are affected asymmetrically: under anesthesia, communication contexts cause global suppression of responses to lagging sounds, while echolocation contexts do not. This asymmetry depends on the frequency composition of sounds, not their temporal patterns. A computational model shows that anesthesia modulates spiking activity in a channel-specific way, decreasing responses to high-frequency sounds and increasing adaptation in corresponding cortical synapses. These findings indicate that ketamine anesthesia unbalances cortical inputs, altering how neurons respond to natural vocalizations in ways not predictable from known anesthetic effects.