exteroception

Exteroception is the sensory process by which an organism perceives stimuli originating outside the body. It provides information about the external environment and contrasts with interoception, which concerns internal bodily states, and with proprioception, which relates to the position and movement of the body.

The primary modalities of exteroception include vision, audition, somatosensation (touch, pressure, temperature, and pain at the skin and surfaces), olfaction (smell), and gustation (taste). Receptors are specialized for each modality: photoreceptors in the retina for light, hair cells in the inner ear for sound, mechanoreceptors, thermoreceptors, and nociceptors in the skin for mechanical forces, heat, and pain, and chemoreceptors in the olfactory epithelium and taste buds for chemical stimuli.

Neural pathways carry exteroceptive information from peripheral receptors to the brain, where it is processed in modality-specific primary sensory cortices—the visual cortex for vision, the auditory cortex for hearing, the somatosensory cortex for touch and proprioceptive-related information, and the olfactory and gustatory regions for smell and taste. Higher-order association areas integrate these signals to form coherent perceptions of the external world, enabling object recognition, spatial orientation, navigation, and alert responses to potential threats or changes in the environment.

Clinically, exteroceptive processing can be affected by sensory loss, neuropathies, or cortical damage, illustrating its dependence on intact peripheral receptors, peripheral nerves, and central neural pathways. Exteroception thus underpins most everyday interactions with the external environment.