Neuro term. An unlearned response in which animals alert to new features of their environment, e.g., to novel sights, sounds, and smells in the speechless sense-surround of Nonverbal World.
Usage I: The orienting reflex (OR) is an innate, protective response
designed to answer the question, "What's that?" The automatic OR provokes both a
cognitive and an emotional concern, and also triggers immobility (the
freeze reaction), when we are suddenly
faced with a novel, unusual, or potentially dangerous person, place, or
Usage II: The messaging features of consumer products may be designed to provoke the OR. Attention-grabbing signals from commercial messages broadcast in the media trigger the OR as well.
Reptiles. In reptiles, orienting involves a. refocusing of the sense organs, and b. freezing of the body's gross-motor movements. A slowed heart rate (bradycardia) has been observed, as well, e.g., in iguanas and in the death-feigning of hognose snakes (see BROADSIDE DISPLAY, Saurian size).
Mammals. The reptilian orienting pattern is present in mammals, where it is usually followed by c. a more active (i.e., a non-reflexive or voluntary) attention phase, and by d. an arousal of emotion. That is, after the reptilian orienting reflex itself occurs, a mammal may voluntarily attend (i.e., look, listen, and sniff the air), produce facial expressions, and emit vocal mood signs.
Anatomy I. In mammals and primates, a diagnostic set of nonverbal signs associated with OR is mediated by the five cranial nerves that arise from the pharyngeal arches (i.e., from the primitive gill arches; see, e.g., EYEBROW-RAISE, FLASHBULB EYES, JAW DROOP). The trigeminal (cranial V, for chewing) and facial (cranial VII, for facial expressions) nerves link (i.e., communicate) with the glossopharyngeal (cranial IX, for swallowing), vagus (cranial X, for vocalizing and communicating with the viscera), and accessory (cranial XI, for turning the head and shoulder-shrugging) nerves. The source nuclei for the special visceral efferents of the latter three cranial nerves originate in the medulla oblongata's nucleus ambiguus (NA).
Anatomy II. In mammals and primates, NA mediates control of the pharynx, soft palate, larynx, and esophagus (see ADAM'S-APPLE-JUMP, THROAT-CLEAR). Chemoreceptors enable the third pharyngeal arch's carotid body to sense CO2 and O2 levels. The accessory nerve (cranial XI) positions the neck, assisted by the vagus nerve (cranial X) (Porges 1995).
Anatomy III. NA medites control of the heart and vocal intonation. Its efferent fibers mediate feeding and breathing, as well as some body movements, emotions, and forms of communication (e.g., growling; see SPECIAL VISCERAL NERVE). "The NA-vagus provides the vagal brake that mammals remove instantaneously to increase metabolic output to foster fight or flight behaviors. The NA-vagus provides the motor pathways to shift the intonation of vocalizations (e.g., cry patterns) to express emotion and to communicate internal states in a social context" (Porges 1995).
Anatomy IV. The NA mediates control of the heartbeat rate, the lung's bronchial tubes, and other visceral organs (Porges 1995).
Evolution. In orienting reptiles and mammals, according to Porges (1995), the control of bradycardia (i.e., of slowed hearbeat rate) by the dorsal motor nucleus of the vagus nerve (cranial X) may have evolved from an ancient vertebrate gustatory response. "Gustation is the primary method for identifying prey (including other appropriate food sources) and predators in aquatic environments" (Porges 1995; see AROMA CUE, TASTE CUE).
Neuro-notes I. The separation of the vagus nerve (cranial X) into a dorsal motor nucleus (DMNX, causing bradycardia) and ventrolateral motor nucleus (nucleus ambiguus or NA, which suppresses heart-rate variability) began with reptiles and continues into mammals (Porges 1995). (N.B.: In turtles, however, the nuclei are still connected.)
Neuro-notes II. In mammals, the slowed heart-rate of the OR is of short duration due to their high oxygen needs. The ventrolateral motor nucleus of the vagus nerve brakes the bradycardia (Porges 1995).
Neuro-notes III. "With phylogenetic development, the viscerotropic organization of the vagal system has become more complex, and incorporates pathways from other cranial nerves including trigeminal, facial, accessory and glossopharyngeal. Thus, more specialized functions such as head rotation to orient sensory receptors toward the source of stimulation, mastication to ingest food, and salivation to initiate gustatory and digestive processes are integrated into the vagal system" (Porges 1995).
See also OBJECT FANCY, STARTLE REFLEX.
Copyright 2000 - 2016 (David B. Givens/Center for
Drawing of "Showing My Nonverbal Side" by my son Aaron Huffman (copyright 2012 by Aaron M. Huffman)