| Afferent Signals | Information flowing inward to the CNS from sensors in the periphery. |
| Amplitude | In reference to the Vestibular sensation, the size of a head movement |
| Active Sensing | Sensing that includes self-generated probing of the environment. Animals use echolocation, electrical signals, whiskers/antennae etc |
| Ampulla | An expansion of each semicircular canal duct that inclues that canal's cupula, crista and hair cells where transduction occurs |
| Angular Motion | Rotational motion like the rotation of a spinning top or swinging saloon doors that rotate back and forth |
| Autonomic Nervous System | The part of the nervous system that is responsible for regulating many involuntary actions and that invvervates glands, heart, digestive system etc |
| Balance System | The sensory systems, neural processes and muscl,es that contribute to postural control |
| Crista | Any of the specilised detectors of angular motion located in each semicircular canal in a swelling called the ampulla |
| Efferent Commands | (EFF-OFF!) Information flowing outward from the CNS to the periphery |
| Graviception | The physiological stuctures and processes that sense the relative orientation of gravity with respect to the organism |
| Hair Cell | Any cell that has stereocilia for transducing mechanical movement in the inner ear into neural activity sent to the brain |
| Kinesthesia | Perception of the position and movement of our limbs in space |
| Tactile Agnosia | The inability to identify objects by touch |
| Substantia Gelatinosa | A region of interconnecting neurons in the dorsal horn of the spinal cord |
| Somatotopic | Referring to spatial mapping in the somatosensory cortex in correspondence to spatial events on the skin |
| Somatosensation | Collectively, sensory signals ferom the skin, muscles, tendons, joints and internal receptors |
| Pacinian Corpuscle | A specialised nerve ending associated with fast-adapting (FA II) fibers that have large receptive fields |
| Merkel Cell Neruite Complex | A specialised nerve ending associated with slowly adapting (SA I) fibers that have small receptive fields |
| Labelled Lines | A theory of sensory coding in which each nerve fiber carries a particular stimulus quality. E.g., a taste nerve fiber that responds best to sucrose but also responds with small responses to other stimuli carries only sweet |
| Homonculus | A maplike representation of regions of the body in the brain |
| Gate Control Theory | A description of the pain-transmitting system that incorporates modulating signals from the brain |
| Egocenter | The center of a refernce frame used to represent locations relative to the body |
| Dorsal Horn | A region at the rear of the spinal cord that receives inputs from receptors in the skin |
| Cold Fiber | A sensory nerve fiber that fires when skin temperature decreases |
| Anterior Cingulate Cortex (ACC) | A region of the brain associated with the perceived unpleasantness of a pain sensation |
| A-beta Fiber | A wide-diameter, myelinated sensory nerve fiber that transmits signals from mechanical stimulation |
| Vestibular Organs | Set of 5 organs - three semicircular canals and 2 otolith organs - located in the inner ear that sense head motion and head orientation with respect to gravity |
| Utricle | One of the two otolith organs. A saclike structure. |
| Spatial orientation | A sense of consisting of three interacting modalities: Perception of linear motion, angular motion and tilt |
| Sensory integration | The process of combining different sensory signals. Typically, combining several signals yields more accurate and/or more precise information that can be obtained from individual sensory signals. This is NOT the mathematical process of integration learned in calculus |
| Sense of tilt | The perceptual modality that senses head inclination with respect to gravity |
| Saccule | One of the two otolith organs. A saclike structure. |
| Semicircular Canal | Any of three toroidal tubes in the vestibular system that sense angular motion |
| Macula | 1. In reference to vision, the pigmented region with a diameter of about 5.5mm near the centre of the retinar. 2. In reference to the vestibular system, any of the specilised detecors of linear acceleration and gravity found in each otolith organ |
| Mechanoreceptor | A sensory receptor that responds to mechanical stimulation (pressure, vibration or movement) |
| Macula | 1. In reference to vision, the pigmented region with a diameter of about 5.5mm near the centre of the retinar. 2. In reference to the vestibular system, any of the specilised detecors of linear acceleration and gravity found in each otolith organ |
| Oscillatory | Referring to the back-and-forth movement that has a constant rhythm |
| Otoconia | Tiny calcium carbonate stones in the ear that provide inertial mass for the otolith organs, enabling them to sense gravity and linear acceleration |
| Otolith Organs | Either of two mechanical structures (utricle and saccule) in the vestibular system that sense both linear acceleration and gravity |
| Reception Potential | A change in voltage across the membrane of a sensory receptor cell in response to stimulation |
| Sense of angular motion | The perceptual modality that senses rotation |
| Sense of linear motion | The perceptual modality that senses translation |
| Sensory Conflict | Discrepancies that arise when sensory systems provide conflicting information. E.g., vision may indicate that you are stationary while the vestibular system tells you that you are moving |
| Sensory Exafference | Change in afference caused by external stimuli. For the Vestibular system, vestibular afference evoked by passive head motion would yield sensosry exafference |
| Sensory reafference | Change in afference caused by self-generated activity. For the vestibular system, vestibular afference evoked by an active self-generated head motion would yield sensory reafference |
| Sinusoidal | Referring to any oscillation, such as a sound wave or rotational motion, whose waveform is that of a sine curve |
| Spatial Disorientation | Any impairment of spatial orientation. More specifically, any immpairment of our sense of linear motion, angular motion, or tilt |
| Transduce | To convert one form of energy to another |
| Vection | An illusory sense of self-motion caused by moving visual cues when one is not , in fact, actually moving |
| Vertigo | A sensation of rotation or spinning. The term is often used more generally to mean any form of dizziness |
| Vestibular System | The vestibular organs as well as the vestibular neurons in cranial nerve VIII and the central neurons that contribute to the functional roles that the vestibular system participates in |
| Vestibulo-Ocular Reflex (VOR) | A short-latency reflex that helps stabilise vision by counterrotating the eyes when the vestibular system senses head movement |
| A-delta Fiber | An intermediate-sized myelinated sensory nerve fiber that transmits pain and and temperature signals |
| Analgesia | Decreasing pain sensation during conscious experience |
| C Fiber | A narrow-diameter, unmyelinated sensory nerve fiber that transmits pain and temperature signals |
| C Tactile (CT) Afferent | A narrow-diameter, unmyelinated sensory nerve fiber that transmits signals from pleasant touch |
| Dermis | The inner two major layers of skin, consisting of nutrtitive and connective tissues, within which lie the mechanoreceptors |
| Dorsal Column-Medial Lemnisal (DCML) Pathway | The route from the spinal cor to the brain that carries signals from skin, muscles, tendons and joints |
| Endogenous Opiate | A chemical released by the body that blocks the release or uptake of neurotansmitters necessary to transmit pain sensations to the brain |
| Endogenous | In reference to spatial attention, a form of top-down (knowledge-driven) control in which attention is voluntarily directed toward the site where the observer anticipates a stimulus will occur |
| Epidermis | The outer of two major layers of skin |
| Exogenous | In reference to spatial attention, a form of bottom-up (stimulus driven) attention reflexively (involuntarily) directed toward the site at which a stimulus has abruptly appeared |
| Glabrous | In reference to skin, lacking hair |
| Haptic perception | Knowledge of the world that is derived from sensory receptors in skin, muscles, tendons and joints - usually involving active exploration |
| Hyperalgesia | An increased or heightened response to a normally painful stimulus |
| Kinesthetic | Referring to perception involving sensory mechanoreceptors in muscles, tendons and joints |
| Meissner Corpuscle | A specialised nerve ending associated with fast-adapting (FA I) fibers that have small receptive fields |
| Nociceptor | A sensory receptor that responds to painful input, such as extreme heat or pressure |
| Proprioception | Perception mediated by kinesthetic and internal receptors |
| Ruffini Ending | A specialised nerve ending associated with slowly adapting (SA II) fibers that have large receptive fields |
| Somatosensory Area 1 (S1) | The primary receiving area for touch in the cortex |
| Somatosensory Area 2 (S2) | The secondary receiving area for touch in the cortex |
| Somatotypical | Referring to normal somatosensation |
| Spinothalamic Pathway | The route from the spinal cord to the brain that carries most of the information about skin temperature and pain |
