Chapter 12 (Psy 323) Flashcards
What are the semicircular canals?
They are the three toroidal tubes in the vestibular system that sense angular motion.
What are the otolith organs?
They are the mechanical structures in the vestibular system that sense both linear acceleration and gravity. Each otolith organ contains an utricle, a saccule, and maculae.
What are the three axes of movement coded by the vestibular system?
x-axis: The axis of motion forward and backward
y-axis: The axis of motion leftward and rightward
z-axis: The axis of motion upward and downward
What are the three directions of rotation coded by the vestibular system?
Roll: Rotation around the x-axis
Pitch: Rotation around the y-axis
Yaw: Rotation around the z-axis
What do hair cells do in the vestibular system?
Hair cells support the stereocilia that transduce mechanical movement in the vestibular labyrinth into neural activity sent to the brain stem
What are mechanoreceptors?
Mechanoreceptors are sensory receptors responsive to mechanical stimulation such as pressure, vibration, or movement.
What is a receptor potential?
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It is a change in voltage of sensory receptor cells—hair cells for the vestibular system—in response to stimulation
What are cristae?
Cristae are the specialized detectors of angular motion located in each semicircular canal in a swelling called the ampulla.
What is an utricle?
An utricle is one of the two otolith organs. A saclike structure that contains the utricular macula. Also called utriculus.
What is a saccule?
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A saccule is one of the two otolith organs. A saclike structure that contains the saccular macula. Also called sacculus
What are maculae?
Maculae are specialized detectors of linear acceleration and gravity found in each otolith organ.
What are otoconia?
Otoconia are tiny calcium carbonate stones in the ear that provide inertial mass for the otolith organs, enabling them to sense gravity and linear acceleration.
What do subjects report sensing when they are rotated in the dark (or with their eyes closed) for an extended period of time?
Subjects first feel a sense of motion consistent with their actual motion, but report feeling less and less motion over time until finally reporting no sensation of motion at all.
How well do subjects do at reproducing passive translations of the body experienced in the dark?
Subjects do quite well at this task. When reproducing the translations with a joystick, subjects also reproduce the velocity of the passive-motion trajectory, indicating that the brain remembers and replicates the velocity trajectory.
What is vection?
Vection is an illusory sense of self motion produced when one is not, in fact, moving.
What happens when a subject looks at a rotating display for an extended period of time?
They report an illusory sensation of tilt in the direction opposite to the rotation of the stimulus.
What is the vestibular-ocular reflex?
It is a compensatory eye movement that adjusts for changes in head position in order to keep the eye fixated on a target.
What is the autonomic nervous system?
It is the part of the nervous system innervating glands, heart, digestive system, etc., and responsible for regulation of many involuntary actions.
What is a situation in which the autonomic nervous system interacts with the vestibular system?
Motion sickness results from a discrepancy between visual and vestibular motion signals and results in the autonomic response of dizziness, nausea, and sometimes vomiting.
What area of the cortex is exclusively devoted to processing vestibular information?
There isn’t one. There are areas of the cortex that respond to vestibular input, but they also tend to respond to visual input.
What area of the brain is involved in spatial orientation perception?
The multisensory parieto-insular cortex. It receives input from both the semicircular canals and the otolith organs.
What is Mal de Debarquement Syndrome?
After spending time on a boat or in the ocean, it is normal for people to feel a rocking sensation for a few hours. However, if the illusory sense of spatial disorientation, imbalance, and rocking lasts for a month or more, the person might be suffering from “disembarking sickness” or mal de debarquement syndrome.
Describe Ménière’s Syndrome.
Patients suffering from this syndrome experience the sudden onset of dizziness, imbalance, and orientation as well as tinnitus, an illusory ringing sound. This combination of symptoms can cause patients to lose their balance or vomit, and unfortunately the symptoms can strike at any time.
Vestibular Organs
The set of five organs–three semicircular canals and two otolith organs–located in each inner ear that sense head motion and head orientation with respect to gravity. These organs are also sometimes called the vestibular system or the vestibular labyrinth, but the name vestibular system is often used more generally to refer to the vestibular organs and their neural pathways.
spatial orientation
A sense consisting of three interacting sensory modalities: the senses of linear motion, angular motion and tilt.
dizziness
A commonly used lay term that nonspecifically indicates any form of perceived spatial disorientation, with or without instability.
vertigo
A sensation of rotation or spinning. The term is sometimes used erroneously to mean any form of dizziness.
Spatial disorientation
Any impairment o spatial orientation. More specifically, any impairment of our sense of linear motion, angular motion or tilt.
Imbalance
Lack of balance; unsteadiness; nearly falling over
Angular Motion
Rotational motion like the rotation of a spinning top or swinging saloon doors that rotate back and forth.
Linear Motion
Translational motion like the predominant movement of a train car or bobble head doll.
Tilt
Attaining a sloping position like of the leaning tower of Pisa.
Transduce
To convert from one form of energy to another.
Semicircular canal
Any of three toroidal tubes in he vestibular system that sense angular motion.
Angular acceleration
The rate of change of angular velocity. Mathematically, the integral or angular acceleration of angular velocity and the integral of angular velocity is angular displacement. Angular acceleration, angular velocity, and angular displacement all mathematically represent angular motion.
Otolith organ
Either of two mechanical structures (utricle and saccule) in the vestibular system that sense both linear acceleration and gravity.
Liner acceleration
The rate of change of linear velocity. Mathematically, the integral of linear acceleration is linear velocity, and the integral of linear velocity is linear displacement, which is also referred to as “translation” Linear acceleration, linear velocity, and linear displacement all mathematically represent linear motion.
Sense of angular motion
the spatial orientation modality that senses rotation
Sense of linear motin
the spatial orientation modality that senses transalation
sene of tilt
The spatial orientation modality that sense head inclination with respect to gravity
amplitude (chapter 12)
The size (increase or decrease) of a head movement
direcction
The line along which one faces or moves, with reference to the point or region toward which one is facing or moving.
velocity
The speed and direction in which something moves.
acceleration
A change in velocity
Hair cell (chapter 12)
any cell that has stereocillia for transducing mechanical movement in the inner ear into neural activity sent to the brain; some hair cells also receive input from the brain.
mechanoreceptor
A sensory receptor that responds to mechanical stimulation (pressure, vibration, or movement).
Receptor potential
A change in voltage across the membrane of a sensory receptor cell (in the vestibular system, a hair cell) in response to stimulation
