MODULE 6 Flashcards
T/F: Specific types of sensory information are carried along specific afferent pathways and processed by specific brain regions.
True
Converting mechanical energy into a neural signal is an example of which of the following?
A: Absolute threshold
B: Sensory transduction
C: Signal detection theory
B: Sensory transduction
T/F: The type of stimulus that a sensory receptor is adapted to respond to is considered the adequate stimulus for that receptor.
true
What do exteroceptors detect? What do they allow us to sense?
stimuli from the external world that come in contact with our body surfaces
allow us to sense touch, pressure, vibration, pain, and temperature
What do proprioceptors detect? What do they allow us to sense?
detect stimuli from muscles, tendons and joint capsule
allow us to sense limb position and movement
What do interoceptors/enteroceptors detect? What do they allow us to sense?
sense stimuli from viscera
allow us to sense internal changes in our body; allow us to plan movement and monitor
movement as they unfold
What do special sensory receptors detect? What do they allow us to sense?
detect various types of stimuli (e.g.,
photons of light, sound waves)
allow us to have our five special senses: taste, smell, hearing, equilibrium/balance, and
vision
Describe an adequate stimulus.
stimulus for which the
sensory receptor is particularly sensitive; the type of stimulus a receptor is adapted to respond to –
aka what the receptor is selecting for
Describe the absolute threshold.
minimum amount of stimulus energy that must be present for the stimulus
to be detected 50% of the time
Ex: asking how dim can a light be/how soft can a touch be and still be detected half the
time; every system has this
Describe the signal detection theory.
detection of a sensory signal depends on the stimulus intensity and the
physical and psychological state of the individual.
Ex: when ur at a parking lot alone at night you become much more aware of noises bc the
situation is threatening
Describe the just noticeable difference.
the minimum amount by which stimulus intensity must be changed
in order to produce a noticeable variation in sensory experience; changes depending on intensity
of stimulus (Weber’s law); size of the just noticeable difference is a direct proportion to the
original stimulus intensity
Ex: if you are in a very dark movie theater and an audience member receives a text message
causing their phone to light up, many people would notice the illumination in the movietheater, but if the same thing happened at a basketball game this would not be the case –
the brightness of the cell phone did not change, only the ability to detect the illumination
List the 4 mechanisms through which the nervous system encodes information:
- modality (what?)
- location (where?)
- duration/temporal dynamics (how long?)
- intensity (how strong?)
Define sensory integration.
perceiving, modulating, organizing, and interpreting sensations to optimize occupational performance and integration
Describe sensory gating.
Thalamus determines information to pass to the cortex
Describe sensory weighing.
sensory inputs are combined; more reliable input assigned greater weight (ex. vision)
T/F: The minimum amount by which stimulus intensity must be changed in order to produce a noticeable variation in sensory experience is called the absolute threshold for that stimulus.
false – answer is the “just noticeable difference”
Receptive field properties of neurons and the topographical organization in the central nervous system allows the sensory system to encode which of the following
- Stimulus modality
- Stimulus location
- Stimulus duration
Stimulus location
T/F: An increasing number of action potentials being fired by a single sensory receptor as stimulus intensity increases is an example of population coding.
False – this is an ex of frequency coding; activation of a greater number of receptors as stimulus intensity increases is an example of population coding.
What type of information does conscious processing integrate?
awareness & appreciation of sensory information
What type of information does unconscious processing integrate?
coordination & refinement of movement/reflexes
what types of sensation does conscious processing receive? what tracts do these signals travel through?
exteroceptive: discriminative touch, pressure, and vibration (PCMLS tract)
exteroceptive: pain, temp, and crude touch (ALS tract)
proprioceptive: info from muscles tendons and joints to signal awareness of body position and movement (corticospinal tract)
what types of sensation does conscious processing receive? what tracts do these signals travel through?
exteroceptive: discriminative touch, pressure, and vibration (PCMLS tract)
proprioceptive: info from muscles tendons and joints to signal awareness of body position and movement (trigeminal system – mesenphalic nucleus; cerebellar tracts)
Which of the following receptors detects stimuli from muscles, tendons, and joints?
- exteroceptors
- proprioceptors
- special sensory receptors
proprioceptors
T/F: The somatosensory system can be divided into 3 subsystems: one that processes touch, pressure, & vibration; one that processes proprioception; and one that processes pain and temperature information.
true
T/F: The primary afferents of the somatosensory system are pseudo-unipolar neurons.
true
Cell bodies of primary afferent neurons for body sensation are located in the __________, while cell bodies of primary afferent neurons for facial sensation are located in the ____________
dorsal root; cranial root ganglion (trigeminal/semilunar ganglia)
Which of the following fiber types conducts action potentials at the highest speed?
A: Group Ia
B: Group II
C: Group III
D: Group IV
A
which fiber types are associated with proprioception?
Groups Ia & Ib AND Group II
T/F: The majority of the mechanoreceptors contain stress gated ion channels selective for anions.
false – answer is cations
In what 2 ways do neurons encode stimulus intensity?
- frequency coding: the greater the stimulus, the greater the frequency of action potentials (signals shoot out faster)
- population coding (recruitment): as the intensity of the stimulus inc, the number of primary afferents responding will inc
Define receptive fields.
the area of skin surface over which stimulation results in a significant change in the rate of APs from a primary afferent
Receptive fields vary in _____, which is dependent on the ______ of the receptors
size; density
Which of the following statements best reflects the density of receptors, receptive field size, and cortical representations in somatosensory cortex?
A: As receptor density decreases, receptive field size decreases, and cortical representation decreases.
B: As receptor density increases, receptive field size increases, and cortical representation increases.
C: As receptor density decreases, receptive field size decreases, and cortical representation decreases.
D: As receptor density increases, receptive field size decreases, and cortical representation increases.
D
Which of the following cutaneous mechanoreceptors is rapidly adapting and important for sensing tapping or movement in non-hairy skin?
A: Meissner’s corpuscle
B: Pacinian corpuscle
C: Ruffini corpuscle
A: Meissner’s corpuscle
Which of the following cutaneous mechanoreceptors is located deep in the dermis or subcutaneous tissue? Select all that apply.
A: Pacinian corpuscle
B: Meissner’s corpuscle
C: Merkel cell
D: Ruffini corpuscle
E: Hair follicle
A, D, & E
T/F: Merkel cells allow us to have discriminitative touch.
True – also localization of touch & the ability to determine object characteristics
Which proprioceptor is important for monitoring muscle length and transmits information about the velocity of limb movements to the CNS?
A: Golgi tendon organ
B: Hair follicle
C: Muscle spindle
C – limb dynamics info processed by group Ia primary afferent fibers
which primary afferent fibers are associated with muscle spindle proprioception?
Group Ia (limb dynamics) and Group II (static position of limb)
which primary afferent fibers are associated with golgi tendon organ proprioception?
Group Ib (muscle tension)
which receptors are associated with joint capsule and ligament proprioception?
raffini corpuscles and pacinian corpuscles (deep pressure/vibration)
Which of the following central pathways relays touch, pressure, vibration and proprioceptive sensations to primary somatosensory cortex? Select all that apply.
A: Posterior Columns-Medial Lemniscal System
B: Anterior spinocerebellar tract
C: Cuneocerebellar tract
D: Trigeminal System
A & D
T/F: The lower limb representation in primary somatosensory cortex is located in the posterior paracentral gyrus.
true – the lower limb is represented in the posterior paracentral gyrus, and the upper limb and face are represented in the postcentral gyrus (upper limb in the upper 1/2 and the face in the lower 1/2).
T/F: The somatotopic organization of primary somatosensory cortex is fixed and cannot be changed.
false – can change as a result of experience and injury.
T/F: The primary proprioceptive afferents of the trigeminal system are located in the principal sensory nucleus.
false – the primary proprioceptive afferents are located in the mesencepahlic nucleus
***the primary afferents for discriminative touch, pressure, & vibration for the face (also trigem system) are loc in the sensory root of CN V, while the principle sensory nucleus houses the 2nd neurons
T/F: In order to sense the spatial location of two separate stimuli on the surface of the digits, two separate populations of cortical neurons must be activated in primary somatosensory cortex.
true
