Sensory Receptors Flashcards
What are the 3 common steps to coding/processing of all sensory information?
- Physical stimulus is present that reaches the body
- Stimulus is transduced into a message of electrical signals
- Those signals are relayed to CNS and there is a response to that message by the CNS
The accurate organization of the essential properties of an object/stimulus that allows us to interpret and manage/manipulate it successfully:
perception
What allows information from our environment to reach our cerebral cortex?
receptors
What are the 3 main functions of receptors?
- Sensation
- Control/coordination of movements
- Arousal (w/o sensory stimulation, CNS could not function/interact w/ envt)
What are the 4 elementary attributes of a stimulus?
- Modality (one of 5 senses)
- Intensity (strength of stimulus)
- Duration (“perceived” time a stimulus is present)
- Location (there is a “map” of entire human body in cortex for each modality)
What are submodalities? Provide some examples.
Submodalities are subsets of each modality. Ex: vision modalities=color, brightness, movement, etc.; taste modalities=bitter, sweet, salty, sour, umami
The majority of receptors are which type?
mechanoreceptors and chemoreceptors
The lowest detectable intensity which can be perceived at least 50% of the time and is often characterized by a sigmoid curve:
sensory threshold
Is a sensory threshold fixed or variable?
It is variable and can be influenced by a variety of factors, including fatigue, habituation, practice, context, etc.
Can sensory threshold change in response to changes in the receptor or the receptor’s threshold?
No! While it is true that sensory thresholds are variable, they are NOT due to changes in the receptor.
What are two important concepts related to intensity?
- Detectability: need the correct receptor in order to process a certain type of signal
- Criterion: an attitude/bias exists toward certain sensations, allowing us to “tolerate” certain stimuli and prevent false alarms
Perception of stimuli is greatest/sharpest at regions of ___________.
greatest contrast
The perceived duration of a stimulus is a function of what?
the CNS and NOT the receptor
How is 2 point discrimination related to location?
It tells us how fine our detection of stimuli is in terms of location.
Signal transduction is always _______.
excitatory
What is a stimulus called that produces no action potentials?
subthreshold stimulus
What is frequency vs. population coding?
- Frequency: stronger stimuli evoke greater # of AP’s from a single receptor
- Population: stronger stimuli excite a greater # of receptors
Rapidly adapting receptors give good ______ information, while slowly adapting receptors give good _______ information.
temporal; spatial
Why is the resulting sensory output very much different from the afferent information from any single input?
This is due to modulation of sensory information, in which sensory inputs to the CNS follow a pattern of extensive convergence and/or divergence and activate both excitatory and inhibitory interneurons at each relay station. (information is lost or modified as it moves from synapse to synapse)
What is the purpose of modulating sensory information?
It functions to make the information more precise; also serves as a means for sensory adaptation.
All somatic sensory receptors project to ______ of the cortex.
postcentral gyrus (area 312)
What is cortical layer I responsible for?
fibers of passage (anything that needs to go somewhere else will send an axon to layer I)
What are cortical layers II and III responsible for?
integration/modification
What is cortical layer IV responsible for?
always input (from thalamus)
