W4 L1 (Sensory Transduction) Flashcards
What is an example of a sensory input we are conscious of but then forget about?
Wearing clothes
What is sensory info used for?
For perception and to guide action
What is the PNS a link between?
The periphery and the CNS
What is the somatic and what is autonomic?
Somatic-Efferent nerves that are consciously used
Autonomic-Afferent nerves that are unconsciously used
What is another name for afferent neurons?
Sensory or receptor neurons
Do we perceive the world as it is, why or why not?
No, we don’t have receptors for everything. Our limited bandwidth also decreases with age.
How does our brain play tricks on us so that we are more functional?
Our brain often tunes out irrelevant information and adds some that aren’t there
What do out sense organs do?
Give us a useful model of the world, might not be realistic
How have howler monkeys adapted?
They gained color vision over time which aided in them seeing the more nutritious leaves
What are 4 key components of sensory physiology?
- Understand the stimulus being coded
- Understand the perception that results from varying the stimulus
- Understand how the receptor at the periphery transduces the stimulus
- Understand neural coding in the CNS
What is the method of adjustment?
A method of slowly increasing a stimulus to find a threshold
What is the method of constant stimuli?
A stimulus is transduced on a person the person says whether they can feel it or not at the given level.
What is the method of limits?
The stimuli is slowly brought from outside of the range until it just meets the threshold
Explain a descending and ascending series in the method of limits
Ascending series-Start below lower threshold and work up until detectable
Descending series-Start above higher threshold and work down until detectable
What is the staircase method?
Go from undetectable to detectable then turn around and go other direction (back and forth)
What is a psychometric function?
A model that shows when certain stimuli can be detected and at which intensities
What is the path of sensory info from receptors on the skin?
- Skin receptors
- Spinal nerve
- Spinal cord
- Brainstem
- Thalamus
- Cortex
What is the path of sensory info from receptors on the skin?
1. Skin receptors 1st order neuron (afferent) 2. Spinal nerve 3. Spinal cord 4. Brainstem 2nd order neuron 5. Thalamus 3rd order neuron 6. Cortex
What does it mean that receptor potential is graded?
It is graded based on stimulus intensity
What does receptor potential turn into?
An action potential
What 4 properties must the brain be able to distinguish between?
- Stimulus Modality
- Stimulus Location
- Stimulus Intensity
- Stimulus Duration
What is stimulus modality?
The type of stimulus
What is stimulus location?
The receptive field or coverage of a stimulus
What is stimulus intensity?
The frequency of coding
What is stimulus duration?
The time of a stimulus
How does the brain determine stimulus modality?
Each receptor is most sensitive to a particular type of stimulus. The brain thus associates a signal coming from a specific group of receptors with a
specific modality.
How does the brain determine stimulus modality?
Each receptor is most sensitive to a particular type of stimulus. The brain thus associates a signal coming from a specific group of receptors with a
specific modality
What is label line coding?
The direct association between a receptor and a sensation
How does a receptor determine the location of a stimulus?
Each sensory receptor is most sensitive to stimulation of a specific area (Receptive field)
What is a receptive field?
An area of the body, of out sight etc. that a receptor is most sensitive to
What is lateral inhibition?
A method used to give a more precise location of stimuli, it enhances the contrast between the site of stimulation
What do inhibitory neurons do?
They localize a stimulus by silencing receptors around the main point of stimulation
What happens to the level of action potentials around a central stimulated neuron when there is lateral inhibition?
The stimulated neuron is at a peak and the neurons to the sides drop below the baseline level
What do more intense stimuli lead to?
More frequent action potentials being fired
What is population coding and how is it a way to measure stimuli strength?
More neurons are activated ie. the population activated
Explain stimulus duration
Receptors can respond slow or fast to sustained stimulation (tonic or phasic)