Sensory Processing Flashcards
The swaying of stereocilia in response to sound waves results in an influx of _______ at the base of the hair cell.
- K+
- Cl-
- Ca2+
- Na+
Ca2+
(The correct answer is ‘Ca2+’ - after depolarization by the influx of Na+ and K+ when stereocilia are bent, voltage-gated Ca2+ channels will open and cause vesicles to release glutamate into the synapse.)
Which of the following would disrupt sound perception?
- An antagonist for glutamate at the synapse between IHCs and afferent nerve fibers
- At the synapse between IHCs and afferent nerve fibers
- An agonist for glutamate at the synapse between IHCs and afferent nerve fibers
- An agonist for GABA at the synapse between IHCs and afferent nerve fibers
An antagonist for glutamate at the synapse between IHCs and afferent nerve fibers.
(The correct answer is ‘An antagonist for glutamate at the synapse between IHCs and afferent nerve fibers’ - glutamate is the NT released from the IHCs. Based on knowledge from our chemistry of behavior unit, we know that an antagonist will bind but not activate a neuron.)
For most senses, the sensory pathway ______________.
- Passes through the thalamus
- Passes through the spinal cord
- Goes directly to its designated area of cortex
- Passes through the temporal cortex
Passes through the thalamus
(The correct answer is ‘passes through the thalamus’ - the thalamus is the sensory relay station in the brain and processes all incoming sensory information except if its coming from the olfactory system.)
Complete the analogy, thinking about the concept of ‘coding’: Place theory: _______________: Temporal theory: ____________.
- number of neurons firing; rhythm of neuronal firing
- IHC identity; number of neurons firing
- action potential firing rate (frequency); IHC location
- IHC identity; action potential firing rate (frequency)
IHC identity; action potential firing rate (frequency)
(The correct answer is ‘IHC identity; action potential firing rate (frequency)’ - the location (and thus identity) of an IHC determines what pitch it encodes, based on the place theory. But the rate (frequency) at which it fires is how pitch is coded based on the temporal theory.)
The brain can differentiate between each sensory modality through the principle of labeled lines because
- The action potentials for each one are sent along separate nerve tracts.
- Each sense uses different neurotransmitters.
- Each sensory input, passing through the same lines, triggers action potentials in a different pattern.
- The action potentials, sent along the same nerve tracts, get sorted by the thalamus.
The action potentials for each one are sent along separate nerve tracts.
(The correct answer is ‘the action potentials for each one are sent along separate nerve tracts.’ - this is why if you press lightly on your eye you will see a blob in your visual field – your brain expects information coming from cells in your eye to be visual.)
Receptors in our skin transduce pressure information into neural signals when deformation of the skin…
- causes depolarization subcutaneously such that voltage-gated ion channels open and potassium enters the cell
- causes ion channels to change shape and open, letting sodium enter the cell
- causes ion channels to change shape and open, letting sodium exit the cell
- causes depolarization subcutaneously such that voltage-gated ion channels open and potassium exits the cell
Causes ion channels to change shape and open, letting sodium enter the cell.
(The correct answer is ‘causes ion channels to change shape and open, letting sodium enter the cell’ - these receptors are mechanoreceptors, and are a special class of receptor, just like ligand-gated or voltage-gated.)
Sensory transduction is the process by which
- Energy is converted into a change in membrane potential – action potentials are used by neurons to communicate.
- Electrical responses are converted into movement.
- Adaptive responses are produced
- One type of sensory stimulus is converted into a different type of sensory stimulus.
Energy is converted into a change in membrane potential – action potentials are used by neurons to communicate.
(The correct answer is ‘energy is converted into a change in membrane potential – action potentials are used by neurons to communicate.’ - this has to happen in sensory receptor cells or environmental stimuli cannot be processed by the brain.)
Your younger cousin learned in class that birds can sense the earth’s magnetic field. She thinks this is a cool skill, and asks if you know how she can learn to do this too. You explain that unfortunately, this isn’t something she can learn. If you wanted to explain why in technical terms, which of the following should be incorporated into your explanation?
- Labeled lines
- Absolute threshold
- Adequate stimulus
- Sensory adaptation
Adequate stimulus
(The correct answer is ‘adequate stimulus’ - for stimulus energies to be processed by our brains, they need to be an adequate stimulus for a particular type of sensory receptor. We don’t have sensory receptors that can process the magnetic field.)
Which skin receptors are especially sensitive to stretching of the skin?
- Messiner corpuscles
- Merkel discs
- Pacinian corpuscles
- Ruffini endings
Ruffini endings
The correct answer is ‘Ruffini endings’ - these are deep in the skin and respond to stretch.
You would expect a sensory receptor in the lips to have a ________________ than a sensory receptor in the elbow. If the sensory receptor stopped responding to a repetitive stimulus, you would also say that it was _______________.
- smaller receptive field; phasic
- smaller receptive field; tonic
- larger receptive field; tonic
- larger receptive field; phasic
smaller receptive field; phasic
(The correct answer is ‘smaller receptive field; phasic’ - you need more precise perception of touch in your lips than in your elbow, thus you will have smaller receptive fields. If a neuron stops responding during static stimulation, we call it phasic.)
True or False:
Environmental input affects how our brains develop and function and even what parts of our genes are transcribed
True
What is sensation?
The process of receiving stimulus energies from the external environment and transforming them into neural energy
How we organize and interpret this information so it has meaning is the process of _______.
perception
How do we sense stimuli?
- Sensory receptor organs
- Sensory receptor cells
To be detected, a receptor cell must receive…
an adequate stimulus
True or False:
Receptors in our skin are distributed uniformly
False
To be detected, a receptor cell must receive stimulus energy passing an…
absolute threshold
What is sensory transduction?
Receptor cells convert energy into electrical signals
Action potentials!
___________ changes based on input
Receptor potential
Generally, similar to an EPSP
(All-or-none signal)
How can we process such a wide variety of stimuli with just action potentials to relay messages (initially)?
By coding
What is coding?
Rules by which action potentials in a sensory system reflect a physical stimulus
What affects stimulus intensity?
- Frequency of AP
- Rhythm of AP
- Number of neurons firing AP
- Identity of neurons firing
(Range fractionation)
True or False:
Each sensory system we have has a different processing pathway
True
These are so distinctive, you can trick your brain.
What are the levels of sensory processing?
Receptors –> spinal cord/brainstem –> thalamus –> primary sensory cortices
What system does not experience the typical levels of sensory processing?
The olfactory system
The olfactory system does not synapse through the thalamus.
What is adaptation?
the phenomenon by which receptors become less and less responsive as stimulus is maintained
(Phasic vs. tonic receptors)
__________ can reduce the level of input we get through a sensory receptor.
Accessory structures
Why is sensory processing considered top-down processing?
Through processing and integration, we perceive our surroundings.
What are phasic receptors?
Receptors that show adaptation
What are tonic receptors?
Receptors that do not show adaptation
In the somatic sensory system, what is the sensory organ and sensory receptors?
Sensory organ: skin
Sensory receptor: different types
What types of information do you have to pick up through your skin?
Mediates a range of sensations:
- Touch
- Pressure
- Vibration
- Heat/Cold
- Pain
- Limb position
Information is transduced by ________ in skin and muscles and innervated by __________.
mechanoreceptors; dorsal root ganglion neurons
What does it take for an AP to fire?
- Depolarization of neurons
- Ligand-gated ion channels
- Voltage-gated ion channels
What are the steps for mechanoreceptors?
Deformation of channel –> channel opens –> Na+ into cell
What are the different types of terminal endings?
- Meissner corpuscle
- Merkel cell
- Ruffini ending
- Pacinian corpuscle
What distinguishes between the receptor types?
- Receptive fields
- Adaptation properties
- Sensory thresholds
What are receptive fields?
The region of skin in which a stimulus will modify the firing of an action potential
Receptive fields are affected by…
- Branching characteristics of afferent within skin
- Density of afferent fibers supplying the area
