Exam 3: L1 Flashcards
Every perceptual pathway includes three predominant processing stages (list and explain each)
1.
2.
3.
Every perceptual pathway includes three predominant processing stages:
- Trandsuction (translation of energy into neural signals)
- Transmission: carry out signal to cortex (oligosynaptic)
- Modulation (modification of sensation by context)
All sensory info except _____ makes a stop at the thalamus before reaching the cerebral cortex
All sensory info except olfaction makes a stop at the thalamus before reaching the cerebral cortex
Explain the term coding
Coding:
Stimulus info is represented in the pattern of APs that neurons fire, this is termed coding
Coding is an important concept because it is the way that meaning is represented in the nervous system
Explain the term the “Land Effect”
Land Effect:
light from a single wavelength (the same wavelength) is interepreted as different colors depending on the surroundings
A stimulus only registers to the extent that we have what?
A stimulus only registers to the extend that we have the machinery to transduce that stimulus into a neural potential
Explain the receptor types and the receptor names for the following senses:
Visual
Auditory
Vestibular (balance)
Somatosensory
Gustatory and olfactory
Visual: photoreceptors, rods and cones
Auditory: mechanoreceptors, hair cells (cochlea)
Vestibular: mechanoreceptors, hair cells (vestibular labyrinth)
Somatosensory: can be mechanoreceptors, thermoreceptors, chemoreceptors: all dorsal root ganglion cells
Gustatory and olfactory: chemoreceptors (taste buds and olfactory sensory neurons)
The brain uses fourier analysis
Explain what that means
Fourier Analysis: any signal consists of a number of component sinusoidal waves
Visual: low frequency is BIG PICTURE (forest) whereas high frequency is details (trees)
Nervous System uses a form of fourrier analysis to process sensory signals
The activation of a receptor is _____ (meaning stimuli w/ certain characteristics are more likely to excite the receptor)
A _____ shows the combo of stimulus itensities and features required to excite receptor
Example: Pacinian corpusle is a somatosensory afferent that responds to ____ (optimally at ____ Hz)
The stimulus intensity (amount of indentation) needed to excite the Pacinian corpusle is ____ at optimal frequency, whereas it is ____ at other frequencies
The activation of a receptor is probabilistic (meaning stimuli w/ certain characteristics are more likely to excite the receptor)
A tuning curve shows the combo of stimulus intensities and features required to excite the receptor
Example: Pacinian corpusle is a somatosensory afferent that responds to deep vibrations (optimally at 300 Hz)
The sitmulus intensity (amount of indentation) required to excite the Pacinian corpusle is minimal at optimal frequency, whereas it is greater at other frequencies
We have a finite number of receptors which provide a finite number of stimulus types… but world contains and infinite number of stimulus properties
The brain uses a _________ , combining input from multiple receptor types
The brain uses a combinatorial code, combining input from multiple receptor types
Sensory receptors tranduce stimulus energy into changes in membrane potentials:
- Transduction produces a local change in membrane protential called a _____
- This causes NT release
- Each system is different
- Some cells produce it within the afferent terminals, others just depolarize
Transduction produces a local change in membrane potential called a receptor potential or generator potential
This causes NT release
Some cells produce the receptor potential within the afferent terminals, others just depolarize transmit the depolarization onto a nerve which in turn fires an AP
Adaptation allows primary afferents to code for a large range of stimulus intensities:
We detect a wide range of stimuli
A mechanism of adaptation shifts the sensitivity range to stimuli in sensory systems
Weber’s law states that the magnitude of a detected stimulus is _______
Adaptation: we code for stimulus intensity relative to a background level
Our ability to detect a stimulus is proprotional to the background level of sitmulation
Weber’s law states that the magnitude of a detected stimulus is a fixed proportion of the background level of stimulation (equation attached)
Adaptation and Stimulus Detection:
The magnitude of perception is ______ related to the stimulus intensity (think of the graph)
The magnitude of perception is logrithmically related to the stimulus intensity
If you hold a quarter, and then a book
Vs holding a book and then adding a quarter
For sensory trasmission, the minimum of three synpases include:
1.
2.
3.
The minimum of three synapses include:
- Primary afferent (located in periphery) to secondary sensory neuron (located centrally)
- Secondary sensory neuron to thalamic neuron
- Thalamic neuron to cortical neuron
What are components of sensory discrimination:
1.
2.
3.
4.
The following are components of sensory discrimination:
- stimulus modality
- stimulus location
- time of stimulus : onset and offset
- Intensity of stimulus
Draw out the sensory pathway from the periphery to the brain for the canonical sensory pathway
Explain the sensory pathway from periphery to the brain for color vision
Explain the sensory pathway from the periphery to the brain for somatosensory tract
Explain the sensory transduction pathway for audition
Draw out all sensory transduction pathways for the following:
canonical
color vision
somatosensation
audition
