Perception Midterm Flashcards
Absolute Threshold
the smallest detectable unit of a physical quality
Difference Threshold
the smallest detectable difference between two physical qualities
so if it says something has a weber fraction of 25% then that means a stimulus must be 25% higher or lower in order to find JND
Two types of threshold seeking methods
classical and adaptive
Three types of classical methods? Describe what they are and their pros and cons.
Method of Adjustment: stimuli is adjusted until they can just detect it, fast but not always accurate
Method of Limits: stimuli goes in ascending and descending order and person says whether they can see it or not, easy on observer and fairly fast and accurate
Method of Constant Stimuli: 5 to 9 stimuli of different intensities are presented many times each, in random order, accurate but takes very long
what is the relationship between the difference threshold and magnitude of stimulus
when magnitude of stimulus increases so does difference threshold
response compression
(b<1)
as intensity increases, the perceived magnitude increases slower than the intensity
response expansion
(b>1)
as intensity increases, the perceived magnitude increases faster than the intensity
Three main categories of mechanoreceptors
encapsulated
accessory-structure-associated
free nerve endings
encapsulated types
meissner
pacinian
ruffini
accessory-structure-associated typed
merkel disk
tactile hair
what is a receptive field
the area of a sense organ affecting the firing of a given neuron
spatial resolution
how many mechnoreceptors are across an area of a sense organ can determine how precisely one can know where a stimulus occurred
temporal resolution
how off does a receptor respond to a given stimulus can determine how precisely one can know when a stimulus occurred
Two pathways from skin to brain
dorsal column-medial lemnisical pathway
anterolateral pathway
serial processing
neurones connect to one another in a sequences
parallel processing
several streams or channels bring information to the brain simultaneously and the brain is able to process it
contralateral processing
sensations from left side of the body cross over to right side of the brain and vice versa
topographic organization
adjacent neurones carry signals from adjacent parts of the body
what determines the size of a brain area?
the number of receptors in the area, not the size of the area
focal dystonia
cortical areas fuse together from neural plasticity
tactile acuity
the ability to locate touch on your body with precision
What area of the body has greatest tactile acuity? Why?
the fingers because they have the highest density of SA-1 Merkel mechanoreceptors in them
what type of fibres and mechanoreceptors are responsible for perceiving vibration?
FA fibres, meissner and pacinian corpuscles
sensory channels
overall subsystems working together to create sensory behaviour (meissner and pacinian corpuscles creating vibration)