Source Paper
The analysis of visual motion: a comparison of neuronal and psychophysical performance
KH Britten, MN Shadlen, WT Newsome, JA Movshon
Journal of Neuroscience • 1992
Direction Discrimination Task
Objective: Compare the ability of psychophysical observers and single cortical neurons to discriminate weak motion signals in a stochastic visual display near perceptual threshold
Protocol Steps
Animal training
Rhesus monkeys were trained to perform a direction discrimination task
Note: Training was conducted near psychophysical threshold
View evidence from paper
“rhesus monkeys trained to perform a direction discrimination task near psychophysical threshold”
Stimulus presentation
Present weak motion signals in a stochastic visual display to the trained animal
Note: Visual display was tailored to the physiological properties of the neuron under study and matched to each neuron's preference for size, speed, and direction of motion
View evidence from paper
“the psychophysical task was tailored in each experiment to the physiological properties of the neuron under study; the visual display was matched to each neuron's preference for size, speed, and direction of motion”
Simultaneous data collection
Obtain both psychophysical and physiological data from the same animals on the same sets of trials using the same visual display
Note: Data collection conditions were ideal for comparison as both psychophysical and physiological data were obtained in the same animals, on the same sets of trials, and using the same visual display
View evidence from paper
“both psychophysical and physiological data were obtained in the same animals, on the same sets of trials, and using the same visual display”
Measure discrimination performance
Record the animal's ability to discriminate direction of motion signals at varying signal strengths
Note: Performance is related to the strength of the motion signal to generate psychometric functions
View evidence from paper
“the shape of the psychometric function relating performance to the strength of the motion signal”
Record neural responses
Record single cortical neuron responses during the direction discrimination task
Note: Focus on MT neurons and their responses to motion signals
View evidence from paper
“the responses of single neurons typically provided a satisfactory account of both absolute psychophysical threshold and the shape of the psychometric function”