PURPOSE:Neurons in macaque middle temporal visual area (MT) show a diversity of direction tuning properties, exhibiting a broad distribution of tuning width, baseline activity, peak response, and circular variance (CV). Previous studies of the direction discrimination power of neurons in V1 focused on resolving two nearby orientations close to the psychophysical threshold of direction discrimination.
METHODS: Here, we developed the information tuning curve, that measures the discrimination power of cells as a function of the direction difference, δθ, of the two stimuli, to study how the tuning features affect the discrimination of neurons. This tuning curve also represents the mutual information between the neuronal responses and the stimulus direction.
RESULTS: The shape of information tuning curve is similar to the direction-selective (DS) tuning curve with one peak. It also enables us to compare the discrimination capability of neurons quantitatively. Studies of discrimination performance of neurons in MT indicates that Chernoff distance (D_C) decreases monotonically as relative baseline increases and has a maximum as the tuning width (σ) increases.
CONCLUSIONS: The information tuning curve measures the discrimination power of cells as a function of the direction difference. δθ, of the two stimuli. And most of the neuronal population exhibits favorable tuning properties for relatively large δθ.