A comparison of monkey and human motion processing mechanisms.
Single-cell recording studies have provided vision scientists with a detailed understanding of motion processing at the neuronal level in non-human primates. However, despite the development of brain imaging techniques, it is not known to what extent the response characteristics of motion-sensitive neurons in monkey brain mirror those of human motion-sensitive neurons. Using a motion adaptation paradigm, the direction aftereffect, we recently provided evidence of a strong resemblance in the response functions of motion-sensitive neurons in monkey and human to moving dot patterns differing in dot density. Here we describe a series of experiments in which measurements of the direction aftereffect are used to infer the response characteristics of human motion-sensitive neurons when viewing transparent motion and moving patterns that differ in their signal-to-noise ratio (motion coherence). In the case of transparent motion stimuli, our data suggest suppressed activity of motion-sensitive neurons similar to that reported for macaque monkey. In the case of motion coherence, our results are indicative of a linear relationship between signal intensity (coherence) and neural activity; a pattern of activity which also bears a striking similarity to macaque neural activity. These findings strongly suggest that monkey and human motion-sensitive neurons exhibit similar response and inhibitory characteristics.
Lynn
Catherine
C
School of Psychology, Queen's University Belfast, Belfast BT71NN, UK.
Curran
William
W
D000818:Animals; D006801:Humans; D008251:Macaca; D008954:Models, Biological; D009039:Motion Perception / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011601:Psychophysics; D014793:Visual Cortex / Q000502:physiology*