Title : Long-range traveling waves of activity triggered by 1 local dichoptic stimulation in V 1 of behaving monkeys 2 Abbreviated title : Traveling waves in V 1 3

25 Traveling waves of cortical activity, in which local stimulation triggers lateral spread of activity to 26 distal locations, have been hypothesized to play an important role in cortical function. However, 27 there is conflicting physiological evidence for the existence of spreading traveling waves of 28 neural activity triggered locally. Dichoptic stimulation, in which the two eyes view dissimilar 29 monocular patterns, can lead to dynamic wave-like fluctuations in visual perception and 30 therefore provides a promising means for identifying and studying cortical traveling waves. Here 31 we used voltage-sensitive dye imaging to test for the existence of traveling waves of activity in 32 V1 of awake, fixating monkeys viewing dichoptic stimuli. We find clear traveling waves that are 33 initiated by brief localized contrast increments in one of the monocular patterns and, then, 34 propagate at speeds of about 30 mm/s. These results demonstrate that under an appropriate 35 visual context, circuitry in visual cortex in alert animals is capable of supporting long-range 36 traveling waves triggered by local stimulation. 37