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Abstract In principle, the development of sensory receptive fields in cortex could arise from experience-independent mechanisms that have been acquired through evolution, or through an online analysis of the sensory experience of the individual animal. Here we review recent experiments that suggest that the development of direction selectivity in carnivore visual cortex requires experience, but also suggest that the experience of an individual animal cannot greatly influence the parameters of the direction tuning that emerges, including direction angle preference and speed tuning. The direction angle preference that a neuron will acquire can be predicted from small initial biases that are present in the naïve cortex prior to the onset of visual experience. Further, experience with stimuli that move at slow or fast speeds does not alter the speed tuning properties of direction-selective neurons, suggesting that speed tuning preferences are built in. Finally, unpatterned optogenetic activation of the cortex over a period of a few hours is sufficient to produce the rapid emergence of direction selectivity in the naïve ferret cortex, suggesting that information about the direction angle preference that cells will acquire must already be present in the cortical circuit prior to experience. These results are consistent with the idea that experience has a permissive influence on the development of direction selectivity.

The main goal of the experiment was to test whether deployment ofattention could be strategically controlled. Subjects viewed five-letter arrays.Each array included a letter unique in shape (i.e. target). One of the letters ineach array (target or non-target) also differed from other letters in color orin position in relation to the array. That letter will be referred to as a featuresingleton. The probability ratio of the feature singleton being the target or anon-target letter was varied throughout three experiments. The ratios were (1)0.5 (target) : 0.5 (non-target); (2) 0.2 (target) : 0.8 (non-target); (3) 0.8 (target): 0.2 (non-target). Subjects in all three experimental conditions deployed serialprocesses, but failed to maintain complete intentional control during the courseof the search.