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Neurons That Detect Motion Know What Meets the Eye

Visually responsive neurons in the brain only respond to a limited portion of the visual scene known as their "receptive field." How can these neurons interpret what they see given their restricted view of the world? Salk researchers Gene Stoner, senior staff scientist, Thomas Albright, director of the Vision Center Laboratory and Xin Huang, the study's first author, have discovered that motion-selective neurons in visual cortex know much more about what is outside their receptive field than was previously realized.

For a study published in Neuron, the researchers recorded the responses of neurons in monkeys while stimuli passed through each neuron's receptive field. They found that when moving features outside the receptive field were part of the same object as the feature within the receptive field, these neurons responded as if all the object's features were inside the receptive field — allowing them to correctly interpret the motion of the whole object.

However, when the features inside and outside the receptive field were part of different objects, the same neurons correctly distinguished the motions within the receptive field from those outside.

Human perception relies on the activity of billions of neurons. This new research suggests that visual perception owes much to the sophisticated properties of individual neurons, each of which dynamically adjusts its receptive field around the objects that populate a given visual scene.