When people look at something, that visual information is converted to electric signals in the retina of the eye. These signals are then processed in the portion of the brain called the visual cortex, located in the occipital lobe. Based on these signals, neurons in the visual cortex reproduce the visual information in the shape of the image within the brain. When neurons in the visual cortex are activated, the consumption of oxygen becomes more active, and blood flow in the vicinity of these neurons changes. Measurements of these changes using functional magnetic resonance imaging (fMRI) can be used to ascertain the state of activity of the neurons, and the visual information in the brain can be reconstructed based on this information.

A previous method of reconstructing images refers to patterns in the change in the brain’s blood flow. A subject first looks at a number of images and the changes in blood flow are measured. Then, by referring to the changes when the subject is shown a new picture, the shape of the new image is distinguished. With this method, however, images that have not been measured in advance cannot be distinguished, and it is thus impossible in practice to reproduce complex images.

1 ＞ 2

Articles List