Mental Rotation - Mental Rotation and The Brain

Mental Rotation and The Brain

In 1999, a study done by seven scientists was conducted to find out which part of the brain is activated during mental rotation. Seven volunteers between the ages of twenty-nine to sixty-six participated in this experiment. None of the volunteers had a history of neurological illness. A PET scan was used to record the brain activity. Each subject was presented with eight characters during each scan, twice in its normal position and twice reversed. Scanning was conducted with the lights dimmed and the noise level low. After being placed in the scanner, each subject received both oral and written instructions and was given thirty-two practice trials. Each trial started with showing the subjects a black screen for two seconds, followed by thirty-two stimuli presented at a rate of two seconds each. The subject had those two seconds to respond to each stimuli or else the image would immediately switch to the next. If they did respond, the screen went black until the end of the two-second interval. With each stimulus presented, the subject had one of two buttons to push: one if the image shown was normal and one if the image was mirror-reversed. rCBF was measured in the brain by recording the distribution of the cerebral radioactivity following an injection of H215O into a small vein in each of the subject’s left forearm. The only area of the brain in which the rCBF levels changed and that was found directly correlated with the mental rotation tasks was in the right posterior parietal lobe, specifically surrounded around the intraparietal sulcus. A small area of activation was also recorded in the left parahippocampal gyrus. The results this study collected are evidence that the task of mental rotation recruits visual-spatial changes that are implemented in this brain region (Irnia, Egan, 1999).