Lucia Riggio | PubMed Health

PubMed2004

The mirror neuron system and action recognition.

Mirror neurons, first described in the rostral part of monkey ventral premotor cortex (area F5), discharge both when the animal performs a goal-directed hand action and when it observes another individual performing the same or a similar action. More recently, in the same area mirror neurons responding to the observation of mouth actions have been also found. In humans, through an fMRI study, it has been shown that the observation of actions performed with the hand, the mouth and the foot leads to the activation of different sectors of Broca's area and premotor cortex, according to the effector involved in the observed action, following a somatotopic pattern which resembles the classical motor cortex homunculus. These results strongly support the existence of an execution-observation matching system (mirror neuron system). It has been proposed that this system is involved in action recognition. Experimental evidence in favor of this hypothesis both in the monkey and humans are shortly reviewed.

Animals↗

PubMed2003

Location and shape in inhibition of return.

Inhibition of return (IOR) is characterized by a delay in responding to a target preceded by an irrelevant stimulus (cue) at the same location, or, in other words, by a response delay when the same location is stimulated twice. It is not clear, however, if the same phenomenon is present when there is a repetition of a simple nonspatial attribute of the stimulus. The present study examines the repetition of shape. Six experiments were conducted. In Experiments 1, 2, 3, and 6 the stimuli were geometrical shapes, whereas in Experiments 4 and 5 letters were used. In Experiment 1 all the stimuli were presented at fixation, whereas in Experiments 2 to 6 they were presented in the periphery. In Experiments 2 and 3, location and shape of the cue and the target were independently manipulated in order to test independently inhibitory effects (IOR?) attributable to location repetition and shape repetition. Results showed an inhibitory effect for location and a much smaller inhibitory effect for shape. The latter was restricted to the cued location. Experiments 4 and 5 tested the possibility that inhibition caused by shape repetition is due to repetition blindness. Experiment 6 contrasted the presence or absence of a central neutral attractor in the delay interval between presentation of the cue and the target. Taken together the results seem to favor IOR as the basis for the inhibition caused by shape repetition.

Adult↗