!!!Understanding Intentions: Through the Looking Glass
Science, Vol 308, Issue 5722, 644-645 , 29 April 2005
doi:10.1126/science.1112174
Kiyoshi Nakahara and Yasushi Miyashita
A class of neurons in the brain called "mirror neurons" may be crucial for understanding motor actions. Mirror neurons are activated not only during the execution of a particular action, but also during observation of that action carried out by someone else. In their Perspective, Nakahara and Miyashita discuss a new study in monkeys (Fogassi et al.) suggesting that mirror neurons also are able to encode the intention of a particular action as well as the action itself and observation of the action.
!!!Altered awareness of voluntary action after damage to the parietal cortex
Nature Neuroscience January 2004 Volume 7 Number 1 pp 80 - 84
doi:10.1038/nn1160
Angela Sirigu1, Elena Daprati1, 2, Sophie Ciancia1, Pascal Giraux1, Norbert Nighoghossian3, Andres Posada1 & Patrick Haggard4
A central question in the study of human behavior is the origin of willed action. EEG recordings of surface brain activity from human subjects performing a self-initiated movement show that the subjective experience of wanting to move follows, rather than precedes, the 'readiness potential'—an electrophysiological mark of motor preparation. This raises the issue of how conscious experience of willed action is generated. Here we show that patients with parietal lesions can report when they started moving, but not when they first became aware of their intention to move. This stands in contrast with the performance of cerebellar patients who behaved as normal subjects. We thus propose that when a movement is planned, activity in the parietal cortex, as part of a cortico-cortical sensorimotor processing loop, generates a predictive internal model of the upcoming movement. This model might form the neural correlate of motor awareness.
!!!Attention to Intention
Science Volume 303, Number 5661, Issue of 20 Feb 2004, pp. 1208-1210.
doi:10.1126/science.1090973
Hakwan C. Lau, Robert D. Rogers, Patrick Haggard, Richard E. Passingham1
Intention is central to the concept of voluntary action. Using functional magnetic resonance imaging, we compared conditions in which participants made self-paced actions and attended either to their intention to move or to the actual movement. When they attended to their intention rather than their movement, there was an enhancement of activity in the pre-supplementary motor area (pre-SMA). We also found activations in the right dorsal prefrontal cortexand left intraparietal cortex. Prefrontal activity, but not parietal activity, was more strongly coupled with activity in the pre-SMA. We conclude that activity in the pre-SMA reflects the representation of intention.
!!!Mirror neurons
Kohler E., Keysers C., Umilta M.A., Fogassi L., Gallese V., Rizzolatti G.
Hearing sounds, understanding actions: action representation in mirror neurons.
Science, 297: 846-848, 2002.
doi:10.1126/science.1070311
Many object-related actions can be recognized by their sound. We found neurons in monkey premotor cortex that discharge when the animal performs a specific action and when it hears the related sound. Most of the neurons also discharge when the monkey observes the same action. These audiovisual mirror neurons code actions independently of whether these actions are performed, heard,or seen. This discovery in the monkey homolog of Broca’s area might shed light on the origin of language: audiovisual mirror neurons code abstract contents - the meaning of actions - and have the auditory access typical of human
language to these contents.
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