Agent-dependent modulation of corticospinal excitability during painful transcutaneous electrical stimulation.

Pain has an inhibitory effect on the corticospinal excitability that has been interpreted as an evolutionary mechanism, directed to down-regulate cortical activity in order to facilitate rapid protective spinal reflexes. Here, we focused on the link between defensive mechanisms and motor system and we asked whether voluntary actions can modulate the corticospinal excitability during painful stimulations. To this aim, we manipulated the volition-related aspects of our paradigm by comparing conditions in which either the participant (self-generated action) or the experimenter (other-generated action) pressed the button to deliver painful high-intensity transcutaneous electric shocks to the right digit V. MEPs to TMS were recorded from the FDI and APB muscles of the stimulated hand. A compelling agent-dependent modulation of the corticospinal excitability was found, showing, in self-generated compared to other-generated actions, a significantly lower inhibitory effect, as measured by greater MEP amplitude. This finding suggests a top-down modulation of volitional actions on defensive mechanisms, promoting the view that predictive information from the motor system attenuates the responses to the foreseeable adverse events generated by one's own actions as compared to unpredictable events generated by someone else's actions.

Estimation of premorbid intelligence: the word accentuation test-- Buenos Aires version.

We have sought to adapt and validate a NART-like Spanish test, the Word Accentuation Test (WAT: Del Ser, Montalvo, Espinosa, Villapalos, & Bermejo, 1997) to estimate acquired intelligence in local normal older adults. The test requires examinees to read aloud infrequent, irregularly stressed Spanish words, a situation that presumably requires lexical knowledge. Results in a sample of 74 participants show that the revised WAT (i.e., the WAT for Buenos Aires) has good concurrent validity with the WAIS Vocabulary subtest and number of years of formal education, as well as high internal consistency. Performance on this test was dissociated from age, memory, or frontal/executive measures.