transcranial

Although facilitation of the corticospinal system during action observation is widely accepted, it remains controversial whether this facilitation reflects a replica of the observed movements or the goal of the observed motor acts. In the present study, we asked whether, when an object is grasped by using a tool, corticospinal facilitation represents 1) the movements of the hand, 2) the movements of the tool, or 3) the distal goal of the action. To address this question, we recorded motor-evoked potentials (MEPs) to transcranial magnetic stimulation while participants observed a hand reaching and grasping a mothball by using 3 types of pliers, requiring different hand--tool movements to achieve the same goal (grasping the object). We found that MEPs recorded from the opponens pollicis and from the first dorsal interosseous reflected the observed hand movements rather than the movements of the tool or the distal goal of the action. These results suggest that during observation of too...

It is well known that acute liver failure (ALF) in children is rare but potentially a life-threatening disorder. Its true incidence in the pediatric population is undetermined but is responsible for 10-15% of all pediatric liver transplantations. 1 Unlike adults, a specific cause of pediatric ALF is not identified in almost half of the cases, 2 and the etiology is classified as indeterminate in 18-47% of all patients. 1 The etiology is important because the survival rate and need for liver transplantation vary depending on the diagnosis. Spontaneous recovery is better in children with toxic etiology and worst for those with indeterminate or other causes. 1,2 There is no specific treatment for most ALF cases, and the mainstay of medical care is to minimize complications and to limit additional morbidity. 3 ALF can be associated with rapidly progressive multiorgan failure and high mortality rates. One of the leading causes of death is cerebral edema and intracranial hypertension (ICH), responsible for about 20-25% of all deaths. 3 From that perspective, it is desirable to develop new therapies/technologies for diagnostic investigation and interventions. The use of transcranial Doppler (TCD) is an important component in the assessment of cerebral edema, which should be monitored. Some centers use invasive intracranial pressure (ICP) monitoring; however, non-invasive monitoring of cerebral arterial flow is becoming a useful tool to identify ICH. 1 Two relevant articles 4,5 tried to demonstrate the usefulness of TCD to characterize the cerebral hemodynamics patterns in patients diagnosed with ALF. TCD is becoming an important tool since there is no risk of complications like bleeding or infection, which can occur in the use of invasive ICP monitoring. 4,6 The complication risk is around 20%, and there are limited therapeutic options for ICH, 6 which should be taken into consideration to indicate invasive procedures. Besides that, Aggarwal et al 6 studied whether TCD waveform features could be used to differentiate ALF patients with respect to ICP or cerebral perfusion pressure (CPP) levels. They concluded that TCD could provide information about the dynamic state of the intracranial circulation and perfusion with clinical complications. Another issue is the use of continuous renal replacement therapy (CRRT) on pediatric ALF. 7 As mentioned before, the pediatric ALF is a dramatic clinical syndrome in which children has rapid deterioration of hepatic function and can evolve to multiorgan failure and cere-bral edema. As found by Deep et al 7 patients who benefited most from CRRT were those with toxic cause unlike the patients with metabolic causes. Therefore, clinicians should be careful in the selection of patients who underwent CRRT, as the cause of pediatric ALF is determinant for prognosis. That is important to consider because of the possible complications related to CRRT. Santiago et al 8 found in their study that CRRT-complications are common in children and some are potentially serious, the majority were problems of venous catheterization, hypotension on connection to CRRT, electrolytes disturbances and clinically significant hemorrhage. Probably this can be diminished by ultrasound-guided catheter placement, as well as the choice to use prostacyclin instead of regional citrate anticoagulation, and standardized service practices. 9 Despite these two useful tools, another relevant resource to be used by intensivists is the ammonia level. It is well known that the ammonia level is an independent risk factor for the development of severe hepatic encephalopathy and ICH. Bernal et al 10 demonstrated that

Controlling neural representations of the self and other people is fun-damental to social cognition. Brain imaging studies have implicated the right temporoparietal junction (rTPJ) in this ability, but causal evidence for its role is lacking. A debate is also ongoing regarding whether the control of, or switching between, self and other rep-resentations is a specialized or domain-general process: the rTPJ’s well-established role in reorienting attention supports a domain-general process, but a role specific to social cognition has also been proposed. Neuronavigated repetitive transcranial magnetic stimu-lation was used to target the rTPJ (and a control mid-occipital site) during a task requiring participants to switch between represen-tations of others ’ actions on both a social and a nonsocial level, by manipulating imitative and spatial compatibility simultaneously and independently. Both imitative and spatial compatibility effects were apparent on response times; however, the eff...