Tracking dynamic adjustments to decision making and performance monitoring processes in conflict tasks.

How we exert control over our decision-making has been investigated using conflict tasks, which involve stimuli containing elements that are either congruent or incongruent. In these tasks, participants adapt their decision-making strategies following exposure to incongruent stimuli. According to conflict monitoring accounts, conflicting stimulus features are detected in medial frontal cortex, and the extent of experienced conflict scales with response time (RT) and frontal theta-band activity in the Electroencephalogram (EEG). However, the consequent adjustments to decision processes following response conflict are not well-specified. To characterise these adjustments and their neural implementation we recorded EEG during a modified Flanker task. We traced the time-courses of performance monitoring processes (frontal theta) and multiple processes related to perceptual decision-making. In each trial participants judged which of two overlaid gratings forming a plaid stimulus (termed the S1 target) was of higher contrast. The stimulus was divided into two sections, which each contained higher contrast gratings in either congruent or incongruent directions. Shortly after responding to the S1 target, an additional S2 target was presented, which was always congruent. Our EEG results suggest enhanced sensory evidence representations in visual cortex and reduced evidence accumulation rates for S2 targets following incongruent S1 stimuli. Results of a follow-up behavioural experiment indicated that the accumulation of sensory evidence from the incongruent (i.e. distracting) stimulus element was adjusted following response conflict. Frontal theta amplitudes positively correlated with RT following S1 targets (in line with conflict monitoring accounts). Following S2 targets there was no such correlation, and theta amplitude profiles instead resembled decision evidence accumulation trajectories. Our findings provide novel insights into how cognitive control is implemented following exposure to conflicting information, which is critical for extending conflict monitoring accounts.

Off-pump coronary artery bypass is an alternative to conventional cardiopulmonary bypass when repair of traumatic coronary artery injuries is indicated.

Coronary artery injuries after penetrating cardiac trauma are rare. The standard approach to these injuries has traditionally been coronary artery ligation. When cardiac perfusion is profoundly compromised, cardiopulmonary bypass has been used to facilitate revascularization, although with serious morbidity. We report a case of traumatic left anterior descending coronary artery transection repaired off-pump in a young stabbing victim. Penetrating traumatic cardiac injuries are highly lethal injuries. Cardiopulmonary bypass has been used for myocardial revascularization when cardiac perfusion is compromised, although with significant complications. Off-pump coronary artery bypass is a safe alternative in the traumatized patient.

Robotic-assisted coronary artery bypass on a beating heart: initial experience and implications for the future.

BACKGROUND: Although totally endoscopic coronary artery bypass using facilitated anastomotic devices is still in development, practical less invasive surgical strategies using sophisticated robotic microsurgical systems have been applied to facilitate the journey to a completely endoscopic procedure. This report summarizes the initial clinical experience with off-pump coronary artery bypass grafting using the Intuitive da Vinci Surgical Robotic System. METHODS: Robotically-assisted coronary artery bypass grafting through a small thoracotomy on a beating heart without the use of cardiopulmonary bypass was performed on 70 patients from February 16, 2004 through September 20, 2005. Postoperative morbidity, mortality, and length of stay were recorded. RESULTS: Operative mortality was 0%. The average operative time per case for the entire series was 4 hours, 3 minutes. The average operative time per case for the first 10 cases was 5 hours, 56 minutes, which decreased to 3 hours, 52 minutes for the last 10 cases of the series. The incidents of postoperative complications were as follows: reoperations for bleeding (2 patients; 2.8%); transfusions (7 patients; 10%); atrial fibrillations (6 patients; 8.5%); infections (2 patients; 2.8%); neurologic (0%); renal failure (0%); and ventilation greater than 1 day (0%). The average postoperative length of stay was 5.7 days. CONCLUSIONS: Early results suggest robotic-assisted coronary artery bypass grafting is a safe and effective means of myocardial revascularization and its continued clinical use is justified. Operative time has decreased with experience. Robotic-assisted coronary artery bypass grafting performed through a small thoracotomy on a beating heart without the use of cardiopulmonary bypass may pave the way to a completely endoscopic, closed chest procedure for coronary artery bypass grafting.