The perturbation paradigm modulates error-based learning in a highly automated task: outcomes in swallowing kinematics.

Traditional motor learning studies focus on highly goal-oriented, volitional tasks that often do not readily generalize to real-world movements. The goal of this study was to investigate how different perturbation paradigms alter error-based learning outcomes in a highly automated task. Swallowing was perturbed with neck surface electrical stimulation that opposes hyo-laryngeal elevation in 25 healthy adults (30 swallows: 10 preperturbation, 10 perturbation, and 10 postperturbation). The four study conditions were gradual-masked, gradual-unmasked, abrupt-masked, and abrupt-unmasked. Gradual perturbations increasingly intensified overtime, while abrupt perturbations were sustained at the same high intensity. The masked conditions reduced cues about the presence/absence of the perturbation (pre- and postperturbation periods had low stimulation), but unmasked conditions did not (pre- and postperturbation periods had no stimulation). Only hyo-laryngeal range of motion measures had significant outcomes; no timing measure demonstrated learning. Systematic-error reduction occurred only during the abrupt-masked and abrupt-unmasked perturbations. Only the abrupt-masked perturbation caused aftereffects. In this highly automated task, gradual perturbations did not induce learning similarly to findings of some volitional, goal-oriented adaptation task studies. Furthermore, our subtle and brief adjustment of the stimulation paradigm (masked vs. unmasked) determined whether aftereffects were present. This suggests that, in the unmasked group, sensory predictions of a motor plan were quickly and efficiently modified to disengage error-based learning behaviors.

Breast reconstruction.

Mastectomy has been used for the treatment of breast cancer for many years, but the importance of the positive psychosocial benefits of breast reconstruction in breast cancer treatment has been recognized in the past years. Now, more women seek breast reconstruction and surgeons perform more reconstructions. A breast can be reconstructed by two methods: prosthetic implants and autologous tissue. The reconstruction can be performed immediately at the time of mastectomy or on a delayed basis. Factors associated with implant reconstruction include timing, patient selection, method of reconstruction, and filler material. The prosthetic implant reconstruction can be performed in one or two stages. The principal methods of breast reconstruction using autologous tissue include flaps from lower abdominal tissue, the latissimus dorsi musculocutaneous flap, other flaps, and the autologous fat grafting. In this article the main reconstruction methods either with implants or autologous tissue are reviewed and their advantages and disadvantages are discussed.

New end-to-end microvascular anastomosis with geometrically adaptable ends technique: an experimental study on rats.

OBJECTIVE: The aim of this study was to develop an effective arterial anastomosis model with a high patency rate and low operation time. We introduced a new end-to-end microvascular anastomosis with geometrically adaptable ends. METHODOLOGY: In this technique, two triangular flaps were prepared at the end of the vessels and four stitches applied on the tip of those flaps. During this study, 15 new technique anastomoses were compared to 15 conventional 8 stitches anastomoses in 30 rat femoral arteries. Operating time, patency rates and number of stitches with consequential effects on the vessel wall were analyzed statistically. The anastomotic patency of both groups was assessed by: (1) in vivo observation using the milking test under the operating microscope and (2) flow study using laser Doppler ultrasound. Healing was assessed by the light and electron microscopy. RESULTS: According to statistical results and compared to the conventional method, the new technique was associated with a significant time savings (mean 18 vs 26 minutes, p < 0.001). The patency rates were equivalent to the conventional technique by observation and laser Doppler ultrasound (p > 0.05). Histological evaluation of both techniques showed that rats operated with the new technique healed faster and with less endothelial damage. CONCLUSIONS: This new "Geometrically Adaptable Ends Technique" is faster, easier to perform and a reliable method with patency and flow characteristics similar to those of the conventional end-to-end anastomoses (Fig. 7, Ref. 20).

Dipyrone increases the blood flow of arterial dorsal skin flaps.

BACKGROUND: Findings have shown that dipyrone has a beneficial effect on skin flap survival. A pharmacologic explanation for this effect points to its vascular smooth muscle-relaxing effect. This study evaluated the effect of dipyrone on blood flow and thus survival of rat random dorsal skin flaps. METHODS: For this study, 27 male Wistar albino rats were randomly assigned to control (treated with sterile saline) and treatment (treated with dipyrone 100 mg/kg) groups. A random dorsal skin flap measuring 4 x 10 cm was raised in each animal. The edges of the flap were sutured back into their original place. Dipyrone treatment continued at 100 mg/kg per day during the 7-day observation period. Blood flow was recorded by laser Doppler preoperatively (baseline), immediately after the flap was sutured back to its original position (acute), and on postoperative day 7. The degree of necrosis was evaluated by the grid method on day 7. Mean percentage necrosis and minimum laser Doppler readings were compared between the two groups. RESULTS: A significant increase in blood flow was observed in the dipyrone group at the acute phase but not on postoperative day 7. The percentage of the necrotic area was lower in the treatment group. However, it did not reach the significance level (p = 0.09). CONCLUSION: Dipyrone significantly increases [corrected] skin blood flow at the acute phase of flap elevation although the necrotic area does not reach the significance level.