NKCC1 in Neonatal Cochlear Support Cells Reloads Ions Necessary for Cochlear Spontaneous Activity.

In the auditory system, the spontaneous activity of cochlear inner hair cells (IHCs) is initiated by the release of ATP from inner supporting cells (ISCs). This ATP release sets off a cascade, activating purinergic autoreceptors, opening of Ca2+-activated Cl- channel TMEM16A, Cl- efflux and osmotic cell shrinkage. Then, the shrunken ISCs efficiently regain their original volume, suggesting the existence of mechanisms for refilling Cland K+, priming them for subsequent activity. This study explores the potential involvement of NKCCs (Na+-K+-Cl- cotransporters) and KCCs (K+-Cl- cotransporters) in ISC spontaneous activity, considering their capability to transport both Cl- and K+ ions across the cell membrane. Employing a combination of immunohistochemistry, pharmacological interventions, and shRNA experiment, we unveiled the pivotal role of NKCC1 in cochlear spontaneous activity. Immunohistochemistry revealed robust NKCC1 expression in ISCs, persisting until the 2nd postnatal week. Intriguingly, we observed a developmental shift in NKCC1 expression from ISCs to synaptophysin-positive efferent terminals at postnatal day 18, hinting at its potential involvement in modulating synaptic transmission during the post-hearing period. Experiments using bumetanide, a well-known NKCC inhibitor, supported the functional significance of NKCC1 in ISC spontaneous activity. Bumetanide significantly reduced the frequency of spontaneous extracellular potentials (sEP) and spontaneous optical changes (sOCs) in ISCs. NKCC1-shRNA experiments conducted in cultured cochlear tissues further supported these findings, demonstrating a substantial decrease in event frequency and area. Taken together, we revealed the role of NKCC1 in shaping the ISC spontaneous activity that govern auditory pathway development.

Enhancing fundamental robot-assisted surgical proficiency by using a portable virtual simulator.

BACKGROUND: The development of a virtual reality (VR) training platform provides an affordable interface. The learning effect of VR and the capability of skill transfer from the VR environment to clinical tasks require more investigation. METHODS: Here, 14 medical students performed 2 fundamental surgical tasks-bimanual carrying (BC) and peg transfer (PT)-in actual and virtual environments. Participants in the VR group received VR training, whereas participants in the control group played a 3D game. The learning effect was examined by comparing kinematics between pretraining and posttraining in the da Vinci Surgical System. Differences between VR and playing the 3D game were also examined. RESULTS: Those who were trained with the VR simulator had significantly better performance in both actual PT (P = .002) and BC (P < .001) tasks. The time to task completion and the total distance traveled were significantly decreased in both surgical tasks in the VR group compared with the 3D game group. However, playing the 3D game showed no significant enhancement of fundamental surgical skills in the actual PT task. The difference between pretraining and posttraining was significantly larger in the VR group than in the 3D game group in both the time to task completion (P = .002) and the total distance traveled (P = .027) for the actual PT task. Participants who played the 3D game seemed to perform even worse in posttraining. CONCLUSIONS: Training with the portable VR simulator improved robot-assisted surgical skill proficiency in comparison to playing a 3D game.

Modeling surgical skill learning with cognitive simulation.

We used a cognitive architecture (ACT-R) to explore the procedural learning of surgical tasks and then to understand the process of perceptual motor learning and skill decay in surgical skill performance. The ACT-R cognitive model simulates declarative memory processes during motor learning. In this ongoing study, four surgical tasks (bimanual carrying, peg transfer, needle passing, and suture tying) were performed using the da Vinci© surgical system. Preliminary results revealed that an ACT-R model produced similar learning effects. Cognitive simulation can be used to demonstrate and optimize the perceptual motor learning and skill decay in surgical skill training.

Electromyographic correlates of learning during robotic surgical training in virtual reality.

The purpose of this study was to investigate the muscle activation and the muscle frequency response of the dominant arm muscles (flexor carpi radialis and extensor digitorum) and hand muscles (abductor pollicis and first dorsal interosseous) during robotic surgical skills training in a virtual environment. The virtual surgical training tasks consisted of bimanual carrying, needle passing and mesh alignment. The experimental group (n=5) was trained by performing four blocks of the virtual surgical tasks using the da Vinci™ surgical robot. During the pre- and post-training tests, all subjects were tested by performing a suturing task on a "life-like" suture pad. The control group (n=5) performed only the suturing task without any virtual task training. Differences between pre- and post-training tests were significantly greater in the virtual reality group, as compared to the control group in the muscle activation of the hand muscle (abductor pollicis) for both the suture tying and the suture running (p<0.05). In conclusion, changes in electrographic activity shows that training in virtual reality leads to specific changes in neuromotor control of robotic surgical tasks.

Accuracy and speed trade-off in robot-assisted surgery.

BACKGROUND: Controlling surgical task speed and maintaining accuracy are vital components of robotic surgical skills. This study was designed to investigate the relationship between accuracy and speed for robot-assisted surgical skills. METHODS: Ten participants were asked to alternately touch two circular targets with various dimensions and distances between two targets, using the da Vinci Surgical System. The design of this study was based on Fitt's law. Statistical correlations between the index of difficulty (ID) and the movement time (MT), as well as the ID and the smoothness of the movement, were analysed. RESULTS: A significant linear correlation between MT and ID was shown. Speed was reduced to maintain accuracy as the level of task difficulty increased. There was no significant correlation between the smoothness of the movement and ID. CONCLUSIONS: The trade-off between speed and accuracy plays an important role in robot-assisted surgical proficiency.

The negative effect of distraction on performance of robot-assisted surgical skills in medical students and residents.

BACKGROUND: Modern surgical practice often requires multitasking in operating rooms, generally full of distractions. The purpose of this research was to investigate the effect of distraction on robot-assisted surgical skill performance in medical students and residents. METHODS: Fourteen subjects performed a suture-tying task with the da Vinci(™) surgical system with distractive secondary tasks simultaneously. The time to task completion, speed and the total distance travelled were analysed. Two-way repeated-measures ANOVA were applied. The scores of secondary tasks were analysed. RESULTS: A significant secondary task effect was found with an increase of the time to task completion (p = 0.003) and decreased average speed (p < 0.001). The performance of secondary task for residents was significantly better than students. CONCLUSIONS: The performance of a robot-assisted surgical task was negatively affected by secondary tasks. However, residents with more surgical experience demonstrated a larger attention capacity for multitasking. Therefore, understanding how medical trainees respond to the distractive secondary tasks while performing robot-assisted surgical task is important in developing a surgical training programme based on the concept of attention.