Declarative memories are thought to be initially stored in the hippocampus, and then transferred to the neocortex. This is a key feature of the standard model of consolidation and is supported by studies reporting a requirement for activity within the neocortex for recall of remote, but not recent, hippocampal-dependent memories. New evidence from our and other laboratories, however, suggests that, for trace fear conditioning, memories are stored in the rodent medial prefrontal cortex and in the hippocampus from the time of training. Consistent with this, we show that activity in the medial prefrontal cortex is necessary for retrieval of recent and remote memories, suggesting that information stored in this neocortical structure from the time of training is necessary for memory recall.

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Lesion studies have provided evidence that the entorhinal cortex (EC) participates in spatial memory. However, the molecular cascades that underlie memory-associated changes in the EC and its specific role in spatial memory, however, have not been clearly delineated. Recently, it has been shown that activation of extracellular signal-regulated kinase (Erk, a mitogen-activated protein kinase family member) in the dorsal hippocampus is necessary for spatial memory. To examine whether similar mechanisms are used for spatial memory storage in the EC, Erk activity was inhibited after training in the Morris water maze. Bilateral infusion of the mitogen-activated protein kinase kinase inhibitor PD098059 into the EC immediately after training resulted in a memory deficit observed during a retention test performed 48 h later. This deficit was abolished with pretraining in a different water maze in which animals were able to learn the general task requirements and the appropriate search strategies. The absence of a deficit indicates that Erk activity in the EC may be involved in storing the task requirements or the search strategies. The findings presented in this article are consistent with the idea that the EC is involved in spatial memory and indicate that Erk activity is necessary for memory consolidation in this structure.

Background: Median sternotomy has been the most commonly used approach for thymectomy to date. Recent advances in video-assisted thoracoscopic surgery (VATS) and robotic access with CO 2 insufflation techniques have allowed more minimally invasive approaches. However, prior reviews have not compared robotic to both open and VATS thymectomy. Methods: A systematic review was conducted in accordance with the PRISMA guidelines using PubMed, Embase and Scopus databases. Original research articles comparing robotic to VATS or to open thymectomy for myasthenia gravis, anterior mediastinal masses, or thymomas were included. Meta-analyses were performed for mortality, operative time, blood loss, transfusions, length of stay, conversion to open, intraoperative and postoperative complication rates, and positive/negative margin rates.