An identified ensemble within a neocortical circuit encodes essential information for genetically-enhanced visual shape learning.

Advanced cognitive tasks are encoded in distributed neocortical circuits that span multiple forebrain areas. Nonetheless, synaptic plasticity and neural network theories hypothesize that essential information for performing these tasks is encoded in specific ensembles within these circuits. Relatively simpler subcortical areas contain specific ensembles that encode learning, suggesting that neocortical circuits contain such ensembles. Previously, using localized gene transfer of a constitutively active protein kinase C (PKC), we established that a genetically-modified circuit in rat postrhinal cortex, part of the hippocampal formation, can encode some essential information for performing specific visual shape discriminations. However, these studies did not identify any specific neurons that encode learning; the entire circuit might be required. Here, we show that both learning and recall require fast neurotransmitter release from an identified ensemble within this circuit, the transduced neurons; we blocked fast release from these neurons by coexpressing a Synaptotagmin I siRNA with the constitutively active PKC. During learning or recall, specific signaling pathways required for learning are activated in this ensemble; during learning, calcium/calmodulin-dependent protein kinase II, MAP kinase, and CREB are activated; and, during recall, dendritic protein synthesis and CREB are activated. Using activity-dependent gene imaging, we showed that during learning, activity in this ensemble is required to recruit and activate the circuit. Further, after learning, during image presentation, blocking activity in this ensemble reduces accuracy, even though most of the rest of the circuit is activated. Thus, an identified ensemble within a neocortical circuit encodes essential information for performing an advanced cognitive task.

Increased incidence of surgical site infection with a body mass index ≥ 35 kg/m2 following abdominal wall reconstruction with open component separation.

BACKGROUND: To quantify the impact of body mass index (BMI) on surgical site infection (SSI) following abdominal wall reconstruction (AWR) using component separation techniques and attempt to identify obesity-related targets, such as BMI, that can be potentially used to guide preoperative patient optimization. Though AWR has established perioperative outcomes for hernia repair, the applicability in the obese population is not well established. METHODS: The 2005-2013 ACS-NSQIP participant use file was reviewed to compare SSI, severe, and overall morbidity in non-emergent AWR patients based on BMI. Multivariable logistic regression was used to control for patient demographics and comorbidities. Odds ratios (OR) with 95% confidence intervals were reported. RESULTS: We identified 4488 patients. The average BMI was 32.76 ± 7.70 kg/m2. The majority of cases (76.8%) had wound classified as clean. The SSI rate significantly increased at a BMI of ≥ 35 kg/m2 compared to < 35 (18.5% vs. 10.5%, p < 0.0001). There was no significant different in SSI rate between BMI 35-40 and > 40. After controlling for differences in baseline characteristics and wound classification, BMI ≥ 35 kg/m2 was independently associated with SSI (OR 1.47, 1.21-1.78), minor complications (OR 1.65, 1.41-1.94), major complications (OR 1.91, 1.60-2.27), re-operation (OR 1.59, 1.23-2.05), and hospital re-admission (OR 1.93, 1.23-3.02). CONCLUSION: There is a significant increase in SSI and other perioperative complications in patients with a BMI ≥ 35 kg/m2 undergoing AWR. Higher BMI is also independently associated with higher resource utilization in this patient population. Severely obese patients in need of AWR may benefit from a structured preoperative weight loss intervention.

Endoscopic Evaluation and Treatment of Postoperative Bariatric Surgery Complications.

The number of patients undergoing bariatric surgery continues to increase. The American Society for Metabolic and Bariatric Surgery (ASMBS) estimates the number of bariatric surgical procedures performed increased from 158 000 in 2011 to 190 000 in 2015. Concurrently, the incidence of postoperative complications specific to bariatric patients will inevitably increase as well. Endoscopic evaluation of postoperative bariatric patients and endoscopic interventions are rapidly evolving. We present a review of the postoperative anatomy of bariatric patients, what complications to expect, and treatment options.

CaMKII, MAPK, and CREB are coactivated in identified neurons in a neocortical circuit required for performing visual shape discriminations.

Current theories postulate that the essential information for specific cognitive tasks is widely dispersed in multiple forebrain areas. Nonetheless, synaptic plasticity and neural network theories hypothesize that activation of specific signaling pathways, in specific neurons, modifies synaptic strengths, thereby encoding essential information for performance in localized circuits. Consistent with these latter theories, we have shown that gene transfer of a constitutively active protein kinase C into several hundred glutamatergic and GABAergic neurons in rat postrhinal cortex enhances choice accuracy in visual shape discriminations, and the genetically-modified circuit encodes some of the essential information for performance. However, little is known about the role of specific signaling pathways required for learning, in specific neurons within a critical circuit. Here we show that three learning-associated signaling pathways are coactivated in the transduced neurons during both learning and performance. After gene transfer, but before learning a new discrimination, the calcium/calmodulin-dependent protein kinase (CaMKII), MAP kinase, and CREB pathways were inactive. During learning, these three pathways were coactivated in the transduced neurons. During later performance of the discrimination, CaMKII activity declined, but MAP kinase and CREB activity persisted. Because the transduced neurons are part of a circuit that encodes essential information for performance, activation of these learning-associated signaling pathways, in these identified neurons, is likely important for both learning and performance.

Characteristic and intermingled neocortical circuits encode different visual object discriminations.

Synaptic plasticity and neural network theories hypothesize that the essential information for advanced cognitive tasks is encoded in specific circuits and neurons within distributed neocortical networks. However, these circuits are incompletely characterized, and we do not know if a specific discrimination is encoded in characteristic circuits among multiple animals. Here, we determined the spatial distribution of active neurons for a circuit that encodes some of the essential information for a cognitive task. We genetically activated protein kinase C pathways in several hundred spatially-grouped glutamatergic and GABAergic neurons in rat postrhinal cortex, a multimodal associative area that is part of a distributed circuit that encodes visual object discriminations. We previously established that this intervention enhances accuracy for specific discriminations. Moreover, the genetically-modified, local circuit in POR cortex encodes some of the essential information, and this local circuit is preferentially activated during performance, as shown by activity-dependent gene imaging. Here, we mapped the positions of the active neurons, which revealed that two image sets are encoded in characteristic and different circuits. While characteristic circuits are known to process sensory information, in sensory areas, this is the first demonstration that characteristic circuits encode specific discriminations, in a multimodal associative area. Further, the circuits encoding the two image sets are intermingled, and likely overlapping, enabling efficient encoding. Consistent with reconsolidation theories, intermingled and overlapping encoding could facilitate formation of associations between related discriminations, including visually similar discriminations or discriminations learned at the same time or place.

Ciprofloxacin-resistant Aeromonas hydrophila infection following leech therapy: a case report and review of the literature.

Compromised flap perfusion can lead to the use of leech therapy to aid in flap salvage. Aeromonas hydrophila, a symbiont of the leech, is a well-known bacterial pathogen that has the potential to cause infection in patients receiving leech therapy. Ciprofloxacin is commonly regarded as the antibiotic of choice for prophylaxis against this pathogen. We present patient who underwent leech therapy during salvage attempts for a venous congested flap. A resultant infection developed despite being on appropriate antibiotics. Culture sensitivities indicated that A. hydrophila was resistant to ciprofloxacin.