Variation in spatial dependencies across the cortical mantle discriminates the functional behaviour of primary and association cortex.

Recent theories of cortical organisation suggest features of function emerge from the spatial arrangement of brain regions. For example, association cortex is located furthest from systems involved in action and perception. Association cortex is also 'interdigitated' with adjacent regions having different patterns of functional connectivity. It is assumed that topographic properties, such as distance between regions, constrains their functions, however, we lack a formal description of how this occurs. Here we use variograms, a quantification of spatial autocorrelation, to profile how function changes with the distance between cortical regions. We find function changes with distance more gradually within sensory-motor cortex than association cortex. Importantly, systems within the same type of cortex (e.g., fronto-parietal and default mode networks) have similar profiles. Primary and association cortex, therefore, are differentiated by how function changes over space, emphasising the value of topographical features of a region when estimating its contribution to cognition and behaviour.

The role of the lateral orbitofrontal cortex in creating cognitive maps.

We use mental models of the world-cognitive maps-to guide behavior. The lateral orbitofrontal cortex (lOFC) is typically thought to support behavior by deploying these maps to simulate outcomes, but recent evidence suggests that it may instead support behavior by underlying map creation. We tested between these two alternatives using outcome-specific devaluation and a high-potency chemogenetic approach. Selectively inactivating lOFC principal neurons when male rats learned distinct cue-outcome associations, but before outcome devaluation, disrupted subsequent inference, confirming a role for the lOFC in creating new maps. However, lOFC inactivation surprisingly led to generalized devaluation, a result that is inconsistent with a complete mapping failure. Using a reinforcement learning framework, we show that this effect is best explained by a circumscribed deficit in credit assignment precision during map construction, suggesting that the lOFC has a selective role in defining the specificity of associations that comprise cognitive maps.

A Multifaceted Surgical Site Infection Prevention Bundle for Cesarean Delivery.

OBJECTIVE: Surgical site infections (SSI, including wound infections, endometritis, pelvic abscess, and sepsis) may complicate cesarean section (C/S). We report outcomes before and after the introduction of an SSI prevention bundle that did not include antibiotics beyond routine prophylaxis (cefazolin, or gentamicin/clindamycin for penicillin-allergic patients). STUDY DESIGN: The prevention bundle was introduced following an increase in C/S-associated SSI, which itself was associated with an institutional switch in preoperative scrub from povidone-iodine to chlorhexidine gluconate (CHG)/isopropanol. Components of the bundle included: (1) full-body preoperative wash with 4% CHG cloths; (2) retraining on surgeon hand scrub; (3) retraining for surgical prep; and (4) patient education regarding wound care. Patients delivered by C/S at ≥24 weeks of gestation were segregated into four epochs over 7 years: (1) baseline (18 months when povidone-iodine was used); (2) CHG scrub (18 months after skin prep was switched to CHG); (3) bundle implementation (24 months); and (4) maintenance (24 months following implementation). RESULTS: A total of 3,637 patients were included (n = 667, 796, 1098, and 1076, respectively, in epochs 1-4). A rise in SSI occurred with the institutional switch from povidone-iodine to CHG (i.e., from baseline to the CHG scrub epoch, 8.4-13.3%, p < 0.01). Following the intervention (maintenance epoch), this rate decreased to below baseline values (to 4.5%, p < 0.01), attributable to a decline in wound infection (rates in the above three epochs 6.9, 12.9, and 3.5%, respectively, p < 0.01), with no change in endometritis. In multivariable analysis, only epoch and body mass index (BMI) were independently associated with SSI. The improvement associated with the prevention bundle held for stratified analysis of specific risk factors such as chorioamnionitis, prior C/S, obesity, labor induction, and diabetes. CONCLUSION: Implementation of a prevention bundle was associated with a reduction in post-C/S SSI. This improvement was achieved without the use of antibiotics beyond standard preoperative dosing.

When elephants fall asleep: A literature review on elephant rest with case studies on elephant falling bouts, and practical solutions for zoo elephants.

Little attention has been paid to the resting and sleeping behavior of zoo elephants so far. An important concern is when elephants avoid lying down, due to degenerative joint and foot disease, social structure, or stressful environmental changes. Inability or unwillingness to lie down for resting is an important welfare issue, as it may impair sleep. We emphasize the importance of satisfying rest in elephants by reviewing the literature on resting behavior in elephants (Loxodonta africana and Elephas maximus) as well as the documentation of four cases from European zoos and our own direct observations in a zoo group of four female African elephants during 12 entire days. The common denominator in the case reports is the occurrence of a falling bout out of a standing position subsequently to a cessation of lying rest for different periods of time. Although well-known in horses as "episodic collapse" or "excessive drowsiness," this syndrome has not been described in elephants before. To enable its detection, we recommend nocturnal video monitoring for elephant-keeping institutions. The literature evaluation as well as own observational data suggest an inverse relationship between lying rest and standing rest. Preventative measures consist of enclosure modifications that facilitate lying rest (e.g., sand hills) or standing rest in a leaning position as a substitute. Anecdotal observations suggest that the provision of appropriate horizontal environmental structures may encourage safe, sleep-conducive standing rest. We provide drawings on how to install such structures. Effects of providing such structures should be evaluated in the future.

Increased rate of amygdala growth in children aged 2 to 4 years with autism spectrum disorders: a longitudinal study.

CONTEXT: Precocious amygdala enlargement is commonly observed in young children with autism. However, the age at which abnormal amygdala enlargement begins and the relative growth trajectories of the amygdala and total brain remain unclear. OBJECTIVE: To determine whether the rate of amygdala growth is abnormal and disproportionate to total brain growth in very young children with autism spectrum disorders (ASDs). DESIGN: Longitudinal structural magnetic resonance imaging study. SETTING: Neuroimaging and diagnostic assessments were performed at an academic medical center. Participants were recruited from the community. PARTICIPANTS: Baseline scans were acquired in 132 boys (85 with ASD and 47 control subjects with typical development [TD]; mean age, 37 months). Longitudinal magnetic resonance images were acquired in 70 participants (45 with ASD and 25 TD controls) 1 year later. MAIN OUTCOME MEASURE: Amygdala volumes and total cerebral volumes (TCVs) were evaluated at both time points, and 1-year growth rates were calculated. RESULTS: The amygdala was larger in children with ASD at both time points, but the magnitude of enlargement was greater at time 2. The TCV was also enlarged in the children with ASD by the same magnitude at both time points. When we controlled for TCV, amygdala enlargement remained significant at both time points. The rate of amygdala growth during this 1-year interval was faster in children with ASD than in TD controls. The rate of TCV growth did not differ between groups. Post hoc exploratory analyses revealed 3 patterns of amygdala and TCV growth rates in the ASD group. CONCLUSIONS: Disproportionate amygdala enlargement is present by 37 months of age in ASD. The amygdala continues to grow at an increased rate, but substantial heterogeneity exists in amygdala and TCV growth patterns. Future studies aimed at clinical characterization of different growth patterns could have implications for choice and outcomes of treatment and behavioral therapy.

Interview with an Insignia doctor: David M. Sarver.

Insignia (Ormco, Orange, Calif) offers custom-designed orthodontic appliances via fully interactive software. It is a precise, start-to-finish process that works with Damon, Inspire ICE, and conventional appliances. Insignia software incorporates the clinician's treatment plan into a virtual 3-dimensional model of each patient's ideal occlusion and delivers a complete custom solution: patient-specific brackets, precision (computer-assisted) bracket placement, and custom wires to eliminate time-consuming adjustments in all phases of treatment. Dr David Sarver, an orthodontist in Birmingham, Alabama, has treated patients with the Insignia technique since 1997.