Decoding Odor Mixtures in the Dog Brain: An Awake fMRI Study.

In working and practical contexts, dogs rely upon their ability to discriminate a target odor from distracting odors and other sensory stimuli. Using awake functional magnetic resonance imaging (fMRI) in 18 dogs, we examined the neural mechanisms underlying odor discrimination between 2 odors and a mixture of the odors. Neural activation was measured during the presentation of a target odor (A) associated with a food reward, a distractor odor (B) associated with nothing, and a mixture of the two odors (A+B). Changes in neural activation during the presentations of the odor stimuli in individual dogs were measured over time within three regions known to be involved with odor processing: the caudate nucleus, the amygdala, and the olfactory bulbs. Average activation within the amygdala showed that dogs maximally differentiated between odor stimuli based on the stimulus-reward associations by the first run, while activation to the mixture (A+B) was most similar to the no-reward (B) stimulus. To clarify the neural representation of odor mixtures in the dog brain, we used a random forest classifier to compare multilabel (elemental) versus multiclass (configural) models. The multiclass model performed much better than the multilabel (weighted-F1 0.44 vs. 0.14), suggesting the odor mixture was processed configurally. Analysis of the subset of high-performing dogs' brain classification metrics revealed a network of olfactory information-carrying brain regions that included the amygdala, piriform cortex, and posterior cingulate. These results add further evidence for the configural processing of odor mixtures in dogs and suggest a novel way to identify high-performers based on brain classification metrics.

Amniotic band sequence in paternal half-siblings with vascular Ehlers-Danlos syndrome.

Familial amniotic band sequence (ABS) is rare but has been reported in the offspring of mothers with connective tissue disorders. We present a family of two half-siblings with ABS who share the same biological father. Following a serious vascular event a de novo pathogenic variant in COL3A1 was detected in the father, confirming a diagnosis of vascular Ehlers-Danlos syndrome (vEDS). The same variant was found in both his ABS-affected children but not in his unaffected child. The amniotic membrane is derived from fetal tissue, type III collagen being a component. As the affected children are paternal half-siblings, ABS was less likely due to maternal factors. Rather, the amniotic bands may have resulted from decreased type III collagen production as seen in people with vEDS, causing fragility of the amniotic membrane. Consequently, it is important to consider vEDS in patients with ABS.

Transvaginal specimen extraction after combined laparoscopic splenectomy and hysterectomy: Introduction to NOSE (Natural Orifice Specimen Extraction) in a community hospital.

INTRODUCTION: Developments in the field of minimally invasive surgery have led to interest in NOTES (natural orifice transluminal endoscopic surgery). Even as technologies continue to evolve and develop, interest in some of the advantages of specimen retrieval transvaginally has been roused and we describe a case of combined laparoscopic splenectomy and hysterectomy with transvaginal retrieval of both specimens. PRESENTATION OF CASE: Patient underwent laparoscopic splenectomy and robot-assisted hysterectomy with transvaginal delivery of specimens. Total operative time was 245min with no complications. Closure of the colpotomy was achieved laparoscopically. Post-operative course was unremarkable. Patient has done well clinically at 18 months follow-up except for an episode of post-coital spotting, which resolved spontaneously. DISCUSSION: We explored the technical feasibility of concurrent laparoscopic splenectomy and hysterectomy along with transvaginal retrieval of both solid organs without morcellation. We wanted to illustrate the fact that transvaginal organ extraction may be performed safely in a community or district hospital with standard instruments without incurring additional cost, morbidity or increased operating time. CONCLUSION: Transvaginal specimen retrieval was technically easy to accomplish. Our patient has not experienced any infectious complications or sexual dysfunction to date. For surgeons exploring an alternative to transabdominal specimen retrieval, transvaginal NOSE is an attractive proposition with several advantages. When combined with a gynecological procedure that involves a colpotomy, this may present a unique opportunity to explore the utility of NOSE.

Effects of modified short-leg walkers on ground reaction force characteristics.

BACKGROUND: Although short-leg walkers are often used in the treatment of lower extremity injuries (ankle and foot fractures and severe ankle sprains), little is known about the effect the short-leg walker on gait characteristics. The purpose was to examine how heel height modifications in different short-leg walkers and shoe side may affect ground reaction forces in walking. METHODS: Force platforms were used to collect ground reaction force data on 10 healthy participants. Five trials were performed in each of six conditions: lab shoes, gait walker, gait walker with heel insert on shoe side, gait walker modified with insert on walker side, equalizer walker, and equalizer walker with heel insert on shoe side. Conditions were randomized and walking speed was standardized between conditions. A 2x6 (sidexcondition) repeated analysis of variance was used on selected ground reaction force variables (P<0.05). FINDINGS: The application of a walker created peak vertical and anteroposterior ground reaction forces prior to the normal peaks associated with the loading response. Wearing a walker introduced an elevated minimum vertical ground reaction force in all conditions except the equalizer walker when compared to shoe on the shoe side. Peak propulsive anteroposterior ground reaction forces were smaller in all walker conditions compared to shoe on walker side. INTERPRETATION: The application of heel insert in gait walker with heel insert (on shoe side) and gait walker modified (on walker side) does not diminish the minimum vertical ground reaction force as hypothesized. Wearing a walker decreases the peak propulsive anteroposterior ground reaction force on the walker side and induces asymmetrical loading.

Commentary: EMS Education Agenda for the Future: Flexner Revisited.

[King JA. NHTSA Notes Commentary: EMS Education Agenda for the Future: Flexner revisited. Ann Emerg Med. June 2000;35:624-625.].