Incorporation of a cost of deliberation time in perceptual decision making.

Many decisions benefit from the accumulation of evidence obtained sequentially over time. In such circumstances, the decision maker must balance speed against accuracy, and the nature of this tradeoff mediates competing desiderata and costs, especially those associated with the passage of time. A neural mechanism to achieve this balance is to accumulate evidence in suitable units and to terminate the deliberation when enough evidence has accrued. To accommodate time costs, it has been hypothesized that the criterion to terminate a decision may become lax as a function of time. Here we tested this hypothesis by manipulating the cost of time in a perceptual choice-reaction time task. Participants discriminated the direction of motion in a dynamic random-dot display, which varied in difficulty across trials. After each trial, they received feedback in the form of points based on whether they made a correct or erroneous choice. They were instructed to maximize their points per unit of time. Unbeknownst to the participants, halfway through the experiment, we increased the time pressure by canceling a small fraction of trials if they had not made a decision by a provisional deadline. Although the manipulation canceled less than 5% of trials, it induced the participants to make faster decisions while lowering their decision accuracy. The pattern of choices and reaction times were explained by bounded drift-diffusion. In all phases of the experiment, stopping bounds were found to decline as a function of time, consistent with the optimal solution, and this decline was exaggerated in response to the time-cost manipulation.

Specialized structure of neural population codes in parietal cortex outputs.

Do cortical neurons that send axonal projections to the same target area form specialized population codes for transmitting information? We used calcium imaging in mouse posterior parietal cortex (PPC), retrograde labeling, and statistical multivariate models to address this question during a delayed match-to-sample task. We found that PPC broadcasts sensory, choice, and locomotion signals widely, but sensory information is enriched in the output to anterior cingulate cortex. Neurons projecting to the same area have elevated pairwise activity correlations. These correlations are structured as information-limiting and information-enhancing interaction networks that collectively enhance information levels. This network structure is unique to sub-populations projecting to the same target and strikingly absent in surrounding neural populations with unidentified projections. Furthermore, this structure is only present when mice make correct, but not incorrect, behavioral choices. Therefore, cortical neurons comprising an output pathway form uniquely structured population codes that enhance information transmission to guide accurate behavior.

A distributed and efficient population code of mixed selectivity neurons for flexible navigation decisions.

Decision-making requires flexibility to rapidly switch one's actions in response to sensory stimuli depending on information stored in memory. We identified cortical areas and neural activity patterns underlying this flexibility during virtual navigation, where mice switched navigation toward or away from a visual cue depending on its match to a remembered cue. Optogenetics screening identified V1, posterior parietal cortex (PPC), and retrosplenial cortex (RSC) as necessary for accurate decisions. Calcium imaging revealed neurons that can mediate rapid navigation switches by encoding a mixture of a current and remembered visual cue. These mixed selectivity neurons emerged through task learning and predicted the mouse's choices by forming efficient population codes before correct, but not incorrect, choices. They were distributed across posterior cortex, even V1, and were densest in RSC and sparsest in PPC. We propose flexibility in navigation decisions arises from neurons that mix visual and memory information within a visual-parietal-retrosplenial network.

Cognitive experience alters cortical involvement in goal-directed navigation.

Neural activity in the mammalian cortex has been studied extensively during decision tasks, and recent work aims to identify under what conditions cortex is actually necessary for these tasks. We discovered that mice with distinct cognitive experiences, beyond sensory and motor learning, use different cortical areas and neural activity patterns to solve the same navigation decision task, revealing past learning as a critical determinant of whether cortex is necessary for goal-directed navigation. We used optogenetics and calcium imaging to study the necessity and neural activity of multiple cortical areas in mice with different training histories. Posterior parietal cortex and retrosplenial cortex were mostly dispensable for accurate performance of a simple navigation task. In contrast, these areas were essential for the same simple task when mice were previously trained on complex tasks with delay periods or association switches. Multiarea calcium imaging showed that, in mice with complex-task experience, single-neuron activity had higher selectivity and neuron-neuron correlations were weaker, leading to codes with higher task information. Therefore, past experience is a key factor in determining whether cortical areas have a causal role in goal-directed navigation.

Antimicrobial prophylaxis for transurethral resection of bladder tumor: A retrospective comparison of preoperative single-dose administration of piperacillin and tazobactam/piperacillin.

We aimed to clarify prophylactic antimicrobial effects of single-dose piperacillin (PIPC) for perioperative infections in the transurethral resection of bladder tumor (TURBT) in comparison with those of single-dose tazobactam/piperacillin (TAZ/PIPC) through a retrospective analysis. We analyzed data from 192 TURBT patients treated with single-dose (4 g) intravenous PIPC (P group) between April 2015 and April 2017. For comparison, we analyzed data from 50 TURBT patients treated with single-dose (4.5 g) intravenous TAZ/PIPC (T/P group) between June 2013 and April 2014. We compared the perioperative incidences of fever (≥38 °C) and bacteriuria in the two groups. The number of febrile patients was four (2.1%) in the P group and one (2.0%) in the T/P group, without significant difference (p = 0.970). Among these febrile patients, urine and blood samples of two patients in the P group tested positive for bacterial cultures of Citrobacter koseri and Enterococcus faecalis, respectively. None of the patients in the T/P group tested positive for urine culture, postoperatively. However, 22 patients (18.2%) in the P group tested positive for urine culture, and Staphylococcus epidermidis (six patients), E. faecalis (three patients), Escherichia coli (three patients), Streptococcus agalactiae (two patients), Staphylococcus aureus (two patients), and C. koseri (one patient) were isolated. There was no significant difference in the incidence of bacteriuria in these two groups (p = 0.055). Based on these results, single-dose PIPC administration for the prevention of perioperative infections in TURBT was as effective as TAZ/PIPC.

Evaluation of a Spray-type, Novel Dextrin Hydrogel Adhesion Barrier Under Laparoscopic Conditions in a Porcine Uterine Horn Adhesion Model.

STUDY OBJECTIVE: To establish a porcine uterine horn adhesion model that mimicked laparoscopic procedures and use it to investigate the effect of a spray-type, novel dextrin hydrogel adhesion barrier (AdSpray; Terumo Corporation, Tokyo, Japan) on postsurgical adhesions. DESIGN: A single-blind randomized controlled trial (Canadian Task Force Classification I). SETTING: A Certified animal research facility. SUBJECTS: Sixteen female pigs. INTERVENTIONS: All animals underwent laparoscopically assisted adhesion-inducing surgery. The uterine horns and the peritoneum of the pelvic sidewall were injured. In the experimental group, AdSpray was applied to the injured site, and the handling of the sprayer was assessed. At 28 ± 1 days after surgery, animals were sacrificed, and adhesions at the injured site were evaluated. Uterine horn suture sites were examined under a light microscope to assess healing of the incised wound, the inflammatory reaction, abscess, and the foreign body reaction to the surgical suture. MEASUREMENTS AND MAIN RESULTS: The control group showed severe adhesions over the entire surface interface at the uterine horn suture sites and peritoneal resection site. Compared with the control treatment, AdSpray exhibited a higher percentage of adhesion-free sites (p < .001) and reduced the total adhesion score (p < .001). In the AdSpray group, no inflammation or abscess formation was observed on histopathological examination, and ideal healing of the suture sites was confirmed in all cases. CONCLUSION: Based on the results of the present study, the novel dextrin hydrogel shows excellent adhesion prevention and can be easily applied during laparoscopy using a dedicated sprayer.

[Vesico-appendiceal fistula caused by appendiceal cancer: a case report].

A case of vesico-appendiceal fistula caused by appendiceal cancer is reported. A 37-year-old male was admitted with the chief complaint of suspended dust in the urine. Under cystoscopy, a tumor (1 cm diameter) was found in the right posterior wall of the bladder. Transurethral resection of the bladder tumor was performed. The pathological outcome was intestinal metaplasia without malignancy. Preoperative abdominal computed tomography suggested vesico-appendiceal fistula, retrospectively. Therefore, appendectomy with partial cystectomy was attempted. However, the appendix was adhered to the sigmoid mesocolon, therefore, appendectomy, partial cystectomy, and sigmoid colectomy were performed. We diagnosed the tumor as mucinous adenocarcinoma. The patient has been receiving adjuvant chemotherapy with tegafur-gimeracil-oteracil potassium for 17 months, because he refused right hemicolectomy. There was no evidence of recurrence after 58 months of follow-up. Vesico-appendiceal fistula caused by appendiceal cancer is very rare. Our case is the 21st case reported in Japan.

A neural implementation of Wald's sequential probability ratio test.

Difficult decisions often require evaluation of samples of evidence acquired sequentially. A sensible strategy is to accumulate evidence, weighted by its reliability, until sufficient support is attained. An optimal statistical approach would accumulate evidence in units of logarithms of likelihood ratios (logLR) to a desired level. Studies of perceptual decisions suggest that the brain approximates an analogous procedure, but a direct test of accumulation, in units of logLR, to a threshold in units of cumulative logLR is lacking. We trained rhesus monkeys to make decisions based on a sequence of evanescent, visual cues assigned different logLR, hence different reliability. Firing rates of neurons in the lateral intraparietal area (LIP) reflected the accumulation of logLR and reached a stereotyped level before the monkeys committed to a decision. The monkeys' choices and reaction times, including their variability, were explained by LIP activity in the context of accumulation of logLR to a threshold.

Occurrence of infection following prostate biopsy procedures in Japan: Japanese Research Group for Urinary Tract Infection (JRGU) - a multi-center retrospective study.

We retrospectively investigated the incidence of genitourinary tract infection in 5895 patients who underwent transrectal and/or transperineal prostate biopsy procedure between January and December 2011 at 46 institutions belonging to Japanese Research Group for Urinary Tract Infection (JRGU). The total rate of genitourinary tract infection after prostate biopsy was 0.76%, while that following transrectal procedure was 0.83% and following transperineal procedure was 0.57%, which were not significantly different. In contrast, febrile infection associated with a fever (≥38 °C) occurred significantly more frequently after transrectal (0.71%) than transperineal (0.16%) approach (P = 0.04). Notably, in infectious cases, Escherichia coli was most frequently isolated. Of the 9 E. coli strains isolated by urine culture, 6 (66.7%) produced extended spectrum ß-lactamase (ESBL) and 7 (77.8%) showed levofloxacin resistance. Similarly, of 6 E. coli strains isolated by blood culture, 4 (66.7%) produced ESBL and 6 (100%) showed levofloxacin resistance. When the efficacy of antimicrobial prophylaxis (AMP) with levofloxacin for the patients undergoing transrectal or transperineal biopsy was compared between a single dose (500 mg) and that given for 2 or more days, no significant difference was observed for the rate of infection (transrectal: 0.82% vs. 1.04%, p = 0.94; transperineal: 0.30% vs. 0.46%, p = 0.68). Although a single dose of levofloxacin for AMP is sufficient to prevent genitourinary infection after transrectal or transperineal prostate biopsy, and recommended in this era of increased multi-drug resistant pathogens, the increase in fluoroquinolone-resistant E. coli and ESBL-producing E. coli has emerged as a profound problem for surveillance.

Reexpansion pulmonary edema: review of pediatric cases.

Reexpansion pulmonary edema (RPE) is an increased permeability pulmonary edema that usually occurs in the reexpanded lung after several days of lung collapse. This condition is recognized to occur more frequently in patients under the age of 40 years, but there has been no detailed analysis of reported pediatric cases of RPE to date. For this review, PubMed literature searches were performed using the following terms: 're(-)expansion pulmonary (o)edema' AND ('child' OR 'children' OR 'infant' OR 'boy' OR 'girl' OR 'adolescent'). The 22 pediatric cases of RPE identified were included in this review. RPE was reported in almost the entire pediatric age range, and as in adult cases, the severity ranged from subclinical to lethal. No specific treatment for RPE was identified, and treatment was administered according to the clinical features of each patient. Of the 22 reported cases, 10 occurred during the perioperative period, but were not related to any specific surgical procedures or anesthetic techniques, or to the duration of lung collapse. Pediatric anesthesiologists should be aware that pediatric RPE can occur after reexpansion of any collapsed lung and that some invasive therapies can be useful in severe cases.

[Prospective multi-institutional analysis according to the "Japanese guidelines for prevention of perioperative infections in urological field"].

OBJECTIVE: The "Japanese guidelines for prevention of perioperative infections in urological field" was edited by the Japanese Urological Association in 2007. They are the first Japanese guidelines for antimicrobial prophylaxis specifically to prevent perioperative infections in the urological field. We report here the results of a multicenter prospective study conducted to examine the validity and usefulness of these guidelines. PATIENTS AND METHODS: The subjects were 513 patients who had undergone urological surgeries between July and September 2008 at 10 nationwide university institutions in the Japanese Society of UTI Cooperative Study Group. These surgeries were transurethral resection of bladder (TURBT), transurethral resection of prostate (TURP), adrenalectomy, nephrectomy, nephroureterectomy, radical prostatectomy and total cystectomy. Analysis was performed on patient information, surgical procedures, types and durations of administration of prophylactic antibiotic agents, and the presence of surgical site infections (SSI) and remote infections (RI). RESULTS: Of 513 patients, 387 (75.4%) were administered prophylactic antibiotic agents according to the guidelines. In these patients, the incidences of SSI and RI were 5.9% and 4.1%, respectively. Multivariate analysis showed that significant factors for SSI were the surgical risk (according to the ASA physical status classification system), diabetes, and operation time, and that the only significant factor for RI was the operation time. CONCLUSIONS: More large-scale study and evidences are necessary in order to demonstrate the validity and usefulness of these guidelines.

[Resistance to vecuronium induced muscle relaxation in a patient with mental retardation receiving phenytoin for chronic anticonvulsant therapy].

A 36-year-old woman weighing 31.7 kg with mental retardation was scheduled for dental treatment under general anesthesia. She had undergone anticonvulsant therapy (phenytoin, clonazepam, zonisamide) for years. Standard monitors and bispectral index (BIS) monitor were applied except for an accelomyography. Anesthesia was induced with propofol and vecuronium, and maintained with nitrous oxide in oxygen, with 1.5-2.0% end-tidal concentration of sevoflurane. Forty minutes after induction of anesthesia, spontaneous respiration (SR) started suddenly despite adequate depth of anesthesia (BIS value 35-40). Vecuronium 1 mg was administered and SR stopped immediately. After the event, however, SR started repeatedly and then additional vecuronium was administered every 30-40 minutes to stop SR until the end of the treatment. During the treatment, no factors (hypercapnia, hypoxemia, hyperthermia and so on) to shorten the muscle relaxation were observed. The treatment finished uneventfully She became awake rapidly and extubated. Post-extubation period was also uneventful. In this case, chronic phenytoin therapy induced resistance to vecuronium was highly suspected; however, since clonazepam and zonisamide have elevation effects on blood concentration of phenytoin, they might be also cofactors in resistance to vecuronium. Therefore, patients undergoing chronic anticonvulsant therapy should be paid more attention because they have resistance to neuromuscular blocking drugs.

[Emphysematous pyelonephritis and cystitis concurrence; A case report].

We report a case of emphysematous pyelonephritis coexisting with emphysematous cystitis. A 57-year-old woman seen for abdominal pain, diarrhea, and high fever had been referred after computed tomography (CT) elsewhere had shown an air density mass in the left kidney and pelvis. Abdominal CT on admission showed emphysematous change in the left renal parenchyma and intramural bladder. Serum analysis results showed disseminated intravascular coagulation (DIC) and uncontrolled diabetes. Klebsiella pneumoniae was isolated in the blood. She was diagnosed with sepsis based on these findings due to concurrent emphysematous pyelonephritis and cystitis caused by K. pneumoniae. She was treated conservatively with meropenem, intravenous immunoglobulin, and gabexate mesilate and cured. Concurrent emphysematous cystitis and pyelonephritis is rare., with ours only the fourth case reported in Japan.