Motor Control by Sensory Cortex Matyas, Ferenc; Sreenivasan, Varun; Marbach, Fred ...
Science (American Association for the Advancement of Science),
11/2010, Letnik:
330, Številka:
6008
Journal Article
Recenzirano
Classical studies of mammalian movement control define a prominent role for the primary motor cortex. Investigating the mouse whisker system, we found an additional and equally direct pathway for ...cortical motor control driven by the primary somatosensory cortex. Whereas activity in primary motor cortex directly evokes exploratory whisker protraction, primary somatosensory cortex directly drives whisker retraction, providing a rapid negative feedback signal for sensorimotor integration. Motor control by sensory cortex suggests the need to reevaluate the functional organization of cortical maps.
Tactile sensory information from facial whiskers provides nocturnal tunnel-dwelling rodents, including mice and rats, with important spatial and textural information about their immediate ...surroundings. Whiskers are moved back and forth to scan the environment (whisking), and touch signals from each whisker evoke sparse patterns of neuronal activity in whisker-related primary somatosensory cortex (wS1; barrel cortex). Whisking is accompanied by desynchronized brain states and cell-type-specific changes in spontaneous and evoked neuronal activity. Tactile information, including object texture and location, appears to be computed in wS1 through integration of motor and sensory signals. wS1 also directly controls whisker movements and contributes to learned, whisker-dependent, goal-directed behaviours. The cell-type-specific neuronal circuitry in wS1 that contributes to whisker sensory perception is beginning to be defined.
Pancreatitis is a known risk factor for pancreatic cancer; however, an unknown fraction of the disease is thought to be a consequence of tumor-related duct obstruction.
A pooled analysis of a history ...of pancreatitis and risk of pancreatic cancer was carried out considering the time interval between diagnoses and potential modification by covariates. Adjusted pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from 10 case–control studies (5048 cases of ductal pancreatic adenocarcinoma and 10 947 controls) taking part in the International Pancreatic Cancer Case-Control Consortium (PanC4).
The association between pancreatitis and pancreatic cancer was nearly three-fold at intervals of >2 years between diagnoses (OR: 2.71, 95% CI: 1.96–3.74) and much stronger at intervals of ≤2 years (OR: 13.56, 95% CI: 8.72–21.90) probably reflecting a combination of reverse causation and antecedent misdiagnosis of pancreas cancer as pancreatitis. The younger (<65 years) pancreatic cancer cases showed stronger associations with previous (>2 years) pancreatitis (OR: 3.91, 95% CI: 2.53–6.04) than the older (≥65 years) cases (OR: 1.68, 95% CI: 1.02–2.76; P value for interaction: 0.006).
Despite a moderately strong association between pancreatitis (diagnosed before >2 years) and pancreatic cancer, the population attributable fraction was estimated at 1.34% (95% CI: 0.612–2.07%), suggesting that a relatively small proportion of pancreatic cancer might be avoided if pancreatitis could be prevented.
In patients with intestinal failure who are receiving home parenteral support (HPS), catheter-related bloodstream infections (CRBSIs) inflict health impairment and high costs.
This study investigates ...the efficacy and safety of the antimicrobial catheter lock solution, taurolidine-citrate-heparin, compared with heparin 100 IE/mL on CRBSI occurrence.
Forty-one high-risk patients receiving HPS followed in a tertiary HPS unit were randomly assigned in a double-blinded, placebo-controlled trial. External, stratified randomization was performed according to age, sex, and prior CRBSI incidence. The prior CRBSI incidence in the study population was 2.4 episodes/1000 central venous catheter (CVC) days 95% Poisson confidence limits (CLs): 2.12, 2.71 episodes/1000 CVC days. The maximum treatment period was 2 y or until occurrence of a CRBSI or right-censoring because of CVC removal. The exact permutation tests were used to calculate P values for the log-rank tests.
Twenty patients received the taurolidine-citrate-heparin lock and 21 received the heparin lock, with 9622 and 6956 treatment days, respectively. In the taurolidine-citrate-heparin arm, no CRBSIs occurred, whereas 7 CRBSIs occurred in the heparin arm, with an incidence of 1.0/1000 CVC days (95% Poisson CLs: 0.4, 2.07/1000 CVC days; P = 0.005). The CVC removal rates were 0.52/1000 CVC days (95% Poisson CLs: 0.17, 1.21/1000 CVC days) and 1.72/1000 CVC days (95% Poisson CLs: 0.89, 3.0/1000 CVC days) in the taurolidine-citrate-heparin and heparin arm, respectively, tending to prolong CVC survival in the taurolidine arm (P = 0.06). Costs per treatment year were lower in the taurolidine arm (€2348) than in the heparin arm (€6744) owing to fewer admission days related to treating CVC-related complications (P = 0.02).
In patients with intestinal failure who are life dependent on HPS, the taurolidine-citrate-heparin catheter lock demonstrates a clinically substantial and cost-beneficial reduction of CRBSI occurrence in a high-risk population compared with heparin. This trial was registered at clinicaltrials.gov as NCT01948245.
Lysosomal membrane permeabilization and subsequent cell death may prove useful in cancer treatment, provided that cancer cell lysosomes can be specifically targeted. Here, we identify acid ...sphingomyelinase (ASM) inhibition as a selective means to destabilize cancer cell lysosomes. Lysosome-destabilizing experimental anticancer agent siramesine inhibits ASM by interfering with the binding of ASM to its essential lysosomal cofactor, bis(monoacylglycero)phosphate. Like siramesine, several clinically relevant ASM inhibitors trigger cancer-specific lysosomal cell death, reduce tumor growth in vivo, and revert multidrug resistance. Their cancer selectivity is associated with transformation-associated reduction in ASM expression and subsequent failure to maintain sphingomyelin hydrolysis during drug exposure. Taken together, these data identify ASM as an attractive target for cancer therapy.
•Lysosomal ASM is an essential target of siramesine’s anticancer action•Many clinically relevant drugs that inhibit ASM display potent anticancer activity•ASM inhibition enhances lysosomal cell death and reduces multidrug resistance•Altered sphingomyelin metabolism renders cancer cells sensitive to ASM inhibition
Internal brain states form key determinants for sensory perception, sensorimotor coordination and learning. A prominent reflection of different brain states in the mammalian central nervous system is ...the presence of distinct patterns of cortical synchrony, as revealed by extracellular recordings of the electroencephalogram, local field potential and action potentials. Such temporal correlations of cortical activity are thought to be fundamental mechanisms of neuronal computation. However, it is unknown how cortical synchrony is reflected in the intracellular membrane potential (Vm) dynamics of behaving animals. Here we show, using dual whole-cell recordings from layer 2/3 primary somatosensory barrel cortex in behaving mice, that the Vm of nearby neurons is highly correlated during quiet wakefulness. However, when the mouse is whisking, an internally generated state change reduces the Vm correlation, resulting in a desynchronized local field potential and electroencephalogram. Action potential activity was sparse during both quiet wakefulness and active whisking. Single action potentials were driven by a large, brief and specific excitatory input that was not present in the Vm of neighbouring cells. Action potential initiation occurs with a higher signal-to-noise ratio during active whisking than during quiet periods. Therefore, we show that an internal brain state dynamically regulates cortical membrane potential synchrony during behaviour and defines different modes of cortical processing.
Network meta-analysis (NMA), combining direct and indirect comparisons, is increasingly being used to examine the comparative effectiveness of medical interventions. Minimal guidance exists on how to ...rate the quality of evidence supporting treatment effect estimates obtained from NMA. We present a four-step approach to rate the quality of evidence in each of the direct, indirect, and NMA estimates based on methods developed by the GRADE working group. Using an example of a published NMA, we show that the quality of evidence supporting NMA estimates varies from high to very low across comparisons, and that quality ratings given to a whole network are uninformative and likely to mislead.
Computations in neocortical circuits are predominantly driven by synaptic integration of excitatory glutamatergic and inhibitory GABAergic inputs. New optical, electrophysiological, and genetic ...methods allow detailed in vivo investigation of the superficial neocortical layers 2 and 3 (L2/3). Here, we review current knowledge of mouse L2/3 sensory cortex, focusing on somatosensory barrel cortex with comparisons to visual and auditory cortex. Broadly tuned, dense subthreshold synaptic input accompanied by sparse action potential (AP) firing in excitatory neurons provides a simple and reliable neural code useful for associative learning. Sparse AP firing is enforced by strong inhibition from genetically defined classes of GABAergic neurons. Subnetworks of strongly and specifically connected excitatory neurons may drive L2/3 network function, with potential contributions from dendritic spikes evoked by spatiotemporally clustered synaptic input. These functional properties of L2/3 are under profound regulation by brain state and behavior, providing interesting avenues for future mechanistic investigations into context-specific processing of sensory information.
Petersen and Crochet review recent advances in the understanding of cell type-specific synaptic circuits driving neocortical layer 2/3 networks gained through application of new optical, electrophysiological, behavioral, and genetic techniques.
Aims
To determine inactivation of Cryptosporidium parvum oocysts and reduction of Escherichia coli and enterococci in cattle slurry added aqueous ammonia.
Methods and Results
Escherichia coli, ...enterococci and nonviable C. parvum oocysts (DAPI+PI+) were enumerated every second day for 2 weeks in cattle slurry amended with 60 mmol l−1 aq. ammonia and compared with untreated slurry at three temperatures. Regardless of temperature, the proportion of nonviable C. parvum oocysts increased significantly faster over time in slurry with added ammonia than raw slurry (P = 0·021) corresponding to 62·0% higher inactivation (P = 0·001) at day 14. Additionally, 91·8% fewer E. coli and 27·3% fewer enterococci were observed in slurry added ammonia at day 14 compared to raw slurry.
Conclusion
The addition of aqueous ammonia to raw slurry significantly reduced the viability of C. parvum oocysts and numbers of bacterial indicators. Hence, ammonia is usable at lower pathogen concentrations in slurry before application to agricultural land.
Significance and Impact of the Study
Livestock waste is a valuable source of plant nutrients and organic matter, but may contain high concentrations of pathogens like E. coli and Cryptosporidium sp. that can be spread in the environment, and cause disease outbreaks. However, die‐off rates of pathogens in organic waste can increase following increasing ammonia concentrations.
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