Timing is a very abstract representation that shares with other magnitudes, such as numerosity, the peculiarity of being independent from any particular sensory modality. Not only we can time stimuli ...in different modalities but we can also compare the durations of different visual, auditory and somatosensory stimuli. Furthermore, even though time is not directly associated with space, and we are inclined to consider space and time as two different perceptual dimensions of our existence, an increasing number of studies challenge this idea by showing that timing and spatial processing have some relationship that involves sharing computation resources and that time may have a spatial representation. A more general theory, called theory of magnitude (ATOM), considers both timing and spatial computations, together with other magnitudes, as originating from a general magnitude system Walsh VA, Trends Cogn Sci 7(11):483-8, 2003. The neural underpinnings of time and its relationship to the processing of spatial information have started to be investigated only recently, but the field is rapidly growing. It is addressing the representation of time in several cortical and subcortical brain areas. Information processing of time and space are not strictly specialized in neural and cognitive mechanisms and we believe that studying them only separately may restrict our understanding of these processes. In this chapter, we will firstly introduce the role of the prefrontal cortex (PF) in coding relative durations. We will point out that the comparison of durations makes use of intermediate computations based on the order of the events. Secondly, we will describe the comparison mechanisms that are implemented by PF to make perceptual decisions about durations in relation to those involved in making decisions about spatial locations and distances. We will distinguish the decision processes from the goal choices, and we will examine which computational resources are shared between different magnitudes and which are domain-specific. We will summarize our results within the context of a more general PF function in promoting the generation of goals from the current context, consisting of domain- and modality-specific coding of stimuli of different modalities or magnitudes.
Background
Spinal anaesthesia carries a risk of hypotension. We hypothesized that pleth variability index and perfusion index would assess maternal volume status, and thus, allow identification of ...patients at higher risk of developing hypotension after spinal anaesthesia for caesarean delivery.
Methods
Fifty patients undergoing elective caesarean delivery were enrolled. All patients received spinal anaesthesia with 0.5% hyperbaric bupivacaine (10 mg) and fentanyl (10 mcg). Blood pressure was measured every minute. Pleth variability index and perfusion index were automatically measured throughout the procedure using pulse oximetry on the index finger. In case of hypotension (systolic blood pressure below 90 mmHg or 80% of the baseline value), ephedrine 5 mg was administered. Receiver‐operating characteristic and multivariate logistic regression analyses for spinal anaesthesia‐induced hypotension were performed.
Results
Hypotension occurred in 32 patients (64%). The areas under the receiver‐operating characteristic curve were 0.751 (95% confidence interval: 0.597–0.904) for pleth variability index before anaesthesia, 0.793 (95% confidence interval: 0.655–0.930) for pleth variability index after anaesthesia and 0.731 (95% confidence interval: 0.570–0.892) for perfusion index change (percent change in perfusion index induced by spinal anaesthesia). The optimal threshold value of pleth variability index (after anaesthesia) for predicting hypotension was 18% (sensitivity: 78.1%, specificity: 83.3%). Pleth variability index after spinal anaesthesia was an independent factor for hypotension (odds ratio: 1.21, P = 0.041).
Conclusions
Pleth variability index after spinal anaesthesia was a good predictor of spinal anaesthesia‐induced hypotension in patients undergoing caesarean delivery. In addition, perfusion index change after spinal anaesthesia has the potential to predict hypotension.
It is well known that lateral areas of the prefrontal cortex (LPFC) play a central role in working memory (a critical basis of various cognitive functions), but it remains unknown whether the LPFC of ...children of preschool age is responsible for working memory. To address this issue, we adopted a recently developed non-invasive imaging technique, optical topography (OT), which can potentially be applied to functional mapping in childhood. We firstly examined changes of activity in the LPFC using OT while adult subjects performed an item-recognition task, which requires working memory, under different memory-load conditions. We observed activation in the bilateral LPFC during performance of this task, the magnitude of which differed depending on memory-load. Then, we applied the same technique on 5- and 6-year-old children and observed the activation associated with working memory in the LPFC. Areas and properties of such activity were similar in adults and preschool children. Thus, for the first time, we demonstrate that the LPFC of preschoolers is active during working memory processes, indicating that in 5- and 6-year-old children, the LPFC has already developed processing of this important cognitive function.
For flexible control of behaviour, it is important to associate preceding behavioural response with its outcome. Since the dorsolateral prefrontal cortex (dlPFC) plays a major role in such control, ...it is likely that this area has a neuronal mechanism of coding response–outcome, such as reward/non-reward, based on the nature of the behavioural response made immediately before. To test this hypothesis, we examined neuronal activity in the dlPFC while monkeys performed a variant of the oculomotor delayed-response (ODR) task that had two reward conditions. In this task, the correct response was rewarded in half of the trials only and the subject could not expect the outcome (reward/non-reward). The response was followed by a fixation of 2 s (F2-period). We also employed a fixation (FIX) task that required monkeys to fixate on the peripheral target only, with two reward conditions that were similar to those in the ODR task. Post-response activity of a subset of dlPFC neurons was modulated by both the direction of the preceding response and its outcome. None of these neurons showed directional F2-period activity in the FIX task. These results suggest that a subset of dlPFC neurons represent response–outcome (i.e. reward/non-reward associated with directional saccade made immediately before).
We have developed synthetic double-stranded oligodeoxynucleotides (ODN) as 'decoy' cis elements that block the binding of nuclear factors to promoter regions of targeted genes, resulting in the ...inhibition of gene transactivation in vivo. In the present study, we employed decoy ODN targeting the transcription factor nuclear factor-kappaB (NF-kappaB) binding cis-elements to hepatic metastasis of murine reticulosarcoma M5076 in mice. Intravenous inoculation of M5076 into mice caused a marked increase in gene expression of interleukin-1beta, tumor necrosis factor-alpha and intercellular adhesion molecule-1 in the liver, whereas intravenous treatment with NF-kappaB decoy ODN reduced M5076-induced transactivation of these genes. Treatment with NF-kappaB decoy ODN, but not scrambled decoy ODN, significantly inhibited hepatic metastasis of M5076 in mice, and furthermore the combined treatment of NF-kappaB decoy ODN with an anti-cancer drug resulted in complete inhibition of hepatic metastasis in half of the mice, without affecting myelosuppression induced by the anti-cancer drug. Here, NF-kappaB decoy ODN inhibited hepatic metastasis of M5076 in mice possibly through a decrease in transactivation of important NF-kappaB-driven genes and also potentiated the anti-metastatic effect of an anti-cancer drug, demonstrating the first successful in vivo therapy for cancer metastasis using NF-kappaB decoy ODN as a novel molecular decoy approach.
The document image processes used in a recently developed text reading system are described. The system consists of three major components: document analysis, document understanding, and character ...segmentation/recognition. The document analysis component extracts lines of text from a page for recognition. The document understanding component extracts logical relationships between the document constituents. The character segmentation/recognition component extracts characters from a text line and recognizes them. Experiments on more than a hundred documents have proved that the proposed approaches to document analysis and document understanding are robust even for multicolumned and multiarticle documents containing graphics and photographs, and that the proposed character segmentation/recognition method is robust enough to cope with omnifont characters which frequently touch each other.< >
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