scholarly journals Early Visual Processing and Perception Processes in Object Discrimination Learning

2021 ◽  
Vol 15 ◽  
Author(s):  
Matías Quiñones ◽  
David Gómez ◽  
Rodrigo Montefusco-Siegmund ◽  
María de la Luz Aylwin
Keyword(s):  
Recognition Memory ◽  
Information Extraction ◽  
Discrimination Learning ◽  
Visual Processing ◽  
Early Stage ◽  
Matching Task ◽  
Perceptual Expertise ◽  
Object Discrimination ◽  
Memory Processes ◽  
Early Stages

A brief image presentation is sufficient to discriminate and individuate objects of expertise. Although perceptual expertise is acquired through extensive practice that increases the resolution of representations and reduces the latency of image decoding and coarse and fine information extraction, it is not known how the stages of visual processing impact object discrimination learning (ODL). Here, we compared object discrimination with brief (100 ms) and long (1,000 ms) perceptual encoding times to test if the early and late visual processes are required for ODL. Moreover, we evaluated whether encoding time and discrimination practice shape perception and recognition memory processes during ODL. During practice of a sequential matching task with initially unfamiliar complex stimuli, we find greater discrimination with greater encoding times regardless of the extent of practice, suggesting that the fine information extraction during late visual processing is necessary for discrimination. Interestingly, the overall discrimination learning was similar for brief and long stimuli, suggesting that early stages of visual processing are sufficient for ODL. In addition, discrimination practice enhances perceive and know for brief and long stimuli and both processes are associated with performance, suggesting that early stage information extraction is sufficient for modulating the perceptual processes, likely reflecting an increase in the resolution of the representations and an early availability of information. Conversely, practice elicited an increase of familiarity which was not associated with discrimination sensitivity, revealing the acquisition of a general recognition memory. Finally, the recall is likely enhanced by practice and is associated with discrimination sensitivity for long encoding times, suggesting the engagement of recognition memory in a practice independent manner. These findings contribute to unveiling the function of early stages of visual processing in ODL, and provide evidence on the modulation of the perception and recognition memory processes during discrimination practice and its relationship with ODL and perceptual expertise acquisition.

scholarly journals Platelets as messengers of early-stage cancer

2021 ◽  
Author(s):  
Siamack Sabrkhany ◽  
Marijke J. E. Kuijpers ◽  
Mirjam G. A. oude Egbrink ◽  
Arjan W. Griffioen
Keyword(s):  
Tumor Angiogenesis ◽  
Blood Test ◽  
Early Stage ◽  
Human Studies ◽  
Early Stage Cancer ◽  
Reciprocal Interaction ◽  
Early Stages ◽  
New Strategy ◽  
Mrna Content

AbstractPlatelets have an important role in tumor angiogenesis, growth, and metastasis. The reciprocal interaction between cancer and platelets results in changes of several platelet characteristics. It is becoming clear that analysis of these platelet features could offer a new strategy in the search for biomarkers of cancer. Here, we review the human studies in which platelet characteristics (e.g., count, volume, protein, and mRNA content) are investigated in early-stage cancer. The main focus of this paper is to evaluate which platelet features are suitable for the development of a blood test that could detect cancer in its early stages.

scholarly journals The expression of microRNA-331-3p and microRNA-23b3 in Egyptian patients with early-stage hepatocellular carcinoma in hepatitis C-related liver cirrhosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reham A. Aboelwafa ◽  
Walid Ismail Ellakany ◽  
Marwa A. Gamaleldin ◽  
Marwa A. Saad
Keyword(s):  
Hepatocellular Carcinoma ◽  
Liver Cirrhosis ◽  
Hepatitis C ◽  
Early Stage ◽  
Group Iii ◽  
Real Time Quantitative Pcr ◽  
Early Stages ◽  
Group I ◽  
Egyptian Patients ◽  
Cirrhotic Patients

Abstract Background Hepatocellular carcinoma and hepatitis C are strongly associated. The current work aimed to study the expression levels of microRNA-331-3p and microRNA-23b-3p as propable biomarkers for detecting liver cancer (HCC) at its early stages in patients with HCV-related liver cirrhosis. The current prospective study included two hundred participants, divided into three groups: group I, 100 patients with HCV-related liver cirrhosis; group II, 50 HCC patients at early stages; and group III, 50 apparentlyhealthy controls. All patients had routine laboratory workup and ultrasound hepatic assessment. Values of microRNA-331-3p and microRNA-23b-3p were measured by real-time quantitative PCR. Results Levels of miR-331-3p were significantly higher in HCC patients than in cirrhotic patients and controls (p < 0.001), while levels of miR-23b-3p were significantly lower in HCC patients compared to cirrhotics and controls (p < 0.001). ROC curve revealed that miR-23b-3p had 80% sensitivity and 74% specificity, miR-331-3p had 66% sensitivity and 61% specificity, and AFP had 64% sensitivity and 61% specificity of 61% in discrimination between HCC patients from controls. Conclusion Serum miR-23b-3p is a more effective predictor than miR-331-3p and AFP for the development of hepatocellular carcinoma in hepatitis C (HCV)-related cirrhotic patients.

Computing with Self-Excitatory Cliques: A Model and an Application to Hyperacuity-Scale Computation in Visual Cortex

1999 ◽  
Vol 11 (1) ◽  
pp. 21-66 ◽  
Author(s):  
Douglas A. Miller ◽  
Steven W. Zucker
Keyword(s):  
Visual Processing ◽  
Network Architecture ◽  
Early Stage ◽  
Cortical Cell ◽  
Pyramidal Cells ◽  
Direct Calculation ◽  
Formal Theory ◽  
Cortical Cells ◽  
Cell Counts ◽  
Spatiotemporal Response

We present a model of visual computation based on tightly inter-connected cliques of pyramidal cells. It leads to a formal theory of cell assemblies, a specific relationship between correlated firing patterns and abstract functionality, and a direct calculation relating estimates of cortical cell counts to orientation hyperacuity. Our network architecture is unique in that (1) it supports a mode of computation that is both reliable and efficent; (2) the current-spike relations are modeled as an analog dynamical system in which the requisite computations can take place on the time scale required for an early stage of visual processing; and (3) the dynamics are triggered by the spatiotemporal response of cortical cells. This final point could explain why moving stimuli improve vernier sensitivity.

scholarly journals Detection of KRAS Mutations in Circulating Tumor DNA by Digital PCR in Early Stages of Pancreatic Cancer

2016 ◽  
Vol 62 (11) ◽  
pp. 1482-1491 ◽  
Author(s):  
Nora Brychta ◽  
Thomas Krahn ◽  
Oliver von Ahsen
Keyword(s):  
Pancreatic Cancer ◽  
Early Stage ◽  
Digital Pcr ◽  
Circulating Tumor Dna ◽  
Surgical Removal ◽  
Plasma Samples ◽  
Kras Mutations ◽  
Detection Rates ◽  
Early Stages ◽  
Tumor Dna

Abstract BACKGROUND Since surgical removal remains the only cure for pancreatic cancer, early detection is of utmost importance. Circulating biomarkers have potential as diagnostic tool for pancreatic cancer, which typically causes clinical symptoms only in advanced stage. Because of their high prevalence in pancreatic cancer, KRAS proto-oncogene, GTPase [KRAS (previous name: Kirsten rat sarcoma viral oncogene homolog)] mutations may be used to identify tumor-derived circulating plasma DNA. Here we tested the diagnostic sensitivity of chip based digital PCR for the detection of KRAS mutations in circulating tumor DNA (ctDNA) in early stage pancreatic cancer. METHODS We analyzed matched plasma (2 mL) and tumor samples from 50 patients with pancreatic cancer. Early stages (I and II) were predominant (41/50) in this cohort. DNA was extracted from tumor and plasma samples and tested for the common codon 12 mutations G12D, G12V, and G12C by chip-based digital PCR. RESULTS We identified KRAS mutations in 72% of the tumors. 44% of the tumors were positive for G12D, 20% for G12V, and 10% for G12C. One tumor was positive for G12D and G12V. Analysis of the mutations in matched plasma samples revealed detection rates of 36% for G12D, 50% for G12V, and 0% for G12C. The detection appeared to be correlated with total number of tumor cells in the primary tumor. No KRAS mutations were detected in 20 samples of healthy control plasma. CONCLUSIONS Our results support further evaluation of tumor specific mutations as early diagnostic biomarkers using plasma samples as liquid biopsy.

The “Mosaic Stage” in Amodal Completion as Characterized by Magnetoencephalography Responses

2006 ◽  
Vol 18 (8) ◽  
pp. 1394-1405 ◽  
Author(s):  
Gijs Plomp ◽  
Lichan Liu ◽  
Cees van Leeuwen ◽  
Andreas A. Ioannides
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Early Stage ◽  
Amodal Completion ◽  
Peak Latency ◽  
Per Se

We investigated the process of amodal completion in a same-different experiment in which test pairs were preceded by sequences of two figures. The first of these could be congruent to a global or local completion of an occluded part in the second figure, or a mosaic interpretation of it. We recorded and analyzed the magnetoencephalogram for the second figures. Compared to control conditions, in which unrelated primes were shown, occlusion and mosaic primes reduced the peak latency and amplitude of neural activity evoked by the occlusion patterns. Compared to occlusion primes, mosaic ones reduced the latency but increased the amplitude of evoked neural activity. Processes relating to a mosaic interpretation of the occlusion pattern, therefore, can dominate in an early stage of visual processing. The results did not provide evidence for the presence of a functional “mosaic stage” in completion per se, but characterize the mosaic interpretation as a qualitatively special one that can rapidly emerge in visual processing when context favors it.

scholarly journals Slow Motion Analysis of Repetitive Tapping (SMART) Test: Measuring Bradykinesia in Recently Diagnosed Parkinson’s Disease and Idiopathic Anosmia

2021 ◽  
pp. 1-15
Author(s):  
Cristina Simonet ◽  
Miquel A. Galmes ◽  
Christian Lambert ◽  
Richard N. Rees ◽  
Tahrina Haque ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Rating Scales ◽  
Early Stage ◽  
Slow Motion ◽  
Motor Dysfunction ◽  
Prodromal Phase ◽  
Floor Effect ◽  
Cross Sectional ◽  
Early Stages

Background: Bradykinesia is the defining motor feature of Parkinson’s disease (PD). There are limitations to its assessment using standard clinical rating scales, especially in the early stages of PD when a floor effect may be observed. Objective: To develop a quantitative method to track repetitive tapping movements and to compare people in the early stages of PD, healthy controls, and individuals with idiopathic anosmia. Methods: This was a cross-sectional study of 99 participants (early-stage PD = 26, controls = 64, idiopathic anosmia = 9). For each participant, repetitive finger tapping was recorded over 20 seconds using a smartphone at 240 frames per second. From each video, amplitude between fingers, frequency (number of taps per second), and velocity (distance travelled per second) was extracted. Clinical assessment was based on the motor section of the MDS-UPDRS. Results: People in the early stage of PD performed the task with slower velocity (p <  0.001) and with greater frequency slope than controls (p = 0.003). The combination of reduced velocity and greater frequency slope obtained the best accuracy to separate early-stage PD from controls based on metric thresholds alone (AUC = 0.88). Individuals with anosmia exhibited slower velocity (p = 0.001) and smaller amplitude (p <  0.001) compared with controls. Conclusion: We present a simple, proof-of-concept method to detect early motor dysfunction in PD. Mean tap velocity appeared to be the best parameter to differentiate patients with PD from controls. Patients with anosmia also showed detectable differences in motor performance compared with controls which may suggest that some are in the prodromal phase of PD.

Prognostic and predictive factors in early stages of classic Hodgkin’s lymphoma

2022 ◽  
pp. 7-15
Author(s):  
T. I. Bogatyreva ◽  
A. O. Afanasov ◽  
A. Yu. Terekhova ◽  
N. A. Falaleeva
Keyword(s):  
Overall Survival ◽  
Multivariate Analysis ◽  
Hodgkin’S Lymphoma ◽  
Early Stage ◽  
Hodgkin's Lymphoma ◽  
Cure Rate ◽  
First Line ◽  
Bulky Disease ◽  
Cox Regression Analysis ◽  
Early Stages

Rationale. In the early stages of classical Hodgkin’s lymphoma (cHL), the cure rate reaches 85–95 %, but the long-term effects of therapy can worsen overall survival. Current trials for early stages of Hodgkin’s lymphoma with favorable prognosis address the task of maintaining cure rates while reducing sequelae. For early unfavorable stages, the challenge is to improve cure rate without increasing toxicity.Purpose. To assess the potential significance of individual risk factors for optimal choice of the first line chemotherapy in early-stage Hodgkin lymphoma.Materials and methods. This single-center retrospective study included 290 patients with early stage cHL who had received ABVD – based (n = 249; 86 %) or BEACOPP‑21 – based (n = 41; 14 %) combined modality therapy from 2000 to 2017. Progression-free survival (PFS) and overall survival (OS) were assessed in Cox regression analysis including 12 clinical parameters.Main results. At a median follow up of 60 months for the entire group, OS was 95 % and PFS was 89 %. In a multivariate analysis PFS, at 5 years, was significantly inferior in patients with mediastinal bulk, baseline lymphocytopenia (≤ 0.6 × 109/L, р = 0.002; < 1.0 × 109/L, р = 0.000) and male gender; OS was inferior only in patients with an absolute lymphocytopenia (AL). In patients with AL, PFS after ABVD-based regimen was, respectively, 12 % in the high-risk group with mediastinal bulk and 56 % without it. PFS of patients without AL when treated with ABVD did not differ compared to BEACOPP‑21 within the same prognostic group: 95.2 % vs. 92.3 % for non-bulky and 86.4 % vs. 84.2 % for bulky disease. In the absence of AL, mediastinal bulk remained the main and only risk factor in multivariate analysis.Conclusions. The ABVD regimen is highly effective in the first line of chemotherapy for cHL, except for cases with baseline lymphocytopenia, in which the early usage of the BEACOPP regimen in the escalated or 14-day variants might be justified. In patients with mediastinal bulk, standard chemotherapy is not effective enough even in the absence of AL; therefore, if an intermediate PET/CT scan is available, it seems more appropriate to use a milder ABVD regimen on the first line and leave intensive therapy for patients with proven refractory disease. Prospects for improving the efficiency are opened with the new N-AVD and A-AVD schemes, the benefits of which should be evaluated, first of all, in patients with AL and mediastinal bulk.

scholarly journals High Fat Diet Induces Adhesion of Platelets to Endothelium in Two Models of Dyslipidemia

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jaime Gonzalez ◽  
Wendy Donoso ◽  
Natalia Díaz ◽  
María Eliana Albornoz ◽  
Ricardo Huilcaman ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Early Stage ◽  
Endothelial Activation ◽  
Mice Model ◽  
High Fat ◽  
Early Stages ◽  
Endothelial Surface ◽  
Two Stages ◽  
Adhesion Of Platelets

Cardiovascular diseases (CVD) represent about 30% of all global deaths. It is currently accepted that, in the atherogenic process, platelets play an important role, contributing to endothelial activation and modulation of the inflammatory phenomenon, promoting the beginning and formation of lesions and their subsequent thrombotic complications. The objective of the present work was to study using immunohistochemistry, the presence of platelets, monocytes/macrophages, and cell adhesion molecules (CD61, CD163, and CD54), in two stages of the atheromatous process. CF-1 mice fed a fat diet were used to obtain early stages of atheromatous process, denominated early stage of atherosclerosis, and ApoE−/−mice fed a fat diet were used to observe advanced stages of atherosclerosis. The CF-1 mice model presented immunostaining on endothelial surface for all three markers studied; the advanced atherosclerosis model in ApoE−/−mice also presented granular immunostaining on lesion thickness, for the same markers. These results suggest that platelets participate in atheromatous process from early stages to advance d stages. High fat diet induces adhesion of platelets to endothelial cellsin vivo. These findings support studying the participation of platelets in the formation of atheromatous plate.

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