Deficit in object detection (electrolocation) following interruption of cerebellar function in the weakly electric fish, Apteronotus albifrons.
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Afferent Pathways↗
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Results for “object detection”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Objective detection of reversible deficiencies in glaucoma by means of BECP.
The dynamic properties of the VECP trigger mechanism are used as a functional test for the glaucomatous eye. A light-emitting diode is used as stimulator. The test was performed under the condition of the functional isolation of the red colour mechanism (by means of selective colour adaptation technique). In any case, a delayed rise of stimulus luminance causes a delay of the VECP. This delay increases in patients with glaucoma. After a successful glaucoma operation the VECP delay diminishes again.
Color Perception Tests↗
A screening system for cervical cancer cytology.
A system for screening cervical cytological preparations is described which employs the Leitz Texture Analyzer System (E. Leitz, Rockleigh, N. J.) quantitative staining with acridine orange, and a fluorescence standard. The instrumentation scans cells on microscope slides and detects objects which it interprets to be nuclei with excess total nuclear green fluorescence intensity (Previous results employing manual measurements have indicated that normal nuclei do not produce total nuclear green fluorescence greater than a specific absolute intensity level). Detected objects are identified by visual observation. Cells (102,000) from 65 patients (29 normal, 36 abnormal) have been examined. In each abnormal sample, at least one abnormal cell was detected. In over half of the samples, three or fewer other objects (e.g. clumps of polymorphonuclear leukocytes) were detected. These are easily distinguishable from single nuclei, and could be discarded by someone with minimal cytological training.
Cervix Uteri↗
Radiopacity of impression materials.
The radiographic densitites of twenty-six impression materials were measured and the values expressed as an equivalent thickness of aluminum. Under simulated clinical conditions, only ten of the materials tested could be consistently distinguished from the bone structure in periapical radiographs. It was far more dificult to detect objects with beveled margins than objects of uniform thickness. The minimum radiopacity of a material which could be detected in the periodontal tissue on a periapical radiograph was estimated.
Absorptiometry, Photon↗
Thallium-201 imaging with color display computer system in old myocardial infarction.
In 13 patients with old myocardial infarction diagnosed with use of the electrocardiogram, coronary angiogram and left ventriculogram and in 11 patients without infarction, thallium-201 imaging with a color display computer system was carried out. In the group without infarction the average ratio of activities in two regions of interest within the myocardial wall, excluding the apex, was 1.14 (1.08 to 1.23). In the group with infarction the average ratio of noninfarcted to infarcted areas was 1.44 (1.23 to 1.78). Objective detection of infarction was possible in 12 patients (92 percent) in the group with infarction. In two patients, the earlier electrocardiographic pattern of infarction had resolved by the time of imaging. These results suggest that the sensitivity of thallium-201 imaging in the diagnosis of old myocardial infarction may be greatly enhanced by objective and quantitative analysis using a color display computer system.
Adult↗
Human-AI Interaction With AI-Assisted Tumor Overlays in Pediatric Whole-Body Magnetic Resonance Imaging: Exploratory Reader Study.
BACKGROUND: AI tools have the potential to enhance personalized clinical care, particularly in radiology. However, their integration into clinical workflows remains complex, especially in pediatric oncology, where early cancer detection is critical. Children with Li-Fraumeni syndrome (LFS), a rare cancer predisposition disorder, undergo regular surveillance whole-body magnetic resonance imaging (wbMRI), which presents an opportunity for AI-assisted tumor detection. OBJECTIVE: We evaluated the feasibility of an AI-assisted overlay for highlighting tumor-like regions in pediatric surveillance wbMRI and explored how access to the overlay influenced radiologist workflow, candidate-lesion marking behavior, follow-up recommendations, and perceived workload. METHODS: We developed a patch-based AI segmentation model trained on augmented 2D slices from 675 surveillance wbMRI volumes of pediatric patients with LFS. The model was designed to highlight regions with high tumor probability. A reader study was conducted with 2 radiologists who independently reviewed wbMRI cases both with and without AI assistance. We measured evaluation time, number and location of reader-marked candidate lesions, type of follow-up recommendation, and subjective feedback using structured questionnaires. RESULTS: AI assistance altered interpretation workflows for both radiologists, with mixed effects. On average, the time required to evaluate each case increased when using the AI tool for both radiologists. However, one radiologist had an increase in the number of candidate lesion locations selected with the tool, and one had a decrease in the number of candidate lesion locations selected with the tool. Subjective feedback indicated that one of the radiologists reported lower mental demand with the AI tool, while both radiologists reported lower stress with the AI tool. Interrater variability was evident, underscoring the need for personalized calibration of AI tools. CONCLUSIONS: AI-assisted wbMRI interpretation can improve tumor detection in pediatric cancer surveillance by reducing false negatives. However, its influence on workflow efficiency and interradiologist variability highlights the importance of careful implementation. Successful integration requires addressing challenges such as improving the predictive precision of AI models, offering intuitive end-user designs and instructions, and building trust in AI outputs. AI outputs can influence workflow and behavior in reader-specific ways. Clinical translation will require larger, randomized, multireader studies and model refinement to reduce false positives and quantify lesion-level reader performance. This can help ensure better patient outcomes in addition to reduced clinician burnout.
Humans↗
Noninvasive detection and differentiation of gastric malignancy using cell-free DNA biomarkers.
INTRODUCTION: Gastric cancer remains a major global health burden, with high mortality driven by late-stage diagnoses that limit treatment options and reduce survival. Current diagnostic methods such as endoscopy and biopsy are invasive, resource-intensive, and impractical for large-scale early detection. OBJECTIVES: This study aimed to develop and validate an ensemble machine learning model integrating four cell-free DNA (cfDNA) fragmentomic feature classes derived from 5 × whole genome sequencing (WGS) data to non-invasively differentiate malignant gastric cancer from benign gastric lesions in high-risk or symptomatic patients. METHODS: A total of 681 plasma samples were prospectively collected, comprising 329 from patients with gastric cancer or high-grade intraepithelial neoplasia (HGIN) and 352 from individuals with benign gastric conditions. The dataset was divided into a training cohort (n = 333) and a temporally independent validation cohort (n = 348). An external validation cohort of 305 participants was also included. RESULTS: The ensemble model achieved an AUROC of 0.920 in cross-validation testing on the training cohort, 0.912 in the independent validation cohort, and 0.896 (95% CI 0.860-0.932) in the external cohort. At a pre-specified prediction threshold of 0.402, the model demonstrated 93.3% sensitivity and 71.9% specificity in the validation cohort, yielding a PPV of 71.3% and an NPV of 93.5%. In the external cohort, sensitivity and specificity were 91.7% and 69.1%, respectively (PPV 75.7%, NPV 88.8%). Model scores correlated with clinical stage, tumor grade, and histopathological subtype. Approximately 71% of non-cancer patients could have been spared unnecessary endoscopy. CONCLUSIONS: The cfDNA fragmentomics-based ensemble model enables accurate, non-invasive differentiation between gastric cancer and benign gastric lesions in high-risk or symptomatic patients. This approach demonstrates strong potential as a pre-endoscopy triage tool, supporting earlier detection and more efficient use of diagnostic resources.
Humans↗
Cytostatic treatment of meningeal blastoses.
Intrathecal treatment with MTX was attempted in patients with diffuse meningeal blastoses. As a rule, symptoms and clinical findings improved rapidly. As objective parameters, the differential cell pictures of the CSF showed dissimilar results during therapy (25 mg MTX weekly i.t.). In leukoses (n = 10) and malignant lymphomas (n = 12), the CSF could be cleared with three exceptions which concerned differentiated tumors. The success was similarly good with meningeal dissemination of a seminoma. Meningeal carcinoses with mammary carcinoma (n = 7) and melanoma (n = 2) showed dissimilar results. No alteration of the cytograms of four bronchial carcinomas and one colon carcinoma was demonstrable. Besides the growth form, the degree of differentiation appears to be decisive for the success of therapy. The labeling index appears to be a useful indicator. Since symptoms and clinical findings often markedly improve even when a success cannot be objectively detected cytologically, an attempt at therapy is always to be recommended.
Breast Neoplasms↗
Echolocation performance of the vampire bat (Desmodus rotundus).
The neotropical vampire bats (Desmodus rotundus) echolocate using ultrasonic pulses like those of the Latin American phyllostomatid bats. In this paper the orally produced echolocation sounds of Desmodus are analysed and the performance of the echolocation system is studied in two-choice training experiments on two vampire bats. Ability to detect objects is relatively limited; both animals were capable of discerning the presence of a 1 cm wide metal strip at a distance of 50 cm, but they failed with 0.5 cm wide strips. The ultrasonic pulses produced at a distance of 50 cm appear to sample an area with a diameter of 2.5 to 3.0 cm (i.e., the solid angle tested with each pulse is 3 degrees to 3 degrees 40' in extent).
Animals↗
Receptive fields of cerebellar cells receiving exteroceptive input in a Gymnotid fish.
Single neurons in the caudal lobe of the cerebellum of the weakly electric fish Apteronotus albifrons respond to distortions in the normal electric field produced by the animal. Moving plastic or metal objects as well as a simpler stimulus, a moving electrical dipole, produce adequate distortions of the fish's field to cause the cerebellar cells to respond. The moving dipole stimulated small enough areas of the fish's skin, as determined by the responses of single electroreceptors, to allow maps of the receptive fields of single cerebellar cells to be produced. The receptive fields seen varied widely in complexity from relatively small excitatory or inhibitory areas to larger fields containing multiple excitatory and inhibitory areas usually bordering one another. Most cells studied displayed directional responses. Usually qualitatively different responses resulted from opposite directions of movement, and less frequently units were seen in which no response resulted from movement opposite the direction which caused responses; Varying the rate of stimulus movement caused only small changes in the responses of cerebellar cells; however, motionless stimuli applied over areas of skin known to respond to moving stimuli produced weaker responses of the appropriate sign for that area. Movement seems to be an important component of the stimulus for these cells. Cells were also seen which responded to visual as well as to electroreceptive input. Responses to each of these two modalities presented above were quite different. The cells recorded from frequently displayed burst discharges similar to those produced by Purkinje cells in other lower vertebrates, and most of the cells studied are believed to be Purkinje cells. A somatotopic relationship was found between the position of the center of a receptive field on the fish's body and the position of the cell in the brain. All of the results obtained are compatible with the hypothesis that the caudal lobe of the cerebellum is processing electroreceptive information related to object detection.
Animals↗
Spatial aspects of electrolocation in the mormyrid fish, Gnathonemus petersii.
The range of electrolocation in the weakly electric fish, Gnathonemus petersii, was determined for plastic and aluminium cubes. A characteristic change in the fish's EOD activity, and abrupt change to more uniform EOD intervals (regularization), was used as the criterion for object detection. The average response distances extending laterally from the fish's longitudinal axis were significantly different (p less than 0.05) for the aluminium cube (5.4 cm) and the plastic cube (7.0 cm).
Animals↗
Detectability of spherical objects by computed tomography.
A Lucite phantom was constructed with voids cut in long cylinders, short cylinders and spheres in order to quantitate the effect of partial volume averaging on detectability. Typical scans of varying contrast revealed that the long cylinders cinsistently can be detected to a smaller size than either short cylinders or spheres of the same diameter. The authors feel that low contrast detectability must involve the influence of beam profile on partial volume contrast losses for spherical objects.
Physical Phenomena↗
Effect of CT noise on detectability of test objects.
Three types of test objects were superimposed on noisy backgrounds and observed by 58 subjects: large low-contrast disks to simulate tumors, small disks to simulate calcifications, and bars to simulate blood vessels. Three types of noise were used: random noise, CT noise (reconstructed random noise), and an actual water scan taken with an EMI CT1010 scanner. In addition, each image was smoothed by a factor of two, giving six test patterns altogether. Photographic images were presented to 25 lay observers, while 25 other lay observers and eight radiologists used a viewing console. The photographs produced a slightly lower true positive rate than the console, although the degree of confidence in the identifications was slightly greater. The anticorrelation property of CT noise gives it a "lumpy" structure, which aided the identification of bars but impeded the identification of small disks. Smoothing did not significantly affect the detectability with random noise, but with CT noise, smoothing improved the detectability of bars and large disks.
Humans↗
Detection of stationary objects by frogs (Rana pipiens) after ablation of optic tectum.
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Animals↗
Response variability in the mammalian auditory cortex: an objection to feature detection?
Research strategy in the auditory system has tended to parallel that in the visual system, where neurons have been shown to respond selectively to specific stimulus parameters. Auditory neurons have been shown to be sensitive to changes in acoustic parameters, but only rarely have neurons been reported that respond exclusively to only one biologically significant sound. Even at higher levels of the auditory system very few cells have been found that could be described as "vocalization detectors." In addition, variability in responses to artificial sounds have been reported for auditory cortical neurons similar to the response variability that has been reported in the visual system. Recent evidence indicates that the responses of auditory cortical neurons to species-specific vocalizations can also be labile, varying in both strength and selectivity. This is especially true of the secondary auditory cortex. This variability, coupled with the lack of extreme specificity in the secondary auditory cortex, suggests that secondary cortical neurons are not well suited for the role of "vocalization detectors."
Acoustic Stimulation↗
Measurements of the effects of x-ray film--screen characteristics on threshold detectability of small low-contrast objects.
Experiments were performed to test threshold detectability of a small nylon bead radiographed with two different image receptors and under different scattering conditions. In another paper, the present authors predicted, on theoretical grounds, the visibility of small low-contrast objects radiographed in the presence of scattered radiation. The experiments discussed in this paper tested these predictions using an observer-testing method resulting in Receiver Operating Characteristic (ROC) curves. In addition to the rigidly controlled experiments from which the ROC curves were obtained, another experiment was performed in which a human phantom was used and the radiographs rated as to the visibility of small artificial lesions. By and large, the experiments confirmed the predictions made from the theoretical analysis, using visual contrast as a measure of detectability.
Absorptiometry, Photon↗
[Spreading of pathogenic escherichial and methods of their detection in certain environmental objects].
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Child↗
The dorsal compound eye of simuliid flies: an eye specialized for the detection of small, rapidly moving objects.
The highly specialized dorsal compound eye of male Simuliids is especially adapted to detect during flight the females which are very small animals (1X3 mm). At dawn, the eye functions close to the physical limit imposed by the quantum fluctuations of light. In birght illuminations, light-qauntum noise is not a limiting factor as can be shown by behavioural experiments.
Animals↗