Establishing supplementary response time validity indicators in the Word Memory Test (WMT) and directions for future research.

Response time (RT) measures in the Word Memory Test (WMT) offer to complement information derived from conventional accuracy measures. The current study aimed to validate the findings of Lupu, Elbaum, Wagner, and Braw in which RT variability was assessed, for the first time, in the WMT. A secondary aim was to suggest directions for the future research of RT measures in Forced-Choice Recognition Memory Performance Validity Tests (FCRM-PVTs).

Eye tracking as a mean to detect feigned cognitive impairment in the word memory test.

Eye movements showed initial promise for the detection of deception and may be harder to consciously manipulate than conventional accuracy measures. Therefore, we integrated an eye-tracker with the Word Memory Test (WMT) and tested its usefulness for the detection of feigned cognitive impairment. As part of the study, simulators ( = 44) and honest controls ( = 41) performed WMT's immediate-recognition (IR) subtest while their eye movements were recorded.

In vivo noninvasive microscopy of human leucocytes.

Leucocytes play a key role in our immune system, protecting the body against infections using a wide range of biological mechanisms. Effective imaging and identification of leucocytes within the blood stream in patients is challenging, however, because of their low volume fraction in the blood, the high tissue scattering and the rapid blood flow. Spectrally encoded flow cytometry (SEFC) has recently been demonstrated effective for label-free high-resolution in vivo imaging of blood cells using an optical probe that does not require mechanical scanning.

hematocrit measurement using spectrally encoded flow cytometry.

Measuring key physiological parameters of small blood samples extracted from patients could be useful for real-time clinical diagnosis at the point of care. An important parameter required from all blood tests is the blood hematocrit, a measure of the fractional volume occupied by the red cells within the blood. In this work, we present a method for evaluation of hematocrit based on the data acquired using spectrally encoded flow cytometry.

Holographically patterned activation using photo-absorber induced neural-thermal stimulation.

Objective: Patterned photo-stimulation offers a promising path towards the effective control of distributed neuronal circuits. Here, we demonstrate the feasibility and governing principles of spatiotemporally patterned microscopic photo-absorber induced neural-thermal stimulation (PAINTS) based on light absorption by exogenous extracellular photo-absorbers.

Approach: We projected holographic light patterns from a green continuous-wave (CW) or an IR femtosecond laser onto exogenous photo-absorbing particles dispersed in the vicinity of cultured rat cortical cells.

Optically induced cell fusion using bispecific nanoparticles.

Redirecting the immune system to eliminate tumor cells is a promising alternative to traditional cancer therapies, most often requiring direct interaction between an immune system effector cell and its target. Herein, a novel approach for selective attachment of malignant cells to antigen-presenting cells by using bispecific nanoparticles is presented. The engaged cell pairs are then irradiated by a sequence of resonant femtosecond pulses, which results in widespread cell fusion and the consequent formation of hybrid cells.

Holographic optogenetic stimulation of patterned neuronal activity for vision restoration.

When natural photoreception is disrupted, as in outer-retinal degenerative diseases, artificial stimulation of surviving nerve cells offers a potential strategy for bypassing compromised neural circuits. Recently, light-sensitive proteins that photosensitize quiescent neurons have generated unprecedented opportunities for optogenetic neuronal control, inspiring early development of optical retinal prostheses. Selectively exciting large neural populations are essential for eliciting meaningful perceptions in the brain.

High-speed interferometric spectrally encoded flow cytometry.

Spectrally encoded flow cytometry (SEFC) is a promising technique for noninvasive in vivo microscopy of blood cells. Here, we introduce a novel SEFC system for label-free confocal imaging of blood cells flowing at velocities of up to 10  mm/s within 65 μm-diameter vessels. The new system employs interferometric Fourier-domain detection and a high-speed wavelength-swept source, allowing 100 kHz line rate, sufficient for sampling the rapidly flowing cells 80 μm below the tissue surface.

Noninvasive imaging of flowing blood cells using label-free spectrally encoded flow cytometry.

Optical microscopy of blood cells in vivo provides a unique opportunity for clinicians and researchers to visualize the morphology and dynamics of circulating cells, but is usually limited by the imaging speed and by the need for exogenous labeling of the cells. Here we present a label-free approach for in vivo flow cytometry of blood using a compact imaging probe that could be adapted for bedside real-time imaging of patients in clinical settings, and demonstrate subcellular resolution imaging of red and white blood cells flowing in the oral mucosa of a human volunteer. By analyzing the large data sets obtained by the system, valuable blood parameters could be extracted and used for direct, reliable assessment of patient physiology.

Optical nanomanipulations of malignant cells: controlled cell damage and fusion.

Specifically targeting and manipulating living cells is a key challenge in biomedicine and in cancer research in particular. Several studies have shown that nanoparticles irradiated by intense lasers are capable of conveying damage to nearby cells for various therapeutic and biological applications. In this work ultrashort laser pulses and gold nanospheres are used for the generation of localized, nanometric disruptions on the membranes of specifically targeted cells.

Reduction of two-photon holographic speckle using shift-averaging.

Holographic speckle is a major impediment for the emerging applications of multiphoton holographic projection in biomedical imaging, photo-stimulation and micromachining. Time averaging of multiple shifted versions of a single hologram ("shift-averaging") is a computationally-efficient method that was recently shown to deterministically eliminate holographic speckle in single-photon applications. Here, we extend these results and show, computationally and experimentally, that in two-photon holographic excitation shift-averaging also reduces holographic speckle better than "random" averaging of multiple calculated holograms.

Flow cytometry using spectrally encoded confocal microscopy.

Flow cytometry techniques often rely on detecting fluorescence from single cells flowing through the cross section of a laser beam, providing invaluable information on vast numbers of cells. Such techniques, however, are often limited in their ability to resolve clusters of cells or parallel cell flow through large vessels. We present a confocal imaging technique that images unstained cells flowing in parallel through a wide channel, using spectrally encoded reflectance confocal microscopy that does not require mechanical scanning.

Speckle elimination using shift-averaging in high-rate holographic projection.

Speckle is a major source of noise in holographic projection. Time averaging of multiple holograms may be used to reduce speckle contrast, but multiple holograms must be calculated per each frame, costing in computational power. We show that a single hologram may be used to generate a fully speckle-free reconstruction, by cyclic shifting and time averaging.