Working memory load modulates microsaccadic rate.

Microsaccades are tiny eye movements that individuals perform unconsciously during fixation. Despite that the nature and the functions of microsaccades are still lively debated, recent evidence has shown an association between these micro eye movements and higher order cognitive processes. Here, in two experiments, we specifically focused on working memory and addressed whether differential memory load could be reflected in a modulation of microsaccade dynamics.

Altered social attention in anorexia nervosa during real social interaction.

The capacity to devote attentional resources in response to body-related signals provided by others is still largely unexplored in individuals with Anorexia Nervosa (AN). Here, we tested this capacity through a novel paradigm that mimics a social interaction with a real partner. Healthy individuals (Experiment 1) and individuals with AN (Experiment 2) completed a task with another person which consisted in performing, alternatively, rapid aiming movements to lateralised targets.

Are the neural correlates of subitizing and estimation dissociable? An fNIRS investigation.

Human performance in visual enumeration tasks typically shows two distinct patterns as a function of set size. For small sets, usually up to 4 items, numerosity judgments are extremely rapid, precise and confident, a phenomenon known as subitizing. When this limit is exceeded and serial counting is precluded, exact enumeration gives way to estimation: performance becomes error-prone and more variable.

Motion artifacts in functional near-infrared spectroscopy: a comparison of motion correction techniques applied to real cognitive data.

Motion artifacts are a significant source of noise in many functional near-infrared spectroscopy (fNIRS) experiments. Despite this, there is no well-established method for their removal. Instead, functional trials of fNIRS data containing a motion artifact are often rejected completely.

A reference-channel based methodology to improve estimation of event-related hemodynamic response from fNIRS measurements.

Functional near-infrared spectroscopy (fNIRS) uses near-infrared light to measure cortical concentration changes in oxygenated (HbO) and deoxygenated hemoglobin (HbR) held to be correlated with cognitive activity. Providing a parametric depiction of such changes in the classic form of stimulus-evoked hemodynamic responses (HRs) can be attained with this technique only by solving two problems. One problem concerns the separation of informative optical signal from structurally analogous noise generated by a variety of spurious sources, such as heart beat, respiration, and vasomotor waves.

Number-space interactions in the human parietal cortex: Enlightening the SNARC effect with functional near-infrared spectroscopy.

Interactions between numbers and space have become a major issue in cognitive neuroscience, because they suggest that numerical representations might be deeply rooted in cortical networks that also subserve spatial cognition. The spatial-numerical association of response codes (SNARC) is the most robust and widely replicated demonstration of the link between numbers and space: in magnitude comparison or parity judgments, participants' reaction times to small numbers are faster with left than right effectors, whereas the converse is found for large numbers. However, despite the massive body of research on number-space interactions, the nature of the SNARC effect remains controversial and no study to date has identified its hemodynamic correlates.

Exploring the role of primary and supplementary motor areas in simple motor tasks with fNIRS.

Studies employing functional magnetic resonance imaging (fMRI) have highlighted a covariation between the amplitude of hemodynamic responses recorded in primary and supplementary motor areas (M1 and SMA) and the duration of a motor task. A subset of these studies have hinted to a possible functional dissociation between processing carried out in these areas, with SMA primarily involved in action preparation, while M1 involved in action execution. This proposed functional dissociation was explored in the present study using a different technique--functional near-infrared spectroscopy--which enabled a finer-grained monitoring of the temporal characteristics of the hemodynamic response compared to fMRI.

An exploratory fNIRS study with immersive virtual reality: a new method for technical implementation.

For over two decades Virtual Reality (VR) has been used as a useful tool in several fields, from medical and psychological treatments, to industrial and military applications. Only in recent years researchers have begun to study the neural correlates that subtend VR experiences. Even if the functional Magnetic Resonance Imaging (fMRI) is the most common and used technique, it suffers several limitations and problems.

A hemodynamic correlate of lateralized visual short-term memories.

Neuroimaging studies attempting to isolate the neural substrate of visual short-term memory in humans have concentrated on the behavior of neurons populating the posterior part of the parietal cortex as a possible source of visual short-term memory capacity limits. Using a standard change-detection task, fMRI studies have shown that maintenance of bilaterally encoded objects elicited bilateral increases of hemodynamic activation in the intra-parietal and intra-occipital sulci (IPS-IOS) proportional to the number of objects retained in visual short-term memory. We used a spatially cued variant of the change-detection task to record hemodynamic responses to unilaterally encoded objects using functional near-infrared spectroscopy (fNIRS).

A new method based on ICBM152 head surface for probe placement in multichannel fNIRS.

We propose a new probe placement method for multichannel functional Near Infrared Spectroscopy (fNIRS) based on the ICBM152 template, the most commonly used reference brain for neuroimaging. Our method is based on the use of a physical model of the ICBM152 head surface as reference scalp and its validity is supported by previous investigations of cranio-cerebral correlation. The method, intended for fNIRS group studies, dispenses with the use of individual MRI scan and digitizing procedure for each participant.

Selective activation of the superior frontal gyrus in task-switching: an event-related fNIRS study.

In the task-switching paradigm, reaction time is longer and accuracy is worse in switch trials relative to repetition trials. This so-called switch cost has been ascribed to the engagement of control processes required to alternate between distinct stimulus-response mapping rules. Neuroimaging studies have reported an enhanced activation of the human lateral prefrontal cortex and the superior frontal gyrus during the task-switching paradigm.