Yuval Harpaz

• PhD
• Head of Department at InnerEye

Objective: Atypical patterns of language lateralization due to early reorganizational processes constitute a challenge in the pre-surgical evaluation of patients with pharmaco-resistant epilepsy. There is no consensus on an optimal analysis method used for the identification of language dominance in MEG. This study examines the concordance between...

Objective The current study investigated the oscillatory brain activity of PTSD patients during directed and imaginal exposure to the traumatic memory using magnetoencephalography (MEG), in a paradigm resembling exposure therapy. Methods Brain activity of healthy trauma-exposed controls and PTSD participants was measured with MEG as they listened...

Background: In posttraumatic stress disorder (PTSD), the traumatic event is often re-experienced through vivid sensory fragments of the traumatic experience. Though the sensory phenomenology of traumatic memories is well established, neural indications for this qualitative experience are lacking. The current study aimed at monitoring the oscillator...

Aquatic motor activity (AMA) has been reported to affect motor and cognitive abilities. However, the neural mechanisms that may mediate this relationship have never been explored. The traditional functions of the cerebellum include involvement in coordination and balance. Recent studies have shown cerebellar activity during verbal working memory (V...

Melody recognition is an online process of evaluating incoming information and comparing this information to an existing internal corpus, thereby reducing prediction error. The predictive-coding model postulates top-down control on sensory processing accompanying reduction in prediction error. To investigate the relevancy of this model to melody pr...

Objective: Patients suffering from posttraumatic stress disorder (PTSD) exhibit hyper arousal symptoms and attention problems which were frequently investigated using the P3 event-related potentials (ERPs). Our study aimed at providing more precise knowledge of the functional significance of the P3 alteration seen in PTSD by revealing its spatio-t...

Objective: Although simultaneous recording of EEG and MRI has gained increasing popularity in recent years, the extent of its clinical use remains limited by various technical challenges. Motion interference is one of the major challenges in EEG-fMRI. Here we present an approach which reduces its impact with the aid of an MR compatible dual-array...

Introduction: Developmental stuttering is a disorder of fluency, affecting about 1% of the general population (Yairi & Ambrose, 2013). It is characterized by repetitions, prolongations and blocks (Riley, 1972). Whilst the disorder is primarily manifested in the domain of speech, a large body of evidence suggests that stuttering might in fact be a m...

Whereas language processing in neurotypical brains is left lateralized, individuals with schizophrenia (SZ) display a bilateral or reversed pattern of lateralization. We used MEG to investigate the implications of this atypicality on fine (left hemisphere) versus coarse (right hemisphere) semantic processing. Ten SZ and 14 controls were presented w...

Objective To suggest ways to apply the excess kurtosis estimator g2, in the detection of epileptic activity with magnetoencephalography, while avoiding its bias towards detecting high-amplitude, infrequent events. Methods Synthetic aperture magnetometry (SAM), combined with g2, was applied using window lengths ranging from 0.125s to 32s and with s...

Dyslexia is a multifactorial reading deficit that involves multiple brain systems. Among other theories, it has been suggested that cerebellar dysfunction may be involved in dyslexia. This theory has been supported by findings from anatomical and functional imaging. A possible rationale for cerebellar involvement in dyslexia could lie in the cerebe...

EEG studies suggested that the N170 ERP and Gamma-band responses to faces reflect early and later stages of a multiple-level face-perception mechanism, respectively. However, these conclusions should be considered cautiously because EEG-recorded Gamma may be contaminated by noncephalic activity such as microsaccades. Moreover, EEG studies of Gamma...

The time-line of lexical ambiguity resolution in bilateral neuronal networks was investigated using magnetoencephalography (MEG) in a semantic decision task. Dominant and subordinate associations of ambiguous words are considered to be processed in the left and right hemispheres, respectively. In the experiment, ambiguous words were followed by dom...

Background / Purpose: This work aims to create millisecond-by-millisecond MEG beamforming movies of evoked response while dealing with depth bias and oscillating brain regions. Main conclusion: We have found that beamforming weights are useful for normalising depth bias and kurtosis (g2) estimate is useful for masking oscillating brain sources...

Previous studies have reported a hemispheric asymmetry in processing dominant (e.g., paper) and subordinate (e.g., farmer) associations of ambiguous words (e.g., pen). The majority of these studies, however, applied randomly ordered presentation and collected right-hand responses only. Generating responses solely with the right hand and the randoml...

This study examined the capability of the left hemisphere (LH) and the right hemisphere (RH) to perform a visual recognition task independently as formulated by the Direct Access Model (Fernandino, Iacoboni, & Zaidel, 2007). Healthy native Hebrew speakers were asked to categorize nouns and non-words (created from nouns by transposing two middle let...

There is an academic dispute regarding the role of the right hemisphere in language processing. Transcranial Magnetic Stimulation (TMS) was used to test the hypothesis that Wernicke's area processes dominant meanings ("teller") whereas its right homologue processes subordinate meanings ("river") of ambiguous words ("bank"; Jung-Beeman, 2005). Parti...