Wada Testing Reveals Frontal Lateralization for the Memorization of Words and Faces

2002 ◽  
Vol 14 (1) ◽  
pp. 116-125 ◽  
Author(s):  
W. M. Kelley ◽  
J. G. Ojemann ◽  
R. D. Wetzel ◽  
C. P. Derdeyn ◽  
C. J. Moran ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Temporal Cortex ◽  
Memory Formation ◽  
Wada Test ◽  
Memory Impairments ◽  
Reversible Lesion ◽  
The Right ◽  
Open Question ◽  
Normal Performance ◽  
Better Than

Neuroimaging studies have suggested that specific regions of the frontal and medial temporal cortex are engaged during memory formation. Further, there is specialization across these regions such that verbal materials appear to preferentially engage the left regions while nonverbal materials primarily engage the right regions. An open question, however, has been to what extent frontal regions contribute to successful memory formation. The present study investigates this question using a reversible lesion technique known as the Wada test. Patients memorized words and unfamiliar faces while portions of their left and right hemispheres were temporarily anesthetized with sodium amytal. Subsequent memory tests revealed that faces were remembered better than words following left-hemisphere anesthesia, whereas words were remembered better than faces following right-hemisphere anesthesia. Importantly, inspection of the circulation affected by the amytal further suggests that these memory impairments did not result from direct anesthetization of the medial temporal regions. Taken in the context of the imaging findings, these results suggest that frontal regions may also contribute to memory formation in normal performance.

scholarly journals Dissociated Crossed Speech Areas in a Tumour Patient

2017 ◽  
Vol 9 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Jörg Mauler ◽  
Irene Neuner ◽  
Georg Neuloh ◽  
Bruno Fimm ◽  
Frank Boers ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Insular Cortex ◽  
Low Grade ◽  
Wada Test ◽  
Brain Hemispheres ◽  
Eloquent Areas ◽  
Tumour Removal ◽  
Frontal Operculum ◽  
The Right ◽  
Impaired Speech

In the past, the eloquent areas could be deliberately localised by the invasive Wada test. The very rare cases of dissociated crossed speech areas were accidentally found based on the clinical symptomatology. Today functional magnetic resonance imaging (fMRI)-based imaging can be employed to non-invasively localise the eloquent areas in brain tumour patients for therapy planning. A 41-year-old, left-handed man with a low-grade glioma in the left frontal operculum extending to the insular cortex, tension headaches, and anomic aphasia over 5 months underwent a pre-operative speech area localisation fMRI measurement, which revealed the evidence of the transhemispheric disposition, where the dominant Wernicke speech area is located on the left and the Broca’s area is strongly lateralised to the right hemisphere. The outcome of the Wada test and the intraoperative cortico-subcortical stimulation mapping were congruent with this finding. After tumour removal, language area function was fully preserved. Upon the occurrence of brain tumours with a risk of impaired speech function, the rare dissociate crossed speech areas disposition may gain a clinically relevant meaning by allowing for more extended tumour removal. Hence, for its identification, diagnostics which take into account both brain hemispheres, such as fMRI, are recommended.

scholarly journals When brain damage “improves” perception: neglect patients can localize motion-shifted probes better than controls

2015 ◽  
Vol 114 (6) ◽  
pp. 3351-3358 ◽  
Author(s):  
Stefania de Vito ◽  
Marine Lunven ◽  
Clémence Bourlon ◽  
Christophe Duret ◽  
Patrick Cavanagh ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Visual Fields ◽  
Critical Factor ◽  
Significant Shift ◽  
Stimulus Motion ◽  
Attentional Processes ◽  
Position Shift ◽  
The Right ◽  
High Level ◽  
Better Than

When we look at bars flashed against a moving background, we see them displaced in the direction of the upcoming motion (flash-grab illusion). It is still debated whether these motion-induced position shifts are low-level, reflexive consequences of stimulus motion or high-level compensation engaged only when the stimulus is tracked with attention. To investigate whether attention is a causal factor for this striking illusory position shift, we evaluated the flash-grab illusion in six patients with damaged attentional networks in the right hemisphere and signs of left visual neglect and six age-matched controls. With stimuli in the top, right, and bottom visual fields, neglect patients experienced the same amount of illusion as controls. However, patients showed no significant shift when the test was presented in their left hemifield, despite having equally precise judgments. Thus, paradoxically, neglect patients perceived the position of the flash more veridically in their neglected hemifield. These results suggest that impaired attentional processes can reduce the interaction between a moving background and a superimposed stationary flash, and indicate that attention is a critical factor in generating the illusory motion-induced shifts of location.

scholarly journals Localization of Syntactic and Semantic Brain Responses using Magnetoencephalography

2007 ◽  
Vol 19 (7) ◽  
pp. 1193-1205 ◽  
Author(s):  
Elisabet Service ◽  
Päivi Helenius ◽  
Sini Maury ◽  
Riitta Salmelin
Keyword(s):  
Temporal Lobe ◽  
Semantic Processing ◽  
Sentence Comprehension ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Word Class ◽  
Sentence Reading ◽  
Word Onset ◽  
Semantic Errors ◽  
The Right

Electrophysiological methods have been used to study the temporal sequence of syntactic and semantic processing during sentence comprehension. Two responses associated with syntactic violations are the left anterior negativity (LAN) and the P600. A response to semantic violation is the N400. Although the sources of the N400 response have been identified in the left (and right) temporal lobe, the neural signatures of the LAN and P600 have not been revealed. The present study used magnetoencephalography to localize sources of syntactic and semantic activation in Finnish sentence reading. Participants were presented with sentences that ended in normally inf lected nouns, nouns in an unacceptable case, verbs instead of nouns, or nouns that were correctly inflected but made no sense in the context. Around 400 msec, semantically anomalous last words evoked strong activation in the left superior temporal lobe with significant activation also for word class errors (N400). Weaker activation was seen for the semantic errors in the right hemisphere. Later, 600-800 msec after word onset, the strongest activation was seen to word class and morphosyntactic errors (P600). Activation was significantly weaker to semantically anomalous and correct words. The P600 syntactic activation was localized to bilateral sources in the temporal lobe, posterior to the N400 sources. The results suggest that the same general region of the superior temporal cortex gives rise to both LAN and N400 with bilateral reactivity to semantic manipulation and a left hemisphere effect to syntactic manipulation. The bilateral P600 response was sensitive to syntactic but not semantic factors.

A Functional Neuroimaging Description of Two Deep Dyslexic Patients

1998 ◽  
Vol 10 (3) ◽  
pp. 303-315 ◽  
Author(s):  
C. J. Price ◽  
D. Howard ◽  
K. Patterson ◽  
E. A. Warburton ◽  
K. J. Friston ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Word Processing ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Broca's Area ◽  
Enhanced Activity ◽  
Left Posterior ◽  
Deep Dyslexia ◽  
The Right

Deep dyslexia is a striking reading disorder that results from left-hemisphere brain damage and is characterized by semantic errors in reading single words aloud (e.g., reading spirit as whisky). Two types of explanation for this syndrome have been advanced. One is that deep dyslexia results from a residual left-hemisphere reading system that has lost the ability to pronounce a printed word without reference to meaning. The second is that deep dyslexia reflects right-hemisphere word processing. Although previous attempts to adjudicate between these hypotheses have been inconclusive, the controversy can now be addressed by mapping functional anatomy. In this study, we demonstrate that reading by two deep dyslexic patients (CJ and JG) involves normal or enhanced activity in spared left-hemisphere regions associated with naming (Broca's area and the left posterior inferior temporal cortex) and with the meanings of words (the left posterior temporo-parietal cortex and the left anterior temporal cortex). In the right-hemisphere homologues of these regions, there was inconsistent activation within the normal group and between the deep dyslexic patients. One (CJ) showed enhanced activity (relative to the normals) in the right anterior inferior temporal cortex, the other (JG) in the right Broca's area, and both in the right frontal operculum. Although these differential right-hemisphere activations may have influenced the reading behavior of the patients, their activation patterns primarily reflect semantic and phonological systems in spared regions of the left hemisphere. These results preclude an explanation of deep dyslexia in terms of purely right-hemisphere word processing.

Discrepant findings for Wada test and functional magnetic resonance imaging with regard to language function: use of electrocortical stimulation mapping to confirm results

2005 ◽  
Vol 102 (1) ◽  
pp. 169-173 ◽  
Author(s):  
Kuan H. Kho ◽  
Frans S. S. Leijten ◽  
Geert-Jan Rutten ◽  
Jan Vermeulen ◽  
Peter van Rijen ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Right Hemisphere ◽  
Test Results ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Wada Test ◽  
Content Type ◽  
Language Functions ◽  
Imaging Results ◽  
The Right

✓ The Wada test is still considered the gold standard for determining the language-dominant hemisphere prior to brain surgery. The authors report on a 34-year-old right-handed woman whose Wada test results indicated that the right hemisphere was dominant for language. In contrast, functional magnetic resonance (fMR) imaging was indicative of bilaterally represented language functions. Activation in the left hemisphere demonstrated on fMR imaging was most pronounced in the Broca area. Importantly, fMR imaging results in this area were confirmed on electrocortical stimulation mapping. These contradictory findings indicated that a right hemispherre dominance for language according to the Wada test should be questioned and verified using electrocortical stimulation. Nonetheless, the question remains whether involvement of these areas in the left frontal hemisphere is critical for language, as these were spared during surgery.

scholarly journals Neurophysiological Subtypes of Depressive Disorders

Psychiatry ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 63-76
Author(s):  
I. A. Lapin ◽  
T. A. Rogacheva ◽  
A. A. Mitrofanov
Keyword(s):  
Depressive Disorders ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Statistical Research ◽  
Atypical Depression ◽  
Leading Role ◽  
Gamma Coherence ◽  
Left And Right ◽  
The Right ◽  
Bipolar Affective Disorders

Background: the clinical polymorphism of depressive disorders, together with the available data on the different responses of patients to treatment, motivate modern neuroscience to search for models that can explain such heterogeneity.Objective: to identify neurophysiological subtypes of depressive disorders.Patients and methods: 189 patients with moderate depression in the structure of a depressive episode (n = 42), recurrent depressive (n = 102) and bipolar affective disorders (n = 45); 56 healthy subjects. Clinical-psychopathological, psychometric, neurophysiological and statistical research methods were used in the work.The results: with the help of coherent EEG analysis, it is possible to identify at least 6 subtypes of the disorder, which characterize various branches of the pathogenesis of affective pathology, which go beyond the currently accepted nomenclature. The selected subtypes were determined by the profi les of dysfunctional interaction of various cortical zones in the alpha, beta and gamma ranges of the EEG. Subtype 1 was characterized by a decrease relative to the norm of imaginary alpha-coherence between the right parietal and left central, right parietal and left anterior temporal, as well as the right parietal and right anterior temporal EEG leads (P4-C3, P4-F7, P4-F8) and explained part of depressions, in the pathogenesis of which the leading role was played by violations of the promotion of positive and suppression of negative affect. Subtype 2 — an increase in beta-2-imaginary-coherence between the frontal leads of the left and right hemispheres, between the left frontal and right central cortex (F3-F4; F3-C4) and its decrease between the central cortical zones (C4-C3), in clinical terms this subtype was characterized by a persistent hedonic response and was associated with the clinical picture of atypical depression. Subtype 3 — an increase in imaginary alpha-coherence between the frontal (F4-F3) and its decrease between the central leads of the left and right hemisphere (C4-C3), correlated with the severity of depressive rumination. Subtype 4 — a decrease in imaginary alpha-coherence between the anterior temporal and frontal, as well as the anterior temporal and central cortex of the right hemisphere (F8-F4 and F8-C4), explained part of the depressions that developed against the background of avoidance personality disorder. Subtype 5 — a decrease in imaginary gamma coherence between the frontal and parietal, as well as the central and occipital cortical zones of the left hemisphere (F3-P3 and C3-O1), was associated with an outwardly oriented utilitarian style of thinking (alexithymia). Subtype 6 — a decrease in imaginary beta-1 coherence between the left central and right anterior temporal cortex (C3-F8), explained part of the depression with phobic and hypochondriacal disorders in the structure of recurrent depressive disorder. Such a clinical and biological typology seems new and promising in terms of searching for specifi c neurophysiological disorders in different types of depression and, accordingly, reaching differentiated therapeutic recommendations.

Tonotopy of the Auditory-Evoked Field Component N100m in Patients with Schizophrenia

2000 ◽  
Vol 14 (3) ◽  
pp. 131-141 ◽  
Author(s):  
T. Rosburg ◽  
I. Kreitschmann-Andermahr ◽  
T. Ugur ◽  
H. Nestmann ◽  
H. Nowak ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Temporal Cortex ◽  
Dipole Orientation ◽  
Global Field Power ◽  
Functional Reorganization ◽  
Schizophrenic Patients ◽  
Posterior Direction ◽  
The Right ◽  
Main Effects ◽  
Anterior Posterior

Abstract A number of clinical studies on the auditory neuromagnetic evoked field (AEF) component N100m have reported an altered lateralization in schizophrenic patients. This study addresses the problem of a possible functional reorganization of the temporal cortex in schizophrenia by examining the tonotopic organization of the N100m. Thirty-two patients with schizophrenia and 33 healthy controls of both sexes took part. Two tone frequencies (1000 and 5000 Hz tone) were applied for auditory stimuli, and AEF were recorded over both hemispheres successively using a 31-channel biomagnetometer. The comparison of N100m dipole location and orientation between hemispheres revealed no alterations in male or female patients. Between tone frequencies highly significant differences were found for N100m peak latency, mean global field power, dipole orientation, and dipole location in the anterior-posterior direction. Although the main effects of frequency were found to be the same in patients and controls, the balance between hemispheres was altered in patients with schizophrenia, with respect to the dependence between frequency and dipole location in the anterior-posterior direction as well as between frequency and latency. In patients, the influence of frequency on these variables was more pronounced in the right hemisphere and less pronounced in the left, compared to controls.

The Brain Basis of Language Processing: From Structure to Function

2011 ◽  
Vol 91 (4) ◽  
pp. 1357-1392 ◽  
Author(s):  
Angela D. Friederici
Keyword(s):  
Language Processing ◽  
Right Hemisphere ◽  
Structural Connectivity ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Posterior Portion ◽  
Language Functions ◽  
Marker Studies ◽  
The Right ◽  
The Brain

Language processing is a trait of human species. The knowledge about its neurobiological basis has been increased considerably over the past decades. Different brain regions in the left and right hemisphere have been identified to support particular language functions. Networks involving the temporal cortex and the inferior frontal cortex with a clear left lateralization were shown to support syntactic processes, whereas less lateralized temporo-frontal networks subserve semantic processes. These networks have been substantiated both by functional as well as by structural connectivity data. Electrophysiological measures indicate that within these networks syntactic processes of local structure building precede the assignment of grammatical and semantic relations in a sentence. Suprasegmental prosodic information overtly available in the acoustic language input is processed predominantly in a temporo-frontal network in the right hemisphere associated with a clear electrophysiological marker. Studies with patients suffering from lesions in the corpus callosum reveal that the posterior portion of this structure plays a crucial role in the interaction of syntactic and prosodic information during language processing.

scholarly journals Reduction in White Matter Connectivity, Revealed by Diffusion Tensor Imaging, May Account for Age-related Changes in Face Perception

2008 ◽  
Vol 20 (2) ◽  
pp. 268-284 ◽  
Author(s):  
Cibu Thomas ◽  
Linda Moya ◽  
Galia Avidan ◽  
Kate Humphreys ◽  
Kwan Jin Jung ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Face Perception ◽  
Face Processing ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Temporal Cortex ◽  
Age Related ◽  
The Right ◽  
White Matter Connectivity

An age-related decline in face processing, even under conditions in which learning and memory are not implicated, has been well documented, but the mechanism underlying this perceptual alteration remains unknown. Here, we examine whether this behavioral change may be accounted for by a reduction in white matter connectivity with age. To this end, we acquired diffusion tensor imaging data from 28 individuals aged 18 to 86 years and quantified the number of fibers, voxels, and fractional anisotropy of the two major tracts that pass through the fusiform gyrus, the pre-eminent face processing region in the ventral temporal cortex. We also measured the ability of a subset of these individuals to make fine-grained discriminations between pairs of faces and between pairs of cars. There was a significant reduction in the structural integrity of the inferior fronto-occipital fasciculus (IFOF) in the right hemisphere as a function of age on all dependent measures and there were also some changes in the left hemisphere, albeit to a lesser extent. There was also a clear age-related decrement in accuracy of perceptual discrimination, especially for more challenging perceptual discriminations, and this held to a greater degree for faces than for cars. Of greatest relevance, there was a robust association between the reduction of IFOF integrity in the right hemisphere and the decline in face perception, suggesting that the alteration in structural connectivity between the right ventral temporal and frontal cortices may account for the age-related difficulties in face processing.

scholarly journals Attachment Style Predicts Cortical Activity in Temporoparietal Junction (TPJ)

2020 ◽  
Vol 34 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Bora Baskak ◽  
Yagmur Kır ◽  
Nilay Sedes ◽  
Adnan Kuşman ◽  
Eylem Gökce Türk ◽  
...  
Keyword(s):  
Attachment Style ◽  
Attachment Styles ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
First Grade ◽  
Cortical Activity ◽  
Functional Near Infrared Spectroscopy ◽  
Temporoparietal Junction ◽  
Superior Temporal Cortex ◽  
The Right

Abstract. Results of the behavioral studies suggest that attachment styles may have an enduring effect upon theory of mind (ToM). However biological underpinnings of this relationship are unclear. Here, we compared securely and insecurely attached first grade university students ( N = 56) in terms of cortical activity measured by 52 channel Functional Near Infrared Spectroscopy (fNIRS) during the Reading the Mind from the Eyes Test (RMET). The control condition involved gender identification via the same stimuli. We found that the ToM condition evoked higher activity than the control condition particularly in the right hemisphere. We observed higher activity during the ToM condition relative to the control condition in the secure group (SG), whereas the overall cortical activity evoked by the two conditions was indistinguishable in the insecure group (ISG). Higher activity was observed in channels corresponding to right superior temporal and adjacent parietal cortices in the SG relative to the ISG during the ToM condition. Dismissive attachment scores were negatively correlated with activity in channels that correspond to right superior temporal cortex. These results suggest that attachment styles do have an effect on representation of ToM in terms of cortical activity in late adolescence. Particularly, dismissive attachment is represented by lower activity in the right superior temporal cortex during ToM, which might be related to weaker social need and habitual unwillingness for closeness among this group of adolescents.

Sign in / Sign up

Export Citation Format

Share Document