scholarly journals Persistent Hemispheric Differences in the Perceptual Selection of Spatial Frequencies

2014 ◽  
Vol 26 (9) ◽  
pp. 2021-2027 ◽  
Author(s):  
Elise A. Piazza ◽  
Michael A. Silver
Keyword(s):  
Spatial Frequency ◽  
Left Hemisphere ◽  
Hemispheric Asymmetry ◽  
Time Course ◽  
Right Hemisphere ◽  
High Spatial Frequency ◽  
Hemispheric Differences ◽  
Spatial Frequencies ◽  
The Right ◽  
Perceptual Selection

Previous research has shown that the right hemisphere processes low spatial frequencies more efficiently than the left hemisphere, which preferentially processes high spatial frequencies. These studies have typically measured RTs to single, briefly flashed gratings and/or have directed observers to attend to a particular spatial frequency immediately before making a judgment about a subsequently presented stimulus. Thus, it is unclear whether the hemispheres differ in perceptual selection from multiple spatial frequencies that are simultaneously present in the environment, without bias from selective attention. Moreover, the time course of hemispheric asymmetry in spatial frequency processing is unknown. We addressed both of these questions with binocular rivalry, a measure of perceptual selection from competing alternatives over time. Participants viewed a pair of rivalrous orthogonal gratings with different spatial frequencies, presented either to the left or right of central fixation, and continuously reported which grating they perceived. At the beginning of a trial, the low spatial frequency grating was perceptually selected more often when presented in the left hemifield (right hemisphere) than in the right hemifield (left hemisphere), whereas the high spatial frequency grating showed the opposite pattern of results. This hemispheric asymmetry in perceptual selection persisted for the entire 30-sec stimulus presentation, continuing long after stimulus onset. These results indicate stable differences in the resolution of ambiguity across spatial locations and demonstrate the importance of considering sustained differences in perceptual selection across space when characterizing conscious representations of complex scenes.

Spatial Frequency-Dependent Asymmetry of Visual Evoked Potential Amplitudes

1996 ◽  
Vol 82 (3) ◽  
pp. 1011-1018
Author(s):  
Karl F. van Orden ◽  
John F. House
Keyword(s):  
Spatial Frequency ◽  
Left Hemisphere ◽  
Evoked Potential ◽  
Right Hemisphere ◽  
Field Configuration ◽  
Sinusoidal Grating ◽  
Pattern Reversal ◽  
Hemispheric Differences ◽  
The Right ◽  
Male Subjects

The extent to which pattern reversal evoked potential amplitudes are distributed symmetrically over the scalp was investigated as a function of stimulus spatial frequency. Nine right-handed male subjects viewed sinusoidal grating stimuli of 4.0 and 0.5 c/deg phase reversed every 900 msec. A visual half-field configuration enabled selective stimulation of the right- or left-hemisphere visual cortex. Evoked responses were recorded from the 2 cm above the inion (Oz) and at 7 and 13 cm lateral to Oz. Analyses of normalized evoked response amplitudes showed a significant asymmetry for the 4.0 c/deg stimulus; right-hemisphere amplitudes declined as a function of distance from the midline, while left-hemisphere amplitudes were greatest at the 7 cm recording site. No hemispheric differences were observed for the 0.5 c/deg stimulus; amplitudes for both hemispheres declined as a function of distance from the midline. The data are discussed in terms of hemispheric differences in morphology and functional asymmetries at early levels of sensory processing.

Hemispheric Specialization and Cognitive Development: Implications for Mathematics Education

1978 ◽  
Vol 9 (1) ◽  
pp. 20-32
Author(s):  
Grayson H. Wheatley ◽  
Robert Mitchell ◽  
Robert L. Frankland ◽  
Rosemarie Kraft
Keyword(s):  
Left Hemisphere ◽  
Hemispheric Asymmetry ◽  
Right Hemisphere ◽  
Mathematics Curriculum ◽  
Hemispheric Specialization ◽  
Brain Hemispheres ◽  
Spatial Tasks ◽  
Concrete Operational ◽  
The Right ◽  
Hemisphere Specialization

Evidence is presented for hemisphere specialization of the two brain hemispheres: the left hemisphere specialized for logico-analytic tasks and the right hemisphere, visuo-spatial tasks. A hypothesis is put forth for the emergence of the specialization that suggests a shift from predominant right hemisphere processing in infancy to predominant left hemisphere processing in adulthood. Results of the studies reviewed suggest the emergence of concrete-operational thought as the left hemisphere becomes capable of processing logical tasks. Electroencephalography seems particularly useful in determining specialization and mapping changes in hemispheric asymmetry. Implications for school mathematics curriculum are presented.

Hemispheric Processing of Categorical and Coordinate Spatial Relations in the Absence of Low Spatial Frequencies

2002 ◽  
Vol 14 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Matia Okubo ◽  
Chikashi Michimata
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Right Hemisphere ◽  
Spatial Relation ◽  
Spatial Relations ◽  
Right Visual Field ◽  
Spatial Frequencies ◽  
Categorical Task ◽  
The Right ◽  
Coordinate Spatial Relations

Right-handed participants performed the categorical and coordinate spatial relation judgments on stimuli presented to either the left visual field—right hemisphere (LVF-RH) or the right visual field—left hemisphere (RVF-LH). The stimulus patterns were formulated either by bright dots or by contrast-balanced dots. When the stimuli were bright, an RVF-LH advantage was observed for the categorical task, whereas an LVF-RH advantage was observed for the coordinate task. When the stimuli were contrast balanced, the RVF-LH advantage was observed for the categorical task, but the LVF-RH advantage was eliminated for the coordinate task. Because the contrast-balanced dots are largely devoid of low spatial frequency content, these results suggest that processing of low spatial frequency is responsible for the right hemisphere advantage for the coordinate spatial processing.

The Role of High Spatial Frequencies in Hemispheric Processing of Categorical and Coordinate Spatial Relations

2004 ◽  
Vol 16 (9) ◽  
pp. 1576-1582 ◽  
Author(s):  
Matia Okubo ◽  
Chikashi Michimata
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Right Hemisphere ◽  
High Spatial Frequency ◽  
Spatial Relation ◽  
Spatial Relations ◽  
Right Visual Field ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Categorical Task

Right-handed participants performed categorical and coordinate spatial relation tasks on stimuli presented either to the left visual field-right hemisphere (LVF-RH) or to the right visual field-left hemisphere (RVF-LH). The stimuli were either unfiltered or low-pass filtered (i.e., devoid of high spatial frequency content). Consistent with previous studies, the unfiltered condition produced a significant RVF-LH advantage for the categorical task and an LVF-RH advantage for the coordinate task. Low-pass filtering eliminated this Task × Visual Field interaction; thus, the RVF-LH advantage disappeared for the categorical task. The present results suggest that processing of high spatial frequency contributes to the left hemispheric advantage for categorical spatial processing.

Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Perception ◽  
2021 ◽  
Vol 50 (1) ◽  
pp. 27-38
Author(s):  
Ella K. Moeck ◽  
Nicole A. Thomas ◽  
Melanie K. T. Takarangi
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Memory Bias ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Involuntary Memory ◽  
Involuntary Memories ◽  
The Right

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect—termed a right hemisphere memory bias—also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.

Ipsilateral Motor Cortex Activity During Unimanual Hand Movements Relates to Task Complexity

2005 ◽  
Vol 93 (3) ◽  
pp. 1209-1222 ◽  
Author(s):  
Timothy Verstynen ◽  
Jörn Diedrichsen ◽  
Neil Albert ◽  
Paul Aparicio ◽  
Richard B. Ivry
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Time Course ◽  
Right Hemisphere ◽  
Task Complexity ◽  
Hand Movements ◽  
Left Hand ◽  
Sequential Structure ◽  
Single Finger ◽  
The Right

Functional imaging studies have revealed recruitment of ipsilateral motor areas during the production of sequential unimanual finger movements. This phenomenon is more prominent in the left hemisphere during left-hand movements than in the right hemisphere during right-hand movements. Here we investigate whether this lateralization pattern is related specifically to the sequential structure of the unimanual action or generalizes to other complex movements. Using event-related fMRI, we measured activation changes in the motor cortex during three types of unimanual movements: repetitions of a sequence of movements with multiple fingers, repetitive “chords” composed of three simultaneous key presses, and simple repetitive tapping movements with a single finger. During sequence and chord movements, strong ipsilateral activation was observed and was especially pronounced in the left hemisphere during left-hand movements. This pattern was evident for both right-handed and, to a lesser degree, left-handed individuals. Ipsilateral activation was less pronounced in the tapping condition. The site of ipsilateral activation was shifted laterally, ventrally, and anteriorly with respect to that observed during contralateral movements and the time course of activation implied a role in the execution rather than planning of the movement. A control experiment revealed that strong ipsilateral activity in left motor cortex is specific to complex movements and does not depend on the number of required muscles. These findings indicate a prominent role of left hemisphere in the execution of complex movements independent of the sequential nature of the task.

Functional Hemispheric Asymmetry and Belief in ESP: Towards a “Neuropsychology of Belief”

1993 ◽  
Vol 77 (3_suppl) ◽  
pp. 1299-1308 ◽  
Author(s):  
Peter Brugger ◽  
Alex Gamma ◽  
René Muri ◽  
Markus Schafer ◽  
Kirsten I. Taylor
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Left Hemisphere ◽  
Hemispheric Asymmetry ◽  
Right Hemisphere ◽  
Right Visual Field ◽  
Decision Task ◽  
Verbal Tasks ◽  
Hemisphere Dominance ◽  
The Right

30 right-handed subjects were given a lateralized tachistoscopic lexical-decision task. Subjects' belief in extrasensory perception (ESP) was assessed with a single six-point scale; 16 subjects were designated as believers in ESP and 14 subjects as nonbelievers. Believers in ESP did not exhibit a hemispheric asymmetry for the task while nonbelievers exhibited the expected right visual-field/left-hemisphere dominance documented in the literature. Believers' lack of asymmetry was not caused by an impaired left-hemisphere performance but rather by a significantly enhanced lexical-decision accuracy in the left visual field/right hemisphere compared to nonbelievers. These results are compatible with previous studies indicating a correlation between belief in ESP and a bias for right-hemisphere processing. Moreover, the results are relevant for a discussion of an association between paranormal beliefs and schizotypy: highly schizotypal individuals are not only particularly prone to believe in ESP but are also known to show an attenuation of hemispheric asymmetries in lateralized verbal tasks due to an enhanced contribution of the right hemisphere. We suggest that the neurological basis of delusion-like beliefs may involve a release of right-hemisphere function from left-hemisphere control and sketch the focus of research for a future “neuropsychology of belief.”

Selective Attention to Faces in a Rapid Visual Stream: Hemispheric Differences in Enhancement and Suppression of Category-selective Neural Activity

2018 ◽  
Vol 30 (3) ◽  
pp. 393-410 ◽  
Author(s):  
Genevieve Quek ◽  
Dan Nemrodov ◽  
Bruno Rossion ◽  
Joan Liu-Shuang
Keyword(s):  
Selective Attention ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Hemispheric Differences ◽  
Face Categorization ◽  
The Face ◽  
Left And Right ◽  
The Right ◽  
The Impact ◽  
Selective Activity

In daily life, efficient perceptual categorization of faces occurs in dynamic and highly complex visual environments. Yet the role of selective attention in guiding face categorization has predominantly been studied under sparse and static viewing conditions, with little focus on disentangling the impact of attentional enhancement and suppression. Here we show that attentional enhancement and suppression exert a differential impact on face categorization supported by the left and right hemispheres. We recorded 128-channel EEG while participants viewed a 6-Hz stream of object images (buildings, animals, objects, etc.) with a face image embedded as every fifth image (i.e., OOOOFOOOOFOOOOF…). We isolated face-selective activity by measuring the response at the face presentation frequency (i.e., 6 Hz/5 = 1.2 Hz) under three conditions: Attend Faces, in which participants monitored the sequence for instances of female faces; Attend Objects, in which they responded to instances of guitars; and Baseline, in which they performed an orthogonal task on the central fixation cross. During the orthogonal task, face-specific activity was predominantly centered over the right occipitotemporal region. Actively attending to faces enhanced face-selective activity much more evidently in the left hemisphere than in the right, whereas attending to objects suppressed the face-selective response in both hemispheres to a comparable extent. In addition, the time courses of attentional enhancement and suppression did not overlap. These results suggest the left and right hemispheres support face-selective processing in distinct ways—where the right hemisphere is mandatorily engaged by faces and the left hemisphere is more flexibly recruited to serve current tasks demands.

scholarly journals Revisiting Hemispheric Asymmetry in Mood Regulation: Implications for rTMS for Major Depressive Disorder

2022 ◽  
Vol 12 (1) ◽  
pp. 112
Author(s):  
Benjamin C. Gibson ◽  
Andrei Vakhtin ◽  
Vincent P. Clark ◽  
Christopher C. Abbott ◽  
Davin K. Quinn
Keyword(s):  
Major Depressive Disorder ◽  
Depressive Disorder ◽  
Left Hemisphere ◽  
Emotional Regulation ◽  
Emotional Processing ◽  
Right Hemisphere ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Hemispheric Differences ◽  
Major Depressive ◽  
The Right

Hemispheric differences in emotional processing have been observed for over half a century, leading to multiple theories classifying differing roles for the right and left hemisphere in emotional processing. Conventional acceptance of these theories has had lasting clinical implications for the treatment of mood disorders. The theory that the left hemisphere is broadly associated with positively valenced emotions, while the right hemisphere is broadly associated with negatively valenced emotions, drove the initial application of repetitive transcranial magnetic stimulation (rTMS) for the treatment of major depressive disorder (MDD). Subsequent rTMS research has led to improved response rates while adhering to the same initial paradigm of administering excitatory rTMS to the left prefrontal cortex (PFC) and inhibitory rTMS to the right PFC. However, accumulating evidence points to greater similarities in emotional regulation between the hemispheres than previously theorized, with potential implications for how rTMS for MDD may be delivered and optimized in the near future. This review will catalog the range of measurement modalities that have been used to explore and describe hemispheric differences, and highlight evidence that updates and advances knowledge of TMS targeting and parameter selection. Future directions for research are proposed that may advance precision medicine and improve efficacy of TMS for MDD.

Right-Hemisphere Superiority in the Discrimination of Spatial Phase

Perception ◽  
1984 ◽  
Vol 13 (6) ◽  
pp. 695-708 ◽  
Author(s):  
Adriana Fiorentini ◽  
Nicoletta Berardi
Keyword(s):  
Spatial Frequency ◽  
Right Hemisphere ◽  
Frequency Discrimination ◽  
High Contrast ◽  
Spatial Phase ◽  
Phase Discrimination ◽  
Visual Hemifield ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
The Right

Visual field differences have been investigated in various detection and discrimination tasks for simple sinusoidal gratings or for complex gratings composed of two sinusoids of spatial frequencies f and 3 f. Sinusoidal gratings were employed to evaluate contrast sensitivity, subthreshold summation effects, aftereffects of adaptation to a high-contrast grating, and spatial-frequency discrimination. The tasks with complex gratings were detection of the 3 f component in the presence of a high-contrast f component and spatial-phase discrimination. The stimuli were presented either in the left or in the right visual hemifield. The results indicate a lack of lateralization for detection and spatial-frequency discrimination of sinusoidal gratings, and for the bandwidth of subthreshold summation effects and adaptation aftereffects, whereas the detection of the 3 f component in the presence of a high-contrast f component, as well as spatial-phase discrimination of f + 3 f gratings, show a left-field advantage. This suggests a right-hemisphere superiority in the processing of spatial phase.

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