Divided Visual Field Presentation Research Articles

Hemispheric engagement during the processing of affective adjectives—an ERP divided visual field study

ABSTRACT The study looked into the hemispheres’ involvement in emotional word encoding. It combined brain activity measures (ERPs) with behavioural data during the affective categorization task in the divided visual field presentation paradigm. Forty healthy right-handed student volunteers took part in the study, in which they viewed and evaluated 33 positive and 33 negative emotional adjectives presented to either the left or right visual field. We observed a marginally significant effect on the earlier time window (220–250 ms, the P2 component) with higher mean amplitudes evoked to the words presented to the right hemisphere, and then a strong effect on the 340–400 ms (the P3) with a reversed pattern (higher amplitudes for words presented to the left hemisphere). The latter effect was also visible in the error rates and RTs, with better overall performance for adjectives presented to the left hemisphere. There was also an effect on behavioural data of positive words only (higher error rates, shorter RTs). Thus, the study showed a particular “progression” pattern of hemispheric engagement: dependence of the initial stages of affective lexico-semantic processing on the right hemisphere, replaced by the left-hemispheric dominance for content evaluation and response programming stages.

Interhemispheric transfer of semantic information facilitates bilateral word recognition.

Language comprehension is left-lateralized but with variable contributions from the right hemisphere. When both hemispheres are stimulated simultaneously using divided visual field presentation, performance may be enhanced or hindered depending on the complexity of the task, and these effects may relate to independent processing in both hemispheres or to information transfer between hemispheres. Simultaneous stimulation of both hemispheres is thought to suppress interhemispheric interactions, but information transfer may nonetheless occur. Studies with simultaneous bilateral displays have demonstrated that semantic information from the contralateral visual field (and hemisphere) can facilitate relatedness judgments and lexical decisions. The current study extends this line of research by assessing semantic information transfer in a bilateral word identification task. Task manipulations involving directed spatial attention and asymmetric primes (e.g., ATOM → BOMB) were used to isolate automatic priming as opposed to top-down processing. The results revealed 2 main findings: (a) interhemispheric priming in the form of improved word recognition occurred specifically in conditions designed to isolate automatic transfer of semantic information, that is, in the attended visual field for the target word in asymmetric prime pairs, and (b) there is evidence for an asymmetrical transfer of semantic information, in that the subordinate left visual field-right hemisphere benefited more from such transfer. Together, these results demonstrate evidence for automatic interhemispheric transfer of semantic information, even under conditions of simultaneous bilateral display. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Hemispheric asymmetry in holistic processing of words

ABSTRACTHolistic processing has been regarded as a hallmark of face perception, indicating the automatic and obligatory tendency of the visual system to process all face parts as a perceptual unit rather than in isolation. Studies involving lateralized stimulus presentation suggest that the right hemisphere dominates holistic face processing. Holistic processing can also be shown with other categories such as words and thus it is not specific to faces or face-like expertize. Here, we used divided visual field presentation to investigate the possibly different contributions of the two hemispheres for holistic word processing. Observers performed same/different judgment on the cued parts of two sequentially presented words in the complete composite paradigm. Our data indicate a right hemisphere specialization for holistic word processing. Thus, these markers of expert object recognition are domain general.

Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention.

Two dominant theories on lateralized processing of emotional information exist in the literature. One theory posits that unpleasant emotions are processed by right frontal regions, while pleasant emotions are processed by left frontal regions. The other theory posits that the right hemisphere is more specialized for the processing of emotional information overall, particularly in posterior regions. Assessing the different roles of the cerebral hemispheres in processing emotional information can be difficult without the use of neuroimaging methodologies, which are not accessible or affordable to all scientists. Divided visual field presentation of stimuli can allow for the investigation of lateralized processing of information without the use of neuroimaging technology. This study compared central versus divided visual field presentations of emotional images to assess differences in motivated attention between the two hemispheres. The late positive potential (LPP) was recorded using electroencephalography (EEG) and event-related potentials (ERPs) methodologies to assess motivated attention. Future work will pair this paradigm with a more active behavioral task to explore the behavioral impacts on the attentional differences found.

The effect of cognitive load on hemispheric asymmetries in true and false memory

ABSTRACTStudies examining hemispheric asymmetries in false memory have shown that the right hemisphere (RH) is more susceptible to false memories compared to the left hemisphere (LH). Theories suggest that hemispheric asymmetries in true and false memory may be due to differences in representational coding and the use of top-down mechanisms in each hemisphere. In the current study, the Deese–Roediger–McDermott false memory paradigmwas used in conjunction with divided visual field presentation to examine the role of top-down mechanisms in hemispheric asymmetries of true and false memory. In Experiment 1, participants studied lists of related words while completing secondary cognitive load tasks. In Experiment 2, the secondary tasks were administered during memory retrieval instead of memory encoding. Results revealed that cognitive loads imposed during the study phase influenced veridical memory in the LH more than the RH, but cognitive loads imposed during retrieval did not influence veridical memory in either hemisphere. Surprisingly, false memory rates were not influenced by cognitive loads and were higher in the LH. These data provide evidence that, at least for veridical memory, top-down control mechanisms are used more readily for the encoding of information into memory in the LH compared to the RH.

What forgetting tells us about remembering: The influence of top–down control on hemispheric asymmetries in verbal memory

It has been suggested that left hemisphere (LH) advantages in verbal processing is due to superior top–down control of verbal information. It is not clear how top–down mechanisms affect the encoding and retrieval of verbal information from hemispheric memory and whether they only influence activation or also encompass the inhibition of verbal information. The directed forgetting method, in conjunction with divided visual field presentation, was used to examine the influence of top–down control mechanisms on hemispheric asymmetries in verbal memory. Participants were cued to remember or forget words. Cues were presented either simultaneously with targets or after a short delay. A recognition memory test using divided visual field presentation was then given. Response times (RTs) revealed effects of cue timing in the LH. With simultaneous cues, RTs were faster to “Remember” words compared to “Forget” words. With delayed cues, RTs for “Remember” and “Forget” words were equivalent. In the right hemisphere (RH), “Remember” words were consistently faster than “Forget” words, regardless of cue timing. These data provide evidence that top–down mechanisms influenced LH verbal memory retrieval more than RH verbal memory retrieval. Finally, there was little evidence to suggest the hemispheres differ in inhibitory processing.

Hemispheric asymmetry in discriminating faces differing for featural or configural (second-order relations) aspects

The human capacity to discriminate among different faces relies on distinct parallel subprocesses, based either on the analysis of configural aspects or on the sequential analysis of the single elements of a face. A particular type of configural processing consists of considering whether two faces differ in terms of internal spacing among their features, referred to as second-order relations processing. Findings from electrophysiological, neuroimaging, and lesion studies suggest that, overall, configural processes rely more on the right hemisphere, whereas analysis of single features would involve more the left. However, results are not always consistent, and behavioral evidence for a right-hemisphere specialization in second-order relations processing is lacking. Here, we used divided visual field presentation to investigate the possible different contributions of the two hemispheres to face discrimination based on relational versus featural processing. Our data indicate a right-hemispheric specialization in relational processing of upright (but not inverted) faces. Furthermore, we provide evidence regarding the involvement of both the right and left hemispheres in the processing of faces differing for inner features, suggesting that both analytical and configural modes of processing are at play.

Hemispheric asymmetry in interpreting novel literal language: An event-related potential study

Conceptual mapping, or making connections between conceptual structure in different domains, is a key mechanism of creative language use whose neural underpinnings are not well understood. The present study involved the combination of event-related potentials (ERPs) with the divided visual field presentation technique to explore the relative contributions of the left and right hemispheres (LH and RH) to the construction of novel meanings in fully literal language. Electroencephalogram (EEG) was recorded as healthy adults read sentences that supported either a conventional literal reading of the sentence final word (“His main method of transportation is a boat,”), or a novel literal meaning derived from conceptual mapping (“The clever boys used a cardboard box as a boat,”). The novel and conventional conditions were matched for cloze probability (a measure of predictability based on the sentence context), lexical association between the sentence frame and the final word (using latent semantic analysis), and other factors known to influence ERPs to language stimuli. To compare effects of novelty to previously reported effects of predictability, a high-cloze conventional condition (“The only way to get around Venice is to navigate the canals in a boat.”) was included. ERPs were time-locked to sentence final words (“boat”) presented in either the left visual field, to preferentially stimulate the RH (lvf/RH), or in the right visual field, targeting the LH (rvf/LH). The N400 component of the ERP was affected by predictability in both presentation sides, but by novelty only in rvf/LH. Two distinct late frontal positive effects were observed. Word predictability modulated a frontal positivity with a LH focus, but semantic novelty modulated a frontal positivity focused in RH. This is the first demonstration that the frontal positivity may be composed of multiple overlapping components with distinct functional and anatomical characteristics. Extending contemporary accounts of the frontal positivity, we suggest that both frontal positivities reflect learning mechanisms involving prediction based on statistical regularities in language (LH) and world knowledge (RH).

Hemispheric Asymmetry of Visual Scene Processing in the Human Brain: Evidence from Repetition Priming and Intrinsic Activity

Asymmetrical specialization of cognitive processes across the cerebral hemispheres is a hallmark of healthy brain development and an important evolutionary trait underlying higher cognition in humans. While previous research, including studies of priming, divided visual field presentation, and split-brain patients, demonstrates a general pattern of right/left asymmetry of form-specific versus form-abstract visual processing, little is known about brain organization underlying this dissociation. Here, using repetition priming of complex visual scenes and high-resolution functional magnetic resonance imaging (MRI), we demonstrate asymmetrical form specificity of visual processing between the right and left hemispheres within a region known to be critical for processing of visual spatial scenes (parahippocampal place area [PPA]). Next, we use resting-state functional connectivity MRI analyses to demonstrate that this functional asymmetry is associated with differential intrinsic activity correlations of the right versus left PPA with regions critically involved in perceptual versus conceptual processing, respectively. Our results demonstrate that the PPA comprises lateralized subregions across the cerebral hemispheres that are engaged in functionally dissociable yet complementary components of visual scene analysis. Furthermore, this functional asymmetry is associated with differential intrinsic functional connectivity of the PPA with distinct brain areas known to mediate dissociable cognitive processes.

INTERHEMISPHERIC CONNECTIVITY DURING COGNITIVE CONTROL IS RELATED TO CALLOSAL STRUCTURAL INTEGRITY IN SCHIZOPHRENIA: A COMBINED DTI AND fMRI STUDY

A divided visual field presentation of the Stroop colour-word test was used to study interhemispheric (transcallosal) function in schizophrenic and normal subjects. The modified test used a colour strip paired with either an incongruent, neutral or congruent colour word. Interference and facilitation were defined as t he difference between the mean reaction times for incongruent stimuli and neutral stimuli and that between neutral stimuli and congruent stimuli, respectively. The stimuli were presented tachistoscopically with the two components either separated across the midline centrally, up or down from the midpoint (bilateral presentation), or presented to a single visual half-field (unilateral presentation). The inclusion of the ‘up’ and ‘down’ bilateral conditions controlled for the reaction time advantage for central compared with unilateral stimulus presentations noted in an earlier study (David, 1993a). The difference in reaction time to an incongruent compared with a congruent colour-word pairing, the Combined Stroop Effect (CSE), was not affected significantly by stimulus presentation position (bilateral vs. unilateral) in either the control or schizophrenic group, unlike in the earlier study of David. For controls, interference was significantly greater than facilitation for both bilaterally- and unilaterally-presented stimuli. Schizophrenics had a significantly smaller interference effect for bilaterally-presented stimuli, indicating reduced interhemispheric interference in this group. For the control group, there was no significant difference between right and left CSEs, interference being significantly greater than facilitation on both visual half-field presentations. For schizophrenics, the CSE for left-presented stimuli was significantly greater than that for right-presented stimuli. In addition, left-field facilitation was significantly greater than right-field. Reduced Stroop facilitation with right-field presentations in schizophrenic subjects may reflect increased vulnerability of colour-naming by word-reading in the left hemisphere - evidence for the non-unitary nature of attentional processes and disintegration of these in schizophrenia.

Phonological processing of words in right- and left-handers

It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors such as characteristics of the stimuli and subjects' handedness can modulate the right visual field advantage. Thus, the goal of this study was to compare the hemispheric dynamics of right-handers and left-handers during a divided visual field presentation of words that varied in terms of their phonological transparency. For non-transparent words, the left hemisphere seems more competent in both handedness groups. With regard to transparent words, the right hemisphere of both groups also appears competent. Surprisingly, left-handers achieved optimal processing with a functionally isolated left hemisphere, whereas right-handers needed the participation of both hemispheres. The pattern of performance cannot be fully explained by either the callosal or the direct access model.

Initial right hemisphere take-over and subsequent bilateral participation during recovery from aphasia

Background: In 1887, Gowers proposed that supplemental action by the right frontal cortex could sustain language following aphasia. Since then, many studies using a wide variety of experimental paradigms have examined the role of the right hemisphere in the recovery from aphasia. Aims: This study examines the right hemisphere's participation in the recovery from aphasia between four and sixteen months following brain damage. Methods & Procedures: RJ, a young woman with severe Broca's aphasia resulting from a left fronto-temporal hematoma, was followed up at four-month intervals with a divided visual field presentation lexical decision task (LDT). At each time of measurement, we examined her performance with high- and low-imageability nouns and verbs, directed to either cerebral hemisphere and in central vision. A language test was used to examine the pattern of language recovery over time, and a non-verbal version of the Stroop test (NVST) served to follow up changes in attention. The results obtained with the LDT and the NVST were analyzed with ANOVAs; the changes in the pattern of language recovery and the results on the attentional task were also considered in the analysis. Outcomes & Results: There was a left visual field advantage with high-imageability words, regardless of their grammatical class, at four months post stroke. The right hemisphere advantage extended to low-imageability words at eight months after aphasia onset. Concurrently, language comprehension tasks made a significant recovery, whereas language expression tasks recovered only slightly. Furthermore, there was no significant improvement on the attentional task within the same time period. One year after the stroke, RJ's pattern of lateralization changed; there was a marginally significant central vision advantage on word processing, and no significant difference in her performance on lateralized presentations. There was a remarkable recovery on oral expression tasks, and some improvement on the attentional task within the same period. Conclusions: The results of the present study indicate that recovery from aphasia may be sustained by both cerebral hemispheres. The participation of either hemisphere may vary with time elapsed. Our results suggest that high-imageability nouns and verbs may constitute a good target for speech therapy during the first months post stroke, in order to benefit from right hemisphere takeover capacities. Furthermore, low imageability nouns and verbs are candidates for right hemisphere takeover as well, if enough time is allowed. Finally, the results of this study suggest that right hemisphere involvement in language recovery may occur in the absence of a concurrent improvement of attention. In line with previous studies, our results indicate that the recovery of oral expression coincides with the improvement of left hemisphere function. Hence, the fact that language expression started to improve one year after the stroke suggests that recovery from a severe language expression deficit is a long process, and may require long-term follow-up.

Stroop interference and facilitation in the cerebral hemispheres in schizophrenia

A divided visual field presentation of the Stroop colour-word test was used to study interhemispheric (transcallosal) function in schizophrenic and normal subjects. The modified test used a colour strip paired with either an incongruent, neutral or congruent colour word. Interference and facilitation were defined as t he difference between the mean reaction times for incongruent stimuli and neutral stimuli and that between neutral stimuli and congruent stimuli, respectively. The stimuli were presented tachistoscopically with the two components either separated across the midline centrally, up or down from the midpoint (bilateral presentation), or presented to a single visual half-field (unilateral presentation). The inclusion of the ‘up’ and ‘down’ bilateral conditions controlled for the reaction time advantage for central compared with unilateral stimulus presentations noted in an earlier study (David, 1993a). The difference in reaction time to an incongruent compared with a congruent colour-word pairing, the Combined Stroop Effect (CSE), was not affected significantly by stimulus presentation position (bilateral vs. unilateral) in either the control or schizophrenic group, unlike in the earlier study of David. For controls, interference was significantly greater than facilitation for both bilaterally- and unilaterally-presented stimuli. Schizophrenics had a significantly smaller interference effect for bilaterally-presented stimuli, indicating reduced interhemispheric interference in this group. For the control group, there was no significant difference between right and left CSEs, interference being significantly greater than facilitation on both visual half-field presentations. For schizophrenics, the CSE for left-presented stimuli was significantly greater than that for right-presented stimuli. In addition, left-field facilitation was significantly greater than right-field. Reduced Stroop facilitation with right-field presentations in schizophrenic subjects may reflect increased vulnerability of colour-naming by word-reading in the left hemisphere - evidence for the non-unitary nature of attentional processes and disintegration of these in schizophrenia.

Lateralisation of Language Functioning by the Wada Procedure and Divided Visual Field Presentation of a Verbal Task

In cases of intractable epilepsy, language and memory functioning in the hemisphere contralateral to the lesion is determined prior to unilateral temporal surgery. Patients with unilateral temporal lobe lesions were assessed using the intracarotid sodium amytal (Wada) procedure to determine the lateralisation of language and memory functioning. They also performed a divided visual field task in which letters were presented in pairs for brief durations on a computer screen in a phonemic matching task. The results showed only moderate agreement between the two methods with regard to identification of the speech-dominant hemisphere, indicating the divided visual field matching paradigm to be unsuitable as a basis for surgical decision-making.

Lateralized Priming in a Levels of Processing Task

This study investigated the effect of divided visual field presentation of stimuli upon a levels of processing memory task. Subjects (N=15) were asked questions designed to prompt processing at orthographic, phonemic, syntactic or semantic levels. Results indicated no main effect when the prime was semantically related to the target or for visual field of presentation of the prime. However, an interaction was observed such that significantly improved recall obtained with right visual field prime presentation when subjects were first prompted with questions about semantic category information. Further analysis suggested that the increased recall was due to semantically-related prime words which had been presented to the right visual field. Implications for lateralized styles of processing within a levels of processing framework are discussed.