Tachistoscopic Task Research Articles

Can the right hemisphere read? A behavioral and disconnectome study on implicit reading in a patient with pure alexia

ABSTRACT Patients with pure alexia have major difficulties in reading aloud. However, they often perform above chance level in reading tasks that do not require overt articulation of the target word – like lexical decision or semantic judgment – a phenomenon usually known as “implicit reading.” There is no agreement in the literature on whether implicit reading should be attributed to relative sparing of some left hemisphere (LH) reading centers or rather to signs of compensatory endeavors by the right hemisphere (RH). We report the case of an 81-year-old patient (AA) with pure alexia due to a lesion involving the left occipital lobe and the temporal infero-mesial areas, as well as the posterior callosal pathways. Although AA’s reading was severely impaired and proceeded letter by letter, she showed an above-chance-level performance for frequent concrete words in a tachistoscopic lexical decision task. A structural disconnectome analysis revealed that AA’s lesion not only affected the left occipital cortex and the splenium: it also disconnected white-matter tracts meant to connect the visual word-form system to decision-related frontal areas within the LH. We suggest that the RH, rather than the LH, may be responsible for patient AA’s implicit reading.

Music Rehearsal Increases the Perceptual Span for Notation

DESPITE EVIDENCE FOR IMPROVED VISUAL PROCESSING of the printed score among skilled musicians, the effect of music rehearsal on the effective visual field ("perceptual span") for a musical score has never been directly examined. Following 1–20 rehearsals, 11 skilled and 10 less skilled adult musicians reported whether a variant note appeared within a melodic sequence of 3–18 notes, presented onscreen for 200 ms in a tachistoscopic task designed to evaluate the perceptual span. Initially, skilled musicians showed a slightly larger perceptual span for challenging passages (5 notes vs. 4 notes for less skilled musicians). Perceptual spans increased incrementally in both groups, but skill differences in span size disappeared by 20 rehearsals (span of 11 notes). A correlation between improvements in visual perceptual span and performance speed suggests that perceptual learning could underlie early improvements in performance during music rehearsals.

Space-based and object-based capacity limitations in visual search

Space-based accounts of visual attention assume that we select a limited spatial region independent of the number of objects it contains. In contrast, object-based accounts suggest that we select objects independent of their location. We investigated the boundary conditions on the selection modes of attention in a series of tachistoscopic visual search tasks, where the nature of capacity limitations on search was examined. Observers had to search for a horizontally oriented target ellipse among differently oriented distractor ellipses. Across four experiments, we orthogonally manipulated target-distractor (TD) similarity and distractor-distractor (DD) similarity. Each experiment consisted of a two-way design: Firstly, with a central cue, we indicated the spatial extent of the relevant search area. Secondly, we varied the number and spatial proximity of items in the display. Performance could be accounted for in terms of capacity limited object-based attention, assuming also that the spatial proximity of items enhances performance when there is high DD-similarity (and grouping). In addition, the cueing effect interacted with spatial proximity when DD-similarity was high, suggesting that grouping was influenced by attention. We propose that any capacity limits on visual search are due to object-based attention, and that the formation of perceptual objects and object groups is also subject to attentional modulation.

Semantic, perceptual and number space: Relations between category width and spatial processing

Coarse semantic encoding and broad categorization behavior are the hallmarks of the right cerebral hemisphere's contribution to language processing. We correlated 40 healthy subjects’ breadth of categorization as assessed with Pettigrew's category width scale with lateral asymmetries in perceptual and representational space. Specifically, we hypothesized broader category width to be associated with larger leftward spatial biases. For the 20 men, but not the 20 women, this hypothesis was confirmed both in a lateralized tachistoscopic task with chimeric faces and a random digit generation task; the higher a male participant's score on category width, the more pronounced were his left-visual field bias in the judgement of chimeric faces and his small-number preference in digit generation (“small” is to the left of “large” in number space). Subjects’ category width was unrelated to lateral displacements in a blindfolded tactile-motor rod centering task. These findings indicate that visual-spatial functions of the right hemisphere should not be considered independent of the same hemisphere's contribution to language. Linguistic and spatial cognition may be more tightly interwoven than is currently assumed.

Is defensiveness associated with cognitive bias away from emotional information?

The role of defensiveness and repressive coping style for the performance on a combined emotional Stroop and tachistoscopic identification task with masked and unmasked words was studied in a community sample. Defensiveness was associated with a decrease in Stroop interference for masked threat words, but not for unmasked threat words. The most robust results, however, were found with regard to overall test performance (independent of emotional valence). On the emotional Stroop task, high-defensive men (but not women) were faster to colour-name words in general, irrespective of emotional valence. On the tachistoscopic identification task, high-defensive women identified fewer words in general than low-defensive participants. The results are discussed in terms of defensiveness being associated with (a) avoidance of emotional information at an automatic, pre-attentive level, and (b) a general avoidance of potentially emotional information that takes different form in men and women depending on possible differences in what is seen as socially desirable for the two genders.

DYNAMIC LATERALIZATION: HOSTILITY, CARDIOVASCULAR REGULATION, AND TACHISTOSCOPIC RECOGNITION

This experiment tested a hypothesis linking the right cerebral regulation of hostility and cardiovascular arousal. It also replicates related research regarding hostility, cardiovascular regulation, and auditory recognition (Shenal and Harrison, 2003) through the visual modality. Thirty low- and high-hostile participants (n = 30) were identified using the Cook Medley Hostility Scale (CMHS). Only right-handed male participants with no significant medical or psychological history completed the experiment. All participants completed the cold pressor paradigm. Cardiovascular measures (systolic blood pressure [SBP] and diastolic blood pressure [DBP]) were recorded and tachistoscopic lexical recognition procedures were administered before and after the physical stressor.The primary finding of this research was greater left cerebral activation (decreased cardiovascular reactivity) following the tachistoscopic lexical recognition tasks and greater right cerebral activation following the painful (cold pressor) stressor

Visual and Lexical Factors in Naming Speed by Children with Reading Disorders

Reaction times of 12 reading disordered and 12 normally reading children and 12 adults were investigated with a visual half-field tachistoscopic picture-naming task. Analysis indicated slower picture-naming times for children with reading disorders. Hemispheric processing models suggested neurolinguistic maturation for rapid picture-naming speed.

Hemispheric specialisation, spatial activity experience, and sex differences on tests of mental rotation ability

A sex difference in mental rotation ability is well established. Among the explanations offered for this difference are that males are more frequently right hemisphere specialised for spatial processing and that they receive more spatial processing experience because of the sex stereotyping of activities involving spatial ability that exists in Western societies. Several studies have shown that males do report more spatial activity experiences on the Spatial Activity Questionnaire of Newcombe, Bandura, and Taylor (1983) and that such experience does correlate with performances on tests of mental rotation. However, two prior lateralised tachistoscopic studies failed to show right hemisphere superiority for spatial task performance or that it was positively associated with better performances on the Vandenberg Mental Rotation Test. The tachistoscopic tasks used in these studies can be criticised on methodological grounds. The present study employed a new tachistoscopic task that showed that males were significantly more right hemisphere specialised (left visual-field superior) for the tachistoscopic task than females. Magnitudes of right hemisphere specialisation on the tachistoscopic task were positively and significantly related to mental rotation ability. Spatial activity experiences were also more common in males. Covariance and partial correlation analyses indicated that the sex difference in spatial ability was primarily due to sex differences in right hemisphere specialisation for mental rotation, while sex differences in spatial activity experiences were only secondarily involved.

Timing of right parietal and frontal cortex activity in visuo-spatial perception: a TMS study in normal individuals

In a recent study we showed that repetitive transcranial magnetic stimulation (rTMS) with train duration of 400 ms over right frontal and right posterior parietal cortices gives rise to transitory contralateral visuo-spatial neglect in normal subjects. In the present experiment we investigated whether using single-pulse TMS it is possible to obtain information about the timing of cortical activity related to spatial cognition. Nine healthy subjects performed in baseline condition and during TMS a tachistoscopic task, requiring a forced-choice estimation of the length of the two segments of prebisected horizontal lines. Single-pulse TMS was triggered at various time intervals (150 ms, 225 ms, 300 ms) after visual stimulus onset with a focal coil over P6 and F4 (according to 10/20 EEG system). Relative transitory rightward bias was observed only when parietal TMS was delivered 150 ms after visual stimulus presentation. Frontal stimulation induced no effect on visuo-spatial perception with the time intervals explored.

Interhemispheric transfer evaluation in multiple sclerosis 1The authors would like to thank Claude-Alain Hauert and Christoph Michel for their assistance in the evaluation of motor tapping and Michel Habib for his suggestions and comments. This work was supported by a grant from the Swiss Society of Multiple Sclerosis.

Patients suffering from Multiple Sclerosis (MS) have frequently been found to suffer from damage to callosal fibers. Investigations have shown that this damage is associated with signs of hemisphere disconnections. The aim of our study was to provide evidence for the first signs of interhemispheric dysfunction in a mildly disabled MS population. Therefore, we explored whether the Interhemispheric Transfer (IT) deficit is multi-modal and sought to differentiate two MS evolution forms, on the basis of an interhemispheric disconnection index. Twenty-two patients with relapsing-remitting form of MS (RRMS) and 14 chronic-progressive (CPMS) were compared with matched controls on four tasks: a tachistoscopic verbal and non-verbal decision task, a dichotic listening test, cross tactile finger localization and motor tapping. No overall impairment was seen. The dichotic listening and lexical decision tasks were the most sensitive to MS. In addition, CPMS patients' IT was more impaired and was related to the severity of neurological impairment. The different sizes of the callosal fibers, which determine their vulnerability, may explain the heterogeneity of transfer through the Corpus Callosum. Therefore, evaluation of IT may be of value as an index of evolution in MS.

Word perceptual priming with a same or different typography using the tachistoscopic identification task: a PET study

Word perceptual priming with a same or different typography using the tachistoscopic identification task: a PET study

Individual Differences in Callosal Efficiency: Correlation with Attention

Previous studies of clinical populations and normal children have suggested that the efficiency of callosal transfer correlates with the ability to sustain attention. The purpose of the present study was to determine whether the same might be true for normal adults. Subjects were 42 right-handed adults. The efficiency of the transfer via the anterior callosum was assessed on a bimanual coordination task. The efficiency of the posterior callosum was measured on a tachistoscopic task that required subjects to compare two lines when both were presented either to the same visual field or to opposite visual fields. Sustained attention was measured on a vigilance task in which the time between target presentations (ISI) was varied. Performance on the bimanual task correlated with the ability to sustain attention over the entire 20 min of the vigilance task. The efficiency of the posterior callosum was related to the ability to detect targets that occurred after relatively long ISIs.

Preattentive bias for emotional information in panic disorder with agoraphobia.

A combined emotional Stroop and implicit memory (tachistoscopic identification) task with 3 types of words (panic-related, interpersonal threat, and neutral words) and 2 exposure conditions (subliminal, supraliminal) was administered to 35 patients with panic disorder and 35 age- and sex-matched controls. The patients showed Stroop interference for panic-related words both sub- and supraliminally and a similar but not equally robust effect on interpersonal threat words. On the tachistoscopic identification task, the patients identified more panic-related words than the controls did but showed no implicit memory bias effect. The patients' subliminal Stroop interference for panic-related words was found to correlate with trait anxiety and depression, although not with anxiety sensitivity.

Dermatoglyphic Asymmetry is Related to Perceptual Asymmetry and to Interhemispheric Transmission

The numbers of ridges on the fingertips is asymmetrical between hands and is also sexually dimorphic. Most people have more ridges on the right hand (rightward dermatoglyphic asymmetry; R >) and men typically have more ridges than women. The direction of dermatoglyphic asymmetry has been shown to be related to patterns of cognitive abilities in men and women and to perceptual asymmetry in homosexual men. W e assessed presumptively heterosexual, right-handed men and women who had either R > (n = 35) or L > (n = 30) ridge count, on: (1) dichotic listening to words; (2) two tachistoscopic tasks sampling visual field asymmetries (dot location and letter identification); and (3) a tachistoscopic task designed to examine interhemispheric transmission. L > subjects had a smaller right-ear advantage than R > subjects, but this was accounted for by an increased incidence of an atypical left-ear advantage in the L > group. Visual field asymmetries were also smaller in the L > group but the asymmetry measures did not reach significance, with the exception of an increased incidence of an atypical field advantage (left) for letter recognition only. On the interhemispheric transfer task, L > subjects performed relatively faster on tasks requiring interhemispheric comparisons than did R > subjects. These findings confirm an association between the direction of dermatoglyphic asymmetry and aspects of brain organisation.

Dermatoglyphic Asymmetry is Related to Perceptual Asymmetry and to Interhemispheric Transmission

The numbers of ridges on the fingertips is asymmetrical between hands and is also sexually dimorphic. Most people have more ridges on the right hand (rightward dermatoglyphic asymmetry; R >) and men typically have more ridges than women. The direction of dermatoglyphic asymmetry has been shown to be related to patterns of cognitive abilities in men and women and to perceptual asymmetry in homosexual men. W e assessed presumptively heterosexual, right-handed men and women who had either R > (n = 35) or L > (n = 30) ridge count, on: (1) dichotic listening to words; (2) two tachistoscopic tasks sampling visual field asymmetries (dot location and letter identification); and (3) a tachistoscopic task designed to examine interhemispheric transmission. L > subjects had a smaller right-ear advantage than R > subjects, but this was accounted for by an increased incidence of an atypical left-ear advantage in the L > group. Visual field asymmetries were also smaller in the L > group but the asymmetry measures did not reach significance, with the exception of an increased incidence of an atypical field advantage (left) for letter recognition only. On the interhemispheric transfer task, L > subjects performed relatively faster on tasks requiring interhemispheric comparisons than did R > subjects. These findings confirm an association between the direction of dermatoglyphic asymmetry and aspects of brain organisation.

Sex-related engagement of the hemispheres in visuospatial processing.

Hemispheric asymmetries in visuospatial functions were investigated in women and men with a tachistoscopic task using lateralized presentation of "Necker" cubes. A lexical decision task served as control. In either of the two tasks the procedure involved a bilateral presentation of correct and distorted items and responses had to be given by means of a nonverbal decision task. The analysis of hits in the cube task showed a right visual field advantage for women and a left visual field advantage for men, but women had more false alarms in the right visual field, whereas men showed the reverse pattern again. The lexical decision task showed similar response patterns for men and women. The distinct response behavior supports the hypothesis that tasks allowing for various strategies to choose from obviously are better suited to elicit a differential engagement of the two hemispheres in women and men.

Anomalous perceptual asymmetries for negative emotional stimuli in the psychopath.

This study tested the hypothesis that when processing negative emotional material, psychopaths, compared with nonpsychopaths, would rely less on connotative-emotional processes based in the right hemisphere and more on denotative-linguistic processes based in the left hemisphere. Psychopathic and nonpsychopathic inmate groups, defined by their scores on the Psychopathy Checklist--Revised (R. D. Hare 1985), completed 2 analogous tachistoscopic tasks (words and faces). Accuracy and reaction times of inmates' responses in identifying which of 2 bilaterally presented stimuli (1 neutral and 1 emotional) was the emotional stimulus were measured. Significant lateral processing differences between the 2 groups emerged on the word task but not on the face task, providing partial support for the experimental hypothesis. Psychopaths also showed lower generalized emotional responsivity than nonpsychopaths on the Affect Intensity Measure.

Tachistoscopic applications of Micro Experimental Laboratory (MEL) used with IBM PC compatibles: Stimulus and response timing issues

IBM PCs and compatibles are increasingly used in psychological research for tachistoscopic tasks, which require precise control of timing of stimulus durations and accurate measurement of response latencies. The application of MEL in such research is discussed; several precautions which influence stimulus timing are noted, and some data on measurement error with keypress responses are presented.

On language laterality in normal dextrals and sinistrals: Results from the Bilateral Object Naming Latency Task

Rasmussen and Milner [ N.Y. Acad. Sci. Vol. 299, pp. 355–379, 1977] published data on late-lesioned (after age 6) epileptic patients who had suffered left hemisphere lesions. They estimated that left hemisphere dominance occurred in 96% of dextrals and 70% of sinistrals. These figures have been regarded as valid estimates for normal dextrals and sinistrals. We administered the Bilateral Object Naming Latency Task, a verbal tachistoscopic task with very good psychometric properties, to 188 dextral and 72 sinistral normals. Results showed that 93.6% of the dextrals and 80.3% of the sinistrals were left hemisphere dominant. A consideration of results from a number of carefully conducted dichotic listening studies suggests, as do present results, that the 70% left-dominance estimate of Rasmussen and Milner for normal sinistrals may be too low by about 10%. It is suggested that ‘bilateral dominance’, present in 15% of the epileptic sinistrals of Rasmussen and Milner, may be much less common in normal sinistrals.

Spring‐autumn variations in hemispheric asymmetry

Abstract 48 right‐handed subjects performed verbal and spatial hemifield tachistoscopic tasks, half of them during spring and the other half during autumn. Results showed increased visual field advantage both in performance speed and accuracy in the right visual field during spring and in the left visual field during autumn. This suggests a seasonal‐hemispheric shift favouring the left hemisphere during spring and the right hemisphere during autumn, and provides a clue to understanding seasonal variations in mood and affective states as related to variations in cognitive style.