scholarly journals Reassessing lateralization in calculation

2018 ◽  
Vol 373 (1740) ◽  
pp. 20170044 ◽  
Author(s):  
Carlo Semenza ◽  
Silvia Benavides-Varela
Keyword(s):  
Left Hemisphere ◽  
Clinical Studies ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Simple Calculation ◽  
The Other ◽  
Precise Calculation ◽  
The Right ◽  
Specific Contribution

The role of the left hemisphere in calculation has been unequivocally demonstrated in numerous studies in the last decades. The right hemisphere, on the other hand, had been traditionally considered subsidiary to the left hemisphere functions, although its role was less clearly defined. Recent clinical studies as well as investigations conducted with other methodologies (e.g. neuroimaging, transcranial magnetic stimulation and direct cortical electro-stimulation) leave several unanswered questions about the contribution of the right hemisphere in calculation. In particular, novel clinical studies show that right hemisphere acalculia encompasses a wide variety of symptoms, affecting even simple calculation, which cannot be easily attributed to spatial disorders or to a generic difficulty effect as previously believed. The studies reported here also show how the right hemisphere has its own specific role and that only a bilateral orchestration between the respective functions of each hemisphere guarantees, in fact, precise calculation. Vis-à-vis these data, the traditional wisdom that attributes to the right hemisphere a role mostly confined to spatial aspects of calculation needs to be significantly reshaped. The question for the future is whether it is possible to precisely define the specific contribution of the right hemisphere in several aspects of calculation while highlighting the nature of the cross-talk between the two hemispheres. This article is part of a discussion meeting issue ‘The origins of numerical abilities’.

Phrase comprehension after brain damage

1982 ◽  
Vol 3 (3) ◽  
pp. 263-278 ◽  
Author(s):  
Rita Sloan Berndt ◽  
Alfonso Caramazza
Keyword(s):  
Brain Damage ◽  
Left Hemisphere ◽  
Language Comprehension ◽  
Right Hemisphere ◽  
The Other ◽  
Right Hemisphere Damage ◽  
Dimensional Adjectives ◽  
Neurologically Normal ◽  
The Right

ABSTRACTComprehension of six dimensional adjectives was found to be intact in groups of left hemisphere-damaged, right hemisphere-damaged and neurologically normal patients. Phrases with those adjectives were interpreted quite differently by left hemisphere-damaged patients than by the other two groups, and a subgroup of left-damaged patients appeared to be responsible for that group's deviant responses to phrases such as slightly bigger. All patients in the left-damaged group had some difficulty with negative phrases such as not big, however. Patients with right hemisphere-damage had difficulty interpreting only negative phrases with small. Results are interpreted with reference to Luria's discussion of semantic aphasia, and with regard to recent findings concerning the role of the right hemisphere in language comprehension.

The Role of Cognitive and Hemispheric Processing Styles in L2 Learning

1989 ◽  
Vol 85-86 ◽  
pp. 105-121
Author(s):  
Cem Alptekin
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Hemispheric Processing ◽  
Processing Styles ◽  
Field Independent ◽  
Educational Implications ◽  
L2 Learners ◽  
Analytic Processing ◽  
The Right

L2 learners fall into two major categories in terms of their cognitive styles. The first group comprises the relatively analytical individuals, who are said to be predominantly field independent. The second group, on the other hand, embodies the relatively holistic persons, who are said to be chiefly field dependent. L2 learners are further classified in terms of their hemispheric processing styles. Some learners are left-hemisphere dominant while others are right-hemisphere dominant. The former are thought to be more efficient with analytic processing in which the left hemisphere specializes. By contrast, the latter are described as more efficient with holistic processing in which the right hemisphere specializes. After reviewing the available evidence for the associations between cognitive and hemispheric processing styles, the paper discusses the educational implications of L2 learners' differences with respect to cognitive and hemispheric dimensions.

Memory Processes and Gestural Performance in Apraxia

1993 ◽  
Vol 10 (4) ◽  
pp. 293-311 ◽  
Author(s):  
Eric A. Roy ◽  
Liana Brown ◽  
Tammi Winchester ◽  
Paula Square ◽  
Craig Hall ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Special Populations ◽  
Complex Nature ◽  
Special Population ◽  
Cognitive Neuropsychology ◽  
Memory Processes ◽  
Motor Processes ◽  
The Right

Apraxia is an impairment in the ability to pantomime or imitate gestures usually caused by a stroke more frequently to the left than the right hemisphere. Due to the complex nature of apraxia, disruptions to a number of different cognitive and motor processes have been proposed to underly this disorder. In order to examine disruptions to these processes the participation of a special population of people who have suffered a stroke has been enlisted. The role of memory has been particularly well elucidated in studies of this special population, as patients with left hemisphere damage exhibit a particular deficit in performing gestures from memory. In this paper, through use of a model depicting the stages involved in gestural production, the processes that might be affected at each stage by left hemisphere damage are examined. The implications of the “cognitive neuropsychology” approach for incorporating special populations into research in the movement sciences are considered.

Lateralised semantic and indirect semantic priming effects in people with schizophrenia

1998 ◽  
Vol 172 (2) ◽  
pp. 142-146 ◽  
Author(s):  
Matthias Weisbrod ◽  
Sabine Maier ◽  
Sabine Harig ◽  
Ulrike Himmelsbach ◽  
Manfred Spitzer
Keyword(s):  
Left Hemisphere ◽  
Semantic Priming ◽  
Language Processing ◽  
Semantic Processing ◽  
Right Hemisphere ◽  
Contextual Information ◽  
Striking Difference ◽  
Semantic Associations ◽  
The Right

BackgroundIn schizophrenia, disturbances in the development of physiological hemisphere asymmetry are assumed to play a pathogenetic role. The most striking difference between hemispheres is in language processing. The left hemisphere is superior in the use of syntactic or semantic information, whereas the right hemisphere uses contextual information more effectively.MethodUsing psycholinguistic experimental techniques, semantic associations were examined in 38 control subjects, 24 non-thought-disordered and 16 thought-disordered people with schizophrenia, for both hemispheres separately.ResultsDirect semantic priming did not differ between the hemispheres in any of the groups. Only thought-disordered people showed significant indirect semantic priming in the left hemisphere.ConclusionsThe results support: (a) a prominent role of the right hemisphere for remote associations; (b) enhanced spreading of semantic associations in thought-disordered subjects; and (c) disorganisation of the functional asymmetry of semantic processing in thought-disordered subjects.

scholarly journals Handedness Does Not Impact Inhibitory Control, but Movement Execution and Reactive Inhibition Are More under a Left-Hemisphere Control

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1602
Author(s):  
Christian Mancini ◽  
Giovanni Mirabella
Keyword(s):  
Left Hemisphere ◽  
Inhibitory Control ◽  
Right Hemisphere ◽  
Dominant Role ◽  
Hemispheric Specialization ◽  
Arm Movement ◽  
Proactive Inhibition ◽  
Stop Signal Task ◽  
The Right

The relationship between handedness, laterality, and inhibitory control is a valuable benchmark for testing the hypothesis of the right-hemispheric specialization of inhibition. According to this theory, and given that to stop a limb movement, it is sufficient to alter the activity of the contralateral hemisphere, then suppressing a left arm movement should be faster than suppressing a right-arm movement. This is because, in the latter case, inhibitory commands produced in the right hemisphere should be sent to the other hemisphere. Further, as lateralization of cognitive functions in left-handers is less pronounced than in right-handers, in the former, the inhibitory control should rely on both hemispheres. We tested these predictions on a medium-large sample of left- and right-handers (n = 52). Each participant completed two sessions of the reaching versions of the stop-signal task, one using the right arm and one using the left arm. We found that reactive and proactive inhibition do not differ according to handedness. However, we found a significant advantage of the right versus the left arm in canceling movements outright. By contrast, there were no differences in proactive inhibition. As we also found that participants performed movements faster with the right than with the left arm, we interpret our results in light of the dominant role of the left hemisphere in some aspects of motor control.

Incomplete Gustatory Lateralization as Shown by Analysis of Taste Discrimination After Callosotomy

2000 ◽  
Vol 12 (2) ◽  
pp. 238-245 ◽  
Author(s):  
Salvatore Aglioti ◽  
Giancarlo Tassinari ◽  
Michael C. Corballis ◽  
Giovanni Berlucchi
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
The Other ◽  
Callosal Agenesis ◽  
Speed Of Response ◽  
Complete Section ◽  
Taste Discrimination ◽  
The Right ◽  
Lateral Organization ◽  
Normal Controls

The lateral organization of the gustatory pathway in man is incompletely understood. Majority of the studies support an uncrossed projection from each side of the tongue to the cortex, but reports of an opposite crossed organization continue to appear in the neurological literature. We studied the lateral organization of the gustatory pathway in normal controls, a man with a complete callosal agenesis, and a man with a complete section of the corpus callosum, a right anterior-frontal lesion, and language in the left hemisphere. Sapid solutions were applied to one or the other side of the tongue, and subjects reported the taste of the stimulus either verbally or by manually pointing to the name of the taste. There were no differences in accuracy and reaction time between the right and left hemitongues of the controls and the genetically acallosal observer. By contrast, the callosotomy subject showed a constant marked advantage of the left hemitongue over the right for both accuracy and speed of response, though performance with right stimuli was clearly above chance. The left advantage can be attributed to the left hemisphere being favored by the essentially verbal nature of the task, or to the presence of a lesion in cortical gustatory areas in the right hemisphere, or to both factors. Whichever of these hypotheses turns out to be correct, the results unequivocally reject the notion of an exclusively crossed organization of the gustatory pathway from the tongue to the cortex, and favor the notion of a bilaterally distributed organization of this pathway with a marked predominance of the uncrossed over the crossed component.

Bias for the Left Visual Field in Rapid Serial Visual Presentation: Effects of Additional Salient Cues Suggest a Critical Role of Attention

2015 ◽  
Vol 27 (2) ◽  
pp. 266-279 ◽  
Author(s):  
Kamila Śmigasiewicz ◽  
Dariusz Asanowicz ◽  
Nicole Westphal ◽  
Rolf Verleger
Keyword(s):  
Visual Field ◽  
Left Visual Field ◽  
Right Hemisphere ◽  
Critical Role ◽  
Visual Presentation ◽  
The Other ◽  
Early Posterior Negativity ◽  
Left And Right ◽  
The Right

Everyday experience suggests that people are equally aware of stimuli in both hemifields. However, when two streams of stimuli are rapidly presented left and right, the second target (T2) is better identified in the left hemifield than in the right hemifield. This left visual field (LVF) advantage may result from differences between hemifields in attracting attention. Therefore, we introduced a visual cue shortly before T2 onset to draw attention to one stream. Thus, to identify T2, attention was correctly positioned with valid cues but had to be redirected to the other stream with invalid ones. If the LVF advantage is caused by differences between hemifields in attracting attention, invalid cues should increase, and valid cues should reduce the LVF advantage as compared with neutral cues. This prediction was confirmed. ERP analysis revealed that cues evoked an early posterior negativity, confirming that attention was attracted by the cue. This negativity was earlier with cues in the LVF, which suggests that responses to salient events are faster in the right hemisphere than in the left hemisphere. Valid cues speeded up, and invalid cues delayed T2-evoked N2pc; in addition, valid cues enlarged T2-evoked P3. After N2pc, right-side T2 evoked more sustained contralateral negativity than left T2, least long-lasting after valid cues. Difficulties in identifying invalidly cued right T2 were reflected in prematurely ending P3 waveforms. Overall, these data provide evidence that the LVF advantage is because of different abilities of the hemispheres in shifting attention to relevant events in their contralateral hemifield.

scholarly journals The Representation of Polysemy: MEG Evidence

2006 ◽  
Vol 18 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Liina Pylkkänen ◽  
Rodolfo Llinás ◽  
Gregory L. Murphy
Keyword(s):  
Natural Language ◽  
Semantic Similarity ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Lexical Representation ◽  
The Other ◽  
Lexical Activation ◽  
The Right ◽  
Identity And Difference ◽  
Polysemous Words

Most words in natural language are polysemous, that is, they can be used in more than one way. For example, paper can be used to refer to a substance made out of wood pulp or to a daily publication printed on that substance. Although virtually every sentence contains polysemy, there is little agreement as to how polysemy is represented in the mental lexicon. Do different uses of polysemous words involve access to a single representation or do our minds store distinct representations for each different sense? Here we investigated priming between senses with a combination of behavioral and magnetoencephalographic measures in order to test whether different senses of the same word involve identity or mere formal and semantic similarity. Our results show that polysemy effects are clearly distinct from similarity effects bilaterally. In the left hemisphere, sense-relatedness elicited shorter latencies of the M350 source, which has been hypothesized to index lexical activation. Concurrent activity in the right hemisphere, on the other hand, peaked later for sense-related than for unrelated target stimuli, suggesting competition between related senses. The obtained pattern of results supports models in which the representation of polysemy involves both representational identity and difference: Related senses connect to same abstract lexical representation, but are distinctly listed within that representation.

Excitatory Deep Transcranial Magnetic Stimulation With H-Coil Over the Right Homologous Broca’s Region Improves Naming in Chronic Post-stroke Aphasia

2013 ◽  
Vol 28 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Raffaella Chieffo ◽  
Federico Ferrari ◽  
Petronilla Battista ◽  
Elise Houdayer ◽  
Arturo Nuara ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Random Sequence ◽  
Inferior Frontal Gyrus ◽  
Naming Task ◽  
Broca’S Region ◽  
The Right

Background. The role of the right hemisphere in poststroke aphasia recovery is still controversial and the effects of repetitive transcranial magnetic stimulation (rTMS) over the right homologous Broca’s region have been seldom investigated. Objective. This study aimed to compare the effect of excitatory, inhibitory, and sham rTMS delivered with H-coil over the right inferior frontal gyrus in chronic aphasic patients. Methods. Five right-handed poststroke aphasic patients underwent a picture naming task before and immediately after each of 3 sessions of rTMS: excitatory (10 Hz), inhibitory (1 Hz), and sham rTMS, in random sequence and separated by at least 1 week. Results. Only the excitatory 10-Hz stimulation was associated with a significant improvement in naming performance ( P = .043) and was significantly more effective than 1-Hz rTMS ( P = .043). Conclusions. A single session of excitatory deep brain rTMS over the right inferior frontal gyrus with H-coil significantly improves naming in right-handed chronic poststroke aphasic patients. This result is in line with the hypothesis of a positive, rather than detrimental, role of the right hemisphere in chronic aphasia due to a left-hemispheric stroke.

Transcranial Magnetic Stimulation of the Human Frontal Eye Field: Effects on Visual Perception and Attention

2002 ◽  
Vol 14 (7) ◽  
pp. 1109-1120 ◽  
Author(s):  
Marie-Hélène Grosbras ◽  
Tomáš Paus
Keyword(s):  
Eye Movements ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Visual Detection ◽  
Frontal Eye Field ◽  
Target Onset ◽  
Eye Field ◽  
The Right

When looking at one object, human subjects can shift their attention to another object in their visual field without moving the eyes. Such shifts of attention activate the same brain regions as those involved in the execution of eye movements. Here we investigate the role of one of the main cortical oculomotor area, namely, the frontal eye field (FEF), in shifts of attention. We used transcranial magnetic stimulation (TMS), a technique known to disrupt transiently eye-movements preparation. We hypothesized that if the FEF is a necessary element in the network involved in shifting attention without moving the eyes, then TMS should also disrupt visuospatial attention. For each volunteer, we positioned the TMS coil over the probabilistic anatomical location of the FEF, and we verified that single pulses delayed eye movements. We then applied TMS during a visuospatial attention task. In this task, a central arrow directed shifts of attention and the subject responded by a keypress to a subsequent visual peripheral target without moving the eyes from the central fixation point. In a few trials, the cue was invalid or uninformative, yielding slower responses than when the cue was valid. We delivered single pulses either 53 msec before or 70 msec after target onset. Contrary to our prediction, the main effect of the stimulation was a decrease in reaction time when it was applied 53 msec before target onset. TMS over the left hemisphere facilitated responses to targets in the right hemifield only and for all cueing conditions, whereas TMS over the right hemisphere had a bilateral effect for valid and neutral but not invalid cueing. Thus, TMS interfered with shift of attention only in the case of right hemisphere stimulation: it increased the cost of invalid cueing. Our results suggest that TMS over the FEF facilitates visual detection, and thereby reduces reaction time. This finding provides new insights into the role of the human FEF in processing visual information. The functional asymmetry observed for both facilitation of visual detection and interference with shifts of attention provides further evidence for the dominance of the right hemisphere for those processes. Our results also underline that the disruptive or facilitative effect of TMS over a given region depends upon the behavioral context.

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