Modulation of Cortical Activity During Different Imitative Behaviors

2003 ◽  
Vol 89 (1) ◽  
pp. 460-471 ◽  
Author(s):  
Lisa Koski ◽  
Marco Iacoboni ◽  
Marie-Charlotte Dubeau ◽  
Roger P. Woods ◽  
John C. Mazziotta

Imitation is a basic form of motor learning during development. We have a preference to imitate the actions of others as if looking in a mirror (specular imitation: i.e., when the actor moves the left hand, the imitator moves the right hand) rather than with the anatomically congruent hand (anatomic imitation: i.e., actor and imitator both moving the right hand). We hypothesized that this preference reflects changes in activity in previously described frontoparietal cortical areas involved in directly matching observed and executed actions (mirror neuron areas). We used functional magnetic resonance imaging to study brain activity in normal volunteers imitating left and right hand movements with their right hand. Bilateral inferior frontal and right posterior parietal cortex were more active during specular imitation compared with anatomic imitation and control motor tasks. Furthermore this same pattern of activity was also observed in the rostral part of the supplementary motor area (SMA-proper) of the right hemisphere. These findings suggest that the degree of involvement of frontoparietal mirror areas in imitation depends on the nature of the imitative behavior, ruling out a linguistic mediation of these areas in imitation. Moreover, activity in the SMA appears to be tightly coupled to frontoparietal mirror areas when subjects copy the actions of others.

2012 ◽  
Vol 24 (3) ◽  
pp. 543-552 ◽  
Author(s):  
Matthew R. Longo ◽  
Jason Jiri Musil ◽  
Patrick Haggard

Integration of information across sensory modalities is enhanced when stimuli in both modalities are in the same location. This “spatial rule” of multisensory integration has been primarily studied in humans by comparing stimuli located either in the same versus opposite side of the body midline or in peripersonal versus extrapersonal space, both of which involve large, categorical differences in spatial location. Here we used psychophysics and ERPs to investigate visuo-tactile integration in personal space (i.e., on the skin surface). We used the mirror box technique to manipulate the congruence of visual and tactile information about which finger on either the right or left hand had been touched. We observed clear compatibility effects for both visual and tactile judgments of which finger on the left hand had been touched. No such effects, however, were found for judgments about the right hand. ERP data showed a similar pattern. Amplitude of the vertex P200 potential was enhanced and that of the N2 was reduced for congruent visuo-tactile events on the left, but not the right, hand. Similarly, a later positivity over posterior parietal cortices (P300) showed contralateral enhancement for congruent visuo-tactile events on both the left and right hands. These results provide clear evidence for spatial constraints on visuo-tactile integration defined in personal space and also reveal clear lateralization of these effects. Furthermore, these results link these “ultraprecise” spatial constraints to processing in the right posterior parietal cortex.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Selene Schintu ◽  
Elisa Martín-Arévalo ◽  
Michael Vesia ◽  
Yves Rossetti ◽  
Romeo Salemme ◽  
...  

Rightward prism adaptation ameliorates neglect symptoms while leftward prism adaptation (LPA) induces neglect-like biases in healthy individuals. Similarly, inhibitory repetitive transcranial magnetic stimulation (rTMS) on the right posterior parietal cortex (PPC) induces neglect-like behavior, whereas on the left PPC it ameliorates neglect symptoms and normalizes hyperexcitability of left hemisphere parietal-motor (PPC-M1) connectivity. Based on this analogy we hypothesized that LPA increases PPC-M1 excitability in the left hemisphere and decreases it in the right one. In an attempt to shed some light on the mechanisms underlying LPA’s effects on cognition, we investigated this hypothesis in healthy individuals measuring PPC-M1 excitability with dual-site paired-pulse TMS (ppTMS). We found a left hemisphere increase and a right hemisphere decrease in the amplitude of motor evoked potentials elicited by paired as well as single pulses on M1. While this could indicate that LPA biases interhemispheric connectivity, it contradicts previous evidence that M1-only MEPs are unchanged after LPA. A control experiment showed that input-output curves were not affected by LPAper se. We conclude that LPA combined with ppTMS on PPC-M1 differentially alters the excitability of the left and right M1.


2011 ◽  
Vol 366 (1564) ◽  
pp. 572-585 ◽  
Author(s):  
L. Pisella ◽  
N. Alahyane ◽  
A. Blangero ◽  
F. Thery ◽  
S. Blanc ◽  
...  

We review evidence showing a right-hemispheric dominance for visuo-spatial processing and representation in humans. Accordingly, visual disorganization symptoms (intuitively related to remapping impairments) are observed in both neglect and constructional apraxia. More specifically, we review findings from the intervening saccade paradigm in humans—and present additional original data—which suggest a specific role of the asymmetrical network at the temporo-parietal junction (TPJ) in the right hemisphere in visual remapping: following damage to the right dorsal posterior parietal cortex (PPC) as well as part of the corpus callosum connecting the PPC to the frontal lobes, patient OK in a double-step saccadic task exhibited an impairment when the second saccade had to be directed rightward . This singular and lateralized deficit cannot result solely from the patient's cortical lesion and, therefore, we propose that it is due to his callosal lesion that may specifically interrupt the interhemispheric transfer of information necessary to execute accurate rightward saccades towards a remapped target location. This suggests a specialized right-hemispheric network for visuo-spatial remapping that subsequently transfers target location information to downstream planning regions, which are symmetrically organized.


1998 ◽  
Vol 86 (3) ◽  
pp. 967-975 ◽  
Author(s):  
Brian K. V. Maraj ◽  
Digby Elliott ◽  
James Lyons ◽  
Eric A. Roy ◽  
Tamara Winchester

Two experiments were conducted to examine manual asymmetries in a one-dimensional aiming task. In Exp. 1, 10 right-handed adults slid a computer mouse 13 cm on a graphics tablet with both the right and left hands to targets of 3 different diameters. Under these conditions, the movement time for the right hand was significantly faster as expected. In Exp. 2, subjects performed similar movements to move a cursor 13 cm on a computer monitor. Thus the study was identical except the stimulus-response mapping was indirect. In this situation, there were no significant differences for either movement time or movement error between hands despite these performance measures indicating that target aiming was more difficult in Exp. 2. Because increases in task difficulty generally result in a greater advantage for the right hand, as indicated by Todor & Smiley, 1985, the present studies suggest that superiority of the right hand in aiming tasks may be diminished when spatial translation is required. Perhaps the spatial translation requires greater involvement of the right hemisphere, a process associated with manual advantage for the left hand, previously suggested by Roy and MacKenzie.


Author(s):  
Sherma Zacharias ◽  
Andrew Kirk

ABSTRACT:Background:Constructional impairment following left vs. right hemisphere damage has been extensively studied using drawing tasks. A confounding factor in these studies is that right-handed patients with left hemisphere damage (LHD) are often forced by weakness to use their non-dominant (left) hand or hemiparetic dominant hand. Qualitative differences in the drawing characteristics of left and right hand drawings by normal subjects have not previously been characterized. The present study was undertaken to determine the qualitative differences between left and right hand drawings of normal subjects.Methods:Thirty right-handed, elderly subjects without a history of neurological disease were asked to draw, from memory, seven objects using the right and left hand. Half of the subjects were randomly assigned to draw with the left hand first, and half the right hand first. Right and left hand drawings were compared using a standardized scoring system utilized in several previous studies of drawing in focal and diffuse neurological disease. Each drawing was scored on eighteen criteria. Right and left hand drawing scores were then compared using the t-test for paired samples or the Wilcoxon matched-pairs testResults:Drawings made using the left hand were found to be significantly simpler, more tremulous and of poorer overall quality than drawings made by the same subjects using the right hand.Conclusions:The deficits found in left versus right hand drawings of normals are similar to those found in patients with LHD, suggesting that much of the drawing impairment seen following LHD is due to an elementary motor disturbance related to use of the non-dominant hand.


2012 ◽  
Vol 69 (8) ◽  
pp. 681-685
Author(s):  
Natasa Djukic-Macut ◽  
Slobodan Malobabic ◽  
Natalija Stefanovic ◽  
Predrag Mandic ◽  
Tatjana Filipovic ◽  
...  

Background/Aim. Both superior parietal lobule (SPL) of dorsolateral hemispheric surface and precuneus (PEC) of medial surface are the parts of posterior parietal cortex. The aim of this study was to determine the numerical density (NV) of pyramidal neurons in the layer V of SPL and PEC and their potential differences. Methods. From 20 (40 hemispheres) formaline fixed human brains (both sexes; 27- 65 years) tissue blocks from SPL and PEC from the left and right hemisphere were used. According to their size the brains were divided into two groups, the group I with the larger left (15 brains) and the group II with the larger right hemisphere (5 brains). Serial Nissl sections (5 ?m) of the left and right SPL and PEC were used for stereological estimation of NV of the layer V pyramidal neurons. Results. NV of pyramidal neurons in the layer V in the left SPL of brains with larger left hemispheres was significantly higher than in the left SPL of brains with larger right hemisphere. Comparing sides in brains with larger left hemisphere, the left SPL had higher NV than the right one, and then the left PEC, and the right SPL had significantly higher NV than the right PEC. Comparing sides in brains with the larger right hemisphere, the left SPL had significantly higher NV than left PEC, but the right SPL had significantly higher NV than left SPL and the right PEC. Conclusion. Generally, there is an inverse relationship of NV between the medial and lateral areas of the human posterior parietal cortex. The obtained values were different between the brains with larger left and right hemispheres, as well as between the SPL and PEC. In all the comparisons the left SPL had the highest values of NV of pyramidal neurons in the layer V (4771.80 mm-3), except in brains with the larger right hemisphere.


1984 ◽  
Vol 59 (3) ◽  
pp. 933-934 ◽  
Author(s):  
James K. Maxwell ◽  
Fred Wise ◽  
Mary Pepping ◽  
Brenda D. Townes ◽  
John Peel ◽  
...  

Records from 495 psychiatric patients from two neuropsychology laboratories indicated the Fingertip Number Writing test shows a significant and reliable left-hand advantage within and between laboratories. While the left-hand advantage may reflect a right-hemisphere superiority for tactile-spatial processing, it is not possible to distinguish between right hemispheric functional superiority and practice effects between hands because the standard fingertip writing task always starts with the right hand.


2020 ◽  
Author(s):  
Helena Hartmann ◽  
Markus Rütgen ◽  
Federica Riva ◽  
Claus Lamm

AbstractThe shared representations account of empathy suggests that sharing other people’s emotions relies on neural processes similar to those engaged when directly experiencing such emotions. Recent research corroborated this by showing that placebo analgesia resulted in reduced pain empathy and decreased activation in shared neural networks. However, those studies did not report any placebo-related variation of somatosensory engagement during pain empathy. The experimental paradigms used in these studies did not direct attention towards a specific body part in pain, which may explain the absence of effects for somatosensation. The main objective of this preregistered study was to implement a paradigm overcoming this limitation, and to investigate whether placebo analgesia may also modulate the sensory-discriminative component of empathy for pain. We induced a localized, first-hand placebo analgesia effect in the right hand of 45 participants by means of a placebo gel and conditioning techniques, and compared this to the left hand as a control condition. Participants underwent a pain task in the MRI scanner, receiving painful or non-painful electrical stimulation on their left or right hand, or witnessing another person receiving such stimulation. In contrast to a robust localized placebo analgesia effect for self-experienced pain, the empathy condition showed no differences between the two hands, neither for behavioral nor neural responses. We thus report no evidence for somatosensory sharing in empathy, while replicating previous studies showing overlapping brain activity in the affective-motivational component for first-hand and empathy for pain. Hence, in a more rigorous test aiming to overcome limitations of previous work, we again find no causal evidence for the engagement of somatosensory sharing in empathy. Our study refines the understanding of the neural underpinnings of empathy for pain, and the use of placebo analgesia in investigating such models.HighlightsInvestigated placebo modulation of somatosensory and affective components of painLocalized placebo analgesia effects for self-report and fMRI of first-hand painNo evidence for such effects in empathy for painSuggests that somatosensory sharing does not play a critical role in pain empathy


2021 ◽  
Author(s):  
Lorenzo Diana ◽  
Patrick Pilastro ◽  
Edoardo N. Aiello ◽  
Aleksandra K. Eberhard-Moscicka ◽  
René M. Müri ◽  
...  

ABSTRACTIn the present work, we applied anodal transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and frontal eye field (FEF) of the right hemisphere in healthy subjects to modulate attentional orienting and disengagement in a gap-overlap task. Both stimulations led to bilateral improvements in saccadic reaction times (SRTs), with larger effects for gap trials. However, analyses showed that the gap effect was not affected by tDCS. Importantly, we observed significant effects of baseline performance that may mediate side- and task-specific effects of brain stimulation.


1988 ◽  
Vol 67 (3) ◽  
pp. 927-933 ◽  
Author(s):  
Linda Z. Podbros ◽  
Maria A. Wyke

Multiple or sequential finger tapping is preferential to the dominant right hand with respect to speed. However, in more complex movement, variables other than speed become important. The present investigation uses a sequential finger-rapping task which permits assessment of between-hands differences with respect to rate and control of movement, with and without vision. 36 right-handed normal adults rapidly tapped their fingers in sequential order on a block (2.54 cm. sq.), trying not to move the block. Analyses of variance (mode × hand) performed for taps and shift of the block show the right hand to be faster than the left hand with and without vision, adding further to the notion that the left hemisphere predominates in increases in rapid movement and in sequencing aspects of motor activity. However, while both hands were steadier with vision than without, there were no between-hand differences with regard to control, suggesting equivalency of cerebral function for factors of manual sequencing other than speed.


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