The Role of the Right Posterior Parietal Cortex in Letter Migration between Words

2015 ◽  
Vol 27 (2) ◽  
pp. 377-386 ◽  
Author(s):  
Dario Cazzoli ◽  
René M. Müri ◽  
Christopher Kennard ◽  
Clive R. Rosenthal
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Word Reading ◽  
Letter Position ◽  
Control Group ◽  
Neural Basis ◽  
Specific Effects ◽  
Letter Position Coding ◽  
Posterior Parietal ◽  
The Right

When briefly presented with pairs of words, skilled readers can sometimes report words with migrated letters (e.g., they report hunt when presented with the words hint and hurt). This and other letter migration phenomena have been often used to investigate factors that influence reading such as letter position coding. However, the neural basis of letter migration is poorly understood. Previous evidence has implicated the right posterior parietal cortex (PPC) in processing visuospatial attributes and lexical properties during word reading. The aim of this study was to assess this putative role by combining an inhibitory TMS protocol with a letter migration paradigm, which was designed to examine the contributions of visuospatial attributes and lexical factors. Temporary interference with the right PPC led to three specific effects on letter migration. First, the number of letter migrations was significantly increased only in the group with active stimulation (vs. a sham stimulation group or a control group without stimulation), and there was no significant effect on other error types. Second, this effect occurred only when letter migration could result in a meaningful word (migration vs. control context). Third, the effect of active stimulation on the number of letter migrations was lateralized to target words presented on the left. Our study thus demonstrates that the right PPC plays a specific and causal role in the phenomenon of letter migration. The nature of this role cannot be explained solely in terms of visuospatial attention, rather it involves an interplay between visuospatial attentional and word reading-specific factors.

scholarly journals Attentional bias to threat and gray mater volume morphology in high anxious individuals

2020 ◽  
Author(s):  
Joshua M. Carlson ◽  
Lin Fang
Keyword(s):  
Attentional Bias ◽  
Parietal Cortex ◽  
Gray Matter ◽  
Posterior Parietal Cortex ◽  
Gray Matter Volume ◽  
Anterior Cingulate ◽  
Brain Morphology ◽  
Matter Volume ◽  
Posterior Parietal ◽  
The Right

AbstractIn a sample of highly anxious individuals, the relationship between gray matter volume brain morphology and attentional bias to threat was assessed. Participants performed a dot-probe task of attentional bias to threat and gray matter volume was acquired from whole brain structural T1-weighted MRI scans. The results replicate previous findings in unselected samples that elevated attentional bias to threat is linked to greater gray matter volume in the anterior cingulate cortex, middle frontal gyrus, and striatum. In addition, we provide novel evidence that elevated attentional bias to threat is associated with greater gray matter volume in the right posterior parietal cortex, cerebellum, and other distributed regions. Lastly, exploratory analyses provide initial evidence that distinct sub-regions of the right posterior parietal cortex may contribute to attentional bias in a sex-specific manner. Our results illuminate how differences in gray matter volume morphology relate to attentional bias to threat in anxious individuals. This knowledge could inform neurocognitive models of anxiety-related attentional bias to threat and targets of neuroplasticity in anxiety interventions such as attention bias modification.

Paired pulse TMS over the right posterior parietal cortex modulates visuospatial perception

2006 ◽  
Vol 247 (2) ◽  
pp. 144-148 ◽  
Author(s):  
Brigida Fierro ◽  
Filippo Brighina ◽  
Giuseppe Giglia ◽  
Antonio Palermo ◽  
Margherita Francolini ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Paired Pulse ◽  
Visuospatial Perception ◽  
Posterior Parietal ◽  
The Right

Far Space Remapping by Tool Use: A rTMS Study Over the Right Posterior Parietal Cortex

2015 ◽  
Vol 8 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Giuseppe Giglia ◽  
Lorenzo Pia ◽  
Alessia Folegatti ◽  
Angela Puma ◽  
Brigida Fierro ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Tool Use ◽  
Posterior Parietal Cortex ◽  
Posterior Parietal ◽  
The Right

Representation of time intervals in the right posterior parietal cortex: Implications for a mental time line

NeuroImage ◽  
2009 ◽  
Vol 46 (4) ◽  
pp. 1173-1179 ◽  
Author(s):  
Massimiliano Oliveri ◽  
Giacomo Koch ◽  
Silvia Salerno ◽  
Sara Torriero ◽  
Emanuele Lo Gerfo ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Time Intervals ◽  
Time Line ◽  
Mental Time Line ◽  
Posterior Parietal ◽  
The Right ◽  
Representation Of Time

scholarly journals Asymmetries in numerical density of pyramidal neurons in the fifth layer of the human posterior parietal cortex

2012 ◽  
Vol 69 (8) ◽  
pp. 681-685
Author(s):  
Natasa Djukic-Macut ◽  
Slobodan Malobabic ◽  
Natalija Stefanovic ◽  
Predrag Mandic ◽  
Tatjana Filipovic ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Pyramidal Neurons ◽  
Right Hemisphere ◽  
Numerical Density ◽  
Group I ◽  
Posterior Parietal ◽  
Left And Right ◽  
Layer V ◽  
The Right

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.

Hemispheric Asymmetry in Memory-Guided Pointing During Single-Pulse Transcranial Magnetic Stimulation of Human Parietal Cortex

2006 ◽  
Vol 96 (6) ◽  
pp. 3016-3027 ◽  
Author(s):  
Michael Vesia ◽  
Jachin A. Monteon ◽  
Lauren E. Sergio ◽  
J. D. Crawford
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Magnetic Stimulation ◽  
Hemispheric Asymmetry ◽  
Posterior Parietal Cortex ◽  
Single Pulse ◽  
Pointing Movements ◽  
Posterior Parietal ◽  
The Right ◽  
Stimulation Of

Dorsal posterior parietal cortex (PPC) has been implicated through single-unit recordings, neuroimaging data, and studies of brain-damaged humans in the spatial guidance of reaching and pointing movements. The present study examines the causal effect of single-pulse transcranial magnetic stimulation (TMS) over the left and right dorsal posterior parietal cortex during a memory-guided “reach-to-touch” movement task in six human subjects. Stimulation of the left parietal hemisphere significantly increased endpoint variability, independent of visual field, with no horizontal bias. In contrast, right parietal stimulation did not increase variability, but instead produced a significantly systematic leftward directional shift in pointing (contralateral to stimulation site) in both visual fields. Furthermore, the same lateralized pattern persisted with left-hand movement, suggesting that these aspects of parietal control of pointing movements are spatially fixed. To test whether the right parietal TMS shift occurs in visual or motor coordinates, we trained subjects to point correctly to optically reversed peripheral targets, viewed through a left–right Dove reversing prism. After prism adaptation, the horizontal pointing direction for a given visual target reversed, but the direction of shift during right parietal TMS did not reverse. Taken together, these data suggest that induction of a focal current reveals a hemispheric asymmetry in the early stages of the putative spatial processing in PPC. These results also suggest that a brief TMS pulse modifies the output of the right PPC in motor coordinates downstream from the adapted visuomotor reversal, rather than modifying the upstream visual coordinates of the memory representation.

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