Visual interhemispheric communication and callosal connections of the occipital lobes

Cortex ◽  
2014 ◽  
Vol 56 ◽  
pp. 1-13 ◽  
Author(s):  
Giovanni Berlucchi
Keyword(s):  
Interhemispheric Communication ◽  
Callosal Connections ◽  
Occipital Lobes

scholarly journals Is the Imitative Competence an Asymmetrically Distributed Function?

2021 ◽  
Vol 15 ◽  
Author(s):  
Mara Fabri ◽  
Chiara Pierpaoli ◽  
Nicoletta Foschi ◽  
Gabriele Polonara
Keyword(s):  
White Matter ◽  
Corpus Callosum ◽  
Human Brain ◽  
Mental Rotation ◽  
Functional Data ◽  
Healthy Subjects ◽  
Interhemispheric Communication ◽  
Split Brain ◽  
Callosal Connections ◽  
Asymmetrically Distributed

This study reconsiders behavioral and functional data from studies investigating the anatomical imitation (AI) and the related mental rotation (MR) competence, carried out by our group in healthy subjects, with intact interhemispheric connections, and in split-brain patients, completely or partially lacking callosal connections. The results strongly point to the conclusion that AI and MR competence requires interhemispheric communication, mainly occurring through the corpus callosum, which is the largest white matter structure in the human brain. The results are discussed in light of previous studies and of future implications.

scholarly journals Functional Expansion of Sensorimotor Representation and Structural Reorganization of Callosal Connections in Lower Limb Amputees

2012 ◽  
Vol 32 (9) ◽  
pp. 3211-3220 ◽  
Author(s):  
E. L. Simoes ◽  
I. Bramati ◽  
E. Rodrigues ◽  
A. Franzoi ◽  
J. Moll ◽  
...  
Keyword(s):  
Lower Limb ◽  
Structural Reorganization ◽  
Callosal Connections ◽  
Functional Expansion ◽  
Lower Limb Amputees

Interhemispheric communication of abstract and specific visual-form information

2002 ◽  
Vol 40 (12) ◽  
pp. 1983-1999 ◽  
Author(s):  
Chad J Marsolek ◽  
Christopher D Nicholas ◽  
David R Andresen
Keyword(s):  
Interhemispheric Communication ◽  
Visual Form ◽  
Form Information

scholarly journals The Callosal Relay Model of Interhemispheric Communication: New Evidence from Effective Connectivity Analysis

2017 ◽  
Vol 31 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Saskia Steinmann ◽  
Jan Meier ◽  
Guido Nolte ◽  
Andreas K. Engel ◽  
Gregor Leicht ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Connectivity Analysis ◽  
Interhemispheric Communication ◽  
New Evidence

scholarly journals Morphology of the vertebral artery in Asian population

2014 ◽  
Vol 5 (4) ◽  
pp. 84-88 ◽  
Author(s):  
Maryna Alfaouri-Kornieieva ◽  
Azmy M Al-Hadidi
Keyword(s):  
Vertebral Artery ◽  
Asian Population ◽  
Outer Diameter ◽  
Medical Sciences ◽  
The Third ◽  
Asian Patients ◽  
Distal Loop ◽  
The Right ◽  
Occipital Lobes ◽  
The Brain

Background: Recent clinical trials have shown a rising trend of stroke in Asian population. Approximately 20% strokes of total occur at the vertebrobasilar basin that supplies the occipital lobes of the brain, the cerebellum, and the brainstem. The anatomical features and variability of the third segment of the vertebral artery (VA) in Asians are analyzed in this study. Methods: A prospective cohort study of 68 consecutive Asian patients underwent MRA examination for head and neck in the Department of Radiology of Hospital of University of Jordan from 1.10.2011 to 30.04.2012. The 116 VA were analyzed on the obtained angiograms. Results: The third segment (V3) of the VA was studied according to its conventional division into vertical, horizontal, and oblique parts. The mean outer diameter of the V3 varied up 3.18 ± 0.73 to 4.28 ± 1.08 mm. The parameter prevailed on the left in 91% cases and was greater in males, than in females. The distal loop of the VA projected downward in 26 cases on the right (78%) and in 28 cases on the left (74%). The tortuosity of loop?formations of V3 was evaluated subject to angles between their ascending and descending bends. Conclusion: In comparison with other ethnic groups, the V3 of the VA in Asians has lesser outer diameter, especially along its oblique part; the zero?distance between the occipital bone and horizontal segment of VA occurs more often (up to 26%); the Lang’s III type of V3 variability is the most common in Asians. DOI: http://dx.doi.org/10.3126/ajms.v5i4.6150 Asian Journal of Medical Sciences 2014 Vol.5(4); 84-88

scholarly journals The corpus callosum in primates: processing speed of axons and the evolution of hemispheric asymmetry

2015 ◽  
Vol 282 (1818) ◽  
pp. 20151535 ◽  
Author(s):  
Kimberley A. Phillips ◽  
Cheryl D. Stimpson ◽  
Jeroen B. Smaers ◽  
Mary Ann Raghanti ◽  
Bob Jacobs ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Conduction Velocity ◽  
Processing Speed ◽  
Hemispheric Asymmetry ◽  
Brain Size ◽  
Myelinated Axon ◽  
Primate Species ◽  
Limiting Factor ◽  
Interhemispheric Communication ◽  
Transmission Delays

Interhemispheric communication may be constrained as brain size increases because of transmission delays in action potentials over the length of axons. Although one might expect larger brains to have progressively thicker axons to compensate, spatial packing is a limiting factor. Axon size distributions within the primate corpus callosum (CC) may provide insights into how these demands affect conduction velocity. We used electron microscopy to explore phylogenetic variation in myelinated axon density and diameter of the CC from 14 different anthropoid primate species, including humans. The majority of axons were less than 1 µm in diameter across all species, indicating that conduction velocity for most interhemispheric communication is relatively constant regardless of brain size. The largest axons within the upper 95th percentile scaled with a progressively higher exponent than the median axons towards the posterior region of the CC. While brain mass among the primates in our analysis varied by 97-fold, estimates of the fastest cross-brain conduction times, as conveyed by axons at the 95th percentile, varied within a relatively narrow range between 3 and 9 ms across species, whereas cross-brain conduction times for the median axon diameters differed more substantially between 11 and 38 ms. Nonetheless, for both size classes of axons, an increase in diameter does not entirely compensate for the delay in interhemispheric transmission time that accompanies larger brain size. Such biophysical constraints on the processing speed of axons conveyed by the CC may play an important role in the evolution of hemispheric asymmetry.

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