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Multi-region hemispheric specialization differentiates human from nonhuman primate brain function.

Wey HY, Phillips KA, McKay DR, Laird AR, Kochunov P, Davis MD, Glahn DC, Blangero J, Duong TQ, Fox PT - Brain Struct Funct (2013)

Bottom Line: Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization.However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity.Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates.

View Article: PubMed Central - PubMed

Affiliation: Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, 78229, USA.

ABSTRACT
The human behavioral repertoire greatly exceeds that of nonhuman primates. Anatomical specializations of the human brain include an enlarged neocortex and prefrontal cortex (Semendeferi et al. in Am J Phys Anthropol 114:224-241, 2001), but regional enlargements alone cannot account for these vast functional differences. Hemispheric specialization has long believed to be a major contributing factor to such distinctive human characteristics as motor dominance, attentional control and language. Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization. Identifying the mechanisms that underlie these functional differences remains a goal of considerable interest. Here, we investigate the intrinsic connectivity networks in four primate species (humans, chimpanzees, baboons, and capuchin monkeys) using resting-state fMRI to evaluate the intra- and inter- hemispheric coherences of spontaneous BOLD fluctuation. All three nonhuman primate species displayed lateralized functional networks that were strikingly similar to those observed in humans. However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity. Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates.

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Related in: MedlinePlus

Lateralization Indices (LI). Lateralization indices (LI) for ICNs illustrated in Figs. 2 and 3. ICNs are considered lateralized when the LI is larger than 0.2 or lower than −0.2. While separate frontal and parietal networks were lateralized in all four groups (not shown), the fronto-parietal human networks were the only multi-region lateralized ICNs in any of the species
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Figure 4: Lateralization Indices (LI). Lateralization indices (LI) for ICNs illustrated in Figs. 2 and 3. ICNs are considered lateralized when the LI is larger than 0.2 or lower than −0.2. While separate frontal and parietal networks were lateralized in all four groups (not shown), the fronto-parietal human networks were the only multi-region lateralized ICNs in any of the species

Mentions: Lateralization index (LI) was calculated using equation: , where Left and Right represents voxel counts from the region-of-interests (ROIs) defined within the left and right hemisphere of each ICN (Z > 3), respectively. LI was derived from all primate species and plotted in Fig. 4. A LI larger than 0 is considered left-lateralized, while a LI<0 is considered right-lateralized. A /LI/ ≥ 0.2 is typically considered as strongly lateralized.


Multi-region hemispheric specialization differentiates human from nonhuman primate brain function.

Wey HY, Phillips KA, McKay DR, Laird AR, Kochunov P, Davis MD, Glahn DC, Blangero J, Duong TQ, Fox PT - Brain Struct Funct (2013)

Lateralization Indices (LI). Lateralization indices (LI) for ICNs illustrated in Figs. 2 and 3. ICNs are considered lateralized when the LI is larger than 0.2 or lower than −0.2. While separate frontal and parietal networks were lateralized in all four groups (not shown), the fronto-parietal human networks were the only multi-region lateralized ICNs in any of the species
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219928&req=5

Figure 4: Lateralization Indices (LI). Lateralization indices (LI) for ICNs illustrated in Figs. 2 and 3. ICNs are considered lateralized when the LI is larger than 0.2 or lower than −0.2. While separate frontal and parietal networks were lateralized in all four groups (not shown), the fronto-parietal human networks were the only multi-region lateralized ICNs in any of the species
Mentions: Lateralization index (LI) was calculated using equation: , where Left and Right represents voxel counts from the region-of-interests (ROIs) defined within the left and right hemisphere of each ICN (Z > 3), respectively. LI was derived from all primate species and plotted in Fig. 4. A LI larger than 0 is considered left-lateralized, while a LI<0 is considered right-lateralized. A /LI/ ≥ 0.2 is typically considered as strongly lateralized.

Bottom Line: Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization.However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity.Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates.

View Article: PubMed Central - PubMed

Affiliation: Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, 78229, USA.

ABSTRACT
The human behavioral repertoire greatly exceeds that of nonhuman primates. Anatomical specializations of the human brain include an enlarged neocortex and prefrontal cortex (Semendeferi et al. in Am J Phys Anthropol 114:224-241, 2001), but regional enlargements alone cannot account for these vast functional differences. Hemispheric specialization has long believed to be a major contributing factor to such distinctive human characteristics as motor dominance, attentional control and language. Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization. Identifying the mechanisms that underlie these functional differences remains a goal of considerable interest. Here, we investigate the intrinsic connectivity networks in four primate species (humans, chimpanzees, baboons, and capuchin monkeys) using resting-state fMRI to evaluate the intra- and inter- hemispheric coherences of spontaneous BOLD fluctuation. All three nonhuman primate species displayed lateralized functional networks that were strikingly similar to those observed in humans. However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity. Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates.

Show MeSH
Related in: MedlinePlus