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Anatomical and functional plasticity in early blind individuals and the mixture of experts architecture.

Bock AS, Fine I - Front Hum Neurosci (2014)

Bottom Line: As described elsewhere in this special issue, recent advances in neuroimaging over the last decade have led to a rapid expansion in our knowledge of anatomical and functional correlations within the normal and abnormal human brain.We discuss how lack of power in group comparisons may provide a potential explanation for why extensive anatomical changes in cortico-cortical connectivity are not observed.Finally we suggest a framework-cortical specialization via hierarchical mixtures of experts-which offers some promise in reconciling a wide range of functional and anatomical data.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Washington Seattle, WA, USA.

ABSTRACT
As described elsewhere in this special issue, recent advances in neuroimaging over the last decade have led to a rapid expansion in our knowledge of anatomical and functional correlations within the normal and abnormal human brain. Here, we review how early blindness has been used as a model system for examining the role of visual experience in the development of anatomical connections and functional responses. We discuss how lack of power in group comparisons may provide a potential explanation for why extensive anatomical changes in cortico-cortical connectivity are not observed. Finally we suggest a framework-cortical specialization via hierarchical mixtures of experts-which offers some promise in reconciling a wide range of functional and anatomical data.

No MeSH data available.


Related in: MedlinePlus

Medial view of left and right hemispheres. The upper panels (A,B) are a summary of major findings from the human anatomical connectivity literature, as described in the main text. Increases in anatomical connectivity as a result of early blindness or anophthalmia are shown in orange; decreases in connectivity are shown in teal; types of anatomical measurements are shown in yellow. The lower panels (C,D) are a summary of major findings from the human functional correlations literature. Increases in functional correlations as a result of early blindness or anophthalmia are shown in red; decreases in functional correlations are shown in blue. Some lines represent findings from multiple studies. Explanations of abbreviations can be found in Section Abbreviations.
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Figure 1: Medial view of left and right hemispheres. The upper panels (A,B) are a summary of major findings from the human anatomical connectivity literature, as described in the main text. Increases in anatomical connectivity as a result of early blindness or anophthalmia are shown in orange; decreases in connectivity are shown in teal; types of anatomical measurements are shown in yellow. The lower panels (C,D) are a summary of major findings from the human functional correlations literature. Increases in functional correlations as a result of early blindness or anophthalmia are shown in red; decreases in functional correlations are shown in blue. Some lines represent findings from multiple studies. Explanations of abbreviations can be found in Section Abbreviations.

Mentions: Both human and animal models show that early blindness leads to atrophy of the pathways from the retina to early visual cortex. Several animal models have shown atrophy of the connections between the eye and V1 after early onset blindness (Kahn and Krubitzer, 2002; Karlen et al., 2006), for review see Movshon and Van Sluyters (1981). Similarly, a variety of studies have consistently found decreased white matter volume, decreased axial diffusivity and increased radial diffusivity in the optic nerve/tract (Figures 1A,B: retinae ↔ LGN) and optic radiations (Figures 1A,B: LGN ↔ V1) within both early blind (Noppeney et al., 2005; Shimony et al., 2006; Yu et al., 2007; Ptito et al., 2008; Shu et al., 2009b) and anophthalmic (Bridge et al., 2009) individuals. Yu et al. (2007) also found increased fractional anisotropy in the cortical spinal tract in early blind individuals (Figures 1A,B: CST ↔ PoCG, PreCG, SMA).


Anatomical and functional plasticity in early blind individuals and the mixture of experts architecture.

Bock AS, Fine I - Front Hum Neurosci (2014)

Medial view of left and right hemispheres. The upper panels (A,B) are a summary of major findings from the human anatomical connectivity literature, as described in the main text. Increases in anatomical connectivity as a result of early blindness or anophthalmia are shown in orange; decreases in connectivity are shown in teal; types of anatomical measurements are shown in yellow. The lower panels (C,D) are a summary of major findings from the human functional correlations literature. Increases in functional correlations as a result of early blindness or anophthalmia are shown in red; decreases in functional correlations are shown in blue. Some lines represent findings from multiple studies. Explanations of abbreviations can be found in Section Abbreviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4269126&req=5

Figure 1: Medial view of left and right hemispheres. The upper panels (A,B) are a summary of major findings from the human anatomical connectivity literature, as described in the main text. Increases in anatomical connectivity as a result of early blindness or anophthalmia are shown in orange; decreases in connectivity are shown in teal; types of anatomical measurements are shown in yellow. The lower panels (C,D) are a summary of major findings from the human functional correlations literature. Increases in functional correlations as a result of early blindness or anophthalmia are shown in red; decreases in functional correlations are shown in blue. Some lines represent findings from multiple studies. Explanations of abbreviations can be found in Section Abbreviations.
Mentions: Both human and animal models show that early blindness leads to atrophy of the pathways from the retina to early visual cortex. Several animal models have shown atrophy of the connections between the eye and V1 after early onset blindness (Kahn and Krubitzer, 2002; Karlen et al., 2006), for review see Movshon and Van Sluyters (1981). Similarly, a variety of studies have consistently found decreased white matter volume, decreased axial diffusivity and increased radial diffusivity in the optic nerve/tract (Figures 1A,B: retinae ↔ LGN) and optic radiations (Figures 1A,B: LGN ↔ V1) within both early blind (Noppeney et al., 2005; Shimony et al., 2006; Yu et al., 2007; Ptito et al., 2008; Shu et al., 2009b) and anophthalmic (Bridge et al., 2009) individuals. Yu et al. (2007) also found increased fractional anisotropy in the cortical spinal tract in early blind individuals (Figures 1A,B: CST ↔ PoCG, PreCG, SMA).

Bottom Line: As described elsewhere in this special issue, recent advances in neuroimaging over the last decade have led to a rapid expansion in our knowledge of anatomical and functional correlations within the normal and abnormal human brain.We discuss how lack of power in group comparisons may provide a potential explanation for why extensive anatomical changes in cortico-cortical connectivity are not observed.Finally we suggest a framework-cortical specialization via hierarchical mixtures of experts-which offers some promise in reconciling a wide range of functional and anatomical data.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Washington Seattle, WA, USA.

ABSTRACT
As described elsewhere in this special issue, recent advances in neuroimaging over the last decade have led to a rapid expansion in our knowledge of anatomical and functional correlations within the normal and abnormal human brain. Here, we review how early blindness has been used as a model system for examining the role of visual experience in the development of anatomical connections and functional responses. We discuss how lack of power in group comparisons may provide a potential explanation for why extensive anatomical changes in cortico-cortical connectivity are not observed. Finally we suggest a framework-cortical specialization via hierarchical mixtures of experts-which offers some promise in reconciling a wide range of functional and anatomical data.

No MeSH data available.


Related in: MedlinePlus