Microstructural development: Organizational differences of the fiber architecture between children and adults in dorsal and ventral visual streams

Abstract

Visual perceptual skills are basically mature by the age of 7 years. White matter, however, continues to develop until late adolescence. Here, we examined children (aged 5-7 years) and adults (aged 20-30 years) using diffusion tensor imaging (DTI) fiber tracking to investigate the microstructural maturation of the visual system. We characterized the brain volumes, DTI indices, and architecture of visual fiber tracts passing through white matter structures adjacent to occipital and parietal cortex (dorsal stream), and to occipital and temporal cortex (ventral stream). Dorsal, but not ventral visual stream pathways were found to increase in volume during maturation. DTI indices revealed expected maturational differences, manifested as decreased mean and radial diffusivities and increased fractional anisotropy in both streams. Additionally, fractional anisotropy was increased and radial diffusivity was decreased in the adult dorsal stream, which can be explained by specific dorsal stream myelination or increasing fiber compaction. Adult dorsal stream architecture showed additional intra- and interhemispheric connections: Dorsal fibers penetrated into contralateral hemispheres via commissural structures and projection fibers extended to the superior temporal gyrus and ventral association pathways. Moreover, intra-hemispheric connectivity was particularly strong in adult dorsal stream of the right hemisphere. Ventral stream architecture also differed between adults and children. Adults revealed additional connections to posterior lateral areas (occipital-temporal gyrus), whereas children showed connections to posterior medial areas (posterior parahippocampal and lingual gyrus). Hence, in addition to dorsal stream myelination or fiber compaction, progressing maturation of intra- and interhemispheric connectivity may contribute to the development of the visual system.

Haptic grasping configurations in early infancy reveal different developmental profiles for visual guidance of the Reach versus the Grasp

“…We suggest, however, that early grip selection, as has been proposed for early selection of Reach orientation (McCarty et al 2001), could be mediated by perceptual mechanisms in the ventral visual stream, while dorsal visual control mechanisms, which are needed to accurately synchronize Grasp closure with Reach termination (Goodale and Milner 1992), continue to develop into early childhood. Such a proposition is supported by the fact that older infants in the present study selected not just a power grip, but an exaggerated power grip, compared even with unsighted adults, and also by recent neuroimaging work indicating that connectivity within the dorsal visual stream continues to mature beyond 7 years of age (Loenneker et al 2010). Along this line of thinking, one might also consider that visual control of the Reach might developmentally precede the Grasp because young children favor vision for discriminating object orientation versus haptics for discriminating object size, at least on perceptual tasks (Gori et al 2008).…”

“…First, haptic feedback may be more reliable than vision due to the ongoing development of postural control (Bertenthal and Hofsten 1998;Hadders-Algra 2013;Thelen and Spencer 1998;Van Der Fits and Hadders-Algra 1998), reaching synergies (Konczak and Dichgans 1997), connectivity within the dorsal visual stream (Loenneker et al 2010), and the ability to re-weight visual and proprioceptive inputs to determine limb location (Bremner et al 2013). Second, haptic dissociation of the Reach and the Grasp may facilitate successful acquisition of the target despite significant kinematic inconsistencies within individual Reach and Grasp components prior to 24 months of age (Konczak and Dichgans 1997;von Hofsten 1991).…”

Ventral and Dorsal Stream Interactions during the Perception of the Müller-Lyer Illusion: Evidence Derived from fMRI and Dynamic Causal Modeling

“…As outlined above, our DCM models consisted of bilateral V1, LOC, and right SPC. Reciprocal connections between V1 and (left/right) LOC or right SPC, respectively, as well as a reciprocal link between left and right LOC were taken as core modules for all models tested (Catani, Jones, Donato, & Ffytche, 2003;Felleman & Van Essen, 1991;Lamme & Roelfsema, 2000;Loenneker et al, 2011;Stephan et al, 2007;Zanon, Busan, Monti, Pizzolato, & Battaglini, 2009). Because LOC and SPC have been shown to be related to the processing of illusion strength (Weidner & Fink, 2007), we hypothesized that an interaction of these areas would be mandatory to explain the illusion effect.…”

Occipital cortical thickness in very low birth weight born adolescents predicts altered neural specialization of visual semantic category related neural networks

“…Skranes et al (2013) explained reduced surface area of the superior temporal gyrus in VLBW adolescents to be associated with diffuse white matter injury of long association fiber tracks. That region has also connected more to the dorsal stream of adults than in children by fiber connections crossing the splenium of the corpus callosum (Loenneker et al, 2011). All these tracks are at risk for reduced fractional anisotropy in VLBW adolescents (Eikenes, Lohaugen, Brubakk, Skranes, & Haberg, 2011;Skranes et al, 2007), suggesting that subtle white matter injuries in these tracks have indirect effect on cortical maturation.…”

“…Preterm born children, adolescents and adults have been shown to yield altered networks related to language (Ment, Peterson, Meltzer, et al, 2006; Mullen et al, 2011) (Klaver, Marcar, & Martin, 2011). White matter development of the dorsal visual stream seems to be characterized by strengthened inter-hemispheric connectivity, whereas alteration of regional cortico-cortical connectivity characterizes development of the ventral visual stream (Loenneker et al, 2011). Functional brain imaging studies revealed enhanced dorsal visual stream activity in adults compared to children related to motion defined visual perception as well as visuospatial memory and attention Klingberg, 2006;.…”