Table 2.

TBSS findings for the ASD group and gross characterization and functional role of major white matter fiber tracts

Tract	Findings for ASD group			Gross characterization
	FA	MD	Radial Diffusion
Inferior longitudinal fasciculus	↓	↑	↑	Connects visual cortex in the occipital lobe to the temporal pole
Inferior fronto-occipital fasciculus	↓	↑	↑	Connects frontal lobe to occipital and temporal lobes
Superior longitudinal fasciculus	↓	↑	↑	Connects frontal lobe to temporal and parietal lobes
Cingulum	↓	↑	↑	Connects the limbic lobe with neocortex
Genu of corpus callosum	↓	n.s.	↑	Provides interhemispheric connections between frontal regions
Body of corpus callosum	↓	n.s.	↑	Provides interhemispheric connections between parietal regions
Splenium of corpus callosum	↓	↑	↑	Provides interhemispheric connections between posterior parietal and occipital regions
Anterior limb of internal capsule	↓	↑	↑	Contain ascending and descending axons
Posterior limb of internal capsule	↓	↑	↑
External capsule	n.s.	↑	↑	Connects ventral association areas to the putamen and tail of the caudate nucleus
Corticospinal tract	↓	↑	↑	Contains motor axons
Uncinate fasciculus	n.s.	↑	↑	Connects parts of the limbic system such as hippocampus and amygdala in the temporal lobe with the orbitofrontal cortex
Anterior thalamic radiation	↓	↑	↑	Connects dorsomedial and anterior thalamic nuclei with the prefrontal cortex

(n.s. not significant).