Objective: Ascending Reticular Activating System (ARAS) has a key role in consciousness.
The ARAS is a complex network consisting of a portion of the brainstem reticular formation,
nonspecific thalamic nuclei, hypothalamus, Basal Forebrain (BF), and cerebral cortex. We examined
the reconstruction method and features of the neural tract between the hypothalamus and the
BF in normal subjects, using Diffusion Tensor Tractography (DTT).
Methods: Twenty-three healthy subjects were recruited. The ARAS between the hypothalamus and
the BF was reconstructed by two Regions of Interest (ROIs): 1) seed ROI - the isolated green portion
for the BF on the color map, 2) target ROI - the hypothalamus on the axial image. DTT parameters
of the ARAS between the hypothalamus and the BF were examined.
Results: Among 46 hemispheres in 23 normal subjects, 24 hemispheres (52.2 %) were identified in
the ARAS between the hypothalamus and the BF. The reconstructed ARAS between the hypothalamus
and the BF connected from the hypothalamus to the commissural level and anteriorly
through the anterior commissure and then reached the BF.
Conclusion: Using DTT, the ARAS between the hypothalamus and the BF was identified in normal
subjects. Because the hypothalamus and BF are related to the regulation of wakefulness and
sleep, our reconstruction method and results would be useful in the research on sleep and wakefulness
aspects of consciousness.