Two patients with thalamic hemorrhage exhibiting severe proprioceptive disturbance were examined. They presented with hemiparesis and were unable to recognize their own affected limb without the aid of visual input. The DTI data were obtained during the period of recovery rehabilitation and analyzed to construct DTT using the region of interest (ROI) method by a deterministic approach. The tracts observed were as follows: (1) corticospinal tract (CST); (2) medial lemniscus pathway (MLP); and (3) superior longitudinal fasciculus (SLF).

 (1) In both patients, the density of CST fibers was reduced in the affected hemisphere. (2) Detecting MLP alone was not possible by the method used in this study. The tracts adjacent to MLP were detected together, including other somatosensory pathways and the corticoreticular pathway (CRP). The density of this tract complex was reduced on the affected side in both patients. In the patient presenting with “supernumerary phantom limb (SPL)”, transcallosal aberrant CRP fibers originating from the contralateral premotor area were observed. (3) The density of SLF fibers on the affected side was slightly reduced in both patients. In the patient presenting with SPL, some transcallosal aberrant fibers of SLF connecting to the contralateral parietal lobe were noted on the affected side.

Thalamic hemorrhage interrupted not only projection fibers, but also association fibers. In the period of recovery, the new fibers, including substitutive aberrant fibers, may reconstruct neural tracts and networks related to motor control.