Possible roles of the dominant uncinate fasciculus in naming
objects: A case report of intraoperative electrical stimulation on a patient
with a brain tumour
Affiliations: Department of Psychiatry, Osaka University Graduate
School of Medicine, Suita-city, Osaka, Japan | Department of Neurosurgery, Osaka University Graduate
School of Medicine, Suita-city, Osaka, Japan
Note: [] Corresponding author: Hiroaki Kazui, M.D., Ph.D., Department of
Psychiatry, Osaka University Graduate School of Medicine, D3 2-2 Yamadaoka,
Suita-city, Osaka, 565-0871, Japan. Tel.: +81 6 6879 3051; Fax: +81 6 6879
3059; E-mail: kazui@psy.med.osaka-u.ac.jp
Abstract: How the dominant uncinate fasciculus (UF) contributes to naming
performance is uncertain. In this case report, a patient with an astrocytoma
near the dominant UF was given a picture-naming task during intraoperative
electrical stimulation in order to resect as much tumourous tissues as possible
without impairing the dominant UF function. Here we report that the
stimulations with the picture-naming task also provided some insights into how
the dominant UF contributes to naming performance. The stimulation induced
naming difficulty, verbal paraphasia, and recurrent and continuous
perseveration. Moreover, just after producing the incorrect responses, the
patient displayed continuous perseveration even though the stimulation had
ended. The left UF connects to the inferior frontal lobe, which is necessary
for word production, so that the naming difficulty appears to be the result of
disrupted word production caused by electrical stimulation of the dominant UF.
The verbal paraphasia appears to be due to the failure to select the correct
word from semantic memory and the failure to suppress the incorrect word. The
left UF is associated with working memory, which plays an important role in
recurrent perseveration. The continuous perseveration appears to be due to
disturbances in word production and a failure to inhibit an appropriate
response. These findings in this case suggest that the dominant UF has multiple roles in the
naming of objects.
