**Gray or White? – The Contribution of Gray Matter in a Glioma to Language Deficits**

Ryuta Kinno1,2, Yoshihiro Muragaki3 and Kuniyoshi L. Sakai2 *1Division of Neurology, Department of Internal Medicine, Showa University Northern Yokohama Hospital 2Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3Department of Neurosurgery, Tokyo Women's Medical University Japan* 

#### **1. Introduction**

106 Advances in the Biology, Imaging and Therapies for Glioblastoma

Sloane, B.F., Moin, K. & Lah, T.T. (1994). Regulation of lysosomal endopeptidases in

Strojnik, T., Kavalar, R., Trinkaus, M. & Lah, T.T. (2005). Cathepsin L in glioma progression: comparison with cathepsin B. *Cancer Detection and Prevention,* Vol.29, pp. 448-455 Strojnik, T., Kavalar, R. & Lah, T.T. (2006). Experimental model and immunohistochemical

Strojnik, T., Røsland, G.V., Sakariassen, P.O., Kavalar, R & Lah, T.T. (2007). Neural stem cell

Strojnik, T., Kavalar, R., Zajc, I., Diamandis, E.P., Oikonomopoulou, K. & Lah, T.T. (2009).

Strojnik, T., Kavalar, R., Barone, T.A. & Plunkett, R.J. (2010). Experimantal model and

Takei, H., Bhattacharjee, M.B., Rivera, A., Dancer, Y. & Powell, S.Z. (2007). New

Thomssen, C., Schmitt, M. & Goretzki, L. (1995). Prognostic value of the cysteine proteases

Toda, M., Iizuka, Y., Yu, W., Imai, T., Ikeda, E., Yoshida, K., Kawase, T., Kawakami, Y.,

Tohyama, T., Lee, V.M.-Y., Rorke, L.B., Marvin, M., McKay, R.D.G. & Trajanowski, J.Q.

Wechsler, W., Szymas, J., Bilzer, T. & Hossmann, K.A. (1989). Experimental transplantation gliomas in the adult cat brain. *Acta Neurochirurgica,* Vol.98, pp. 77-89 Wilson, G., Saunders, M. & Dische, S. (1996). Direct comparison of bromodeoxyuridine and Ki-67 labeling indices in human tumours. *Cell Proliferation,* Vol.29, pp. 141-152 Yousef, G.M., Kishi, T. & Diamandis, E.P. (2003). Role of kallikrein enzymes in the central

Yung, W.K.A., Luna, M. & Borit, A. (1985). Vimentin and glial fibrillary acidic protein in

neuroepithelial tumor cells. *Laboratory Investigation,* Vol.66, pp. 303-313 Trapp, B.D. & Herrup, K. (2004). Neurons and neuroglia, In: *Youmans Neurological Surgery,* 

*Archives of Pathology & Laboratory Medicine,* Vol. 131, pp. 234-241

Musashi 1 in human gliomas. *Glia,* Vol.34, pp. 1-7

H.R. Winn, (Ed.), pp. 71-96, W.B. Saunders, Philadelphia

nervous system. *Clinica Chimica Acta,* Vol.329, pp. 1-8

human brain tumours. *Journal of Neuroonocolgy,* Vol.3, pp. 35-38

Pretlow II & T.P. Pretlow (Eds.), pp. 411-466, Academic Press, New York Steinert, P.M. & Liem, R.K.H. (1990). Intermediate filament dynamics. *Cell,* Vol.60, pp. 521-523 Strojnik, T., Kos, J., Židanik, B., Golouh, R. & Lah, T. (1999). Cathepsin B

(March 1999), pp. 559-567

pp. 133-144

pp. 4851-4860

741-746

Vol.29, pp. 3269-3280

brains. *Anticancer Research,* Vol.26, pp. 2887-2900

malignant neoplasia, In: *Biochemical and Molecular Aspects of Selected Cancers,* T.G.

immunohistochemical staining in tumor and endothelial cells is a new prognostic factor for survival in patients with brain tumors. *Clinical Cancer Research,* Vol.5,

analyses of U87 human glioblastoma cell xenografts in immunosuppressed rat

markers, nestin and musashi proteins, in the progression of human glioma: correlation of nestin with prognosis of patient survival. *Surgical Neurology,* Vol.68,

Prognostic impact of CD68 and kallikrein 6 in human glioma. *Anticancer Research,* 

immunohistochemical comparison of U87 human glioblastoma cell xenografts on the chicken chorioallantoic membrane and in rat brains. *Anticancer Research,* Vol.30,

immunohistochemical markers in the evaluation of central nervous system tumors.

cathepsin B and L in human breast carcinoma. *Clinical Cancer Research,* Vol.1, pp.

Okano, H. & Uyemura, K. (2001). Expression of the neural RNA-binding protein

(1992). Nestin expression in embryonic human neuroepithelium and in human

Symptoms of a glioma include not only headaches and seizures, but cognitive deficits including aphasia. One of the most important regions for aphasia is the anterior speech area, the damage of which causes Broca's aphasia, marked by effortful, distorted articulation, reduced speech output, and agrammatic syntax. These patients show relatively good comprehension of single words and simple sentences, but show trouble understanding sentences with more complex syntactic structures, such as passive sentences and sentences with object relative clauses (Schwartz et al., 1980; Caplan et al., 1985; Grodzinsky, 2000); this aspect of Broca's aphasia is called agrammatic comprehension (Goodglass & Menn, 1985; Menn and Obler, 1990; Pulvermüller, 1995). However, methodological problems have been raised (Badecker & Caramazza, 1985), and general processes of short-term memory or decision-making have been proposed to be disrupted in agrammatic comprehension (Just & Carpenter, 1992; Cupples & Inglis, 1993; Dick et al., 2001). Thus, for appropriately assessing a coginitive deficit, it is crucial to use an experimental task in which general cognitive demands such as the memory load are stricly controlled.

In our recent functional magnetic resonance imaging (fMRI) study with a picture-sentence matching task, we examined the effect of sentence structures strictly controlling general cognitive demands such as the memory load (Kinno et al., 2008), where a sentence was visually presented with a picture representing an action (Fig. 1; the same task and stimuli were used in the present study). The participants indicated whether or not the meaning of each sentence matched the action depicted by the corresponding picture. There were three main conditions with different sentence types: canonical / subject-initial active sentences (AS) (e.g., " ∆-ga ○-o hiiteru", " ∆ pulls ○"), noncanonical / subject-initial passive sentences (PS) (e.g., " ○-ga ∆-ni hikareru", " ○ is affected by ∆'s pulling it"; see Kinno et al. (2008) for ni direct passive form), and noncanonical / object-initial scrambled sentences (SS) (e.g., " ○-o ∆-ga hiireru", "as for , ○ pulling it"; this form is allowed not only in Japanese but in German, Finnish, and other languages). Under these conditions, each sentence had a

Gray or White? – The Contribution of Gray Matter in a Glioma to Language Deficits 109

All patients were native Japanese speakers newly diagnosed as having a glioma in the left frontal region, who were scheduled for surgery at the Department of Neurosurgery of Tokyo Women's Medical University. The following conditions comprised the criteria for inclusion of patients in the present study: (i) right-handedness, (ii) no deficits in verbal / written communication or other cognitive abilities reported by the patients or physicians, (iii) no history of neurological or psychiatric disorders other than glioma and seizures, (iv) freedom from seizures with or without antiepileptic drug, and (v) no medical problems for MRI acquisition. Twenty-one patients (Fig. 2 and Table 1) preoperatively underwent a highresolution MRI scan and performed the picture-sentence matching task at the University of Tokyo, Komaba. The laterality quotient (LQ) was also determined by the Edinburgh handedness inventory (Oldfield, 1971). The verbal / nonverbal intelligence quotient (IQ) was assessed with the Japanese version of the WAIS-III (1997, 2006; Harcourt Assessment, Inc., San Antonio, TX, USA), including more general and demanding tests than the aphasic tests. All but one patient underwent amytal testing. Following injection of amytal, the patient counted numbers with both hands raised. As soon as the contralateral hemiplegia occurred, a picture naming task was used to determine hemispheric dominance, which was either left or bilateral. The tumour type and grade were postoperatively and pathologically diagnosed by the WHO Classification of Tumours of the Nervous System (2000). Using the same paradigm and parameters, we also tested 21 right-handed participants with no history of neurological or psychiatric disorders. These age-matched normal controls included 12 males and 9 females (age: 20-58; mean: 37 years). Informed consent was obtained from each participant after the nature and possible consequences of the studies were explained. Approval for the experiments was obtained from the institutional review board of the

Age LQ VIQ non-VIQ Tumor Volume GM Ratio 34 ± 10 88 ± 16 98 ± 5.7 99 ± 6.5 44088 ± 21227 55 ± 3.0

Date are shown as mean ± standard deviation MR images were normalized with SPM8 for determination of tumor location and volume (mm3), as well as the ratio (%) of gray matter

(GM) for each tumor. LQ = laterality quotient VIQ = verbal intelligence quotient.

Fig. 1. The three main conditions used in the picture-sentence matching task.

**2. Material and methods** 

University of Tokyo, Komaba.

Table 1. Characteristics of Patients

**2.1 Participants** 

transitive verb and two arguments (phrases associated with the predicate) with different grammatical relations, i.e., which the subject (S) of a verb (V) is, and which its indirect object (IO) or direct object (DO) is. Sentence comprehension under each condition also explicitly required analysis of two different thematic roles, i.e., who initiates the action, and who is affected by it. In Japanese syntax, the grammatical relations are first marked by case markers (nominative, dative, or accusative in the present stimuli; Fig. 1), which in turn allow the assignment of thematic roles (agent, experiencer, or patient), whereas passiveness is also marked in the verb morphology (-areru). More specifically, the AS, PS, and SS sentences correspond to S-DO-V (agent and patient), S-IO-V (experiencer and agent), and DO-S-V (patient and agent) types, respectively. Therefore, these syntactic analyses for the two-argument relationships were critically required in our paradigm. In the fMRI study, we observed that activations in L. dF3t (extending to L. F3op) and L. LPMC were differentially modulated by these three main conditions. Moreover, we have recently found that a glioma in the opercular and triangular parts of the left inferior frontal gyrus (L. F3op/F3t) or left lateral premotor cortex (L. LPMC) is indeed sufficient to cause agrammatic comprehension that is selective to syntactic decision (Kinno et al., 2009). These findings indicated that our paradigm with three distinct syntactic conditions of AS, PS, and SS would be ideal for appropriately assessing agrammatic comprehension, because the same set of actions depicted by pictures was used under the main conditions, thus controlling semantic comprehension per se. However, it remains to be elucidated whether a cognitive deficit such as agrammatic comprehension is due to the glioma in gray matter (GM) or not, as a glioma extends to both gray and white matter. It is typically supposed that a glioma in a gray matter causes dysfunction of the localized region, whereas a glioma in white matter leads to the disconnection of neural networks. Therefore, a lesion-symptom method, in which brain lesions are precisely divided into gray and white matter, is required to examine the relative contribution of gray matter in a glioma to cognitive deficits.

In this chapter, we firstly propose a modified lesion-symptom method for examining the effect of a GM lesion. Our method is based on the following two methods for processing the structural magnetic resonance imaging (MRI) data and the behavioural data of patients with a glioma: the voxel-based lesion-symptom mapping (VLSM) (Bates et al., 2003) and the "unified segmentation" algorithm (Ashburner & Friston, 2005). The VLSM is a method to analyze the relationship between a lesion location in the structural MRI and behavioural data such as the error rates (ERs) or reaction times (RTs) on a voxel-byvoxel basis. The unified segmentation algorithm is a generative model that combines tissue segmentation, bias correction and spatial normalization in a single unified model. Using our picture-sentence matching task (Fig. 1), we actually applied this new method to real data of patients with a glioma in the left frontal cortex. The tumor locations covered the most of the left frontal regions and thus included L. F3op/F3t and L. LPMC. To precisely localize the glioma, all patients underwent a high-resolution 3D-MRI on the same day as the task examination. All of these results were actually utilized for the preoperative evaluation of detailed language function and for planning a resection of glioma, thereby minimizing the risk of postoperative language deficits (Haglund, Ojemann, & Hochman, 1992). Because neurological data about the real roles of the left frontal regions in syntactic comprehension have been limited, our lesion-symptom method would have both fundamental and clinical implications, which are useful for preserving the quality of life (QOL) for each patient.

Fig. 1. The three main conditions used in the picture-sentence matching task.
