The role of the striatum in sentence processing: Disentangling syntax from working memory in Huntington’s disease Sara Sambin a,b,c,1 , Marc Teichmann a,b,c,1 , Ruth de Diego Balaguer a,b,c,e , Maria Giavazzi a,c , Dominique Sportiche c,f,g , Philippe Schlenker c,g,h , Anne-Catherine Bachoud-Le ´ vi a,b,c,d,n a INSERM U955, Equipe 1, Neuropsychologie Interventionnelle, IMRB, Cre´teil 94000, France b Universite´ Paris-Est, Faculte´ de me ´decine, Cre ´teil 94010, France c Ecole Normale Supe´rieure, De ´partement d’Etudes Cognitives, Paris, France d AP-HP, Hˆ opital H. Mondor – A. Chenevier, Centre de re´fe ´rence maladie de Huntington, Service de neurologie, 54 avenue du Mare´chal de Lattre de Tassigny, Cre ´teil 94000, France e ICREA, Universitat de Barcelona, Departament de Psicologia B  asica, IDIBELL, Barcelona, Spain f UCLA, Department of Linguistics, LA, USA g Institut Jean-Nicod, CNRS, Paris, France h New York University, Department of Linguistics, NY, USA article info Article history: Received 18 July 2011 Received in revised form 29 June 2012 Accepted 10 July 2012 Available online 20 July 2012 Keywords: Striatum Huntington’s Disease Syntax Working memory abstract The role of sub-cortical structures in language processing remains controversial. In particular, it is unclear whether the striatum subserves language-specific processes such as syntax or whether it solely affects language performance via its significant role in executive functioning and/or working memory. Here, in order to address this issue, we attempted to equalize working memory constraints while varying syntactic complexity, to study sentence comprehension in 15 patients with striatal damage, namely Huntington’s disease at early stage, and in 15 healthy controls. More particularly, we manipulated the syntactic relation between a name and a pronoun while holding the distance between them constant. We exploited a formal principle of syntactic theory called Principle C. This principle states that whereas in a sentence such as ‘‘Paul smiled when he entered’’ Paul and he can be a single person, this interpretation is blocked in sentences such as ‘‘He smiled when Paul entered’’. In a second experiment we varied working memory load using noun-adjective gender agreement in center- embedded and right-branching relatives (e.g., ‘‘the girl who watches the dog is green’’ vs. ‘‘the girl watches the dog which is green’’). The results show that HD patients correctly establish name-pronoun coreference but they fail to block it when Principle C should apply. Furthermore, they have good performance with both center-embedded and right-branching relatives, suggesting that their difficul- ties in sentence comprehension do not arise from memory load impairment during sentence processing. Taken together, our findings indicate that the striatum holds a genuine role in syntactic processing, which cannot be reduced to its involvement in working memory. However, it only impacts on particular aspects of syntax that may relate to complex computations whereas other operations appear to be preserved. Hypotheses about the role of the striatum in syntactic processing are discussed. & 2012 Elsevier Ltd. All rights reserved. 1. Introduction Language processing has mainly been ascribed to cortical areas, but several lines of research suggest that it also involves sub-cortical gray matter such as the striatum. A first indication of a role of sub-cortical areas in language processing was provided by patient studies showing that striatal damage leads to difficul- ties both with the production and with the comprehension of words and sentences (e.g., Cambier, Elghozi, & Strube, 1979; Damasio, Damasio, Rizzo, Varney, & Gersh, 1982; Hochstadt, 2009; Kumral, Evyapan, & Balkir, 1999; Lieberman et al., 1992; Teichmann et al., 2005; Ullman et al., 1997). However, it is still a matter of debate whether the striatum subserves genuine lan- guage processes, or whether it merely has a role in more general cognitive operations which modulate language processing (Caplan & Waters, 1999; Colman et al., 2009; Grossman, Carvell, Stern, Gollomp, & Hurtig, 1992; Grossman et al., 2000; Grossman, Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/neuropsychologia Neuropsychologia 0028-3932/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.neuropsychologia.2012.07.014 n Corresponding author. AP-HP, Hˆ opital H. Mondor – A. Chenevier, Centre de re ´fe ´ rence maladie de Huntington, Service de neurologie, 54 avenue du Mare ´ chal de Lattre de Tassigny, Cre ´ teil 94000, France. Tel þ33 149813793; fax: þ33 149812326. E-mail address: bachoud@gmail.com (A.-C. Bachoud-Le ´ vi). 1 Both authors equally contributed to the paper. Neuropsychologia 50 (2012) 2625–2635