The role of the striatum in sentence processing: Evidence from a priming study in early stages of Huntington's disease

Abstract

The role of sub-cortical structures such as the striatum in language remains a controversial issue. Based on linguistic claims that language processing implies both recovery of lexical information and application of combinatorial rules it has been shown that striatal damaged patients have difficulties applying conjugation rules while lexical recovery of irregular forms is broadly spared (e.g., Ullman, M. T., Corkin, S., Coppola, M., Hickok, G., Growdon, J. H., Koroshetz, W. J., et al. (1997). A neural dissociation within language: Evidence that the mental dictionary is part of declarative memory, and that grammatical rules are processed by the procedural system. Journal of Cognitive Neuroscience, 9(2), 266-276). Here we bolstered the striatum-rule hypothesis by investigating lexical abilities and rule application at the phrasal level.Both processing aspects were assessed in a model of striatal dysfunction, namely Huntington's disease (HD). Using a semantic priming task we compared idiomatic prime sentences involving lexical access to whole phrases (e.g., "Paul has kicked the bucket") with idiom-derived sentences that contained passivation changes involving syntactic movement rules (e.g., "Paul was kicked by the bucket"), word changes (e.g., "Paul has crushed the bucket") or either. Target words that were either idiom-related (e.g., "death") reflecting lexical access to idiom meanings, word-related (e.g., "bail") reflecting lexical access to single words, or unrelated (e.g., "table").HD patients displayed selective abnormalities with passivated sentences whereas priming was normal with idioms and sentences containing only word changes. We argue that the role of the striatum in sentence processing specifically pertains to the application of syntactic movement rules whereas it is not involved in canonical rules required for active structures or in lexical processing aspects. Our findings support the striatum-rule hypothesis but suggest that it should be refined by tracking the particular kind of language rules depending on striatal computations.

Humanized Foxp2 accelerates learning by enhancing transitions from declarative to procedural performance

“…How these findings relate to the effect of humanized version of Foxp2 in shaping the development of a human brain to enable traits such as language and speech acquisition is unknown. The relation between declarative and procedural learning strategies and language learning is itself unclear (10)(11)(12). One possibility raised by our findings is that efficient proceduralization might accelerate probabilistic learning of language features (10) by chunking single speech and languagerelated actions into sequences, a chunking function that has been suggested to be a core property of the striatum in experimental work (48,49).…”

“…A key functional distinction has been made between subregions of the striatum that underlie modes of learning also considered to be crucial for speech and language development and performance: declarative learning and procedural learning (9)(10)(11)(12). These learning modes were first distinguished in human cognitive studies to differentiate between a conscious form of…”

Syntax, action verbs, action semantics, and object semantics in Parkinson's disease: Dissociability, progression, and executive influences

“…Thus, BG circuits seem to be key components of the networks underlying these domains, as observed in clinical (Murray, 2000;Teichmann, Dupoux, Cesaro, & Bachoud-Levi, 2008;Teichmann et al, 2005) and neurotypical (Moro et al, 2001) samples. The role of BG in syntactic processing has been proposed to reflect their specialization for the acquisition and execution of hierarchical and sequential motor/cognitive routines (Ullman, 2001), their role in EFs (Grossman, 1999;Grossman, Lee, Morris, Stern, & Hurtig, 2002;Lee et al, 2003), and their involvement in cue-guided predictions (Kotz, Schwartze, & Schmidt-Kassow, 2009).…”

Motor–Language Coupling in Huntington’s Disease Families

“…In HD, typical motor alterations and cognitive deficits (Bachoud-Levi et al, 2001; Montoya et al, 2006) are accompanied by disorders in verbal production (Podoll et al, 1988; Murray and Lenz, 2001), including reduced verbal fluency (Chenery et al, 2002; Ho et al, 2002; Azambuja et al, 2012), affixation errors (Ullman et al, 1997), and syntactic processing difficulties (Teichmann et al, 2005, 2008). Language comprehension deficits have also been reported (Teichmann et al, 2008; Azambuja et al, 2012).…”