Speeded processing of grammar and tool knowledge in Tourette's syndrome

Abstract

Tourette's syndrome (TS) is a developmental disorder characterized by motor and verbal tics. The tics, which are fast and involuntary, result from frontal/basal-ganglia abnormalities that lead to unsuppressed behaviors. Language has not been carefully examined in TS. We tested the processing of two basic aspects of language: idiosyncratic and rule-governed linguistic knowledge. Evidence suggests that idiosyncratic knowledge (e.g., in irregular past-tense formation; bring-brought) is stored in a mental lexicon that depends on the temporal-lobe-based declarative memory system that also underlies conceptual knowledge. In contrast, evidence suggests that rule-governed combination (e.g., in regular past-tenses; walk + -ed) takes place in a mental grammar that relies on the frontal/ basal-ganglia based procedural memory system, which also underlies motor skills such as how to use a hammer. We found that TS children were significantly faster than typically-developing control children at producing rule-governed past-tenses (slip-slipped, plim-plimmed, bring-bringed) but not irregular and other unpredictable past-tenses (bring-brought, splim-splam). They were also faster than controls at naming pictures of manipulated (hammer) but not non-manipulated (elephant) items. These data were not explained by a wide range of potentially confounding subject-and item-level factors. The results suggest that the processing of procedurally-based knowledge, both of grammar and of manipulated objects, is particularly speeded in TS. The frontal/basal-ganglia abnormalities may thus lead not only to tics, but to a wider range of rapid behaviors, including in the cognitive processing of rule-governed forms in language and other types of procedural knowledge. Keywords procedural memory; morphology; basal ganglia; picture naming; past tense; regular inflection Tourette's syndrome (TS) is a developmental disorder characterized by the presence of verbal and motor tics (APA, 1994). Tics, which may be expressed as "simple" or "complex" motor movements or vocalizations (e.g., "simple" grunting, or "complex" shouting of phrases), are both fast and involuntary (see references below and Tulen, Groeneveld, Romers, De Vries, & Van De Wetering, 2001). The tics appear to be caused by disturbances of the basal-ganglia and closely connected regions of cortex, especially motor and cognitive regions of the frontal lobes (Albin & Mink, 2006;Albin, Young, & Penney, 1989;Bradshaw, 2001;Singer & Wendlandt, *Corresponding author. Address: Brain and Language Lab, Department of Neuroscience, Georgetown University, Box 571464, Washington, DC 20057-1464, Tel: (202) Fax: (202) 687-6914, E-mail: michael@georgetown.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note t...

Inflectional morphology in high-functioning autism: Evidence for speeded grammatical processing

“…Participants were asked to produce the past tenses of verbs presented in written sentence contexts (Prado and Ullman 2009; Walenski et al 2007). Five types of verbs were presented (Table 2; Table 3): 32 consistent regulars (i.e., regulars whose stems are not phonologically similar to existing irregulars; e.g., step-stepped ) matched (see just below) to 32 irregulars (e.g., sweep-swept ); 16 inconsistent regulars (i.e., regulars whose stems are phonologically similar to existing irregulars; e.g., squeeze-squeezed , c.f., freeze-froze ); 16 novel “ consistent regular” verbs ( plaw ), which were primarily expected to elicit regularized responses ( plawed ), and 16 novel “irregular” verbs ( splim ), which were phonologically similar to the stems of real irregular verbs (e.g., splim is similar to swim ), increasing the likelihood that participants produce at least some irregularized responses ( splam ) (Ullman 1993; Ullman et al 2005; Walenski et al 2007).…”

“…Five types of verbs were presented (Table 2; Table 3): 32 consistent regulars (i.e., regulars whose stems are not phonologically similar to existing irregulars; e.g., step-stepped ) matched (see just below) to 32 irregulars (e.g., sweep-swept ); 16 inconsistent regulars (i.e., regulars whose stems are phonologically similar to existing irregulars; e.g., squeeze-squeezed , c.f., freeze-froze ); 16 novel “ consistent regular” verbs ( plaw ), which were primarily expected to elicit regularized responses ( plawed ), and 16 novel “irregular” verbs ( splim ), which were phonologically similar to the stems of real irregular verbs (e.g., splim is similar to swim ), increasing the likelihood that participants produce at least some irregularized responses ( splam ) (Ullman 1993; Ullman et al 2005; Walenski et al 2007). The 32 consistent regulars and 32 irregulars were matched groupwise a priori on stem (unmarked form) and past-tense frequency, phonological structure and verb imageability, and did not differ on several other factors (see Table 3, and Covariates section below).…”

“…Verbs with similar-sounding stems (e.g., think, splink ) were never in adjacent positions. Stimuli were presented on the screen of a Macintosh computer using an in-house software presentation program with high timing accuracy (Prado and Ullman 2009; Walenski et al 2007). Each verb stem was visually presented alone and in the context of a sentence, with a second sentence eliciting the past-tense (e.g., dig.…”

“…Since autism has been associated with abnormalities of these brain structures (Amaral et al 2008), atypical production of regular forms might be expected. Just as impaired basal ganglia function may lead to suppressed (e.g., in Parkinson’s disease) or unsuppressed (e.g., in Huntington’s disease or Tourette Syndrome) motor functions, such impairments may also lead to suppressed or unsuppressed language and cognitive functions that also depend on these structures (Ullman 2004; Walenski et al 2007). Thus atypical production might manifest in different ways, depending on the nature of the basal ganglia abnormality – for example as reduced accuracy, and potentially either slowed (suppressed) or speeded (unsuppressed) response times for regular past tenses.…”

How left inferior frontal cortex participates in syntactic processing: Evidence from aphasia☆

“…Note that the degrees of freedom are large because they are based on the number of data points in these regression models, not the number of subjects or items. For similar analyses in a different patient population, see Walenski, Mostofsky, and Ullman (2007). For further discussion of these methods of analysis, see Baayen (2004Baayen ( , 2007.…”