The basal ganglia and semantic engagement: Potential insights from semantic priming in individuals with subcortical vascular lesions, Parkinson's disease, and cortical lesions

Abstract

The impact of basal ganglia dysfunction on semantic processing was investigated by comparing the performance of individuals with nonthalamic subcortical (NS) vascular lesions, Parkinson's disease (PD), cortical lesions, and matched controls on a semantic priming task. Unequibiased lexical ambiguity primes were used in auditory prime-target pairs comprising 4 critical conditions; dominant related (e.g., bank-money), subordinate related (e.g., bank-river), dominant unrelated (e.g., foot-money) and subordinate unrelated (e.g., bat-river). Participants made speeded lexical decisions (word0nonword) on targets using a go-no-go response. When a short prime-target interstimulus interval (ISI) of 200 ms was employed, all groups demonstrated priming for dominant and subordinate conditions, indicating nonselective meaning facilitation and intact automatic lexical processing. Differences emerged at the long ISI (1250 ms), where control and cortical lesion participants evidenced selective facilitation of the dominant meaning, whereas NS and PD groups demonstrated a protracted period of nonselective meaning facilitation. This finding suggests a circumscribed deficit in the selective attentional engagement of the semantic network on the basis of meaning frequency, possibly implicating a disturbance of frontal-subcortical systems influencing inhibitory semantic mechanisms. (JINS, 2003(JINS, , 9, 1041(JINS, -1052

The basal ganglia circuits, dopamine, and ambiguous word processing: A neurobiological account of priming studies in Parkinson's disease

“…In a word pair priming task containing ambiguous words as primes, the NS and PD groups continued to prime both the dominant and subordinate meanings of an ambiguous word at a long interval between prime and target. Copland (2003) interpreted the findings as reflecting a deficit in selective attentional engagement possibly implicating deficits in frontal-subcortical systems related to inhibitory semantic mechanisms.…”

“…Inhibitory deficits in patients with LFC damage are a recurring theme in the literature and are referred to again in studies of patients with PD and patients with nonthalamic subcortical (NS) vascular lesions (Copland, 2003). In a word pair priming task containing ambiguous words as primes, the NS and PD groups continued to prime both the dominant and subordinate meanings of an ambiguous word at a long interval between prime and target.…”

“…we are able to retrieve the alternate meaning of pen that is relevant to the sentential context. What is it in terms of the neurobiological processes underpinning ambiguous word processing that enables us to rarely be confused when we read or hear ambiguous words, yet which causes people with damage to basal ganglia structures to show impaired performance in comprehending sentences containing lexical ambiguities (Copland et al, 2000a) and to show altered patterns of ambiguity processing when tested in priming tasks (e.g., Copland, 2003;Copland et al, 2000b)?…”

Subcortical processing in auditory communication

“…Moro et al, 2001;Friederici et al, 2003), semantic (e.g. Pilgrim et al, 2002;Copland, 2003) and prosodic components (e.g. Brådvik et al, 1991;Breitenstein et al, 1998Breitenstein et al, , 2001Pell and Leonard, 2003;P eron et al, 2013).…”

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

“…Indeed, studies investigating striatal damaged patients have shown various kinds of language disorders ranging from semantic disorganisation to syntactic impairment in both neurodegenerative diseases such as Huntington's and Parkinson's disease (e.g., Copland, 2003;Frank, McDade, & Scott, 1996;Illes, 1989) and in patients with vascular damage (e.g., Damasio, Damasio, Rizzo, Varney, & Gersh, 1982;Wallesch & Papagno, 1988). This might be related to the different lesion patterns regarding the different aetiologies: vascular disorders affect various parts of the striatum and often involve surrounding white matter fibre tracks, Parkinson's disease (PD) is due to neural degeneration in the substantia nigra resulting in dopamine-related dysfunction of the striatum, whereas Huntington's disease (HD) is characterised by neuronal death that specifically originates in the neostriatum comprising the caudate head and the putamen (see Peschanski, Cesaro, & Hantraye, 1995 for a review).…”