TY - JOUR
T1 - Mind-wandering in Parkinson's disease hallucinations reflects primary visual and default network coupling
AU - Walpola, Ishan C.
AU - Muller, Alana J.
AU - Hall, Julie M.
AU - Andrews-Hanna, Jessica R.
AU - Irish, Muireann
AU - Lewis, Simon J. G.
AU - Shine, James M.
AU - O'Callaghan, Claire
PY - 2020/4
Y1 - 2020/4
N2 - Visual hallucinations are an underappreciated symptom affecting the majority of patients during the natural history of Parkinson's disease. Little is known about other forms of abstract and internally generated cognition – such as mind-wandering – in this population, but emerging evidence suggests that an interplay between the brain's primary visual and default networks might play a crucial role in both internally generated imagery and hallucinations. Here, we explored the association between mind-wandering and visual hallucinations in Parkinson's disease, and their relationship with brain network coupling. We administered a validated thought-sampling task to 38 Parkinson's disease patients (18 with hallucinations; 20 without) and 40 controls, to test the hypothesis that individuals with hallucinations experience an increased frequency of mind-wandering. Group differences in the association between mind-wandering frequency and brain network coupling were also examined using resting state functional magnetic resonance imaging. Our results showed that patients with hallucinations exhibited significantly higher mind-wandering frequencies compared to non-hallucinators, who in turn had reduced levels of mind-wandering relative to controls. At the level of brain networks, inter-network connectivity and seed-to-voxel analyses identified that increased mind-wandering in the hallucinating versus non-hallucinating group was associated with greater coupling between the primary visual cortex and dorsal default network. Taken together, our results suggest a relative preservation of mind-wandering in Parkinson's disease patients who experience visual hallucinations, which is associated with increased visual cortex-default network coupling. We propose that the preservation of florid abstract and internally generated cognition in the context of the Parkinson's disease can contribute to visual hallucinations, whereas healthy individuals experience only the vivid images of the mind's eye. These findings refine current models of visual hallucinations by identifying a specific cognitive phenomenon and neural substrate consistent with the top-down influences over perception that have been implicated in hallucinations across neuropsychiatric disorders.
AB - Visual hallucinations are an underappreciated symptom affecting the majority of patients during the natural history of Parkinson's disease. Little is known about other forms of abstract and internally generated cognition – such as mind-wandering – in this population, but emerging evidence suggests that an interplay between the brain's primary visual and default networks might play a crucial role in both internally generated imagery and hallucinations. Here, we explored the association between mind-wandering and visual hallucinations in Parkinson's disease, and their relationship with brain network coupling. We administered a validated thought-sampling task to 38 Parkinson's disease patients (18 with hallucinations; 20 without) and 40 controls, to test the hypothesis that individuals with hallucinations experience an increased frequency of mind-wandering. Group differences in the association between mind-wandering frequency and brain network coupling were also examined using resting state functional magnetic resonance imaging. Our results showed that patients with hallucinations exhibited significantly higher mind-wandering frequencies compared to non-hallucinators, who in turn had reduced levels of mind-wandering relative to controls. At the level of brain networks, inter-network connectivity and seed-to-voxel analyses identified that increased mind-wandering in the hallucinating versus non-hallucinating group was associated with greater coupling between the primary visual cortex and dorsal default network. Taken together, our results suggest a relative preservation of mind-wandering in Parkinson's disease patients who experience visual hallucinations, which is associated with increased visual cortex-default network coupling. We propose that the preservation of florid abstract and internally generated cognition in the context of the Parkinson's disease can contribute to visual hallucinations, whereas healthy individuals experience only the vivid images of the mind's eye. These findings refine current models of visual hallucinations by identifying a specific cognitive phenomenon and neural substrate consistent with the top-down influences over perception that have been implicated in hallucinations across neuropsychiatric disorders.
KW - Parkinson's disease
KW - Mind-wandering
KW - Visual hallucinations
KW - Default network
KW - Resting state functional magnetic resonance imaging
UR - http://www.scopus.com/inward/record.url?scp=85079155081&partnerID=8YFLogxK
UR - http://purl.org/au-research/grants/arc/FT160100096
UR - http://purl.org/au-research/grants/arc/DP180101548
UR - http://purl.org/au-research/grants/nhmrc/1072403
U2 - 10.1016/j.cortex.2019.12.023
DO - 10.1016/j.cortex.2019.12.023
M3 - Article
C2 - 32058090
AN - SCOPUS:85079155081
SN - 0010-9452
VL - 125
SP - 233
EP - 245
JO - Cortex
JF - Cortex
ER -