Disentangling the Neuroanatomical Correlates of Perseveration from Unilateral Spatial Neglect

Kleinman, Jonathan T.; DuBois, Jeffery C.; Newhart, Melissa; Hillis, Argye E.

doi:10.1155/2013/438965

Cited by 13 publications

(13 citation statements)

References 35 publications

(100 reference statements)

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“…Our findings identify a locus of transcranial stimulation that may be used to help steer decision making in cases of pathologies involving deficits in task switching or stereotyped behavior (Ehring and Watkins, 2008;Stuss, 2011;Kleinman et al, 2013). The rFPC is thought to be embedded within a larger neural network regulating the exploration-exploitation tradeoff (Boorman et al, 2011) and is most likely not the only site where transcranial stimulation can have such effects.…”

Section: Discussionmentioning

confidence: 92%

“…Managing this quandary between exploiting well-known choice options and exploring alternative opportunities is a central aspect of behavior for most species (e.g., Krebs et al, 1978;Keasar, 2002;Ame et al, 2004;Ben Jacob et al, 2004;Pratt and Sumpter, 2006;Hayden et al, 2011b) because exploration is critical for organisms to harvest resources optimally for growth and reproduction (Watkinson et al, 2005). When con-fronted with choices requiring a trade-off between exploration and exploitation, organisms ranging from plants to primates behave according to the approximate best solution (Krebs et al, 1978;Stephens and Krebs, 1986;McNickle and Cahill, 2009;Bendesky et al, 2011;Hayden et al, 2011b).…”

Section: Introductionmentioning

confidence: 99%

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Transcranial Stimulation over Frontopolar Cortex Elucidates the Choice Attributes and Neural Mechanisms Used to Resolve Exploration–Exploitation Trade-Offs

et al. 2015

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Optimal behavior requires striking a balance between exploiting tried-and-true options or exploring new possibilities. Neuroimaging studies have identified different brain regions in humans where neural activity is correlated with exploratory or exploitative behavior, but it is unclear whether this activity directly implements these choices or simply reflects a byproduct of the behavior. Moreover, it remains unknown whether arbitrating between exploration and exploitation can be influenced with exogenous methods, such as brain stimulation. In our study, we addressed these questions by selectively upregulating and downregulating neuronal excitability with anodal or cathodal transcranial direct current stimulation over right frontopolar cortex during a reward-learning task. This caused participants to make slower, more exploratory or faster, more exploitative decisions, respectively. Bayesian computational modeling revealed that stimulation affected how much participants took both expected and obtained rewards into account when choosing to exploit or explore: Cathodal stimulation resulted in an increased focus on the option expected to yield the highest payout, whereas anodal stimulation led to choices that were less influenced by anticipated payoff magnitudes and were more driven by recent negative reward prediction errors. These findings suggest that exploration is triggered by a neural mechanism that is sensitive to prior less-than-expected choice outcomes and thus pushes people to seek out alternative courses of action. Together, our findings establish a parsimonious neurobiological mechanism that causes exploration and exploitation, and they provide new insights into the choice features used by this mechanism to direct decision-making.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Transcranial Stimulation over Frontopolar Cortex Elucidates the Choice Attributes and Neural Mechanisms Used to Resolve Exploration–Exploitation Trade-Offs

et al. 2015

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“…Unilateral spatial neglect is defined as the inability to attend or respond to the contralesional hemispace, whereby this inability is not due to primary sensory or motor deficits (Kleinman, DuBois, Newhart, & Hillis, 2013). In severe cases, neglect patients act as if the contralesional hemispace no longer exists (Karnath, Himmelbach, & Rorden, 2002).…”

Section: Introductionmentioning

confidence: 99%

Re‐fixation and perseveration patterns in neglect patients during free visual exploration

Paladini

Wyss

Kaufmann

et al. 2019

Eur J of Neuroscience

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The literature suggests that neglect patients not only show impairments in directing attention toward the left, contralesional space, but also present with perseverative behavior. Moreover, previous studies described re‐fixations during visual search tasks, and interpreted this finding as an impairment of spatial working memory. The aim of the present study was to study re‐fixations and perseverations (i.e., recurrent re‐fixations to same locations) during free visual exploration, a task with high ecological validity. We hypothesized that: (1) neglect patient would perform re‐fixations more frequently than healthy controls within the right hemispace; and, (2) the re‐fixation behavior of neglect patients would be characterized by perseverative fixations. To test these hypotheses, we assessed 22 neglect patients and 23 healthy controls, measuring their eye movements during free exploration of naturalistic pictures. The results showed that neglect patients tend to re‐fixate locations within the ipsilesional hemispace when they freely explore naturalistic pictures. Importantly, the saliency of discrete locations within the pictures has a stronger influence on fixation behavior within the contralesional than within the ipsilesional hemispace in neglect patients. Finally, the results indicated that, for re‐fixations, saliency plays a more important role within the contralesional than the ipsilesional hemispace. Moreover, we found evidence that re‐fixation behavior of neglect patients is characterized by frequent recurrent re‐fixations back to the same spatial locations which may be interpreted as perseverations. Hence, with the present study, we could better elucidate the mechanism leading to re‐fixations and perseverative behavior during free visual exploration in neglect patients.

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“…The authors found that the lesion most commonly associated with motor perseveration was injury to the right dorsolateral frontal lobe. Unlike Nys et al (2006), Kleinman et al (2013) did not find that caudate injury was related to perseveration. However, the dorsolateral frontal lobes are known to have strong connections with the caudate (Leh et al, 2007).…”

Section: Discussionmentioning

confidence: 70%

“…Several studies have shown that right hemisphere dysfunction can be associated with bilateral perseveration (Kleinman et al, 2013;Pia et al, 2009;Sandson and Albert, 1987). The finding that patients with right lateral frontal lobe or caudate injury have bilateral motor perseveration suggests that normally the network formed by the right frontal lobe and caudate plays a critical role in determining when an action should be terminated.…”

Section: Discussionmentioning

confidence: 99%

Unilateral Perseverationnnn

Acosta

Goodman

Heilman

2013

Cognitive and Behavioral Neurology

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The brain's action-intentional ("when") programming system helps to control when to and when not to initiate an action, when to persist at an action, and when to terminate an action. Motor perseveration is a failure to terminate an action. This disengagement disorder most often results from dysfunction of the executive frontal-subcortical networks that control the action-intentional programming system. Reports of unilateral perseveration are unusual. Here we describe a patient with a form of progressive supranuclear palsy (PSP) who exhibited continuous right-hand motor perseveration. This 68-year-old right-handed man had impaired walking and vertical gaze, consistent with PSP. He often repeated words, and on many motor tasks he showed continuous perseveration of his right but not his left hand. Unilateral motor perseveration may be a sign of PSP, the corticobasal syndrome, or a subtype of these disorders. Future studies of patients with both disorders should use tasks that assess for asymmetric hand perseveration. The mechanism of the unilateral perseveration must also be determined. Bilateral perseveration is found most often in patients with unilateral right frontal-subcortical (basal ganglia) or insula dysfunction. Because patients with PSP or corticobasal syndrome have callosal degeneration, their unilateral perseveration might result from a callosal disconnection of the right frontal lobe from the left hemisphere's premotor and motor as well as speech areas.

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Disentangling the Neuroanatomical Correlates of Perseveration from Unilateral Spatial Neglect

Cited by 13 publications

References 35 publications

Transcranial Stimulation over Frontopolar Cortex Elucidates the Choice Attributes and Neural Mechanisms Used to Resolve Exploration–Exploitation Trade-Offs

Transcranial Stimulation over Frontopolar Cortex Elucidates the Choice Attributes and Neural Mechanisms Used to Resolve Exploration–Exploitation Trade-Offs

Re‐fixation and perseveration patterns in neglect patients during free visual exploration

Unilateral Perseverationnnn

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