Monetary rewards modulate inhibitory control

The ability to override a dominant response, often referred to as behavioral inhibition, is considered a key element of executive cognition. Poor behavioral inhibition is a defining characteristic of several neurological and psychiatric populations. Recently, there has been increasing interest in the motivational dimension of behavioral inhibition, with some experiments incorporating emotional contingencies in classical inhibitory paradigms such as the Go/NoGo and Stop Signal Tasks (SSTs). Several studies have reported a positive modulatory effect of reward on performance in pathological conditions such as substance abuse, pathological gambling, and Attention Deficit Hyperactive Disorder (ADHD). However, experiments that directly investigate the modulatory effects of reward magnitudes on the performance of inhibitory tasks are scarce and little is known about the finer grained relationship between motivation and inhibitory control. Here we probed the effect of reward magnitude and context on behavioral inhibition with three modified versions of the widely used SST. The pilot study compared inhibition performance during six blocks alternating neutral feedback, low, medium, and high monetary rewards. Study One compared increasing vs. decreasing rewards, with low, high rewards, and neutral feedback; whilst Study Two compared low and high reward magnitudes alone also in an increasing and decreasing reward design. The reward magnitude effect was not demonstrated in the pilot study, probably due to a learning effect induced by practice in this lengthy task. The reward effect per se was weak but the context (order of reward) was clearly suggested in Study One, and was particularly strongly confirmed in study two. In addition, these findings revealed a 'kick start effect' over global performance measures. Specifically, there was a long lasting improvement in performance throughout the task when participants received the highest reward magnitudes at the beginning of the protocol. These results demonstrate a dynamical behavioral inhibition capacity in humans, as illustrated by the reward magnitude modulation and initial reward history effects. © 2014 Herrera, Speranza, Hampshire and Bekinschtein

Learning to be inflexible: Enhanced attentional biases in Parkinson\u27s disease

Impaired attentional flexibility is considered to be one of the core cognitive deficits in Parkinson\u27s disease (PD). However, the mechanisms that underlie this impairment are contested. Progress in resolving this dispute has also been hindered by the fact that cognitive deficits in PD are heterogeneous; therefore, it is unclear whether attentional impairments are only present in a subgroup of patients. Here, we demonstrate that what differentiates PD patients from age-matched controls is an inability to shift attention away from previously relevant information (perseveration) and an inability to shift attention towards previously irrelevant information (learned irrelevance). In contrast, there was no evidence that PD patients, compared to controls, were impaired in being able to appropriately attend to, or ignore, novel information. Furthermore, when patients were stratified according to their level of executive impairment, the executively impaired group showed a selective deficit in set formation compared to the unimpaired group, a behavioural pattern reminiscent of cortical dopamine depletion. Cumulatively, these results suggest that cognitive inflexibility in PD relates to a specific form of attentional dysfunction, in which learned attentional biases cannot be overcome

Spatial structure normalises working memory performance in Parkinson\u27s disease

Cognitive deficits are a frequent symptom of Parkinson\u27s disease (PD), particularly in the domain of spatial working memory (WM). Despite numerous demonstrations of aberrant WM in patients, there is a lack of understanding about how, if at all, their WM is fundamentally altered. Most notably, it is unclear whether span – the yardstick upon which most WM models are built – is compromised by the disease. Moreover, it is also unknown whether WM deficits occur in all patients or only exist in a sub-group who are executively impaired. We assessed the factors that influenced spatial span in medicated patients by varying the complexity of to-be-remembered items. Principally, we manipulated the ease with which items could enter – or be blocked from – WM by varying the level of structure in memoranda. Despite having similar levels of executive performance to controls, PD patients were only impaired when remembering information that lacked spatial, easy-to-chunk, structure. Patients\u27 executive function, however, did not influence this effect. The ease with which patients could control WM was further examined by presenting irrelevant information during encoding, varying the level of structure in irrelevant information and manipulating the amount of switching between relevant and irrelevant information. Disease did not significantly alter the effect of these manipulations. Rather, patients\u27 executive performance constrained the detrimental effect of irrelevant information on WM. Thus, PD patients\u27 spatial span is predominantly determined by level of structure in to-be-remembered information, whereas their level of executive function may mitigate against the detrimental effect of irrelevant information

Striatum in stimulus-response learning via feedback and in decision making.

Cognitive deficits are recognized in Parkinson\u27s disease. Understanding cognitive functions mediated by the striatum can clarify some of these impairments and inform treatment strategies. The dorsal striatum, a region impaired in Parkinson\u27s disease, has been implicated in stimulus-response learning. However, most investigations combine acquisition of associations between stimuli, responses, or outcomes (i.e., learning) and expression of learning through response selection and decision enactment, confounding these separate processes. Using neuroimaging, we provide evidence that dorsal striatum does not mediate stimulus-response learning from feedback but rather underlies decision making once associations between stimuli and responses are learned. In the experiment, 11 males and 5 females (mean age 22) learned to associate abstract images to specific button-press responses through feedback in Session 1. In Session 2, they were asked to provide responses learned in Session 1. Feedback was omitted, precluding further feedback-based learning in this session. Using functional magnetic resonance imaging, dorsal striatum activation in healthy young participants was observed at the time of response selection and not during feedback, when greatest learning presumably occurs. Moreover, dorsal striatum activity increased across the duration of Session 1, peaking after most associations were well learned, and was significant during Session 2 where no feedback was provided, and therefore no feedback-based learning occurred. Preferential ventral striatum activity occurred during feedback and was maximal early in Session 1. Taken together, the results suggest that the ventral striatum underlies learning associations between stimuli and responses via feedback whereas the dorsal striatum mediates enacting decisions

The mental and physical health profiles of older adults who endorse elevated autistic traits

Objective The mental and physical health profile of autistic people has been studied in adolescence and adulthood, with elevated rates of most conditions being reported. However, this has been little studied taking a dimensional approach to autistic traits, and in older age. Methods A total of 20,220 adults aged 50-81 years from the PROTECT study reported whether they experienced persistent socio-communicative traits characteristic of autism. Approximately 1%, 276 individuals, were identified as endorsing elevated autistic traits in childhood and currently, henceforth the ‘Autism Spectrum Trait’ (AST) group. An age and gender matched comparison group was formed of 10,495 individuals who did not endorse any autistic behavioral traits, henceforth the ‘Control Older Adults’ (COA) group. Differences between AST and COA groups were explored in self-reported psychiatric diagnoses, self-reported symptoms of current depression and anxiety, and self-reported physical health diagnoses. Associations were also examined between autistic traits and health across the whole sample. Results The AST group reported significantly elevated rates of psychiatric diagnoses compared to COAs. Additionally, the AST group showed significantly higher self-reported symptoms of current depression and anxiety than COAs. However, few differences were observed in individual physical health conditions, and no differences in total co-occurring physical diagnoses between groups. Similar associations between autistic traits and health were also found taking a dimensional approach across the whole sample. Discussion These findings suggest that older adults with elevated autistic traits may be at greater risk of poorer mental, but not physical, health in later life. Future studies should incorporate polygenic scores to elucidate the possible genetic links between propensity to autism/high autistic traits and to psychiatric conditions, and to explore whether those with elevated autistic traits experience particular barriers to mental health care

Normal aging and Parkinson's disease are associated with the functional decline of distinct frontal-striatal circuits.

Impaired ability to shift attention between stimuli (i.e. shifting attentional 'set') is a well-established part of the dysexecutive syndrome in Parkinson's Disease (PD), nevertheless cognitive and neural bases of this deficit remain unclear. In this study, an fMRI-optimised variant of a classic paradigm for assessing attentional control (Hampshire and Owen 2006) was used to contrast activity in dissociable executive circuits in early-stage PD patients and controls. The results demonstrated that the neural basis of the executive performance impairments in PD is accompanied by hypoactivation within the striatum, anterior cingulate cortex (vACC), and inferior frontal sulcus (IFS) regions. By contrast, in aging it is associated with hypoactivation of the anterior insula/inferior frontal operculum (AI/FO) and the pre-supplementary motor area (preSMA). Between group behavioural differences were also observed; whereas normally aging individuals exhibited routine-problem solving deficits, PD patients demonstrated more global task learning deficits. These findings concur with recent research demonstrating model-based reinforcement learning deficits in PD and provide evidence that the AI/FO and IFS circuits are differentially impacted by PD and normal aging

The mental and physical health of older adults with a genetic predisposition for autism

Autism commonly aggregates in families, with twin studies stimating heritability to be around 80%. Subclinical autism-like characteristics have also been found at elevated rates in relatives of autistic probands. Physical and psychiatric conditions have been reported at elevated rates in autistic children and adults, and also in their relatives. However, to date there has been no exploration of how ageing may affect this pattern. This study examined cross-sectional data from the ongoing online PROTECT study. A total of 20,220 adults aged 50 years and older reported whether they have an autistic first-degree relative. In total, 739 older adults reported having an autistic first-degree relative (AFDR group) and 11,666 were identified as having no family history of any neurodevelopmental disorder (NFD group). The AFDR group demonstrated significantly higher frequencies of self-reported psychiatric diagnoses and a greater total number of co-occurring psychiatric diagnoses than the NFD group. Furthermore, the AFDR group reported elevated current self-report symptoms of depression, anxiety, traumatic experience, and post-traumatic stress than the NFD group. By contrast, few differences between AFDR and NFD groups were observed in physical health conditions, and no differences were observed in the total number of co-occurring physical health diagnoses. These findings suggest that adults who have an autistic first-degree relative may be at greater risk of poor mental, but not physical, health in later life. Older adults with autistic relatives may benefit from close monitoring to mitigate this susceptibility and to provide timely intervention

Traumatic life experiences and post-traumatic stress symptoms in middle-aged and older adults with and without autistic traits

Objectives Research with younger adults has begun to explore associations between autism/autistic traits and vulnerability to Post Traumatic Stress Disorder (PTSD). Large scale studies and/or examination of age-effects have not been conducted. Methods Adults aged 50 years+ from the PROTECT study (n = 20,220) completed items about current and childhood socio-communicative difficulties characteristic of autism. Approximately 1% (n = 251) endorsed high autistic traits, henceforth the Autism Spectrum Traits (AST) group. Differences between the AST and an age—and sex-matched “Comparison Older Adults” (COA; n = 9179) group were explored for lifetime traumatic experiences and current symptoms of PTSD, depression, and anxiety. Results Almost 30% of the AST group, compared to less than 8% of the COA, reported severe trauma in childhood/adulthood, including emotional, physical or sexual abuse. Elevated current PTSD symptoms were reported by AST compared to COA. An interaction was observed between autistic traits and trauma severity; the effect of level of trauma on PTSD symptoms was significantly greater for AST versus COA participants. This interaction remained significant when controlling for current depression and anxiety symptoms. Conclusions The findings suggest that high autistic traits may increase the likelihood of experiencing trauma across the lifespan, and the impact of severe trauma on PTSD symptoms. Older adults with high (vs. low) autistic traits may be at greater risk of experiencing PTSD symptoms in latter life. Future research should test whether the pattern of results is similar for diagnosed autistic adults

Associations between dimensions of behaviour, personality traits, and mental-health during the COVID-19 pandemic in the United Kingdom.

The COVID-19 pandemic (including lockdown) is likely to have had profound but diverse implications for mental health and well-being, yet little is known about individual experiences of the pandemic (positive and negative) and how this relates to mental health and well-being, as well as other important contextual variables. Here, we analyse data sampled in a large-scale manner from 379,875 people in the United Kingdom (UK) during 2020 to identify population variables associated with mood and mental health during the COVID-19 pandemic, and to investigate self-perceived pandemic impact in relation to those variables. We report that while there are relatively small population-level differences in mood assessment scores pre- to peak-UK lockdown, the size of the differences is larger for people from specific groups, e.g. older adults and people with lower incomes. Multiple dimensions underlie peoples' perceptions, both positive and negative, of the pandemic's impact on daily life. These dimensions explain variance in mental health and can be statistically predicted from age, demographics, home and work circumstances, pre-existing conditions, maladaptive technology use and personality traits (e.g., compulsivity). We conclude that a holistic view, incorporating the broad range of relevant population factors, can better characterise people whose mental health is most at risk during the COVID-19 pandemic