scholarly journals Dual-task walking and automaticity after Stroke: Insights from a secondary analysis and imaging sub-study of a randomised controlled trial

2021 ◽  
pp. 026921552110173
Author(s):  
Johnny Collett ◽  
Melanie K Fleming ◽  
Daan Meester ◽  
Emad Al-Yahya ◽  
Derick T Wade ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Dual Task ◽  
Resting State ◽  
Walking Speed ◽  
Secondary Analysis ◽  
Treadmill Walking ◽  
Gait Control ◽  
Cognitive Distraction ◽  
Group Time ◽  
Resting State Connectivity

Objective: To test the extent to which initial walking speed influences dual-task performance after walking intervention, hypothesising that slow walking speed affects automatic gait control, limiting executive resource availability. Design: A secondary analysis of a trial of dual-task (DT) and single-task (ST) walking interventions comparing those with good (walking speed ⩾0.8 m s−1, n = 21) and limited (walking speed <0.79 m s−1, n = 24) capacity at baseline. Setting: Community. Subjects: Adults six-months post stroke with walking impairment. Interventions: Twenty sessions of 30 minutes treadmill walking over 10 weeks with (DT) or without (ST) cognitive distraction. Good and limited groups were formed regardless of intervention received. Main measures: A two-minute walk with (DT) and without (ST) a cognitive distraction assessed walking. fNIRS measured prefrontal cortex activation during treadmill walking with (DT) and without (ST) Stroop and planning tasks and an fMRI sub-study used ankle-dorsiflexion to simulate walking. Results: ST walking improved in both groups (∆baseline: Good = 8.9 ± 13.4 m, limited = 5.3±8.9 m, Group × time =  P < 0.151) but only the good walkers improved DT walking (∆baseline: Good = 10.4 ± 13.9 m, limited = 1.3 ± 7.7 m, Group × time =  P < 0.025). fNIRS indicated increased ispilesional prefrontal cortex activation during DT walking following intervention ( P = 0.021). fMRI revealed greater DT cost activation for limited walkers, and increased resting state connectivity of contralesional M1 with cortical areas associated with conscious gait control at baseline. After the intervention, resting state connectivity between ipsilesional M1 and bilateral superior parietal lobe, involved in integrating sensory and motor signals, increased in the good walkers compared with limited walkers. Conclusion: In individual who walk slowly it may be difficult to improve dual-task walking ability. Registration: ISRCTN50586966

scholarly journals Resting-state connectivity within the brain’s reward system predicts weight loss and correlates with leptin

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Liane Schmidt ◽  
Evelyn Medawar ◽  
Judith Aron-Wisnewsky ◽  
Laurent Genser ◽  
Christine Poitou ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Weight Gain ◽  
Resting State ◽  
Ventral Striatum ◽  
Ventromedial Prefrontal Cortex ◽  
Hormone Regulation ◽  
Out Of Sample ◽  
Out Of Sample Prediction ◽  
Resting State Connectivity ◽  
Over Time

Abstract Weight gain is often associated with the pleasure of eating food rich in calories. This idea is based on the findings that people with obesity showed increased neural activity in the reward and motivation systems of the brain in response to food cues. Such correlations, however, overlook the possibility that obesity may be associated with a metabolic state that impacts the functioning of reward and motivation systems, which in turn could be linked to reactivity to food and eating behaviour and weight gain. In a study involving 44 female participants [14 patients with obesity, aged 20–63 years (mean: 42, SEM: 3.2 years), and 30 matched lean controls, aged 22–60 years (mean: 37, SEM: 1.8 years)], we investigated how ventromedial prefrontal cortex seed-to-voxel resting-state connectivity distinguished between lean and obese participants at baseline. We used the results of this first step of our analyses to examine whether changes in ventromedial prefrontal cortex resting-state connectivity over 8 months could formally predict weight gain or loss. It is important to note that participants with obesity underwent bariatric surgery at the beginning of our investigation period. We found that ventromedial prefrontal cortex–ventral striatum resting-state connectivity and ventromedial–dorsolateral prefrontal cortex resting-state connectivity were sensitive to obesity at baseline. However, only the ventromedial prefrontal cortex–ventral striatum resting-state connectivity predicted weight changes over time using cross-validation, out-of-sample prediction analysis. Such an out-of-sample prediction analysis uses the data of all participants of a training set to predict the actually observed data in one independent participant in the hold-out validation sample and is then repeated for all participants. In seeking to explain the reason why ventromedial pre-frontal cortex–ventral striatum resting-state connectivity as the central hub of the brain’s reward and motivational system may predict weight change over time, we linked weight loss surgery-induced changes in ventromedial prefrontal cortex–ventral striatum resting-state connectivity to surgery-induced changes in homeostatic hormone regulation. More specifically, we focussed on changes in fasting state systemic leptin, a homeostatic hormone signalling satiety, and inhibiting reward-related dopamine signalling. We found that the surgery-induced increase in ventromedial prefrontal cortex–ventral striatum resting-state connectivity was correlated with a decrease in fasting-state systemic leptin. These findings establish the first link between individual differences in brain connectivity in reward circuits in a more tonic state at rest, weight change over time and homeostatic hormone regulation.

scholarly journals Altered ventral striatal–medial prefrontal cortex resting-state connectivity mediates adolescent social problems after early institutional care

2017 ◽  
Vol 29 (5) ◽  
pp. 1865-1876 ◽  
Author(s):  
Dominic S. Fareri ◽  
Laurel Gabard-Durnam ◽  
Bonnie Goff ◽  
Jessica Flannery ◽  
Dylan G. Gee ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Resting State ◽  
Social Problems ◽  
Ventral Striatum ◽  
Institutional Care ◽  
Increased Risk ◽  
Social Difficulties ◽  
Institutionalized Youth ◽  
Resting State Connectivity

AbstractEarly caregiving adversity is associated with increased risk for social difficulties. The ventral striatum and associated corticostriatal circuitry, which have demonstrated vulnerability to early exposures to adversity, are implicated in many aspects of social behavior, including social play, aggression, and valuation of social stimuli across development. Here, we used resting-state functional magnetic resonance imaging to assess the degree to which early caregiving adversity was associated with altered coritocostriatal resting connectivity in previously institutionalized youth (n = 41) relative to youth who were raised with their biological families from birth (n = 47), and the degree to which this connectivity was associated with parent-reported social problems. Using a seed-based approach, we observed increased positive coupling between the ventral striatum and anterior regions of medial prefrontal cortex (mPFC) in previously institutionalized youth. Stronger ventral striatum–mPFC coupling was associated with parent reports of social problems. A moderated-mediation analysis showed that ventral striatal–mPFC connectivity mediated group differences in social problems, and more so with increasing age. These findings show that early institutional care is associated with differences in resting-state connectivity between the ventral striatum and the mPFC, and this connectivity seems to play an increasingly important role in social behaviors as youth enter adolescence.

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