Biology subjects

Manly, T.

Publications and source records attributed to Manly, T..

5 recordsLinked to original sources

bioRxiv2018

A randomised exploratory investigation of the effects of Attention vs Working Memory Training on cognitive performance and everyday functioning following stroke.

Difficulties with attention are common following stroke and are associated with poor outcome. Home-based online cognitive training may have to the potential to provide an efficient and effective way to improve attentional functions in such patients. Little work has been carried out to assess the efficacy of this approach in stroke patients, and the lack of studies with active control conditions and rigorous evaluations of cognitive functioning pre and post training means understanding is limited as to whether and how such interventions may be effective. Here we compare the effects of 20 days of active cognitive training using either novel Selective Attention Training (SAT) or commercial Working Memory Training (WMT) programme, versus a waitlist control group, on a wide range of attentional and working memory tasks, as well as on self-reported everyday functioning. We demonstrate separable effects of each of the active training conditions, with SAT leading to improvements in both spatial and non-spatial aspects of attention and WMT leading to improvements only on very closely related working memory tasks. Both training groups reported improvements in everyday functioning, which were associated with improvements in attentional functions, suggesting that improving attention may be of particular importance in maximising functional recovery in this patient group.

clinical trials↗

bioRxiv2018

Hierarchical Cognition causes Task Related Deactivations but not just in Default Mode Regions

AbstractThe well-known deactivation of the Default Mode Network (DMN) during external tasks is usually thought to reflect the suppression of internally directed mental activity during external attention. In 3 experiments with human participants we organized sequences of task events identical in their attentional and control demands into larger task episodes. We found that DMN deactivation across such sequential events was never constant, but was maximum at the beginning of the episode, then decreased gradually across the episode, reaching baseline towards episode completion, with the final event of the episode eliciting an activation. Crucially, this pattern of activity was not limited to a fixed set of DMN regions but, across experiments, was shown by a variable set of regions expected to be uninvolved in processing the ongoing task. This change in deactivation across sequential but identical events showed that the deactivation cannot be related to attentional/control demands which were constant across the episode, instead it has to be related to some episode related load that was maximal at the beginning and then decreased gradually as parts of the episode got executed. We argue that this load resulted from cognitive programs through which the entire episode was hierarchically executed as one unit. At the beginning of task episodes, programs related to their entire duration is assembled, causing maximal deactivation. As execution proceeds, elements within the program related to the completed parts of the episode dismantle, thereby decreasing the program load and causing a decrease in deactivation.\n\nSignificance StatementWe prepare breakfasts and write emails, and not individually execute their many component acts. The current study suggests that cognitive entities that enable such hierarchical execution of goal-directed behavior may cause the ubiquitously seen deactivation during external task execution. Further, while this deactivation has previously been associated with a defined set of the so called default mode regions, current study demonstrates that deactivation is shown by any region not currently involved in task execution, and in certain task episodes can even include attention related fronto-parietal regions as well as primary sensory and motor regions.

neuroscience↗

bioRxiv2018

Cognition and behaviour in learning difficulties and ADHD: A dimensional approach

BackgroundAcademic underachievement often accompanies the symptoms of inattention and hyperactivity/ impulsivity associated with ADHD. The aim of the present study is to establish whether learning difficulties have the same cognitive origins in this comorbid condition as in children who do not have ADHD.\n\nMethodsParticipants were 163 school-aged children with learning difficulties. Over a third also had a diagnosis of ADHD. Cognition, behaviour and learning attainments were assessed.\n\nResultsThe sample was distinguished by three cognitive and three behavioural dimensions. Learning was equivalently related to cognitive dimensions for children with and without ADHD. A diagnosis of ADHD was associated only with elevated levels of ADHD symptoms and problems with emotional control.\n\nConclusionsDistinct dimensions underpin academic learning and the control of impulsive and emotional behaviour impaired in ADHD. Phonological deficits are associated with learning problems in literacy and maths, and impairments in nonverbal and executive abilities with mathematical learning difficulties. The comorbid condition of ADHD combined with learning difficulties reflects independent deficits in the cognitive dimensions critical for learning and in the control of impulsive and emotional behaviour.

animal behavior and cognition↗

bioRxiv2017

Cognitive Entities Underpinning Task Episodes

Cognitive Entities Underpinning Task EpisodesAccounts of hierarchical cognition suggest that extended task episodes as one task entity and not individually execute their component acts. Such hierarchical execution is frequently thought to occur by first instantiating a sequence representation in working memory that then controls the identity and sequence of component steps. In contrast, we evidence hierarchical execution of extended behavior in situations where the identity and sequence of component steps was unknown and not linked to any sequence representation. Participants executed unpredictable trials wherein, depending on the margin color, they could either choose the smaller value or the font of the two numbers. Crucially, they were biased into construing a recurring instance of three or five trials as one task episode. Behavioral signs of hierarchy, identical to those seen previously with memorized sequence execution, were seen - High trial 1 RT, higher trial 1 RT before longer task episodes, and absence of trial level switch cost specifically across episode boundaries. This showed that hierarchical task sequence representations are not a requisite for hierarchical organization of cognition. Merely construing behavior to be executed as a task episode is enough for the accompanying cognition to be hierarchically organized. Task episodes are executed through the intermediation of episode related programs that are assembled at the beginning and control and organize cognition across time.

neuroscience↗

bioRxiv2016

When Attended and Conscious Perception Deactivates Fronto-Parietal Regions

Conscious and attended perception is commonly thought to elicit fronto-parietal activity. However, supportive evidence comes largely from studies which involve detecting a target and reporting its visibility. This approach confounds conscious perception with goal completion of either the perceptual task of detection or the metacognitive task of introspective reporting. In contrast, in real life such perceptions are a means of achieving goals and rarely a goal in themselves, and almost never involve explicit metacognitive reports. It therefore remains unclear if fronto-parietal activity is indeed a correlate of conscious perception or is the result of confounds related to goal completion. Here we show that conscious and attended perception when delinked from goals does not increase fronto-parietal activity, and when inconsequential for the goal may even deactivate these regions. In experiments 1 and 2 participants attended to a highly visible stream of letters to detect the occasional targets in their midst. The non-target letters, in spite of being visible and attended to, deactivated fronto-parietal regions. In experiment 3 we looked at the activity elicited by a loud auditory cue that had to be kept in memory for up to 9 s and used to select the correct rule for completing the goal. Even such a salient, attended and remembered event did not elicit prefrontal activity. Across these experiments conscious and attended perception only activated the relevant sensory regions while goal completion events activated fronto-parietal regions.\n\nSignificance statementConsciousness and attended perception has been seen to correlate with fronto-parietal activity. This informs key theories of consciousness and attention, e.g. widespread availability of incoming information or its higher level representation causes perceptual awareness, or that top down attention during perception broadcasts incoming sensations into frontal and parietal regions. However such experiments unwittingly conflate attended and conscious perception with some form of goal completion, whereas such perception in our daily life mostly serves as a means of goal completion and not a goal in itself. Here we show that such perception when delinked from goal completion does not activate fronto-parietal regions, and may even deactivate these regions if the percept is inconsequential for goal completion.

neuroscience↗