9 research outputs found
The effect of directional social cues on saccadic eye movements in Parkinson’s disease
There is growing interest in how social processes and behaviour might be affected in Parkinson’s disease. A task which has been widely used to assess how people orient attention in response to social cues is the spatial cueing task. Socially relevant directional cues, such as a picture of someone gazing or pointing to the left or the right have been shown to cause orienting of visual attention in the cued direction. The basal ganglia may play a role in responding to such directional cues, but no studies to date have examined whether similar social cueing effects are seen in people with Parkinson’s disease. In this study, patients and healthy controls completed a prosaccade (Experiment 1) and an antisaccade (Experiment 2) task in which the target was preceded by arrow, eye gaze or pointing finger cues. Patients showed increased errors and response times for antisaccades but not prosaccades. Healthy participants made most anticipatory errors on pointing finger cue trials, but Parkinson's patients were equally affected by arrow, eye gaze and pointing cues. It is concluded that Parkinson's patients have a reduced ability to suppress responding to directional cues, but this effect is not specific to social cues
Effects of Birth Experience on Relational Memory in Adults
Recent evidence has emerged that being born via planned or emergency cesarean section delivery (CSD) compared to vaginal delivery (VD) not only led to slower allocation of attention in human infants and adults but also affected hippocampal regions responsible for memory in mice. This is concerning as the number of C-sections has risen in the past two decades according to the World Health Organization. Therefore, the current study investigated if a higher-order cognitive function like relational memory, is also affected by CSD and if these effects last into adulthood. Birth experience effects on item-item, item-space and item-time relational memory along with item recognition were assessed in adult participants using a task developed by Konkel et al. (2008). Results indicated that the item-item memory performance was affected by CSD with planned CSD adults showing poorer recognition compared to emergency CSD adults. No differences in memory performance were found between either of the CSD groups and the VD group in any of the relational conditions. As relational binding has implications in forming autobiographical memories and connections between our past, present and future states, healthcare professionals should discuss with expecting mothers the potential long-term effects of planned CSD on their infants’ cognitive development
Effects of Birth Experience on Relational Memory in Adults
Recent evidence has emerged that being born via planned or emergency cesarean section delivery (CSD) compared to vaginal delivery (VD) not only led to slower allocation of attention in human infants and adults but also affected hippocampal regions responsible for memory in mice. This is concerning as the number of C-sections has risen in the past two decades according to the World Health Organization. Therefore, the current study investigated if a higher-order cognitive function like relational memory, is also affected by CSD and if these effects last into adulthood. Birth experience effects on item-item, item-space and item-time relational memory along with item recognition were assessed in adult participants using a task developed by Konkel et al. (2008). Results indicated that the item-item memory performance was affected by CSD with planned CSD adults showing poorer recognition compared to emergency CSD adults. No differences in memory performance were found between either of the CSD groups and the VD group in any of the relational conditions. As relational binding has implications in forming autobiographical memories and connections between our past, present and future states, healthcare professionals should discuss with expecting mothers the potential long-term effects of planned CSD on their infants cognitive development
Cross-species neuroscience: closing the explanatory gap
Neuroscience has seen substantial development in non-invasive methods available for investigating the living human brain. However, these tools are limited to coarse macroscopic measures of neural activity that aggregate the diverse responses of thousands of cells. To access neural activity at the cellular and circuit level, researchers instead rely on invasive recordings in animals. Recent advances in invasive methods now permit large-scale recording and circuit level manipulations with exquisite spatiotemporal precision. Yet, there has been limited progress in relating these microcircuit measures to complex cognition and behaviour observed in humans. Contemporary neuroscience thus faces an explanatory gap between macroscopic descriptions of the human brain and microscopic descriptions in animal models. To close the explanatory gap, we propose adopting a cross-species approach. Despite dramatic differences in the size of mammalian brains this approach is broadly justified by preserved homology. Here, we outline a three-armed approach for effective cross-species investigation that highlights the need to translate different measures of neural activity into a common space. We discuss how a cross-species approach has the potential to transform basic neuroscience while also benefiting neuropsychiatric drug development where clinical translation has, to date, seen minimal success
Eye movements in the “Morris Maze” spatial working memory task reveal deficits in strategic planning
© 2018 Massachusetts Institute of Technology. Analysis of eye movements can provide insights into processes underlying performance of cognitive tasks. We recorded eye movements in healthy participants and people with idiopathic Parkinson disease during a token foraging task based on the spatial working memory component of the widely used Cambridge Neuropsychological Test Automated Battery. Participants selected boxes (using a mouse click) to reveal hidden tokens. Tokens were never hidden under a box where one had been found before, such that memory had to be used to guide box selections. A key measure of performance in the task is between search errors (BSEs) in which a box where a token has been found is selected again. Eye movements were found to be most commonly directed toward the next box to be clicked on, but fixations also occurred at rates higher than expected by chance on boxes farther ahead or back along the search path. Looking ahead and looking back in this way was found to correlate negatively with BSEs and was significantly reduced in patients with Parkinson disease. Refixating boxes where tokens had already been found correlated with BSEs and the severity of Parkinson disease symptoms. It is concluded that eye movements can provide an index of cognitive planning in the task. Refixations on locations where a token has been found may also provide a sensitive indicator of visuospatial memory integrity. Eye movement measures derived from the spatial working memory task may prove useful in the assessment of executive functions as well as neurological and psychiatric diseases in the future
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The relationship between gonadal hormones and neurocognitive functioning in healthy men and women and patients with schizophrenia
The primary aim of this thesis was to examine differences between healthy men and women and men and women with schizophrenia in relation to neurocognitive functioning. The thesis also examined the role of organisational influences of gonadal hormones and gonadotropins to cognitive performance. This was investigated in three studies. Study 1 examined the differences between healthy men and women on a sexually dimorphic cognitive battery (comprising mental rotation, modified judgement of line orientation, computerized Benton judgement of line orientation, cognitive inhibition, letter and category fluency tasks, and a working memory task) in a group of healthy men (n= 42) and women (n = 42). The study also looked at the relationship of organisational influences of gonadal hormones (estrogen, testosterone, progesterone), gonadotropins (lutenizing hormone; LH, follicle stimulating hormones; FSH) and sex hormone binding globulin; SHBG to these cognitive tasks. Study 2 investigated the role of gonadal hormones and the stress hormone cortisol to neurocognitive functioning (comprising domains of attention, verbal abilities, language, memory, executive functioning, motor and speed of information processing) and symptomatology (using the Positive and Negative Syndrome Scale; PANSS) in patients (N = 37) with schizophrenia. Study 3 examined the neural correlates of sex differences in performance on a block design mental rotation task and an overt verbal fluency paradigm using compressed sequence design in a group of healthy men (n = 9) and women (n = 10), controlling for the role of estrogen. Study I showed significant sex differences favouring men on all the spatial tasks and on a cognitive inhibition task, and differences favouring women on the category fluency task. Significant relationships were found between specific conditions of the spatial and inhibition tasks and progesterone, LH, FSH and SHBG. Study 2 found no sex differences in neurocognitive performance in patients with schizophrenia but found that high levels of estrogen were related to low positive symptom scores. Within gender, cortisol levels related to poor performance on the information-processing domain. Study 3 showed sex differences favouring men on the mental rotation and favouring women on the verbal (phonological) fluency task. Analysing the sexes separately revealed activation in the right superior parietal lobe in men and women during mental rotation performance. In general, women activated a greater number of voxels compared to men on the mental rotation and verbal fluency tasks. No sex differences (comparing the groups) in neural activation were found on any of the cognitive tasks. These findings confirmed the previously cited sex differences in cognitive performance and show that with similar activation patterns, men and women showed differential behavioural performance, thus suggesting that women may need more resources to perform better. Overall, this thesis adds to a critical body of literature showing that the relationship between gonadal hormones and cognition is more unsettled than previously thought. The findings also show that hormones other than estrogen and testosterone may also moderate hormone cognition relationships in men and women
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Muscle activation patterns in shoulder impingement patients
Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences.
Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05.
Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance.
Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients