Saudi Cultural Missions Theses & Dissertations
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Item Restricted THE NEUROPHYSIOLGY OF SELECTIVE ATTENTION IN HUMAN SUBCORTICAL MOTOR NUCLEI(University of Toronto, 2025) Alanazi, Frhan; William, HutchisonSelective attention and working memory are fundamental cognitive processes traditionally attributed to cortical regions. Emerging evidence suggests that subcortical motor nuclei, such as the thalamus and basal ganglia, also play crucial roles in these functions, but the mechanism is still unclear. This thesis aimed to examine the neurophysiological mechanisms of selective attention and working memory in subcortical motor nuclei through intraoperative single-unit and local field potential (LFP) recordings in humans. In the first study, neuronal activity was recorded from the ventral intermediate nucleus (Vim) and ventral oral anterior/posterior nuclei of the motor thalamus in 25 patients with parkinsonian and non-parkinsonian tremors during an auditory oddball task. Results showed a significant decrease in neuronal firing rates and in beta-band (13–35 Hz) oscillations to the deviant tones, indicating the involvement of Vim in auditory selective attention. Parkinson’s disease (PD) patients off medication exhibited increased beta power but reduced modulation to attended tones, suggesting dopamine's role in modulating thalamic beta oscillations for selective attention. The second study focused on the centromedian nucleus (CM) of the thalamus in 11 epilepsy patients performing a similar auditory attention task. CM neurons demonstrated selective, multiphasic firing and beta/low gamma (13–45 Hz) modulations to deviant tones in 81% of neurons tested. These findings highlight the CM's participation in cognitive function, supporting its role under top-down control and implicating beta and gamma oscillatory activities in cognitive processing. The third study investigated neuronal activity in the subthalamic nucleus (STN) and Vim during a visual 1-back task in 16 patients with PD or essential tremor. Both nuclei exhibited selective firing rate changes and beta desynchronization in response to target stimuli. Vim beta desynchronization occurred earlier than in the STN, even preceding the stimulus, suggesting a role in stimulus prediction. Collectively, these studies provide evidence that subcortical motor nuclei are actively involved in selective attention and working memory and have significant implications for understanding the neural circuitry underlying cognitive functions and the pathophysiology of neurological disorders like Parkinson’s disease and epilepsy. Furthermore, they offer potential insights for developing deep brain stimulation therapies targeting cognitive symptoms associated with these conditions.11 0Item Restricted “What is the impact of gardening on the psychological health of adults? A scoping review.”(Exeter University, 2024-03-06) Alomiri, Abeer; Garsid, RuthRecently, there have been concerns that the prevalence of mental disorders has increased significantly, threatening the mental health of a large segment of the population. Therefore, there has been a call to improve the psychological health of the general population using non-pharmacological interventions (e.g., gardening and green spaces). Although several scoping reviews have examined the psychological outcomes of green spaces, there is a lack of scoping reviews that examine the psychological outcomes of gardening. Scoping reviews in this research area can be valuable because they identify potential methodological limitations, informing future research. Further, they can explore the scope of evidence, which can identify unanswered research questions. Therefore, this scoping review aimed to explore the scope of evidence as well as identify the methodological limitations in this research area in order to inform future research. The scoping review was guided by a framework developed by Arksey and O'Malley (2005). Different databases were used to access relevant studies, including Scopus, Medline, and the Web of Science Core Collection (WSCC). The search yielded 26 studies. Gardening can lead to a wide range of psychological outcomes, including a reduced risk of depression, with a higher effectiveness of community gardening in decreasing depression compared to individual/home gardening, a decrease in anxiety, mental resilience and relief from stress, escape, enjoyment, and relaxation, better cognitive performance, a sense of community and social relationships, and a greater sense of meaning of life, although there is a greater effect size in individualistic than collectivist cultures and an overly simplistic approach to the association between gardening and psychological outcomes. Further, there were several methodological limitations, such as limited use of objective measures (e.g., salivary cortisol levels, fMRI), a lack of use of the Core Outcome Sets (COS), a lack of studies with long-term follow-up, a lack of studies that examined the difference between doing the gardening activity and the mere presence of being at the gardening site, and a lack of studies from different countries (Africa, Asia, and South America). Limited studies examined the impact of mediators and moderators. Further, known facts were usually not taken into account. Researchers are advised to address these methodological gaps, as this will improve the quality of evidence in this emerging research area. Moreover, policymakers are advised to provide the required financial support to urban planners to increase the presence of gardens, as they can encourage local people to engage in gardening activities. Further, initiatives that introduce community gardening in public gardens can be adopted by local governments worldwide. Keywords: gardening, green spaces, psychological health, depression, anxiety, stress12 0Item Restricted Recognizing Human-Object Interactions in Videos(Saudi Digital Library, 2023-05-11) Almushyti, Muna Ibrahim M; Li, FrederickUnderstanding human actions that involve interacting with objects is very important due to the wide range of real-world applications, such as security surveillance and healthcare. In this thesis, three different approaches are presented for addressing the problem of human-object interactions (HOIs) recognition in videos. Firstly, we propose a hierarchical framework for analyzing human-object interactions in a video sequence. The framework comprises Long Short-Term Memory (LSTM) networks that capture human motion and temporal object information independently. These pieces of information are then combined through a bilinear layer and fed into a global deep LSTM to learn high-level information about HOIs. To concentrate on the key components of human and object temporal information, the proposed approach incorporates an attention mechanism into LSTMs. Secondly, we aim to achieve a holistic understanding of human-object interactions (HOIs) by exploiting both their local and global contexts through knowledge distillation. The local context graphs are used to learn the relationship between humans and objects at the frame level by capturing their co-occurrence at a specific time step. On the other hand, the global relation graph is constructed based on the video-level of human and object interactions, identifying their long-term relations throughout a video sequence. We investigate how knowledge from these context graphs can be distilled to their counterparts to improve HOI recognition. Lastly, we propose the Spatio-Temporal Interaction Transformer-based (STIT) network to reason about spatio-temporal changes of humans and objects. Specifically, the spatial transformers learn the local context of humans and objects at specific frame times. The temporal transformer then learns the relations at a higher level between spatial context representations at different time steps, capturing long-term dependencies across frames. We further investigate multiple hierarchy designs for learning human interactions. The effectiveness of each of the proposed methods mentioned above is evaluated using various video action datasets that include human-object interactions, such as Charades, CAD-120, and Something-Something V1.7 0