Biology subjects

DeSouza, J. F.

Publications and source records attributed to DeSouza, J. F..

8 recordsLinked to original sources

bioRxiv2026

Oculomotor dance learning task: Implications for audio-visual cued spatial learning

Motor sequence learning involves the coordination of both oculomotor and manual motor systems through the practiced repetition of a fixed sequence of actions. This study aims to address whether a sequence-based learning paradigm centered on the visual-motor system can feasibly be measured while listening to music (Bar and DeSouza 2016). It aims to develop a new visual-motor-based learning paradigm with music, potentially promoting neuroplasticity and creating new interventional tools, building upon prior research that shows behavioural and putative neural changes following dance-based neurorehabilitation in people with Parkinsons disease (Bearss et al. 2024). Eye movements of 10 participants (8 female, 2 male) were tracked using the Eyelink 1000 Plus system during a 68-second eye-dance sequence. The experiment consisted of a learning phase, where participants observed the sequence five times with 30-second breaks, and a performance phase, where they performed the sequence five times from memory on a grey screen without visual cues. Music was incorporated into both phases to aid memorization of the 4 spatial locations. After each performance, the participant was shown a visual reinforcer and asked for their thoughts on how well they executed the dance. A visual reinforcer flashes one of three different colours: red, yellow, or green. Each colour corresponds to how many steps in the dance a participant performed correctly, with key points being: under one third, between one to two thirds, and over two thirds of total steps correct. Participants were scored based on timing of the steps as well for exact (1.00), good (0.66), slightly off (0.33) or missed (0) steps. Data was analyzed using R4.3.1, MATLAB, and Experiment Builder: Data Viewer software. Results showed a significant improvement in performance accuracy between the first session (g1; M = 40%, SD = 7.2%) and the last session (g5; M = 69.7%, SD = 22.8%). A repeated-measures ANOVA revealed a significant main effect of session on performance accuracy, F(4, 36) = 6.99, p < 0.001, {superscript 2}G = 0.26, indicating that accuracy significantly improved over sessions. Post-hoc Bonferroni comparisons showed that accuracy in later sessions was significantly higher than earlier sessions, suggesting a defined learning curve and consolidation of performance pattern across repeated practice. Similarly, there was significant improvement in timing accuracy between the first session g1; M = 0.29, SD = 0.06) and the fifth session (g5; M = 0.46, SD = 0.12). A repeated-measures ANOVA revealed a significant main effect of session on timing precision, F(4, 36) = 11.67, p < 0.001, {superscript 2}G = 0.25, indicating significant improvements in temporal control and coordination over sessions. Post-hoc Bonferroni comparisons showed that timing precision significantly improved between early and late sessions (e.g, g1-g4, p <0.01; g1-g5, p < 0.001), suggesting a defined learning curve and increase in precision across repeated practice. These findings suggest that visual-motor-based interventions have the potential to enhance motor and non-motor symptoms like depression and anxiety for neurodegenerative diseases such as Parkinsons Disease (PD). The results provide a foundation for developing targeted therapies that integrate learning paradigms to improve functional outcomes, warranting further exploration of their long-term efficacy.

neuroscience↗

bioRxiv2022

Mixed Models Quantify Annual Volume Change; Linear Regression Determines Thalamic Volume as the Best Subcortical Structure Volume Predictor in Alzheimer's Disease and Aging

BackgroundThalamus-hippocampus-putamen and thalamus-cerebellar interconnections are dense. The extent this connectivity is paralleled by each structures volume impact on another is unquantified in Alzheimers disease (AD). Mixed model quantification of annual volume change in AD is scarce and absent inclusive of the cerebellum, hippocampus, putamen and lateral ventricles and thalamus. Among these structures, autopsy evidence of early-stage AD seems largely but not entirely restricted to the hippocampus and thalamus. ObjectiveVariation in annual volume related to time and baseline age was assessed for the hippocampus, putamen, cerebellum, lateral ventricles and thalamus. Which subcortical structures volume had the largest explanatory effect of volume variation in other subcortical structures was also determined. MethodThe intraclass correlation coefficient was used to assess test-retest reliability of structure automated segmentation. Linear regression (N = 45) determined which structures volume most impacted volume of other structures. Finally, mixed models (N = 36; 108 data points) quantified annual structure volume change from baseline to 24-months. ResultsHigh test-retest reliability was indicated by a mean ICC score of .989 (SD = .012). Thalamic volume consistently had the greatest explanatory effect of hippocampal, putamen, cerebellar and lateral ventricular volume. The group variable proxy for AD significantly contributed to the best-fitting hippocampal linear regression model, hippocampal and thalamic longitudinal mixed models, and approached significance in the longitudinal lateral ventricular mixed model. Mixed models determined time (1 year) had a negative effect on hippocampal, cerebellar and thalamic volume, no effect on putamen volume, and a positive effect on lateral ventricular volume. Baseline age had a negative effect on hippocampal and thalamic volume, no effect on cerebellar or putamen volume and a positive effect on lateral ventricular volume. InterpretationLinear regression determined thalamic volume as a virtual centralized index of hippocampal, cerebellar, putamen, and lateral ventricular volume. Relative to linear regression, longitudinal mixed models had greater sensitivity to detect contribution of early AD, or potential AD pathology (MCI), via the group variable not just to volume reduction in the hippocampus but also in the thalamus.

neuroscience↗

bioRxiv2022

Weekly dance training over eight months reduces depression and correlates with fMRI brain signals in subcallosal cingulate gyrus (SCG) for people with Parkinson's Disease: An observational study

Depression affects 280 million people globally and is considered a prodromal feature for increasingly prevalent neurodegenerative conditions including Parkinsons disease (PD). With age-related neurodegeneration on the rise, its important to consider non-invasive, inexpensive interventions such as dance. Dance has emerged as a complementary treatment that may support adaptive neuroplasticity while diminishing motor and non-motor symptoms including depression. Although dance has been shown to impact brain structures and functions with improvements in motor and psychological symptoms, the neural mechanisms underlying depression/mood remain elusive. Our observational study tracks the relationship between depression scores and functional neuroimaging measures for subgenual cingulate gyrus (SCG). While learning choreography over an 8-month period, 34 dancers [23 people with PD] completed GDS questionnaires before and after their community dance classes. Seventeen of these dancers had BOLD fMRI scans conducted using learning-related protocols to examine underlying neural mechanisms for moving to music over 4 times points of learning. A significant decrease in depression scores correlated with a reduced BOLD signal from SCG, a putative node in the neural network of depression. Conclusions: This is the first study to clearly find a correlation with a neural substrate involved in mood changes as a function of dance for PD. Not only do the results contribute to understanding neural mechanisms involved in adaptive plasticity with a learning task, but they also uncover reduced activity within SCG during longitudinal therapeutic dance interventions. These results are especially illuminating since SCG is a controversial target in deep brain stimulation (DBS) used in the treatment of major depressive disorder (MDD).

neuroscience↗

bioRxiv2021

Neural Correlates of a Trance Process and Alternative States of Consciousness in a Traditional Healer

Trance processes are a form of altered states of consciousness (ASC) widely reported across cultures. Entering these states is often linked to auditory stimuli such as singing, chanting, or rhythmic drumming. While scientific research into this phenomenon is relatively nascent, there is emerging interest in investigating the neural correlates of altered states of consciousness such as trance. This report aims to add to this field of ASC through exploring how the perception of an experienced Sangoma--traditional South African healer--entering a trance process correlates to BOLD signal modulation with auditory stimuli. Functional MRI data were analyzed using a General Linear model comparing music versus no music condition multiplied by the percept of experiencing trance (High or Low). Positive BOLD activation was shown in auditory cortex in both hemispheres during a trance process. Other brain regions tightly correlated to trance perception were right parietal, right frontal, and area prostriata (P<0.05, Bonferroni corrected). Orbitofrontal cortex (part of the Default Mode Network) was negatively activated and most correlated with music when trance was high, showing the largest differential between high and low trance perception. This is the first study to directly correlate BOLD signal variations in an expert subjects percept of trance onset and intensity, providing insight into the neural signature and dynamics of this unique form of ASC. Future studies should examine in greater detail perception of trance processes in expert subjects, adding other neuroimaging modalities to further investigate how these brain regions are modulated by trance expertise.

neuroscience↗

bioRxiv2020

Beauty That Moves: Dance for Parkinson's Effects on Affect, Self-Efficacy, Gait Symmetry and Dual Task Performance

BackgroundPrevious studies have investigated the effects of dance interventions on Parkinsons motor and non-motor symptoms in an effort to develop an integrated view of dance as a therapeutic intervention. This within-subject study questions whether dance can be simply considered a form of exercise by comparing a Dance for Parkinsons class with a matched-intensity exercise session lacking dance elements like music, metaphorical language, and social reality of grace and beauty. MethodsIn this repeated-measure design, 7 adults with Parkinsons were tested four times; (i) before and (ii) after a Dance for Parkinsons class, as well as (iii) before and (iv) after a matched-intensity exercise session. Physiological measures included heart rate and electrodermal activity. Self-reported affect and body self-efficacy were collected. Gait symmetry and dual task cost were analyzed using the 6-minutes walking test (6MWT) and Timed-Up-and-Go test (TUG), respectively. ResultsAverage heart rate was the same for both conditions, while electrodermal activity was higher during Dance for Parkinsons. Significant differences were found in body self-efficacy, beauty subscale, symmetry of gait, and dual task performance. ConclusionsDance, compared to an exercise intervention of matched intensity, yields different outcomes through the means of intrinsic artistic elements, which may influence affective responses, the experience of beauty, self-efficacy, and gait performance.

neuroscience↗

bioRxiv2019

A High Dose Tango Intervention for People with Parkinson’s disease (PwPD)

BackgroundDance has been used extensively to help supplement ongoing therapies for people with PD, most commonly on a weekly or biweekly basis. A daily dose, however, may provide additional benefits. This study examines the dose effect of a dance intervention delivered within a clinic for movement disorders in which PwPD are paired with experienced studio tango dancers.\n\nObjectiveThe current study aims to examine the dose effects of daily dance for PwPD on motor and non-motor functions directly within a movement disorders clinic.\n\nDesignwithin-subject, pre-post-intervention, mixed-methods evaluation including UPDRS III.\n\nSettingThe intervention was held at the Movement Disorders Department of a General Hospital in Buenos Aires, Argentina over two-weeks.\n\nSubjectsThe class had 21 people in total attendance per class. Two were expert tango dancers and instructors, nine were advanced tango dancers (volunteers), two were caregivers and eight were people with mild and moderate severity [Hoehn and Yahr (H&Y) scale 1-2] idiopathic Parkinsons disease.\n\nInterventionTen dance lessons, each 90-minutes daily within a two-week period.\n\nOutcome measuresThe Movement Disorders Society Unified Parkinsons Disease Rating Scale (UPDRS) part III was used for pre- and post-motor assessment. Psychological questionnaires, a Likert scale examining symptoms, and a pictorial scale were used to assess non-motor aspects. Semi-structured interviews were conducted to assess the impact of the dance intervention on participants experience.\n\nResultsOur study found a significant 18% amelioration in motor symptoms as measured by UPDRS III. We also found improvements on activities of daily living (ADL), sleep, Psychological Needs variables - post high dose dance intervention in Likert Scale.\n\nConclusionsA high dose short-term tango intervention for PwPD improved motor and non-motor aspects of PD such as ADL and sleep with high levels of adherence (97.5%) and enjoyment reported by participants. This dance intervention also improved participants perception of their own skills. The frequency or dosage of dance in rehabilitation suggests that an increased dose from once per week to 5 times per week can ameliorate many symptoms of PD and could be used as a short-term intervention.

neuroscience↗

bioRxiv2018

Visual signals suppress Alpha Power Increases & Frequency Decreases before and after a Mindfulness Meditation Intervention for Problem Gambling

The use of mindfulness meditation (MM) in the treatment of problem gambling (PG), has been used effectively for over five years. However, the neural mechanisms responsible for the improvements are unknown. The literature describes healthy individuals with an increase in alpha power and a decrease in alpha frequency after eight weeks of mindfulness meditation, but it is unknown if changes are similar amongst individuals with PG. Using resting-state electroencephalography (rsEEG), we measured the changes in alpha oscillations before and after an eight-week mindfulness meditation intervention (MMi) and a pre/ post-five-minute mindfulness meditation body scan (MMb). For people with PG, we observed an increase in alpha power and decreased alpha peak frequency after the MMi, while the inverse was true for the MMb. The most considerable alpha rhythm changes occurred in the frontal and temporal lobes, areas sensitive to reward and sensory processing in PG. Our observed changes may reflect theories that MMi for PG may improve attentional control as hypothesized by previous research in alpha oscillations and cue-reward processing.

neuroscience↗

bioRxiv2018

Neuromagnetic signatures of the spatiotemporal transformation for reaching

Movement planning involves transforming the sensory goal representation into a command in motor coordinates. Surprisingly, the real-time dynamics of sensorimotor transformations at the whole brain level remain unknown, in part due to the spatiotemporal limitations of fMRI and neurophysiological recordings. Here, we used magnetoencephalography (MEG) during pro-/anti-wrist pointing to determine (1) the cortical areas involved in transforming visual signals into appropriate hand motor commands, and (2) how this transformation occurs in real time, both within and across the regions involved. We computed sensory, motor, and sensorimotor indices in 16 bilateral brain regions for direction coding based on hemispherically lateralized de/synchronization in the (7-15Hz) and {beta} (15-35Hz) bands. We found a visuomotor progression, from pure sensory codes in early occipital-parietal areas, to a temporal transition from sensory to motor coding in the majority of parietal-frontal sensorimotor areas, to a pure motor code, in both the and {beta} bands. Further, the timing of these transformations revealed a top-down pro/anti cue influence that propagated backwards from frontal through posterior cortical areas. These data directly demonstrate a progressive, real-time transformation both within and across the entire occipital-parietal-frontal network that follows specific rules of spatial distribution and temporal order.

neuroscience↗