Bahar Güntekin

Visual-spatial attention (VSA) selects relevant sensory information and supports the preparation of responses to this information. Mental rotation (MR) is the ability to rotate an object seen from a certain perspective to a new orientation in space. Exercise stands out as a promising non-pharmacological treatment for cognitive functions. Balance control is known to be related to the visual system. Therefore, the aim was to investigate the effectiveness of video-based balance games and structured balance exercises on VSA and MR with EEG brain oscillations. 30 healthy participants were included in the study. Participants were divided into two groups (structured balance exercises group (SBEG) and video-based balance exercises group (VBBEG)) by randomization. Both groups received exercise sessions 2 days a week for a total of 6 weeks. The mentioned cognitive functions were evaluated by selecting tests previously used in the literature. For the VSA task, after 6 weeks of exercise, occipital theta (4–7 Hz) power decreased in the VBBEG group, while SBEG increased. In the MR task results, high alpha (11–13 Hz) power decreased in VBBEG and increased in SBEG when centroparietal areas were examined. In conclusion, it is thought that the two different exercise methods may affect visual-spatial attention and mental rotation skills in different ways.

Introduction: The ability to recognize emotional facial expressions relies on brain functional networks, particularly in the right hemisphere, and is impaired in neurodegenerative conditions such as Alzheimer’s disease and Parkinson’s disease. Given that this ability involves brain networks operating within hundreds of milliseconds, we tested the hypothesis of abnormalities in event-related spectral electroencephalographic coherence, with a focus on the right versus left hemispheres in these patients. Methods: Event-related theta (4–7 Hz) magnitude-squared coherence was calculated for both intra-hemispheric (frontal–temporal, frontal–parietal, central–temporal, and related pairs) and inter-hemispheric homologous electrode pairs (F3–F4, C3–C4, T7–T8, TP7–TP8, P3–P4, O1–O2). We enrolled 25 patients with amnestic mild cognitive impairment, 15 Parkinson’s disease patients with mild cognitive impairment, 25 Alzheimer’s disease patients with dementia, and 16 Parkinson’s disease patients with dementia, along with 25 healthy elderly as controls. Participants were presented with three different facial expressions (angry, happy, and neutral) 60 times each in a pseudo-random order. Results: Theta (4–7 Hz) spectral coherence was higher in the right than the left hemisphere across all groups, with Parkinson’s disease patients exhibiting the lowest values. Moreover, interhemispheric theta coherence was lower in Parkinson’s disease patients with mild cognitive impairment and dementia compared to the amnestic mild cognitive impairment and healthy elderly groups. Discussion: These findings indicate that cortical functional connectivity related to emotional facial expression processing is more disrupted in Parkinson’s disease than in Alzheimer’s disease, at both mild cognitive impairment and dementia stages. This disruption affects not only the right hemisphere but also interhemispheric connectivity. Finally, it would occur at theta frequencies.

Background: Human cognition is derived from functional cortical long-range connectivity, as reflected by phase synchronization between electrode pairs of low-frequency electroencephalographic (EEG) activity N = 24) and PD-MCI ( N = 20), PDD ( N = 18), and DLB ( N = 11) patients. Results: Using delta-band coherence as input, the comparison between HC and PD-MCI yielded an AUC of approximately 0.79 and an accuracy of 86.4%. Higher discriminative performance was observed for HC versus PDD, reaching an AUC near 0.92 with an overall accuracy of 94.6%. In the classification of HC versus DLB participants, the model achieved 83.3% sensitivity and 88.9% specificity, with an AUC around 0.77. Theta-band models showed comparable results, with average AUC values of about 0.75 for HC vs. DLB and slightly above 0.80 for HC vs. PDD, while classification of HC vs. PD-MCI remained in a moderate range. Conclusion: These findings suggest that event-related EEG phase coherence at <8 Hz is a promising EEG correlate of cognitive deficits in patients with PDD and DLB, offering insights into disrupted network dynamics of cortical activity related to cognitive processes and potential biomarkers for testing new drugs for cognitive enhancement and disease monitoring.

Introduction: Frequent exposure to video gaming induces changes in cognitive and perceptual functions and alterations in neural structure and functioning. While frequent video gaming has been associated with positive effects in cognitive-perceptual domains, it may concurrently exert adverse impact on social–emotional functioning. This study used event-related EEG brain oscillations to investigate the effect of frequent playing video games on the visual and auditory working memory processes. Methods: The study included 23 healthy young men participants, divided into frequent gamer and infrequent gamer groups based on their exposure to violent video games. An internet-based questionnaire was used for group classification, and the frequent gamer group consisted of participants who played more than 15 h of video games per week. EEG recordings were obtained during visual and auditory memory tasks, and participants’ anxiety levels were assessed using the State–Trait Anxiety Inventory. Event-related power spectrum and phase-locking analyses were conducted for delta, theta, and alpha frequencies. Results: No significant group differences were observed in behavioral performance and anxiety levels; however, there were notable electrophysiological differences. The frequent gamers exhibited lower and shorter visual delta responses compared to infrequent gamers. A left-hemisphere dominance for the frequent gamers was observed in auditory theta and alpha power, particularly in the parietal and occipital regions. Additionally, the frequent gamers showed reduced visual alpha power in posterior regions and less increase in auditory lower alpha phase-locking. Discussion: In conclusion, the observed alterations in low-frequency event-related oscillations suggest that the frequent gamers employ distinct neurocognitive strategies during memory tasks. These strategies may reflect enhanced efficiency in specific domains such as attention and memory, despite similar behavioral performance.

Cognitive reserve (CR), shaped by the interaction of lifestyle and genetics, enhances the efficient use of neural resources, allowing individuals with higher reserve to require less neural activity to accomplish a task than those with lower reserve. Although not solely a mechanism for neural efficiency, hemispheric asymmetries contribute to it through the lateralization of cognitive processes across hemispheres. It is hypothesized that CR may influence the degree of asymmetry in neural activity during various cognitive processes. The aims of this study were to explore the effects of CR on verbal and visuospatial working memory performance and its relationship with the degree of asymmetry in 2–9 Hz phase‐locking responses. The data were collected in two separate laboratories: one in Turkey and one in Germany. The sample included 33 Turkish and 18 German participants, all of whom completed verbal and visuospatial Sternberg tasks at two difficulty levels (one‐item and three‐item). The behavioral performance parameter was d' value, with EEG asymmetry calculated via the laterality coefficient (LC) formula. Under conditions of increased task difficulty, the LCs in the verbal task and CR scores had significant associations, especially in the parietal electrode pairs. Similarly, the LCs in the visuospatial task had significant associations with CR scores in the parietal and occipital electrode pairs. Furthermore, phase‐locking responses were significantly higher in the right hemisphere across both tasks. These findings suggest that CR influences neural asymmetry, emphasizing the right hemisphere's role in CR and its potential as a therapeutic target.

The body schema of amputees may be adversely affected by impairments in attentional mechanisms within the central nervous system. The objective of this study was to examine the potential disparities in behavioral and low-frequency oscillations (LFOs) between individuals with amputations and healthy controls. Participants included upper-limb amputees (ULA; n= 6; 5 Male[M], 1 Female[F]), lower-limb amputees (LLA; n=9; 7M, 2F), and healthy controls (HC; n=11; 8M, 3F). A hand laterality task was performed during the Electroencephalography (EEG) recording, with stimuli of different laterality (right vs. left) and angular orientation (0° vs. 180°). EEG recordings were obtained on two separate occasions for each subject before and following the lateralisation training. The accuracy rates for the hand stimuli presented at 0° compared to those presented at 180° were higher (p < 0.05). Following the training, there was a significant improvement in the accuracy rate (p<0.001). ULA demonstrated a significantly slower reaction time than LLA in the lateralization task (p < 0.05). The results obtained from the EEG revealed a greater increase in delta (1.5-3 Hz) power in the ULA compared to the HC (p < 0.05). The characteristics of the stimuli, specifically right-hand images and those presented at 0°, appeared to modulate the delta phase responses (p < 0.05). The increased theta (4-7 Hz) power and phase responses observed following lateralization training suggest that oscillatory entrainment may be enhanced through attentional engagement (for both, p < 0.05). In addition to behavioural responses, the emphasis on bodily sensations in ULA and LLA can also be assessed through LFOs. This research offers a more sophisticated understanding of bodily attention mechanisms in amputees and may contribute to the field of neurorehabilitation.

Apathy is a cognitive, behavioral, and emotional disorder marked by a decrease in goal-directed activities as well as affective flattening. This multifaceted disorder has been described in Parkinson’s disease as a highly common neuropsychiatric feature. The pathophysiology that underlies apathy, however, is still not entirely understood. The major goal of this study was to determine the microstate correlations of apathy in Parkinson’s disease. This study involved patients with the diagnosis of idiopathic Parkinson’s disease. Based on the Apathy Evaluation Scale criteria, Parkinson’s disease groups were divided into two main groups- apathetic and non-apathetic. Patients underwent clinical, motor, and demographic characteristics as well as neuropsychometric evaluations. Spontaneous EEG brain activity was recorded, and a microstate analysis was conducted. The clinical and motor functions of the apathetic and non-apathetic groups did not differ significantly; nevertheless, the apathetic group performed worse on several executive function and memory tests. A comparison of EEG microstates between the apathetic and non-apathetic groups found that the apathetic group had an increase in the duration and coverage of microstates B and E, whereas the frequency of Microstate D decreased. Additionally, in patients with apathy, an increased transition was observed from Microstate A > B, C > E and C > G. Our findings suggest that the increased transitions from Microstate A to B and from C to E and G, along with an increase in Microstates E and B and a decrease in Microstate D, may reflect changes in the activity or functional connectivity of several large-scale brain circuits in Parkinsonian apathy. On the other hand, Microstate E could be the fundamental microstate reflecting changes associated with the Default Mode Network in Parkinsonian apathy.