Activity In Brain Areas Research Articles

Brain-behavior analysis of transcranial direct current stimulation effects on a complex surgical motor task.

Transcranial Direct Current Stimulation (tDCS) has demonstrated its potential in enhancing surgical training and performance compared to sham tDCS. However, optimizing its efficacy requires the selection of appropriate brain targets informed by neuroimaging and mechanistic understanding. Previous studies have established the feasibility of using portable brain imaging, combining functional near-infrared spectroscopy (fNIRS) with tDCS during Fundamentals of Laparoscopic Surgery (FLS) tasks. This allows concurrent monitoring of cortical activations. Building on these foundations, our study aimed to explore the multi-modal imaging of the brain response using fNIRS and electroencephalogram (EEG) to tDCS targeting the right cerebellar (CER) and left ventrolateral prefrontal cortex (PFC) during a challenging FLS suturing with intracorporeal knot tying task. Involving twelve novices with a medical/premedical background (age: 22-28 years, two males, 10 females with one female with left-hand dominance), our investigation sought mechanistic insights into tDCS effects on brain areas related to error-based learning, a fundamental skill acquisition mechanism. The results revealed that right CER tDCS applied to the posterior lobe elicited a statistically significant (q < 0.05) brain response in bilateral prefrontal areas at the onset of the FLS task, surpassing the response seen with sham tDCS. Additionally, right CER tDCS led to a significant (p < 0.05) improvement in FLS scores compared to sham tDCS. Conversely, the left PFC tDCS did not yield a statistically significant brain response or improvement in FLS performance. In conclusion, right CER tDCS demonstrated the activation of bilateral prefrontal brain areas, providing valuable mechanistic insights into the effects of CER tDCS on FLS peformance. These insights motivate future investigations into the effects of CER tDCS on error-related perception-action coupling through directed functional connectivity studies.

Neurological activation during verbal fluency task and resting-state functional connectivity abnormalities in obsessive-compulsive disorder: a functional near-infrared spectroscopy study.

This study aims to investigate the activation of frontotemporal functional brain areas in patients with Obsessive-Compulsive Disorder (OCD) during a Verbal Fluency Task (VFT), and to compare their brain functional connectivity in a resting state with that of healthy controls. The goal is to deepen our understanding of the neuropathological mechanisms underlying OCD. 32 patients with OCD and 32 controls matched for age, gender, handedness, and years of education participated in this study, they were divided into OCD group and healthy comtrol group. We conducted VFT task tests and 10-minute resting state tests on both groups by using functional Near-Infrared Spectroscopy (fNIRS). The VFT was utilized to assess the activation (beta values) and the integral and centroid values of the frontal and bilateral temporal lobes, including brain areas BA9 and 46 (dorsolateral prefrontal cortex), BA10 (frontal pole), BA45 (inferior frontal gyrus), BA21 (middle temporal gyrus), and BA22 (superior temporal gyrus). We evaluated the functional connectivity levels of these areas during the resting state. Differences in these measures between OCD patients and healthy controls were analyzed using two-sample independent t-tests and non-parametric Mann-Whitney U tests. During VFT, OCD had smaller integral values(z=5.371, p<0.001; t=4.720, p<0.001), and larger centroid values(t=-2.281, p=0.026; z=-2.182, p=0.029) compared to healthy controls, along with a reduced number of activated channels detected by fNIRS. Additionally, activation values (β) in various functional brain areas, including BA9, BA46, BA10, BA45, BA21, and BA22, were significantly lower in the OCD group (all p< 0.01). In the resting state, notable disparities in functional connectivity were observed between the inferior frontal gyrus (IFG) and dorsolateral prefrontal cortex (DLPFC) in the OCD group, in comparison to the control group. Specifically, there was a significant increase in connectivity between the left IFG and right DLPFC, suggesting the presence of altered connectivity patterns in these areas. The study highlights significant disparities in neural activation and functional connectivity between OCD patients and healthy controls during VFT. Specifically, reduced activation was noted in the frontal and bilateral temporal lobes of OCD patients, alongside alterations in resting-state functional connectivity between the IFG and DLPFC. These findings contribute to our understanding of the neurobiological underpinnings of OCD and may guide future therapeutic strategies.

The effect of physical exercise during competitions and in simulated conditions on hormonal-neurophysiological relationships in kickboxers.

K1-format kickboxing is a widely followed combat sport that requires intense physical exercise. However, research into the body's response to this type of combat is sparse. This study aims to assess the alterations in hormone levels and brain activity in elite kickboxers following an actual K1 bout and compare these changes with those observed in a control group engaged in a simulated fight exercise with a punchbag. The study included 100 male professional kickboxers, randomly divided into two groups: an experimental group (K1 fight) and a control group (simulated fight with a punchbag). Blood samples were obtained before and after exercise to evaluate testosterone (T) and cortisol concentrations (C). Concurrently, brain activity was recorded using quantitative electroencephalography (QEEG). After the activity in the experimental group mean testosterone level slightly, non-significantly decreased from 13.7 nmol/l to 12.4 nmol/l, while mean cortisol significantly (p < 0.001) increased from 313 to 570 nmol/l. In the control group after the exertion against a punchbag mean cortisol significantly (p < 0.001) increased from 334 to 452 nmol/l and testosterone increased non-significantly, from 15.1 to 16.3 nmol/l. In both groups, the testosterone/cortisol ratio (T/C ratio) showed significantly lower levels after the intervention (p < 0.001 and p < 0.032) in the experimental and control group respectively. The comparison of groups after exercise revealed significantly higher cortisol levels (experimental group x = 570 nmol/l; control group x = 452 nmol/l) and a significantly lower T/C ratio (experimental group x = 2.7; control group x = 3.9), (p = 0.001) in the experimental group. Significantly higher brain activity was found in selected leads after a bout (experimental group). Furthermore, in the experimental group, significant associations of weak to moderate strength were found between hormone fluctuations and selected areas of brain activity (p < 0.05). K1-format kickboxing induces a stress response, evident in the sharp changes in cortisol and testosterone levels. A notable observation was the inverse direction of changes in both hormones. Brain activity analysis indicated the potential influence of raised cortisol concentrations on specific brain areas. This study augments our understanding of the physiological responses during K1 kickboxing bouts and may inform the future evolution of this sport.

Silence between words: Is solitude important for relatedness?

Chronic loneliness is a risk factor for physical and health problems, in part due to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system. In contrast, temporary moments of positive solitude (passing good times alone and not feeling lonely) appear to have positive effects on mental health, social life, and creativity, and seems to be a buffer against loneliness. Herein, three ways of how solitude may have positive effects on health and relatedness are discussed, namely effects on enhancement of mind-wandering, interoceptive awareness, and spirituality. Solitude may facilitate (1) activation of the default mode network (DMN) underlying mind-wandering including daydreaming about other people; (2) activation of brain areas supporting interoceptive awareness; (3) deactivation of prefrontal cortex, or deactivation and decreased connectivity of the DMN, giving raise to susceptibility to spiritual experiences. The capacity to handle and enjoy solitude is a developmental process that may be difficult for many persons. Craving for social connections and external stimulation with digital technologies (e.g., internet, smartphones, social media) might be interfering with the development of the capacity for solitude and thereby increasing loneliness; this might be partly due to impaired interoceptive awareness and impaired functional mind-wandering (common in solitude). Congruently, overuse of digital technologies was associated with reduced activity, and reduced gray matter volume and density, in brain areas supporting interoceptive awareness, as well as with decreased connectivity of the DMN supporting creative insights. Solitude has been a relatively dismissed topic in neuroscience and health sciences, but a growing number of studies is highlighting its importance for well-being.

Quantifying active brain areas at spatial hearing process using Electroencephalography (EEG) source localization approach

The human ability for spatial hearing encourages the development of spatial audio technology to support many human activities. Spatial audio mimics the real-life sound and provides a more immersive hearing experience as if the listener were present in the environment where the sound source was recorded. Recently, research on how spatial hearing processes are encoded in the brain has begun to be developed. As a modality for brain activity measurement that is non-invasive and has a high temporal resolution, Electroencephalography (EEG) is suitable for studying brain responses to moving sound stimuli. This study compared brain activity in hearing stereo and spatial audio stimulus. Through measurements using 21 EEG electrodes on the scalp, the results showed an increase in the mean PSD for all Theta, Alpha, and Beta waves in the spatial audio stimulus compared to stereo audio. The most significant increase in the mean PSD occurred in the Beta wave of 93.8008 µV2/Hz. Furthermore, the source localization approach with Independent Component Analysis (ICA) and Low-resolution Brain Electromagnetic Tomography (LORETA) method was used to estimate and quantify the active brain area of this process. The results showed an activation of the non-auditory cortex when the subject was hearing spatial audio stimulus. By using Paired T-Test of current density for both hearing processes, the results showed there was no significant difference (p &gt; 0.05) in Brodmann area (BA) 41 (Primary Auditory Cortex) and BA 42 (Secondary Auditory Cortex). Meanwhile, for the spatial audio hearing process, there was a significant difference (p &lt; 0.05) in BA 6 (Premotor Cortex), which is related to spatial orientation, and BA 9 (Dorsolateral Prefrontal Cortex), which is associated with executive functions, including working memory and selective attention. This study offers potential insights into spatial hearing research and immersive audio production.

Action Observation with Rhythm Imagery (AORI): A Novel Paradigm to Activate Motor-Related Pattern for High-Performance Motor Decoding.

The Motor Imagery (MI) paradigm has been widely used in brain-computer interface (BCI) for device control and motor rehabilitation. However, the MI paradigm faces challenges such as comprehension difficulty and limited decoding accuracy. Therefore, we propose the Action Observation with Rhythm Imagery (AORI) as a natural paradigm to provide distinct features for high-performance decoding. Twenty subjects were recruited in the current study to perform the AORI task. Spectral-spatial, temporal and time-frequency analyses were conducted to investigate the AORI-activated brain pattern. Task-discriminant component analysis (TDCA) was utilized to perform multiclass motor decoding. The results demonstrated distinct lateralized ERD in the alpha and beta bands, and clear lateralized steady-state movement-related rhythm (SSMRR) at the movement frequencies and their first harmonics. The activated brain areas included frontal, sensorimotor, posterior parietal, and occipital regions. Notably, the decoding accuracy reached 92.16% ± 7.61% in the four-class scenario. We proposed the AORI paradigm, revealed the activated motor-related pattern and proved its efficacy for high-performance motor decoding. These findings provide new possibilities for designing a natural and robust BCI for motor control and motor rehabilitation.

Correlatos Neurais da Dor, Resiliência e Empatia

Currently, pain is understood as a complex phenomenon infl uenced by biopsychosocial factors, as evidenced by the growing body of research in the “new science of pain.” The neurobiology of pain reveals a complex brain network associated with pain perception, with clear implications for emotional and cognition disorders. Empathy and resilience are crucial behavioral skills observed in both humans and animals, with neurobiological bases related to understanding others’ emotions and adapting to adverse situations. However, the association between neural processes related to resilience and empathy with pain pathways still needs to be clarifi ed. To this end, a systematic review was conducted in two databases (PubMed and Lilacs), including English articles without date limitations to achieve broader coverage. Initially, 3,649 studies were identifi ed, and after inclusion and exclusion criteria were applied, 72 relevant articles exploring this interrelation were identifi ed, highlighting neurobiological convergences in pain modulation by empathy and resilience. Empathy activates brain areas linked to understanding others’ emotions, while resilience is associated with adapting to stressful situations, both sharing neurobiological convergences in pain processing. Therapeutic interventions such as mindfulness and psychotherapy show promise in promoting empathy and resilience, off ering new perspectives for chronic pain management. These fi ndings underscore the importance of a multidimensional approach in chronic pain treatment, integrating biopsychosocial considerations to enhance patient outcomes.Keywords: Empathy, resilience, pain, neural pathways

Simulating combined monoaminergic depletions in a PD animal model through a bio-constrained differential equations system.

Historically, Parkinson's Disease (PD) research has focused on the dysfunction of dopamine-producing cells in the substantia nigra pars compacta, which is linked to motor regulation in the basal ganglia. Therapies have mainly aimed at restoring dopamine (DA) levels, showing effectiveness but variable outcomes and side effects. Recent evidence indicates that PD complexity implicates disruptions in DA, noradrenaline (NA), and serotonin (5-HT) systems, which may underlie the variations in therapy effects. We present a system-level bio-constrained computational model that comprehensively investigates the dynamic interactions between these neurotransmitter systems. The model was designed to replicate experimental data demonstrating the impact of NA and 5-HT depletion in a PD animal model, providing insights into the causal relationships between basal ganglia regions and neuromodulator release areas. The model successfully replicates experimental data and generates predictions regarding changes in unexplored brain regions, suggesting avenues for further investigation. It highlights the potential efficacy of alternative treatments targeting the locus coeruleus and dorsal raphe nucleus, though these preliminary findings require further validation. Sensitivity analysis identifies critical model parameters, offering insights into key factors influencing brain area activity. A stability analysis underscores the robustness of our mathematical formulation, bolstering the model validity. Our holistic approach emphasizes that PD is a multifactorial disorder and opens promising avenues for early diagnostic tools that harness the intricate interactions among monoaminergic systems. Investigating NA and 5-HT systems alongside the DA system may yield more effective, subtype-specific therapies. The exploration of multisystem dysregulation in PD is poised to revolutionize our understanding and management of this complex neurodegenerative disorder.

When direction matters: Neural correlates of interlimb coordination of rhythm and beat

In a previous experiment, we found evidence for a bodily hierarchy governing interlimb coordination of rhythm and beat, using five effectors: 1) Left foot, 2) Right foot, 3) Left hand, 4) Right hand and 5) Voice. The hierarchy implies that, during simultaneous rhythm and beat performance and using combinations of two of these effectors, executing the task by performing the rhythm with an effector that has a higher number than the beat effector is significantly easier than vice versa. To investigate the neural underpinnings of this proposed bodily hierarchy, we here scanned 46 professional musicians using fMRI as they performed a rhythmic pattern with one effector while keeping the beat with another. The conditions combined the voice and the right hand (V + RH), the right hand and the left hand (RH + LH), and the left hand and the right foot (LH + RF). Each effector combination was performed with and against the bodily hierarchy. Going against the bodily hierarchy increased tapping errors significantly and also increased activity in key brain areas functionally associated with top-down sensorimotor control and bottom-up feedback processing, such as the cerebellum and SMA. Conversely, going with the bodily hierarchy engaged areas functionally associated with the default mode network and regions involved in emotion processing. Theories of general brain function that hold prediction as a key principle, propose that action and perception are governed by the brain's attempt to minimise prediction error at different levels in the brain. Following this viewpoint, our results indicate that going against the hierarchy induces stronger prediction errors, while going with the hierarchy allows for a higher degree of automatization. Our results also support the notion of a bodily hierarchy in motor control that prioritizes certain conductive and supportive tapping roles in specific effector combinations.

Brain connectivity networks underlying resting heart rate variability in acute ischemic stroke

Acute strokes can affect heart rate variability (HRV), the mechanisms how are not well understood. We included 42 acute stroke patients (2–7 days after ischemic stroke, mean age 66 years, 16 women). For analysis of HRV, 20 matched controls (mean age 60.7, 10 women) were recruited. HRV was assessed at rest, in a supine position and individual breathing rhythmus for 5 min. The coefficient of variation (VC), the root mean square of successive differences (RMSSD), the powers of low (LF, 0.04–0.14 Hz) and high (HF, 0.15–0.50 Hz) frequency bands were extracted. HRV parameters were z-transformed related to age- and sex-matched normal subjects. Z-values < -1 indicate reduced HRV. Acute stroke lesions were marked on diffusion-weighted images employing MRIcroN and co-registered to a T1-weighted structural volume-dataset. Using independent component analysis (ICA), stroke lesions were related to HRV. Subsequently, we used the ICA-derived lesion pattern as a seed and estimated the connectivity between these brain regions and seven common functional networks, which were obtained from 50 age-matched healthy subjects (mean age 68.9, 27 women). Especially, LF and VC were frequently reduced in patients. ICA revealed one covarying lesion pattern for LF and one similar for VC, predominantly affecting the right hemisphere. Activity in brain areas corresponding to these lesions mainly impact on limbic (r = 0.55 ± 0.08) and salience ventral attention networks (0.61 ± 0.10) in the group with reduced LF power (z-score < -1), but on control and default mode networks in the group with physiological LF power (z-score > -1). No different connectivity could be found for the respective VC groups. Our results suggest that HRV alteration after acute stroke might be due to affecting resting-state brain networks.

Poster Session I: Noninvasive neuromodulation of subcortical visual pathways with transcranial focused ultrasound.

Transcranial ultrasound stimulation (TUS) is an emerging tool to noninvasively modulate neural activity in deep brain areas. In preparation for our first in-human TUS studies, we targeted TUS to the lateral geniculate nucleus (visual thalamus) in a large mammal (sheep). Full-field light flash stimuli were presented with or without concomitant TUS in randomly interleaved trials. Similar to what has previously observed by Fry et al (Nature 1959) in cats, EEG visual-evoked potentials (VEPs) were reversibly suppressed by TUS to the LGN. No changes in VEPs were observed in sheep who received sham-TUS to a control site in the basal ganglia, ruling out potential transducer auditory-somatosensory confounds. Magnetic resonance acoustic radiation force imaging (MR-ARFI), a technique to measure the ultrasound focus in situ, showed a focal volume of microscopic displacement at the expected target. Excitingly, MR-ARFI predicted the suppressive effect on VEPs in individual subjects, suggesting that MR-ARFI can be used to confirm TUS targeting and estimate neurophysiological impact. We are now translating this paradigm into human, targeting TUS to the LGN while participants perform a contrast detection task with EEG recording of steady-state VEPs. MR-ARFI will be measured to evaluate targeting and estimate TUS dosage in each participant. This work provides the foundation for a dissection of the roles of different subcortical nuclei in different aspects of human vision.

Central effects of mouth rinses on endurance and strength performance.

Rinsing the mouth with a carbohydrate (CHO) solution has been shown to enhance exercise performance while reducing neuromuscular fatigue. This effect is thought to be mediated through the stimulation of oral receptors, which activate brain areas associated with reward, motivation, and motor control. Consequently, corticomotor responsiveness is increased, leading to sustained levels of neuromuscular activity prior to fatigue. In the context of endurance performance, the evidence regarding the central involvement of mouth rinse (MR) in performance improvement is not conclusive. Peripheral mechanisms should not be disregarded, particularly considering factors such as low exercise volume, the participant's fasting state, and the frequency of rinsing. These factors may influence central activations. On the other hand, for strength-related activities, changes in motor evoked potential (MEP) and electromyography (EMG) have been observed, indicating increased corticospinal responsiveness and neuromuscular drive during isometric and isokinetic contractions in both fresh and fatigued muscles. However, it is important to note that in many studies, MEP data were not normalised, making it difficult to exclude peripheral contributions. Voluntary activation (VA), another central measure, often exhibits a lack of changes, mainly due to its high variability, particularly in fatigued muscles. Based on the evidence, MR can attenuate neuromuscular fatigue and improve endurance and strength performance via similar underlying mechanisms. However, the evidence supporting central contribution is weak due to the lack of neurophysiological measures, inaccurate data treatment (normalisation), limited generalisation between exercise modes, methodological biases (ignoring peripheral contribution), and high measurement variability.Trial registration: PROSPERO ID: CRD42021261714.

Visually or auditorily induced seizures involve the activation of nonhippocampal brain areas and hippocampal removal does not alleviate seizures in a mouse model of temporal lobe epilepsy.

Several studies have attributed epileptic activities in temporal lobe epilepsy (TLE) to the hippocampus; however, the participation of nonhippocampal neuronal networks in the development of TLE is often neglected. Here, we sought to understand how these nonhippocampal networks are involved in the pathology that is associated with TLE disease. A kainic acid (KA) model of temporal lobe epilepsy was induced by injecting KA into dorsal hippocampus of C57BL/6J mice. Network activation after spontaneous seizure was assessed using c-Fos expression. Protocols to induce seizure using visual or auditory stimulation were developed, and seizure onset zone (SOZ) and frequency of epileptic spikes were evaluated using electrophysiology. The hippocampus was removed to assess seizure recurrence in the absence of hippocampus. Our results showed that cortical and hippocampal epileptic networks are activated during spontaneous seizures. Perturbation of these networks using visual or auditory stimulation readily precipitates seizures in TLE mice; the frequency of the light-induced or noise-induced seizures depends on the induction modality adopted during the induction period. Localization of SOZ revealed the existence of cortical and hippocampal SOZ in light-induced and noise-induced seizures, and the development of local and remote epileptic spikes in TLE occurs during the early stage of the disease. Importantly, we further discovered that removal of the hippocampi does not stop seizure activities in TLE mice, revealing that seizures in TLE mice can occur independent of the hippocampus. This study has shown that the network pathology that evolves in TLE is not localized to the hippocampus; rather, remote brain areas are also recruited. The occurrence of light-induced or noise-induced seizures and epileptic discharges in epileptic mice is a consequence of the activation of nonhippocampal brain areas. This work therefore demonstrates the fundamental role of nonhippocampal epileptic networks in generating epileptic activities with or without the hippocampus in TLE disease.

Alterations of brain activity in patients with alcohol use disorder: a resting-state fMRI study

BackgroundAlcohol use disorder (AUD) has a negative impact on one’s health and wastes a lot of societal resources since it damages one’s brain tissue. Yet the knowledge of the neural mechanisms underlying alcohol addiction still remains limited. This study aims to investigate the neural mechanisms underlying alcohol addiction by using voxel-wise binarized degree centrality (DC), weighted DC and functional connectivity (FC) methods to analyze brain network activity in individuals with AUD.MethodsThirty-three AUD patients and 29 healthy controls (HC) participated in this study. Binarized and weighted DC approach coupled with a second seed-based FC algorithm was used to assess the abnormal intrinsic hub features in AUD. We also examined the correlation between changes in functional network nodes and the severity of alcohol dependence.ResultsThirty AUD patients and 26 HC were retained after head motion correction. The spatial distribution maps of the binarized DC and weighted DC for the AUD and HC groups were roughly similar. In comparison to HC, the AUD group had decreased binarized DC and decreased weighted DC in the left precentral gyrus (PreCG) and the left inferior parietal lobule (IPL). Significantly different brain regions in the DC analysis were defined as seed points in the FC analysis. Compared with HC, changes in FC within the right inferior temporal gyrus (ITG), right middle temporal gyrus (MTG), left dorsolateral superior frontal gyrus (SFGdor), bilateral IPL, left precuneus (PCUN), left lingual gyrus (LING), right cerebellum_crus1/ITG/inferior occipital gyrus (IOG) and right superior parietal gyrus (SPG) were observed. The correlation analysis revealed that FC of right MTG-right PreCG was negatively correlated with MAST scores, and FC of right IPL-left IPL was positively correlated with ADS scores.ConclusionsAlcohol use disorder is associated with aberrant regional activities in multiple brain areas. Binarized DC, weighted DC and FC analyses may be useful biological indicators for the detection of regional brain activities in patients with AUD. Intergroup differences in FC have also been observed in AUD patients, and these variations were connected to the severity of the symptoms. The AUD patients with lower FC value of the right IPL - left IPL has a lighter dependence on alcohol. This difference in symptom severity may be a compensation for cognitive impairment, indicating a difference in pathological pathways. Future AUD research will now have a fresh path thanks to these discoveries.

Dopaminergic D2-like receptor stimulation affects attention on contextual information and modulates BOLD activation of extinction-related brain areas

Contextual information is essential for learning and memory processes and plays a crucial role during the recall of extinction memory, and in the renewal effect, which is the context-dependent recovery of an extinguished response. The dopaminergic system is known to be involved in regulating attentional processes by shifting attention to novel and salient contextual cues. Higher dopamine levels are associated with a better recall of previously learned stimulus-outcome associations and enhanced encoding, as well as retrieval of contextual information which promotes renewal. In this fMRI study, we aimed to investigate the impact of processing contextual information and the influence of dopaminergic D2-like receptor activation on attention to contextual information during a predictive learning task as well as upon extinction learning, memory performance, and activity of extinction-related brain areas. A single oral dose of 1.25 mg bromocriptine or an identical-looking placebo was administered to the participants. We modified a predictive learning task that in previous studies reliably evoked a renewal effect, by increasing the complexity of contextual information. We analysed fixations and dwell on contextual cues by use of eye-tracking and correlated these with behavioural performance and BOLD activation of extinction-related brain areas. Our results indicate that the group with dopaminergic D2-like receptor stimulation had higher attention to task-relevant contextual information and greater/lower BOLD activation of brain regions associated with cognitive control during extinction learning and recall. Moreover, renewal responses were almost completely absent. Since this behavioural effect was observed for both treatment groups, we assume that this was due to the complexity of the altered task design.

Effects of an afforestation activity on thermal and mechanical pain mechanisms: A clinical trial

Sensory stimulation has shown the capacity to modulate pain mechanisms. Yet, the optimal methods of sensory stimulation remain uncertain. Afforestation activities stand out as a potential stimulation method, as they allow individuals to interact with multisensory stimuli produced in green environments. Exposure to natural multisensory stimuli has been shown to induce neurobiological activations in pain-related brain areas in healthy populations. However, the possible impact of the natural multisensory stimuli on the pain mechanisms themselves is yet to be explored. This study aimed to investigate the potential effects of sensory stimulation experienced during participation in an afforestation program on thermal and mechanical pain mechanisms. A single-group, pretest-posttest clinical trial was used. Forty-seven healthy adults performed an afforestation activity for 90 minutes. Measurements included cold pain detection and tolerance thresholds via the Cold Pressor Test, wind-up and mechanical pain sensitivity through a pinprick stimulator, and pressure pain detection and tolerance thresholds utilizing pressure algometry. For both thermal and mechanical pain thresholds, pain intensity was assessed using the 101-point Numeric Rating Scale. The results showed significant reductions in the cold pain intensity at the moment of detection (p = .046), mechanical pain sensitivity (p ≤ .014), and increases in the thresholds of pressure pain detection (p = .005) and tolerance (p ≤ .046). Therefore, the interaction with natural multisensory stimuli could be a possible therapeutic strategy to positively modulate mechanical pain sensitivity and pressure pain thresholds.

29 Smoking as a Risk Factor: Altered Brain Activity in Areas Associated with Preclinical Alzheimer's Disease

Objective:Those at genetic risk for Alzheimer's Disease (AD) because of the ApoE ε4 allele show differences in activation during olfactory information processing and memory in areas such as MTL structures, entorhinal cortex, posterior cingulate, precuneus, and inferior parietal lobule, suggesting preclinical AD neuropathology and olfactory impairment as a biomarker for predicting later AD onset (Murphy, 2019). The effects of smoking on AD have varied, with early studies suggesting either no effect or protective effects, and recent studies suggesting smoking as a risk factor for AD but with the need for further investigation in preclinical stages. Therefore, this study focused on olfaction and smoking as risk factors for preclinical AD neuropathology by studying differences in fMRI BOLD signal changes in smokers and nonsmokers during olfactory tasks.Participants and Methods:Archival data from 25 non-demented older adults recruited from the UCSD Alzheimer's Disease Research Center who completed an Assessment Scale-Cognitive Subscale (ADAS-Cog) and functional MRI scans at 3T, acquired during performance of an odor identification task. Odor Identification (OI) measured correct (hits) or incorrect (misses) identification of odors presented by an olfactometer to deliver the odor stimuli in short, controlled durations during fMRI scanning.Results:fMRI data were preprocessed using fMRIprep, smoothed at 4mm, scaled, and first level analyses were conducted using 3dDeconvolve in AFNI with time points corresponding to hits and misses as regressors. Differences between smokers and nonsmokers revealed smokers show a larger difference in BOLD signal change from hits minus misses at five significant clusters (p = 0.01 with the minimum cluster size [voxels] at 42). Peak areas of significant clusters included the right precuneus, right calcarine gyrus, left inferior parietal lobule, left superior parietal lobule, and left middle occipital gyrus. Analyses suggested a greater difference in activity between hits and misses in smokers compared to nonsmokers, with more activity during hits.Conclusions:Differences in activation between smokers and nonsmokers during an olfactory identification task, with greater activity in smokers during hits, suggests greater effort to correctly identify an odor. These findings of hyperactivation in areas (such as the precuneus and inferior parietal lobule) are similar to findings of hyperactivation during odor memory observed in studies of ε4 carriers during preclinical stages. Results provide further insight into smoking as a risk factor for AD. Moreover, results suggest the risk of smoking could potentially be reflected in altered activity in olfactory information processing networks in preclinical stages of AD. The study highlights the need for research to further understand the role smoking plays in the development of AD and the use of olfaction as a biomarker to aid in disease detection, prevention, and stage-associated treatments.

15 Socioeconomic Status in Association to Memory-Related Brain Activation in Middle-Aged Adults

Objective:Socioeconomic status (SES) has been recognized as an important factor in psychological research within the last few decades. Past literature recognizes that having lower SES can have a negative impact on many aspects of one’s health, especially in diseases related to brain aging. A recent avenue for research regarding SES and the brain-behavior relationship suggests that socioeconomic status can act as a moderator for brain activation during task performance. The hypothesis for this project was that there will be a negative correlational relationship between brain activity and SES when controlling for participants’ age, sex, and performance on the episodic memory tasks, but a positive correlation between task performance and SES was expected.Participants and Methods:With 100 middle-aged healthy adults from the Reference Ability Neural Network (RANN) study (53 male and 47 female, age M=48.0 +/- 7.55 years), three episodic memory fMRI tasks were performed and studied in relation to SES and age. The tasks were Logical Memory, Word Order, and Pair Associates tasks that involved episodic memory for story details, order of words presented, and pairing of words, respectively. We quantified memory performance with average accuracy from performance of the three tasks. We used the FSL software to preprocess and perform voxel-wise group analysis. All brain activation analyses were corrected for multiple comparison using cluster thresholds in FSL.Results:Correlation between SES and memory performance was found to be marginally significant (R=.188, p=.061). All tasks had areas of positively correlated activation for age. The Logical Memory task had multiple areas of brain activation that were positively correlated with age, particularly at the lateral occipital cortex, lingual gyrus, and the occipital fusiform gyrus, all areas that underlie visual processing. There were no areas of correlated brain activation for SES, sex, and task performance for the Pair Associates and Logical Memory tasks. Brain activation for the Word order task in the left precuneous cortex and the right middle frontal gyrus, left lateral occipital cortex, left occipital fusiform gyrus, and parts of the lingual gyrus was positively correlated with memory performance when controlled for age, sex, and SES.Conclusions:The hypothesis was not entirely supported by the results of this study, but the marginal effect between SES and memory performance can suggest that SES may affect memory performance within middle-aged adults. While we did not find a brain association with SES in this age group, we observed regions that underlie task performance. Further research can be done on possible moderating effects of Socioeconomic Status on memory and executive function with structural neuroimaging to further investigate the effects of SES on cognition.

Cortisol decreases activation in extinction related brain areas resulting in an impaired recall of context-dependent extinction memory

Conditioned responding gradually stops during successful extinction learning. The renewal effect is defined as the recovery of a extinguished conditioned response when the context of extinction is different from acquisition. The stress hormone cortisol is known to have an influence on extinction memory and associative learning. Different effects of cortisol on behaviour and brain activity have been observed with respect to stress timing, duration, and intensity. However, the influence of cortisol prior to the initial encoding of stimulus-outcome associations on extinction learning, renewal and its behavioural and neurobiological correlates is still largely unknown. In our study, 60 human participants received 20 mg cortisol or placebo and then learned, extinguished, and recalled the associations between food stimuli presented in distinct contexts and different outcomes in three subsequent task phases. Learning performance during acquisition and extinction phases was equally good for both treatment groups. In the cortisol group, significantly more participants showed renewal compared to placebo. In the subgroup of participants with renewal, cortisol treated participants showed significantly better extinction learning performance compared to placebo. Participants showing renewal had in general difficulties with recalling extinction memory, but in contrast to placebo, the cortisol group exhibited a context-dependent impairment of extinction memory recall. Imaging analyses revealed that cortisol decreased activation in the hippocampus during acquisition. The cortisol group also showed reduced dorsolateral prefrontal cortex activation when extinction learning took place in a different context, but enhanced activation in inferior frontal gyrus during extinction learning without context change. During recall, cortisol decreased ventromedial prefrontal cortex activation. Taken together, our findings illustrate cortisol as a potent modulator of extinction learning and recall of extinction memory which also promotes renewal.

EEG-based assessment of temporal fine structure and envelope effect in mandarin syllable and tone perception.

Abstract In recent years, speech perception research has benefited from low-frequency rhythm entrainment tracking of the speech envelope. However, speech perception is still controversial regarding the role of speech envelope and temporal fine structure, especially in Mandarin. This study aimed to discuss the dependence of Mandarin syllables and tones perception on the speech envelope and the temporal fine structure. We recorded the electroencephalogram (EEG) of the subjects under three acoustic conditions using the sound chimerism analysis, including (i) the original speech, (ii) the speech envelope and the sinusoidal modulation, and (iii) the fine structure of time and the modulation of the non-speech (white noise) sound envelope. We found that syllable perception mainly depended on the speech envelope, while tone perception depended on the temporal fine structure. The delta bands were prominent, and the parietal and prefrontal lobes were the main activated brain areas, regardless of whether syllable or tone perception was involved. Finally, we decoded the spatiotemporal features of Mandarin perception from the microstate sequence. The spatiotemporal feature sequence of the EEG caused by speech material was found to be specific, suggesting a new perspective for the subsequent auditory brain-computer interface. These results provided a new scheme for the coding strategy of new hearing aids for native Mandarin speakers. Highlights