Search Results (123)

Evidence has been provided for a clear structural distinction between the dorsal and ventral portions of the inferior frontal occipital fasciculus (IFOF). As such, there is reason to propose that there might also be a functional differentiation of the dorsal and ventral components of the IFOF. Here, we explored three main hypotheses/schools of thought with regards to the functional frameworks of the dorsal and ventral components of the IFOF: (1) the phonological vs. semantic processing hypothesis, (2) the difficult vs. non-difficult task processing hypothesis and (3) the automatic vs. non-automatic processing hypothesis. Methods: Participants (N = 32) completed a series of behavioral tasks that aligned with each of the main hypotheses. Using a regression-based approach, we assessed the unique contribution of behavioral performance to dorsal and ventral IFOF white matter indicators (i.e., fractional anisotropy and mean diffusivity). Results: We found significant relationships between ventral IFOF indices and orthographic awareness (p = 0.018) and accuracy (p = 0.009). Overall, our results provide converging evidence that the IFOF primarily operates as a ventral language tract in adults. Thus, the structural distinction between dorsal and ventral IFOF does not manifest as a parallel functional distinction. Full article

The twelve cranial nerves play a crucial role in the nervous system, orchestrating a myriad of functions vital for our everyday life. These nerves are each specialized for particular tasks. Cranial nerve I, known as the olfactory nerve, is responsible for our sense of smell, allowing us to perceive and distinguish various scents. Cranial nerve II, or the optic nerve, is dedicated to vision, transmitting visual information from the eyes to the brain. Eye movements are governed by cranial nerves III, IV, and VI, ensuring our ability to track objects and focus. Cranial nerve V controls facial sensations and jaw movements, while cranial nerve VII, the facial nerve, facilitates facial expressions and taste perception. Cranial nerve VIII, or the vestibulocochlear nerve, plays a critical role in hearing and balance. Cranial nerve IX, the glossopharyngeal nerve, affects throat sensations and taste perception. Cranial nerve X, the vagus nerve, is a far-reaching nerve, influencing numerous internal organs, such as the heart, lungs, and digestive system. Cranial nerve XI, the accessory nerve, is responsible for neck muscle control, contributing to head movements. Finally, cranial nerve XII, the hypoglossal nerve, manages tongue movements, essential for speaking, swallowing, and breathing. Understanding these cranial nerves is fundamental in comprehending the intricate workings of our nervous system and the functions that sustain our daily lives. Full article

Some authors use the term cortical–subcortical myoclonus to identify a specific type of myoclonus, which differs from classical cortical myoclonus in that the abnormal neuronal activity spreads between the cortical and subcortical circuits, producing diffuse excitation. The EEG shows generalized spike-and-wave discharges that correlate with the myoclonic jerks. We report the case of a 79-year-old patient with a history of right thalamic deep hemorrhagic stroke, with favorable evolution. Fifteen years later, he was readmitted to the emergency department for episodes characterized by sudden falls without loss of consciousness. An EEG with EMG recording channel on the right deltoid muscle was performed, which documented frequent diffuse spike–wave and polyspike–wave discharges, temporally related to myoclonic jerks in the lower limbs. Brain MRI showed the persistence of a small right thalamic hemosiderin residue at the site of the previous hemorrhage. Antiseizure treatment with levetiracetam was started, with rapid clinical and electroencephalographic improvement. Our case may represent a lesion model of generalized epilepsy with myoclonic seizures. Furthermore, it highlights that lower limb myoclonus of cortical–subcortical origin may be an underestimate cause of gait disturbances and postural instability. Then, it may be reasonable to include the EEG in the diagnostic work-up of patients with recurrent falls. Full article

Neuroinflammation is one of the main mechanisms contributing to the pathogenesis of Alzheimer’s disease (AD), although its key role and the immune cells involved have not yet been identified. Blood monocytes appear to play a role in the clearance of AD-related amyloid-β (Aβ) and tau protein. This retrospective study evaluated a possible correlation between blood monocytes; the concentrations of Aβ, total tau (t-Tau), and phosphorylated tau (p-Tau) in the cerebrospinal fluid (CSF); and cognitive decline assessed according to the Montreal Cognitive Assessment (MoCA). We collected data from 33 patients with AD or mild cognitive impairment (MCI) due to AD (15 men and 18 women) and found, along with a significant reduction in the concentration of blood monocytes in women (p-value = 0.083),significant correlations between the number of blood monocytes and the concentration of t-Tau in CSF (p-value = 0.045) and between blood monocytes and MoCA score (p-value = 0.037). These results confirm the role of blood monocytes in the pathogenesis of AD, provide further evidence of a gender difference in the neuroinflammatory process underlying AD, and show that blood monocyte count may reflect the cognitive impairment of AD patients. Full article

Zinc (Zn²⁺) is an essential element that can promote proper organ function, cell growth, and immune response; it can also, however, be present in too great a quantity. Zinc toxicity caused by overexposure may result in both minor and major physiological effects, with chronic exposure at low levels and acute exposure at high levels being harmful or even toxic. This investigation examines the effects of acute exposure to relatively high concentrations of Zn²⁺ on sensory nerve function and nerve conduction. A proprioceptive nerve in marine crab (Callinectes sapidus) limbs was used as a model to assess the effects of Zn²⁺ on stretch-activated channels (SACs) and evoked nerve conduction. Exposure to Zn²⁺ slowed nerve condition rapidly; however, several minutes were required before the SACs in sensory endings were affected. A depression in conduction speed and an increase followed by a decrease in amplitude were observed for the evoked compound action potential, while the frequency of nerve activity upon joint movement and stretching of the chordotonal organ significantly decreased. These altered responses could be partially reversed via extensive flushing with fresh saline to remove the zinc. This indicates that subtle, long-term exposure to Zn²⁺ may alter an organism’s SAC function for channels related to proprioception and nerve conduction. Full article

Background: The evidence links chemotherapy to cognitive impairment in breast cancer patients. This study assessed the link between subjective chemotherapy-related cognitive impairment and neuroinflammation in breast cancer patients. Methods: In a correlational study, 113 patients aged 21 to 60 years on chemotherapy regimens completed the Functional Assessment of Cancer Therapy-Cognition Test (FACT-Cog) as a measure of subjective cognitive functioning at three time points (baseline- T₀, third cycle- T₁, and sixth cycle- T₂). The levels of inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumour necrosis factor-alpha (TNF-α)) were measured using an assay method and compared with the subjective cognitive impairment. Results: Midway through chemotherapy, higher levels of TNF-α were inversely linked with self-perceived cognitive performance, while higher levels of IL-1β were positively associated (p = 0.030). However, at the end of chemotherapy, only IL-8 (p = 0.50) was associated with higher self-perceived cognitive problems. Conclusions: The specific roles that various cytokines and their interactions may play in neuroinflammation or neuroprotection require further investigation. Full article

Animals are exposed to lithium (Li⁺) in the natural environment as well as by contact with industrial sources and therapeutic treatments. Low levels of exposure over time and high volumes of acute levels can be harmful and even toxic. The following study examines the effect of high-volume acute levels of Li⁺ on sensory nerve function and nerve conduction. A proprioceptive nerve in the limbs of a marine crab (Callinectes sapidus) was used as a model to address the effects on stretch-activated channels (SACs) and evoked nerve conduction. The substitution of Li⁺ for Na⁺ in the bathing saline slowed nerve conduction rapidly; however, several minutes were required before the SACs in sensory endings were affected. The evoked compound action potential slowed in conduction and slightly decreased in amplitude, while the frequency of nerve activity with joint movement and chordotonal organ stretching significantly decreased. Both altered responses could be partially restored with the return of a Na⁺-containing saline. Long-term exposure to Li⁺ may alter the function of SACs in organisms related to proprioception and nerve conduction, but it remains to be investigated. Full article

Narcolepsy is a chronic sleep disorder that disrupts the regulation of a person’s sleep–wake cycle, leading to significant challenges in daily functioning. It is characterized by excessive daytime sleepiness, sudden muscle weakness (cataplexy), sleep paralysis, and vivid hypnagogic hallucinations. A literature search was conducted in different databases to identify relevant studies on various aspects of narcolepsy. The main search terms included “narcolepsy”, “excessive daytime sleepiness”, “cataplexy”, and related terms. The search was limited to studies published until May 2023. This literature review aims to provide an overview of narcolepsy, encompassing its causes, diagnosis, treatment options, impact on individuals’ lives, prevalence, and recommendations for future research. The review reveals several important findings regarding narcolepsy: 1. the classification of narcolepsy—type 1 narcolepsy, previously known as narcolepsy with cataplexy, and type 2 narcolepsy, also referred to as narcolepsy without cataplexy; 2. the genetic component of narcolepsy and the complex nature of the disorder, which is characterized by excessive daytime sleepiness, disrupted sleep patterns, and potential impacts on daily life activities and social functioning; and 3. the important implications for clinical practice in the management of narcolepsy. Healthcare professionals should be aware of the different types of narcolepsies and their associated symptoms, as this can aid in accurate diagnosis and treatment planning. The review underscores the need for a multidisciplinary approach to narcolepsy management, involving specialists in sleep medicine, neurology, psychiatry, and psychology. Clinicians should consider the impact of narcolepsy on a person’s daily life, including their ability to work, study, and participate in social activities, and provide appropriate support and interventions. There are several gaps in knowledge regarding narcolepsy. Future research should focus on further elucidating the genetic causes and epigenetic mechanisms of narcolepsy and exploring potential biomarkers for early detection and diagnosis. Long-term studies assessing the effectiveness of different treatment approaches, including pharmacological interventions and behavioral therapies, are needed. Additionally, there is a need for research on strategies to improve the overall well-being and quality of life of individuals living with narcolepsy, including the development of tailored support programs and interventions. Full article

Evolutionary theory is applied to recent neuroscientific findings on factors associated with risk-and-reward systems, and consequently, aspects of human decision making in spaceflight. Factors include enzymes aiding metabolic pathways of dopamine and serotonin; neurotrophic factors supporting neuronal functioning and plasticity; and genes associated with serotonin and dopamine systems. Not all factors are at risk in spaceflight. Some remain stable. It is hypothesized that neural deconditioning in spaceflight arises from faulty signals sent to the brain and gut in attempting to adapt phenotypically to a novel space environment. There is a mismatch between terrestrial selection pressures during human evolution and conditions of cosmic radiation, microgravity, and higher CO₂, which together cause scattered results. A contrary question is broached: Given these findings, why are human sequelae not worse? Discussion of programmatic issues then focuses on methodologies to determine the suitability of civilians for spaceflight, an issue that grows more pressing while more varied populations prepare for spaceflight in LEO and on, and in orbit around the Moon. Full article

The aim of the present study was to investigate the deficits in timing reproduction in individuals with non-fluent aphasia after a left hemisphere lesion including the inferior frontal gyrus, in which Broca’s region is traditionally localised. Eighteen stroke patients with non-fluent aphasia and twenty-two healthy controls were recruited. We used a finger-tapping Test, which consisted of the synchronisation and the continuation phase with three fixed intervals (450 ms, 650 ms and 850 ms). Participants firstly had to tap simultaneously with the device’s auditory stimuli (clips) (synchronisation phase) and then continue their tapping in the same pace when the stimuli were absent (continuation phase). Patients with aphasia demonstrated less accuracy and greater variability during reproduction in both phases, compared to healthy participants. More specifically, in the continuation phase, individuals with aphasia reproduced longer intervals than the targets, whereas healthy participants displayed accelerated responses. Moreover, patients’ timing variability was greater in the absence of the auditory stimuli. This could possibly be attributed to deficient mental representation of intervals and not experiencing motor difficulties (due to left hemisphere stroke), as the two groups did not differ in tapping reproduction with either hand. Given that previous findings suggest a potential link between the IFG, timing and working memory, we argue that patients’ extra-linguistic cognitive impairments should be accounted for, as possible contributing factors to timing disturbances. Full article

Multiple sclerosis (MS) is an immune inflammatory disease that causes demyelination of the white matter of the central nervous system. It is generally accepted that the etiology of MS is multifactorial and believed to be a complex interplay between genetic susceptibility, environmental factors, and infectious agents. While the exact cause of MS is still unknown, increasing evidence suggests that disease development is the result of interactions between genetically susceptible individuals and the environment that lead to immune dysregulation and CNS inflammation. Genetic factors are not sufficient on their own to cause MS, and environmental factors such as viral infections, smoking, and vitamin D deficiency also play important roles in disease development. Several pathogens have been implicated in the etiology of MS, including Epstein–Barr virus, human herpesvirus 6, varicella-zoster virus, cytomegalovirus, Helicobacter pylori, Chlamydia pneumoniae, and Borrelia burgdorferi. Although vastly different, viruses and bacteria can manipulate host gene expression, causing immune dysregulation, myelin destruction, and neuroinflammation. This review emphasizes the pathogenic triggers that should be considered in MS progression. Full article

The effects of corticomuscular connectivity during object manipulation tasks with different haptic sensations have not been quantitatively investigated. Connectivity analyses enable the study of cortical effects and muscle responses during movements, revealing communication pathways between the brain and muscles. This study aims to examine the corticomuscular connectivity of three Electroencephalography (EEG) channels and five muscles during object manipulation tasks involving contact surfaces of Sandpaper, Suede, and Silk. The analyses included 12 healthy subjects performing tasks with their right hand. Power-Based Connectivity (PBC) and Mutual Information (MI) measures were utilized to evaluate significant differences in connectivity between contact surfaces, EEG channels, muscles, and frequency bands. The research yielded the following findings: Suede contact surface exhibited higher connectivity; Mu and Gamma frequency bands exerted greater influence; significant connectivity was observed between the three EEG channels ($C3$, $Cz$, $C4$) and the Anterior Deltoid (AD) and Brachioradialis (B) muscles; and connectivity was primarily involved during active movement in the AD muscle compared to the resting state. These findings suggest potential implementation in motor rehabilitation for more complex movements using novel alternative training systems with high effectiveness. Full article

Background: Low back pain (LBP) has been shown to have various biological, psychological, and social factors that affect prognosis. However, it is unclear how personality may influence self-reported outcome measures and therapeutic alliance (TA). Methods: Eysenck’s personality inventory was used to assess personality, while the numeric pain rating scale (NPRS), Oswestry Disability Index (ODI), Tampa Scale of Kinesiophobia (TSK), Global Rating of Change (GROC), and the Working Alliance Inventory (WAI) measured patient progress and relationship strength. All outcome measures were formulated in a single survey that both the therapist and patient completed electronically. Results: Sixty-seven patients with LBP and twenty-two licensed physical therapists participated. For personality measures, there was a significant positive correlation between neuroticism and GROC (rho = 0.295, p = 0.015) and a significant negative correlation between extraversion and WAI (rho = −0.243, p = 0.048). Significant correlations were found between ODI and TSK (rho = 0.462, p ≤ 0.001) and between ODI and GROC (rho = −0.416, p ≤ 0.001). A significant negative correlation was found between TSK and GROC (rho = −0.301, p = 0.013). Conclusions: Patients with higher levels of disability seemed to report higher levels of kinesiophobia and less overall improvement in physical therapy. Patients classified as neurotic reported higher levels of improvement while extraverted patients demonstrated a weaker therapeutic alliance with their therapist. Full article

Autism in humans is a lifelong behavioral disorder that typically manifests in early infancy, primarily affecting boys. It arises from neurodevelopmental changes that significantly impact social behavior, with the cerebellum being one of the principal affected regions. In this study, we investigated the cerebellum in an autism animal model, recording the multiunit activity of cerebellar vermis lobules 6 and 7 (L6 and L7) in male rats with autism-like behavior induced by postnatal valproate treatment. Two groups were formed: control (Ctrl) and experimental (VPA) males, which were further divided based on their living conditions into standard (Std) or enriched environments (EE). Social arenas were used for recording purposes. Both groups and lobules showed increased multiunit amplitude during social interaction (SI) and vertical exploration (VE), with higher amplitudes observed in VPA males. Interestingly, the EE significantly reduced the amplitude during SI, suggesting that EE promotes neural plasticity, resulting in improved social responses with fewer activated neurons, meaning improved activity with less energy consumption. Consequently, EE proves to be a valuable strategy for addressing the challenges associated with autism behavior. Full article

Despite the available literature on traumatic brain injury (TBI) biomarkers elsewhere, data are limited or non-existent in sub-Saharan Africa (SSA). The aim of the study was to analyse associations in acute TBI between the admission serum biomarker concentrations and TBI severity, CT-scan findings, and outcome, as well as to explore the influence of concurrent Toxoplasma gondii infection. The concentrations of serum biomarkers (GFAP, NFL Tau, UCH-L1, and S100B) were measured and Toxoplasma gondii were detected in the samples obtained <24 h post injury. GOSE was used to evaluate the 6-month outcome. All of the biomarker levels increased with the severity of TBI, but this increase was significant only for NFL (p = 0.01). The GFAP values significantly increased (p = 0.026) in those with an unfavourable outcome. The Tau levels were higher in those who died (p = 0.017). GFAP and NFL were sensitive to CT-scan pathology (p values of 0.004 and 0.002, respectively). The S100B levels were higher (p < 0.001) in TBI patients seropositive to Toxoplasma gondii. In conclusion, NFL was found to be sensitive to TBI severity, while NFL and GFAP were predictive of CT intracranial abnormalities. Increased levels of GFAP and Tau were associated with poorer outcomes 6 months after TBI, and the S100B levels were significantly affected by concurrent T. gondii infection in TBI patients compared with the seronegative patients. Full article