Volume 28, Issue 1

Stress is an integral part of modern life. Although there is a large body of literature regarding the harmful effects of chronic stress on different aspects of human life, acute stress is the most common form of stress, resulting from the demands and pressures of the recent past and the anticipated demands and pressures of the near future. In spite of its pervasive nature, less attention has been paid to the impact of acute stress on sensory processing than to the consequences of chronic stress, particularly concerning auditory processing. In this systematic review, the impact of experimental acute stress on the auditory processing of healthy adults was investigated. The results revealed the adverse effects of acute physical and psychological stresses on auditory processing. According to the open field of research on stress and the auditory system and the high possibility of experiencing different types of acute stresses in various life environments, including testing places, it seems that more investigations are needed to identify and manage different types of acute stresses in both clinical and research situations.

It has been shown that animal spinal cord compression (using methods such as clips, balloons, spinal cord strapping, or calibrated forceps) mimics the persistent spinal canal occlusion that is common in human spinal cord injury (SCI). These methods can be used to investigate the effects of compression or to know the optimal timing of decompression (as duration of compression can affect the outcome of pathology) in acute SCI. Compression models involve prolonged cord compression and are distinct from contusion models, which apply only transient force to inflict an acute injury to the spinal cord. While the use of forceps to compress the spinal cord is a common choice due to it being inexpensive, it has not been critically assessed against the other methods to determine whether it is the best method to use. To date, there is no available review specifically focused on the current compression methods of inducing SCI in rats; thus, we performed a systematic and comprehensive publication search to identify studies on experimental spinalization in rat models, and this review discusses the advantages and limitations of each method.

Sophisticated methods are currently used to investigate the properties of brain DNA and clarify its role under physiological conditions and in neurological and psychiatric disorders. Attention is now called on a DNA fraction present in the adult rat brain that is characterized by an elevated turnover and is not involved in cell division or DNA repair. The fraction, known as brain metabolic DNA (BMD), is modulated by strain, stress, circadian oscillations, exposure to enriched or impoverished environment, and notably by several training protocols and post-trial sleep. BMD is frequently localized in glial cells but is also present in neurons, often in the perinucleolar region. Its distribution in repetitive and non-repetitive DNA fractions shows that BMD differs from native DNA and that in learning rats its profile differs from that of control rats. More detailed knowledge of the molecular, cellular, and time-dependent BMD features will be necessary to define its role in memory acquisition and processing and in the pathogenesis of neurologic disorders.

Hypoxic-ischemic encephalopathy (HIE), a serious disease leading to neonatal death, is becoming a key area of pediatric neurological research. Despite remarkable advances in the understanding of HIE, the explicit pathogenesis of HIE is unclear, and well-established treatments are absent. Animal models are usually considered as the first step in the exploration of the underlying disease and in evaluating promising therapeutic interventions. Various animal models of HIE have been developed with distinct characteristics, and it is important to choose an appropriate animal model according to the experimental objectives. Generally, small animal models may be more suitable for exploring the mechanisms of HIE, whereas large animal models are better for translational studies. This review focuses on the features of commonly used HIE animal models with respect to their modeling strategies, merits, and shortcomings, and associated neuropathological changes, providing a comprehensive reference for improving existing animal models and developing new animal models.

Temperature maintenance and detection are essential for the survival and perpetuation of any species. This review is focused on thermosensation; thus a detailed and traced explanation of the anatomical and physiological characteristics of each component of this sensation is given. First, the proteins that react to temperature changes are identified; next, the nature of the neurons involved in thermosensation is described; and then, the pathways from the skin through the spinal cord to the brain are outlined. Finally, the areas of the brain and their interconnections where thermoperception arises are explained. Transduction of the external and internal temperature information is essentially mediated by the transient receptor potential ion channels (TRPs). These proteins are embedded in the neurons’ membrane and they hyper- or de-polarize neurons in function of the intrinsic voltage and the temperature changes. There are distinct TRP sensors for different temperature ranges. Interestingly, the primary afferent neurons have either cold or hot receptors, so they are dedicated separately to cold or hot sensation. The information is transmitted by different pathways from the skin to the brain, where it either remains separated or is integrated to generate a response. It seems that both the determination of how thermoperception is produced and how we interact with the world are dependent on the particular arrangement and nature of the components, the way of transduction of information and the communication between these elements.

Pituitary adenoma apoplexy is a well-known clinical syndrome induced by insulin infusion, cardiac surgery, trauma, and hypothalamic releasing factors. Pituitary apoplexy can cause secondary cerebral infarct and internal carotid artery occlusion. With blockade of tumor perfusion, apoplexy triggers a sudden onset of headache, visual impairment, cranial nerve palsy, disturbances of consciousness, eyelid ptosis, and hemiparesis. However, pituitary adenoma cells with high metabolic demand cannot survive with deficient blood supply and glucose concentrations. Moreover, a number of case reports have shown that spontaneous remission of syndromes, such as acromegaly, may be caused by pituitary adenoma after apoplexy. Therefore, understanding mechanism that underlies the balance between pituitary adenoma apoplexy and subsequent spontaneous remission of syndromes may suggest new approaches for treatment of pituitary adenoma apoplexy.

After peripheral nerve damage, injured or stressed primary sensory neurons (PSNs) transmitting pathological pain (pathopain) sensitize central nervous system (CNS) neural circuits and determine behavioral phenotypes of peripheral neuropathic pain (PNP). Therefore, phenotypic profiling of pathopain-transmitting PSNs is vital for probing and discovering PNP conditions. Following peripheral nerve injuries (PNIs), PNP might be potentially transmitted by distinct classes of damaged or stressed PSNs, such as axotomized PSNs without regeneration (axotomy-non-regenerative neurons), axotomized PSNs with accurate regeneration (axotomy-regenerative neurons), and spared intact PSNs adjacent to axotomized neurons (axotomy-spared neurons). Both axotomy-non-regenerative neurons and axotomy-spared neurons have been definitely shown to participate in specific PNP transmission. However, whether axotomy-regenerative neurons could transmit PNP with unique features has remained unclear. Recent studies in rodent models of axonotmesis have clearly demonstrated that axotomy-regenerative neurons alone transmit persistent pathological pain with unique behavioral phenotypes. In this review, we exclusively review this novel category of PNP, reasonably term it ‘regenerative peripheral neuropathic pain’, and finally discuss its potential clinical significance as a new therapeutic dimension for PNIs beyond nerve regeneration.

Today, there is an increased interest in research on lysergic acid diethylamide (LSD) because it may offer new opportunities in psychotherapy under controlled settings. The more we know about how a drug works in the brain, the more opportunities there will be to exploit it in medicine. Here, based on our previously published papers and investigations, we suggest that LSD-induced visual hallucinations/phosphenes may be due to the transient enhancement of bioluminescent photons in the early retinotopic visual system in blind as well as healthy people.

Spinal cord injury (SCI) is a catastrophic event that can profoundly affect a patient’s life, with far-reaching social and economic effects. A consequential sequence of SCI is the significant neurological or psychological deficit, which obviously contributes to the overall burden of this condition. To date, there is no effective treatment for SCI. Therefore, developing novel therapeutic strategies for SCI is highly prioritized. Flavonoids, one of the most numerous and ubiquitous groups of plant metabolites, are the active ingredients of traditional Chinese medicine such as Scutellaria baicalensis Georgi (Huang Qin) or Ginkgo biloba (Ying Xin). Accumulated research data show that flavonoids possess a range of key pharmacological properties such as anti-inflammatory, anti-oxidant, anti-tumor, anti-viral, anti-cardiovascular disease, immunomodulatory, and neuroprotective effects. Based on this, the flavonoids show therapeutic potential for SCI diseases. In this paper, we will review the pharmacological properties of different types of flavonoids for the treatment of SCI diseases, and potential underlying biochemical mechanisms of action will also be described.

Salivary cortisol may be used as a biomarker of stress and anxiety in children with an autism spectrum disorder (ASD). Some suggestions have been made that the measurement of cortisol needs to be undertaken by repeated days’ observations to ensure reliability of the data obtained. These requirements are discussed in regard to 14 studies of the test-retest agreement and stability in cortisol data across repeated daily measurements. Results of those studies almost universally fail to support the argument for repeated daily measurements of cortisol. Implications for the research protocols of studies using cortisol as an index of stress in children with ASD are discussed.