Eye Movement Research in the Twenty-First Century—a Window to the Brain,Mind, and More

The study of eye movements not only addresses debilitating neuro-ophthalmological problems but has become an essential tool of basic neuroscience research. Eye movements are a classic way to evaluate brain function—traditionally in disorders affecting the brainstem and cerebellum. Abnormalities of eye movements have localizing value and help narrow the differential diagnosis of complex neurological problems. More recently, using sophisticated behavioral paradigms, measurement of eye movements has also been applied to disorders of the thalamus, basal ganglia, and cerebral cortex. Moreover, in contemporary neuroscience, eye movements play a key role in understanding cognition, behavior, and disorders of the mind. Examples include applications to higher-level decision-making processes as in neuroeconomics and psychiatric and cognitive disorders such as schizophrenia and autism. Eye movements have become valued as objective biomarkers to monitor the natural progression of disease and the effects of therapies. As specific genetic defects are identified for many neurological disorders, ocular motor function often becomes the cornerstone of phenotypic classification and differential diagnosis. Here, we introduce other important applications of eye movement research, including understanding movement disorders affecting the head and limbs. We also emphasize the need to develop standardized test batteries for eye movements of all types including the vestibulo-ocular responses. The evaluation and treatment of patients with cerebellar ataxia are particularly amenable to such an approach.     

Antipsychotic-associated neuronal changes in the brain: toxic, therapeutic, or irrelevant to the long-term outcome of schizophrenia?

The increasingly wide-spread use of antipsychotics in both adults and children calls for a detailed examination of antipsychotic-associated neuronal changes in the brain, and whether these changes are toxic, therapeutic, or perhaps irrelevant to the outcome of major psychiatric disorders, especially schizophrenia. In this review we will examine the extensive evidence demonstrating both acute and longer-term antipsychotic-associated neurotoxicity and neuroplasticity, as well as the more specific cellular changes that appear to underlie these phenomena. These include changes in proteins affecting cell survival, impairment of the mitochondrial respiratory chain, increases in DNA fragmentation, injury to dendritic microtubules, increases in dopamine-generated reactive oxygen species, changes in cell morphology, and rapid induction of apoptosis. We shall also examine the correlation between these changes and alterations in gross brain structure. There appears to be a disjunction between the widespread cellular and gross structural brain changes in schizophrenia, and the duration of illness, expression of symptoms, and response to treatment. We shall explore possible explanations for this apparent paradox.     

Mirror, mirror, on the wall, is that even my hand at all? Changes in the afterimage of one's reflection in a mirror in response to bodily movement

Successful mirror self-recognition has often been considered a correlate of self-awareness in human development and phylogeny (Gallup, 1982). Studies have also shown that vision and touch interact such that objects viewed in a mirror's reflection are recoded as originating from a location within reachable, or peripersonal, space (Maravita et al. 2002). However, the association of mirror self-recognition and self-awareness is controversial, and the mechanism that underlies the recoding of visual information into peripersonal space remains an open question. In the present study, we address these issues through the novel use of an old paradigm: positive afterimages. It has been shown that when a positive afterimage is induced, and a limb is displaced from its apparent location in the afterimage, the afterimage of the limb fades or “crumbles” (Davies, 1973). We reproduced this effect in conditions where subjects viewed the afterimage of their arms’ reflection using a frontally placed mirror and mirror box (Ramachandran & Rogers-Ramachandran, 1996). Our results suggest that the explicit knowledge that one is looking at a mirror as well as online visual feedback from bodily movement are unlikely to be responsible for previously observed interactions between vision and touch. Instead, we propose that a sense of ownership, and (bodily) self-awareness, might in part explain these interactions between vision and proprioception, which provides a partial vindication of the inference from successful mirror self-recognition to self-awareness.     

Quantifying the contributions of age,sex, methods,and urbanicity to the changing suicide rate trends in South Korea, 2001–2016

Purpose

Suicide rates in South Korea have been one of the highest in the world. The aim of this study is to quantify the contributions of age, sex, method, and place of residence to the trends of the suicide rates between 2001 and 2016 in South Korea.

Methods

Using the suicide data obtained from the South Korean National Death Registration data set for the years 2001–2016, a Joinpoint regression analysis was conducted to determine if there was a significant change in the trend of suicide rates. Next, a decomposition analysis method was used to quantify the contributions of age, sex, method, and places of residence to the changes in the suicide rates.

Results

Suicide rates increased between 2001 and 2010, and decreased between 2010 and 2016. Among all the age groups, the 65–79 age group contributed most to the rise (18% in men and 7% in women) and fall (− 15% in men and − 14% in women) of suicide rates. Men contributed much more than women to the increasing trend of suicide rate (63.0% vs. 37.0%). Hanging was the key method of suicide, dominating the ups and downs of the suicide rates. The rates of suicide by pesticide poisoning have been decreasing since 2005 and suicide by charcoal burning continued to increase against a decreasing trend of suicide rate during the period of 2010–2016. The gap of the metropolitan–city–rural suicide rates was narrowing during the period under study, although the rural areas remained to have the highest suicide rates.

Conclusion

The ups and downs of suicide rates in South Korea were not uniform across different sociodemographic groups. Age, sex, method, and place of residence contributed differently to the changes in suicide rates. Suicide prevention measures can be more focused on certain age–sex–method–region subgroups.

     

NRR focuses on, but is not limited to the following topics in 2008

Neural Regeneration Research （NRR） is a peer-reviewed journal covering neuroregeneration research and delivers the forefront information among experts and physicians. Papers published in the journal cover a wide range of topics in neuroscience and subjects relating to neuroregeneration, including neurophysiology.[第一段]     

Neuroemergencies in South America: How to Fill in the Gaps?

Neurocritical Care - South America is a subcontinent with 393 million inhabitants with widely distinct countries and diverse ethnicities, cultures, political and societal organizations. The...     

What happens in the course of body exposure? Emotional, cognitive, and physiological reactions to mirror confrontation in eating disorders

OBJECTIVE: Though body exposure seems to enhance outcome in cognitive-behavioural therapy of anorexia and bulimia nervosa, the underlying mechanisms are still unknown. METHODS: Participants with eating disorders (ED; n = 21) and normal controls (NC; n = 28) were exposed to their own bodies in front of a mirror for 40 minutes under standardized conditions. Emotions, cognitions, and saliva cortisol were assessed every 10 minutes during body exposure. Heart rate and skin conductance were recorded continuously. RESULTS: ED showed higher negative emotional and cognitive responses to body exposure compared to NC, whereas no group differences were found for physiological reactions. In the course of body exposure, the extent of negative emotions and cognitions decreased significantly with medium effects for emotions and low effects for cognitions. Physiological parameters remained stable during the task. CONCLUSION: Body exposure is a promising technique to overcome negative body-related emotions, but additional cognitive techniques are necessary.     

Glutamatergic pathways from the Kölliker-Fuse nucleus to the phrenic nucleus in the rat

After ipsilateral injections of biotinylated dextran amine (BDA) into the K?lliker-Fuse (KF) nucleus and cholera toxin B subunit (CTb) into the ventral horn in C4 to C5 segments of the spinal cord, an overlapping distribution of BDA-labeled axon terminals and CTb-labeled neurons was found in the rostral ventral respiratory group (rVRG) region ipsilateral to the injection sites. After ipsilateral injections of BDA into the KF and Fluoro-Gold (FG) into the ventral horn in C4 to C5 segments of the spinal cord, BDA-labeled axons were found to make asymmetrical synapses with the somata and dendrites of FG-labeled neurons within the neuropil of the rVRG region. Using retrograde tracing combined with immunohistochemistry for phosphate-activated glutaminase (PAG), we observed that as many as 72% of the rVRG neurons projecting to the PhN were immunoreactive for PAG and that approximately 62% and 75% of the KF neurons projecting respectively to the rVRG region and PhN contain PAG immunoreactivity. Using anterograde tracing combined with immunohistochemistry for vesicular glutamate transporter 2 (VGluT2), we further demonstrated that the KF axon terminals in the rVRG and PhN regions as well as the rVRG axon terminals in the PhN region contain VGluT2 immunoreactivity. The present results suggest that the glutamatergic pathways from the KF to the PhN directly and indirectly via the rVRG region may exist and underlie the inspiratory responses that are elicited by activation of the KF neurons.     

Descending pathways to the spinal cord in the himé salmon (landlocked red salmon, Oncorhynchus nerka)

Distribution and morphology of the cells of origin of the descending spinal pathways and their axonal courses were studied in the himé salmon, using retrograde labelling with cobaltic lysine and horseradish peroxidase (HRP). Following application of the tracers to the cut end of the spinal cord or injection of the tracers at the 10th to 15th spinal segment, neurons mainly labelled via the axons of passage were distributed in the mesencephalon and the rhombencephalon. Mesencephalic cell groups consisted of the nucleus pretectalis, the nucleus fasciculi longitudinalis medialis, and the nucleus ruber. The former two cell groups sent their axons to the fasciculus longitudinalis medialis. The axons of the nucleus ruber formed a separate loose bundle, the "tractus rubrospinalis." The rhombencephalic cell groups consisted of the rhombencephalic reticular formation, the Mauthner cells (one cell for each side), and the octavolateral area. The rhombencephalic reticular formation could be further subdivided into the nucleus reticularis superior, nucleus reticularis medius, and nucleus reticularis inferior. The axons of these cell groups joined the fasciculus longitudinalis medialis and the "tractus bulbospinalis." The Mauthner cell had two main gigantic dendrites, and its giant axons formed a conspicuous fiber of Mauthner throughout the rhombencephalon down to the spinal cord. The octavolateral area could be subdivided into the nucleus vestibularis magnocellularis, nucleus tangentialis, nucleus vestibularis descendens and nucleus intermedius. The axons of the nucleus vestibularis magnocellularis and nucleus intermedius entered the fasciculus longitudinalis medialis and/or the tractus bulbospinalis. Those of the nucleus vestibularis descendens and nucleus tangentialis formed the "tractus vestibulospinalis". The descending spinal pathways of the himé salmon were compared with those of other fishes and other vertebrates. The significance of these descending spinal pathways in the control of locomotion and sexual behavior is also discussed.     

Are Anticorrelated Networks in the Brain Relevant to Schizophrenia?

Most models of schizophrenia are based on basal ganglia-thalamocortical (BGTC) neuronal circuits or brain structures that project to them. Two new neuronal networks have been described which include many of the brain regions associated with BGTC neuronal circuits. These networks have been characterized with a new brain-imaging technique based on low-frequency fluctuations of the blood oxygen level-dependent (BOLD) signal. The new network associated with attention-demanding tasks is referred to as the task-related network and the network associated with stimulus-independent thought during the resting state is referred to as the default network. The 2 networks have been proposed to be negatively correlated or anticorrelated. This article critically reviews the rationale for these anticorrelated networks, the technique with which they are characterized, and preliminary findings in schizophrenia and other neuropsychiatric disorders. Regions associated with the default network overlap with regions important in motivation and are activated by memory retrieval, auditory hallucinations, and ketamine. Task-related networks are necessary for performance of neurocognitive tasks on which schizophrenic patients often perform poorly. It is concluded that anticorrelated networks can be viewed as complementary ways of understanding self-monitoring and task performance which extend present models of schizophrenia based on BGTC circuits. However, there are some limitations with regard the present understanding of brain structures involved in self-monitoring and the lack of asymmetry in the network which may mediate stimulus-independent thought. Further investigations of the default network assessed by low-frequency fluctuations in the BOLD signal seem warranted.     

Teasing,Ridiculing and the Relation to the Fear of Being Laughed at in Individuals with Asperger’s Syndrome

The present paper investigated the fear of being laughed at (gelotophobia) in relation to recalled experiences of having been laughed at in the past in individuals with Asperger’s Syndrome (AS). About 45% of the individuals with AS (N = 40), but only 6% of the controls (N = 83) had at least a slight form of gelotophobia, which is the highest percentage ever found in the literature. Gelotophobia correlated with the frequency and severity of remembered teasing and mocking situations in the past. This indicates that gelotophobia is an important issue in individuals with AS. Furthermore, individuals with AS are less able to laugh at themselves (gelotophilia), but enjoy laughing at others (katagelasticism, a more hostile form of humor) to the same extent as controls do.