Miller fisher syndrome – A rare complication of covid-19 infection

The COVID-19 virus can present with various neurological signs and symptoms involving both the central and peripheral nervous systems. Miller Fisher syndrome (M.F.S.), a variant of Landry Guillain Barre Syndrome (L.G.B.S.), presents with ataxia, areflexia, and ophthalmoplegia. It can develop during and after COVID-19 illness. We are reporting a case of the Miller Fisher variant of L.G.B.S. following a COVID-19 infection. We found no difference in clinical presentation, electrophysiological studies, severity, recovery, and treatment in our patient compared to a non-covid related M.F.S. Our goal is to add a case of the COVID-19-associated Miller Fisher variant of L.G.B.S. to already existing limited literature through this case report.

Where are the cores in this thing? …and what are they computing?

Evolution conserves components below, and goals above, the levels for circuits and computations. This work presents evidence consistent with similar evolutionary conservation of a small, possibly canonical number of circuits and computations, and cites some historical interest in this idea. Electronic circuits are examples of what we would like to know. There are several strikingly common features of nervous systems that may be both conserved and computational essential. There is always a null hypothesis, and the work acknowledges the possibility that computation itself is ad-hoc in multiple areas and nervous systems, and not itself a conserved property. But we don’t know, and we should.

Physiological Role of Bile Acids Modified by the Gut Microbiome

Bile acids (BAs) are produced from cholesterol in the liver and are termed primary BAs. Primary BAs are conjugated with glycine and taurine in the liver and then released into the intestine via the gallbladder. After the deconjugation of glycine or taurine by the gut microbiome, primary BAs are converted into secondary BAs by the gut microbiome through modifications such as dehydroxylation, oxidation, and epimerization. Most BAs in the intestine are reabsorbed and transported to the liver, where both primary and secondary BAs are conjugated with glycine or taurine and rereleased into the intestine. Thus, unconjugated primary Bas, as well as conjugated and unconjugated secondary BAs, have been modified by the gut microbiome. Some of the BAs reabsorbed from the intestine spill into the systemic circulation, where they bind to a variety of nuclear and cell-surface receptors in tissues, whereas some of the BAs are not reabsorbed and bind to receptors in the terminal ileum. BAs play crucial roles in the physiological regulation of various tissues. Furthermore, various factors, such as diet, age, and antibiotics influence BA composition. Here, we review recent findings regarding the physiological roles of BAs modified by the gut microbiome in the metabolic, immune, and nervous systems.

As soon as there was life, there was danger: the deep history of survival behaviours and the shallower history of consciousness

It is often said that fear is a universal innate emotion that we humans have inherited from our mammalian ancestors by virtue of having inherited conserved features of their nervous systems. Contrary to this common sense-based scientific point of view, I have argued that what we have inherited from our mammalian ancestors, and they from their distal vertebrate ancestors, and they from their chordate ancestors, and so forth, is not a fear circuit. It is, instead, a defensive survival circuit that detects threats, and in response, initiates defensive survival behaviours and supporting physiological adjustments. Seen in this light, the defensive survival circuits of humans and other mammals can be conceptualized as manifestations of an ancient survival function—the ability to detect danger and respond to it—that may in fact predate animals and their nervous systems, and perhaps may go back to the beginning of life. Fear, on the other hand, from my perspective, is a product of cortical cognitive circuits. This conception is not just of academic interest. It also has practical implications, offering clues as to why efforts to treat problems related to fear and anxiety are not more effective, and what might make them better. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.

Peripheral Nerve Stimulation: The Evolution in Pain Medicine

Peripheral nerve stimulation (PNS) involves the application of electrical stimulation near the proximity of peripheral nerves. Although the mechanism of action remains unknown, PNS likely modulates both the central and peripheral nervous systems to provide analgesia for a wide variety of pain disorders involving the head, extremities, and trunk. Historically, PNS was not utilized widely due to underwhelming results from earlier studies. However, significant innovations in device technologies, including improved implantation techniques, hardware miniaturization, and externalized pulse generators, have led to the resurgence of PNS in the field of pain medicine. This editorial briefly reviews the evolution of PNS in the field of pain medicine and highlights areas for future investigation.

The PACAP/PAC1 Receptor System and Feeding

Pituitary adenylyl cyclase activating polypeptide (PACAP) belongs to the vasoactive intestinal polypeptide (VIP)/secretin/glucagon superfamily. PACAP is present in two forms (PACAP-38 and PACAP-27) and binds to three guanine-regulatory (G) protein-coupled receptors (PAC1, VPAC1, and VPAC2). PACAP is expressed in the central and peripheral nervous systems, with high PACAP levels found in the hypothalamus, a brain region involved in feeding and energy homeostasis. PAC1 receptors are high-affinity and PACAP-selective receptors, while VPAC1 and VPAC2 receptors show a comparable affinity to PACAP and VIP. PACAP and its receptors are expressed in the central and peripheral nervous systems with moderate to high expression in the hypothalamus, amygdala, and other limbic structures. Consistent with their expression, PACAP is involved in several physiological responses and pathological states. A growing body of literature suggests that PACAP regulates food intake in laboratory animals. However, there is no comprehensive review of the literature on this topic. Thus, the purpose of this article is to review the literature regarding the role of PACAP and its receptors in food intake regulation and to synthesize how PACAP exerts its anorexic effects in different brain regions. To achieve this goal, we searched PubMed and reviewed 68 articles regarding the regulatory action of PACAP on food intake. Here, we present the literature regarding the effect of exogenous PACAP on feeding and the role of endogenous PACAP in this process. We also provide evidence regarding the effect of PACAP on the homeostatic and hedonic aspects of food intake, the neuroanatomical sites where PACAP exerts its regulatory action, which PACAP receptors may be involved, and the role of various signaling pathways and neurotransmitters in hypophagic effects of PACAP.

Nervous Systems

The contributors to Nervous Systems reassess contemporary artists' and critics' engagement with social, political, biological, and other systems as a set of complex and relational parts: an approach commonly known as systems thinking. Demonstrating the continuing relevance of systems aesthetics within contemporary art, the contributors highlight the ways that artists adopt systems thinking to address political, social, and ecological anxieties. They cover a wide range of artists and topics, from the performances of the Argentinian collective the Rosario Group and the grid drawings of Charles Gaines to the video art of Singaporean artist Charles Lim and the mapping of global logistics infrastructures by contemporary artists like Hito Steyerl and Christoph Büchel. Together, the essays offer an expanded understanding of systems aesthetics in ways that affirm its importance beyond technological applications detached from cultural contexts. Contributors. Cristina Albu, Amanda Boetzkes, Brianne Cohen, Kris Cohen, Jaimey Hamilton Faris, Christine Filippone, Johanna Gosse, Francis Halsall, Judith Rodenbeck, Dawna Schuld, Luke Skrebowski, Timothy Stott, John Tyson

The enteric nervous system of C. elegans is specified by the Sine Oculis-like homeobox gene ceh-34

Overarching themes in the terminal differentiation of the enteric nervous system, an autonomously acting unit of animal nervous systems, have so far eluded discovery. We describe here the overall regulatory logic of enteric nervous system differentiation of the nematode C. elegans that resides within the foregut (pharynx) of the worm. A Caenorhabditis elegans homolog of the Drosophila Sine Oculis homeobox gene, ceh-34, is expressed in all 14 classes of interconnected pharyngeal neurons from their birth throughout their life time, but in no other neuron type of the entire animal. Constitutive and temporally controlled ceh-34 removal shows that ceh-34 is required to initiate and maintain the neuron type-specific terminal differentiation program of all pharyngeal neuron classes, including their circuit assembly, without affecting panneuronal features. Through additional genetic loss of function analysis, we show that within each pharyngeal neuron class, ceh-34 cooperates with different homeodomain transcription factors to individuate distinct pharyngeal neuron classes. Our analysis underscores the critical role of homeobox genes in neuronal identity specification and links them to the control of neuronal circuit assembly of the enteric nervous system. Together with the pharyngeal nervous system simplicity as well as its specification by a Sine Oculis homolog, our findings invite speculations about the early evolution of nervous systems.