Neuroscience and Neurobiology Commons^™

Pain-Capable Neural Substrates May Be Widely Available In The Animal Kingdom, Edgar T. Walters

Animal Sentience

Neural and behavioral evidence from diverse species indicates that some forms of pain may be generated by coordinated activity in networks far smaller than the cortical pain matrix in mammals. Studies on responses to injury in squid suggest that simplification of the circuitry necessary for conscious pain might be achieved by restricting awareness to very limited information about a noxious event, possibly only to the fact that injury has occurred, ignoring information that is much less important for survival, such as the location of the injury. Some of the neural properties proposed to be critical for conscious pain in mammals …

Going Beyond Just-So Stories, Brian Key

Animal Sentience

Colloquial arguments for fish feeling pain are deeply rooted in anthropometric tendencies that confuse escape responses to noxious stimuli with evidence for consciousness. More developed arguments often rely on just-so stories of fish displaying complex behaviours as proof of consciousness. In response to commentaries on the idea that fish do not feel pain, I raise the need to go beyond just-so stories and to rigorously analyse the neural circuitry responsible for specific behaviours using new and emerging technologies in neuroscience. By deciphering the causal relationship between neural information processing and conscious behaviour, it should be possible to assess cogently the …

How Not To Move The Line Drawn On Pain, Bjorn H. Merker

Animal Sentience

In this second commentary I outline the inadequacy of Key's responses to the many peer critiques of his thesis that have so far appeared in Animal Sentience. I illustrate with examples drawn from his response to my first commentary.

Understanding Emotional Suffering, Barbara J. King

Animal Sentience

In responding to insightful commentaries from 7 scholars, for which I am grateful, I offer new thoughts on whether animals can conceptualize and express signs of grief. I also discuss why I included both weak and strong examples of animal mourning, and how this work may help us think about enhanced welfare for animals, including freedom from emotional suffering.

Why Animal Welfarism Continues To Fail, Lori Marino

Animal Sentience

Welfarism prioritizes human interests over the needs of nonhuman animals. Despite decades of welfare efforts other animals are mostly worse off than ever before, being subjected to increasingly invasive and harmful treatments, especially in the factory farming and biomedical research areas. A legal rights-based approach is essential in order for other animals to be protected from the varying ethical whims of our species.

High Affinity Block Of Icl,Swell By Thiol-Reactive Small Molecules, Sung H. Park

Theses and Dissertations

Ebselen (Ebs) is considered as a glutathione peroxidase (GPx) mimetic and primarily thought to function by scavenging intracellular reactive oxygen species (ROS). Previous to our work, Deng et al. (2010a) demonstrated complete block of I_Cl,swell with 15 microM Ebs following endothelin-1 (ET-1) induced activation of the current in cardiomyocytes. This block was presumed to take effect mainly via the quenching of ROS. Nonetheless, our work with DI TNC1 astrocytes strongly emphasizes that Ebs might function by an alternative mechanism based on its kinetic profile in blocking I_Cl,swell. Our experiments showed that 45 nM Ebs can fully block …

Allosteric Effects Of G-Protein Coupled Receptor Heteromerization: Relevance To Psychosis, Jason W. Younkin

Theses and Dissertations

G-protein coupled receptors (GPCRs) implicated in disease are the predominant pharmaceutical targets. Growing evidence suggests that GPCRs form homo- and heteromeric complexes, resulting in allosteric functional changes. Ligands targeting one receptor can alter the function of the other receptor or receptors. Knowledge of these functional changes will provide unique opportunities to treat diseases. We examined two GPCR heteromers implicated in psychosis: mGlu2R-5HT2AR and D2R-5HT2AR. Using whole-cell patch clamp, we studied HEK-293 cells stably transfected with mGlu2R and 5HT2AR. Maximal heteromer formation allows inverse agonists to increase the G-protein activity of the opposite receptor, while sub-maximal heteromer formation does not. However, …

Acute And Chronic Effects Of Inhalants In Intracranial Self-Stimulation, Matthew Tracy

Theses and Dissertations

Inhalants are a loosely defined diverse group of volatile substances which people abuse. Despite widespread misuse of inhalants, there are limited preclinical methods available to study the reinforcement-like properties of inhalants. One procedure which has demonstrated substantial promise as a tool to investigate inhalant pharmacology is the intracranial self-stimulation (ICSS) procedure. ICSS utilizes pulses of electrical stimulation to the mesolimbic reward pathway to serve as a temporally defined and controlled operant reinforcer with a highly adjustable efficacy. The first aim of the project was to characterize the effects of commonly abused inhalants: including toluene, trichloroethane, nitrous oxide, isoflurane and R134a …

A Neural Circuit Of Appetite Control In C. Elegans, Kristen C. Davis

Theses and Dissertations

Feeding behavior and its associated neural circuitry is complex and intricate in mammalian systems, however, a simple model organism, such as C. elegans provides a more basic approach to understand factors and molecules involved. The fruit-dwelling nematode provides a unique set of resources; it only consists of 959 cells, 302 of which are neurons. In addition, each neuron’s connectivity and position within the worm is known and consistent between animals. Conservation of neurotransmitters and biochemical processes add to this impressive list. These resources provide an excellent background to address feeding behavior and the neural structures governing it.

Feeding behavior in …

Resolution Of Inflammation Rescues Axon Initial Segment Disruption, Nicholas M. George

Theses and Dissertations

Axonal domains are required for proper neuron function. These domains are unstable and degenerate concurrent with the inflammation in multiple sclerosis (MS) and the inflammatory disease models experimental autoimmune encephalomyelitis (EAE) and lipopolysaccharide (LPS) induced inflammation. Previous studies from our laboratory have shown that the axon initial segment (AIS) is maintained independently of the presence of myelin, but that AIS disruption is seen in MS as well as EAE and LPS-mediated inflammation. AIS loss can be interrupted in the early stage of EAE using the anti-inflammatory drug Didox. However, the potential for Didox directed repair of the AIS in later …

The Role Of Matrix Metalloproteinase 9 And Osteopontin In Synaptogenesis And Reinnervation Of The Olfactory Bulb Following Brain Injury, Melissa A. Powell

Theses and Dissertations

Traumatic brain injury (TBI) is a serious health concern, causing cognitive, motor, and sensory deficits, including olfactory dysfunction. This dissertation explores the effects of TBI on synaptic plasticity within the olfactory system, seeking to define mechanisms guiding postinjury sensory reinnervation. Physical forces induced by TBI can axotomize olfactory receptor neurons (ORNs), which innervate olfactory bulb (OB). These axons regenerate OB projections after injury, a process involving growth through a complex extracellular matrix (ECM). As such, we investigated a potential molecular mechanism capable of modifying local OB ECM to support postinjury synaptogenesis. Since matrix metalloproteinases (MMPs) and their ECM substrates are …

The Neural Dynamics Of Somatosensory Processing And Adaptation Across Childhood: A High-Density Electrical Mapping Study, Neha Uppal, John J. Foxe, John Butler, Frantzy Acluche, Sophie Molholm

Articles

Young children are often hyperreactive to somatosensory inputs hardly noticed by adults, as exemplified by irritation to seams or labels in clothing. The neurodevelopmental mechanisms underlying changes in sensory reactivity are not well understood. Based on the idea that neurodevelopmental changes in somatosensory processing and/or changes in sensory adaptation might underlie developmental differences in somatosensory reactivity, high-density electroencephalography was used to examine how the nervous system responds and adapts to repeated vibrotactile stimulation over childhood. Participants aged 6–18 yr old were presented with 50-ms vibrotactile stimuli to the right wrist over the median nerve at 5 blocked interstimulus intervals (ranging …

Cerebellar Nuclei Neurons Show Only Small Excitatory Responses To Optogenetic Olivary Stimulation In Transgenic Mice: In Vivo And In Vitro Studies, Huo Lu, Bo Yang, Dieter Jaeger

PCOM Scholarly Works

BACKGROUND: To study the olivary input to the cerebellar nuclei (CN) we used optogenetic stimulation in transgenic mice expressing channelrhodopsin-2 (ChR2) in olivary neurons. We obtained in vivo extracellular Purkinje cell (PC) and CN recordings in anesthetized mice while stimulating the contralateral inferior olive (IO) with a blue laser (single pulse, 10 - 50 ms duration). Peri-stimulus histograms were constructed to show the spike rate changes after optical stimulation. Among 29 CN neurons recorded, 15 showed a decrease in spike rate of variable strength and duration, and only 1 showed a transient spiking response. These results suggest that direct olivary …

Comparative Evolutionary Approach To Pain Perception In Fishes, Culum Brown

Animal Sentience

Arguments against the fact that fish feel pain repeatedly appear even in the face of growing evidence that they do. The standards used to judge pain perception keep moving as the hurdles are repeatedly cleared by novel research findings. There is undoubtedly a vested commercial interest in proving that fish do not feel pain, so the topic has a half-life well past its due date. Key (2016) reiterates previous perspectives on this topic characterised by a black-or-white view that is based on the proposed role of the human cortex in pain perception. I argue that this is incongruent with our …

Animal Mourning: Précis Of How Animals Grieve (King 2013), Barbara J. King

Animal Sentience

Abstract: When an animal dies, that individual’s mate, relatives, or friends may express grief. Changes in the survivor’s patterns of social behavior, eating, sleeping, and/or of expression of affect are the key criteria for defining grief. Based on this understanding of grief, it is not only big-brained mammals like elephants, apes, and cetaceans who can be said to mourn, but also a wide variety of other animals, including domestic companions like cats, dogs, and rabbits; horses and farm animals; and some birds. With keen attention placed on seeking where grief is found to occur and where it is absent …

Death In The Family, Maria Botero

Animal Sentience

Barbara King presents grief as the result of the capacity of human and non-human animals for social and affectionate bonds. This is a novel approach that provides a context for interpreting behavioral evidence of grief. The book also offers thought-provoking insights into the relationship between emotion and the expression of emotion. The most surprising element of King’s approach is that, throughout the book, her account of non-human animal grief forces us to reassess the way we treat them.

Could Fish Feel Pain? A Wider Perspective, Yew-Kwang Ng

Animal Sentience

Key’s (2016) target article provides some strong arguments but also makes some logical mistakes. The arguments are not sufficient to support a definite conclusion that fish cannot feel pain. A multi-faceted perspective taking into account brain structure, chemical secretion in brain, animal behavior, and evolutionary biology may be useful and appears, at least in some aspects, to suggest the opposite conclusion from that of the target article.

Should Fish Feel Pain? A Plant Perspective, František Baluška

Animal Sentience

Key (2016) claims fish that fish do not feel pain because they lack the necessary neuronal architecture: their responses to noxious stimuli, according to Key, are executed automatically without any feelings. However, as pointed out by many of his commentators, this conclusion is not convincing. Plants might provide some clues. Plants are not usually thought to be very active behaviorally, but the evidence suggests otherwise. Moreover, in stressful situations, plants produce numerous chemicals that have painkilling and anesthetic properties. Finally, plants, when treated with anesthetics, cannot execute active behaviors such as touch-induced leaf movements or rapid trap closures after localizing …

Fish Pain: An Inconvenient Truth, Culum Brown

Animal Sentience

Whether fish feel pain is a hot political topic. The consequences of our denial are huge given the billions of fish that are slaughtered annually for human consumption. The economic costs of changing our commercial fishery harvest practices are also likely to be great. Key outlines a structure-function analogy of pain in humans, tries to force that template on the rest of the vertebrate kingdom, and fails. His target article has so far elicited 34 commentaries from scientific experts from a broad range of disciplines; only three of these support his position. The broad consensus from the scientific community is …

Fish Pain: A Painful Topic, Carl Safina

Animal Sentience

If fish cannot feel pain, why do stingrays have purely defensive tail spines that deliver venom? Stingrays’ ancestral predators are fish. And why do many fishes possess defensive fin spines, some also with venom that produces pain in humans? These things did not evolve just in case sentient humans would evolve millions of years later and then invent scuba. If fish react purely unconsciously to “noxious” stimuli, why aren’t sharp jabbing spines enough? Why also stinging venom?