Neuroscience and Neurobiology Commons^™

Cellular And Genetic Bases Of Cold Nociception And Nociceptive Sensitization In Drosophila Larvae, Heather N. Turner

Dissertations & Theses (Open Access)

Organisms from flies to mammals utilize thermoreceptors to detect and respond to noxious thermal stimuli. Although much is understood about noxious heat avoidance, our understanding of the basic biology of noxious cold perception is gravely minimal. Numerous clinical conditions disrupt the sensory machinery, such as in patients suffering from tissue damage (from wound or sunburn), or injury to the peripheral nerves, as in patients with diabetes or undergoing chemotherapy. Our goal is to determine the genetic basis for noxious cold perception and injury-induced nociceptive sensitization using the genetically tractable Drosophila model. Using a novel "cold probe" tool and assay we …

Insect Consciousness: Commitments, Conflicts And Consequences, Colin Klein, Andrew B. Barron

Animal Sentience

Our target article, “Insects have the capacity for subjective experience,” has provoked a diverse range of commentaries. In this response we have collated what we see as the major themes of the discussion. It is clear that we differ from some commentators in our commitments to what subjective experience is and what the midbrain is capable of. Here we clarify where we stand on those points and how our view differs from some other influential perspectives. The commentaries have highlighted the most lively areas of disagreement. We revisit here the debates surrounding whether the cortex is essential for any form …

Subjective Experience In Insects: Definitions And Other Difficulties, Shelley Adamo

Animal Sentience

Whether insects have the potential for subjective experiences depends on the definition of subjective experience. The definition used by Klein & Barron (2016) is an unusually liberal one and could be used to argue that some modern robots have subjective experiences. From an evolutionary perspective, the additional neurons needed to produce subjective experiences will be proportionately more expensive for insects than for mammals because of the small size of the insect brain. This greater cost could weaken selection for such traits. Minimally, it may be premature to assume that small neuronal number is unimportant in determining the capacity for consciousness.

The Molecular And Cellular Basis For Cold Sensation, Daniel Brenner

Arts & Sciences Electronic Theses and Dissertations

The ability to sense changes in temperature is crucial to surviving harsh environments. Over the last decade several ion channels that have been proposed to be cold sensitive have been identified, most notably TRPM8 and TRPA1. Although these molecules have been extensively studied in vitro, their exact roles in cold sensation in vivo are still debated. This uncertainty is in large part due to problems with the standard methods of testing cold sensitivity in vivo, which often rely on subjective measures of cold responsiveness. Experiments using these subjective measures have been repeated by different groups and have yielded conflicting results, …

Diffuse Traumatic Brain Injury Induces Prolonged Immune Sysregulation And Potentiates Hyperalgesia Following A Peripheral Immune Challenge, Rachel K. Rowe, Gavin I. Ellis, Jordan L. Harrison, Adam D. Bachstetter, Gregory F. Corder, Linda J. Van Eldik, Bradley K. Taylor, Francesc Marti, Jonathan Lifshitz

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Background: Nociceptive and neuropathic pain occurs as part of the disease process after traumatic brain injury (TBI) in humans. Central and peripheral inflammation, a major secondary injury process initiated by the traumatic brain injury event, has been implicated in the potentiation of peripheral nociceptive pain. We hypothesized that the inflammatory response to diffuse traumatic brain injury potentiates persistent pain through prolonged immune dysregulation.

Results: To test this, adult, male C57BL/6 mice were subjected to midline fluid percussion brain injury or to sham procedure. One cohort of mice was analyzed for inflammation-related cytokine levels in cortical biopsies and serum along an …

Fish Pain: An Inconvenient Truth, Culum Brown

Culum Brown, PhD

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 …

The Effects Of The Ketogenic Diet (Kd) On Inflammatory Pain, Livia S. Wyss

Senior Theses and Projects

BACKGROUND: Pain is the most common ailment around the world, according to the American Academy of Pain Medicine; 100 million Americans suffer with chronic pain, which is more than any other main disorder and is described by more than 60% as impacted their overall enjoyment of life (AAPA). The ketogenic diet (KD) is a high fat, low carbohydrate dietary regimen, which is described to decrease neuronal excitation, increase ketone bodies and ATP levels, while lowering glucose and proinflammatory cytokines. The KD is an effective therapy for epilepsy; a disorder that arises from either lowered inhibition or increased excitation, similar to …

Fish Pain's Burden Of Proof, Carl Safina

Animal Sentience

A hypothesis like Key’s, that fish cannot feel pain, should really be stated as a null hypothesis — an assumption that there is no difference in the things being compared. Then evidence — including anecdotal evidence — for and against rejecting the null hypothesis can be examined and weighed. Key (2016a) has proven only that fish lack mammalian brains.

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 …

Nonverbal Indicators Of Pain, Simon Van Rysewyk

Animal Sentience

In discussing fish pain, Key (2016) privileges pain in humans — “the only species able to directly report on its feelings.” Human experience of pain is not necessarily best reflected by verbal self-report, however. Neural responses to noxious stimuli are influenced by individual differences and by context. Nonverbal pain displays such as facial expressions reflect part of the neural response to noxious stimuli. Most mammals have a specific facial grimace reflecting pain. If fish have a somatic expression of pain, the development of a reliable and accurate somatic pain scale specific to fish could make a contribution to the debate …

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?

Chronic Pancreatitis, Pain, And Anxiety In An Alcohol And High Fat Mouse Model, Tiffanie Clinkinbeard

Theses and Dissertations--Gerontology

Homeodynamic space (HDS) shrinks as vulnerability increases with aging and repeated damage to the cells. HDS is lost in alcoholic pancreatitis patients due to overconsumption of alcohol, smoking, and high fat diets. Etiologically relevant animal models for study of chronic pancreatitis (CP) are needed. In order to begin filling this gap a central purpose of this dissertation research was to examine relationships between the alcohol and high fat diet (AHF) and pancreatitis with attention to hypersensitivity and anxiety-like behaviors. The AHF diet induced pancreatitis described here etiologically mimics human risk factors of AHF consumption for advancement to alcoholic CP.

In …

Fighting Forms Of Expression, Paul J.B. Hart

Animal Sentience

Even though Key (2016) has done a very thorough job of assembling evidence showing that fish are unlikely to have the neurological capacity to be conscious and feel pain, there will still be a significant number of behavioural biologists who want to continue maintaining that fish do have consciousness and suffer from pain. In this commentary the reasons for people resisting the conclusions of the evidence are discussed. The reasons revolve around three aspects of the debate: the overblown respect humans have for the powers of consciousness in our day-to-day behaviour, the often used assumption that the possession of complex …

Cortex Necessary For Pain — But Not In Sense That Matters, Adam J. Shriver

Animal Sentience

Certain cortical regions are necessary for pain in humans in the sense that, at particular times, they play a direct role in pain. However, it is not true that they are necessary in the more important sense that pain is never possible in humans without them. There are additional details from human lesion studies concerning functional plasticity that undermine Key’s (2016) interpretation. Moreover, no one has yet identified any specific behaviors that mammalian cortical pain regions make possible that are absent in fish.

Anthropomorphic Denial Of Fish Pain, Lynne U. Sneddon, Matthew C. Leach

Animal Sentience

Key (2016) affirms that we do not know how the fish brain processes pain but denies — because fish lack a human-like cortex — that fish can feel pain. He affirms that birds, like fish, have a singly-laminated cortex and that the structure of the bird brain is quite different from that of the human brain, yet he does not deny that birds can feel pain. In this commentary we describe how Key cites studies that substantiate mammalian pain but discounts the same kind of data as evidence of fish pain. We suggest that Key's interpretations are illogical, do not …

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: Would It Change Current Best Practice In The Real World?, B. K. Diggles

Animal Sentience

Much of the “fish pain debate” relates to how high the bar for pain should be set. The close phylogenetic affinities of teleosts with cartilaginous fishes which appear to lack nociceptors suggests caution should be applied by those who seek to lower the bar, especially given the equivocal and conflicting nature of the experimental data currently available for teleosts. Nevertheless, even if we assume fish “feel pain,” it is difficult to see how current best practice in aquaculture would change. This is because of the need to avoid stress at all stages of the rearing process to optimize health, growth …

Brain Processes For “Good” And “Bad” Feelings: How Far Back In Evolution?, Jaak Panksepp

Animal Sentience

The question of whether fish can experience pain or any other feelings can only be resolved by neurobiologically targeted experiments. This commentary summarizes why this is essential for resolving scientific debates about consciousness in other animals, and offers specific experiments that need to be done: (i) those that evaluate the rewarding and punishing effects of specific brain regions and systems (for instance, with deep-brain stimulation); (ii) those that evaluate the capacity of animals to regulate their affective states; and (iii) those that have direct implications for human affective feelings, with specific predictions — for instance, the development of new treatments …

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 …

No Evidence That Pain Is Painful Neural Process, Riccardo Manzotti

Animal Sentience

Key (2016) claims that fish do not feel pain because they lack the neural structures that have a contingent causal role in generating and feeling pain in mammals. I counterargue that no conclusive evidence supports the sufficiency of any mammalian neural structure to produce pain. We cannot move from contingent necessity in mammals to necessity in every organism.

Itch Mediation And How It Differs From Pain, Nechama Rappaport

The Science Journal of the Lander College of Arts and Sciences

Itch, to most, is a common nuisance, although when chronic it can negatively affect quality of life. It is obvious that itch is processed differently than pain, but how it differs is not clear. Researchers have been trying to find a path that specifically mediates itch. They have found that itch is mediated through at least two different pathways: histamine dependent and histamine independent. However, many of the mediators involved in the transduction of itch also mediate pain. Although some itch-specific neurons have been found, the majority of the pruritogenic neurons are also responsive to pain stimuli. Two theories that …

Why Fish Do Not Feel Pain, Brian Key

Animal Sentience

Only humans can report feeling pain. In contrast, pain in animals is typically inferred on the basis of nonverbal behaviour. Unfortunately, these behavioural data can be problematic when the reliability and validity of the behavioural tests are questionable. The thesis proposed here is based on the bioengineering principle that structure determines function. Basic functional homologies can be mapped to structural homologies across a broad spectrum of vertebrate species. For example, olfaction depends on olfactory glomeruli in the olfactory bulbs of the forebrain, visual orientation responses depend on the laminated optic tectum in the midbrain, and locomotion depends on pattern generators …

Pain In Fish: Weighing The Evidence, James D. Rose

Animal Sentience

The target article by Key (2016) examines whether fish have brain structures capable of mediating pain perception and consciousness, functions known to depend on the neocortex in humans. He concludes, as others have concluded (Rose 2002, 2007; Rose et al. 2014), that such functions are impossible for fish brains. This conclusion has been met with hypothetical assertions by others to the effect that functions of pain and consciousness may well be possible through unknown alternate neural processes. Key's argument would be bolstered by consideration of other neurological as well as behavioral evidence, which shows that sharks and ray are fishes …