Neuroscience and Neurobiology Commons^™

An Invertebrate Perspective On Pain, Jennifer A. Mather

Animal Sentience

Although Key (2016) argues that mammals feel pain and fish do not, from an invertebrate perspective, it is obvious that the pain experience is shared by animals from a number of different animal groups.

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 …

A Single Strand Of Argument With Unfounded Conclusion, Robert W. Elwood

Animal Sentience

Key (2016) describes the neural system involved in human pain experience in an excellent fashion but then suggests that only that complete system can generate the experience of pain. Thus animals without all components will not feel pain. This argument has been refuted in the past by analogy to vision where it is clear that a broad range of taxa, vertebrate and invertebrate, have good visual abilities albeit with completely different central nervous systems and receptors. This known counterargument to Key’s main idea is not mentioned in the target article. Further criteria that might indicate pain and studies examining these …

Pain In Parallel, Peter Godfrey-Smith

Animal Sentience

Key's (2016) arguments against the view that fish feel pain can be shown to be fallacious by considering some damage-related behaviors in invertebrates. Pain may have different neural bases in different organisms, so the absence in fish of the cortical structures that might underlie pain in mammals does not settle the question of fish pain.

Drawing The Line On Pain, Bjorn Merker

Animal Sentience

The structure of Key's (2016) argument that fish do not feel pain is flawed, betraying a fundamental lack of understanding of the nature of feelings and their role in the brain's functional division of labor. The evidence Key marshals in support of his premature commitment to an exclusively corticocentric view of consciousness in humans is plagued by repeated failures of scholarship.

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.

Why Is Fish “Feeling” Pain Controversial?, E. Don Stevens

Animal Sentience

In his excellent target article, Key (2016) develops a mechanistic argument in an attempt to show why it is unlikely that fish can “feel” pain or for that matter, “feel” anything. The topic is controversial and likely to achieve the goal of getting many hits for the inaugural issue of the new journal, Animal Sentience. In my view, the question is unlikely to be answered, for two reasons. First, because the proponents of the “fish feel pain” controversy are untrained and unskilled in the details and jargon of neurophysiology and/or neuroanatomy, and the opponents of the controversy, like Key, …

Where Is Pain In The Brain?, Marshall Devor

Animal Sentience

Key argues that fish cannot experience pain based on (1) brain imaging in humans, (2) consequences of lesions and (3) direct brain stimulation. Imaging indeed shows that pain-relevant signals reach the cortex, but not that they underlie the subjective experience of pain. Lesions and stimulation data are more to the point, but Key paints an idiosyncratic and misleading picture of their effects. S1 and S2 ablation does not eliminate evoked or spontaneous pain, although there may be up- or down-modulation. Likewise, stimulation of pain-associated cortical areas rarely induces pain, and pain almost never occurs at the onset of epileptic seizures. …

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 …

Leaving The Door Open For Fish Pain: Evolutionary Convergence And The Utility Of ‘Just-So Stories’, David B. Edelman

Animal Sentience

Key argues that fish do not experience pain because they lack the necessary (but not necessarily sufficient) brain structures and associated functional circuitry to engender such conscious percepts. I propose that fish pain may be dependent on neuroanatomical regions and pathways that are structurally and/or functionally analogous — but not strictly homologous — to well-characterized mammalian substrates of pain. An example is the convergent appearance of the complex, single-compartment eye across invertebrate and vertebrate phylogeny. Structural-functional convergence is ubiquitous in evolution. Comparative inferences and correlative lines of evidence play an important role in building evolutionary arguments. The dismissal of the …

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 …

Falsifying The Null Hypothesis That “Fish Do Not Feel Pain", Brian Key

Animal Sentience

The reader of Animal Sentience may surmise that because the weight of the commentaries on my target article, “Why fish do not feel pain,” is leaning towards not supporting my argument, it follows that the premise "fish do not feel pain" is incorrect. However, science does not prevail by popular opinion. History is plagued with numerous (and often widely accepted) examples of biological phenomena being explained by mysterious forces. In the absence of a mechanistic understanding, the many different guises of vitalism (the principle that life involves a vital energy) are often invoked to explain the unknown. Spurious …

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.

Neuroscience And Behavioral Genetics In Us Criminal Law: An Empirical Analysis, Nita A. Farahany

Faculty Scholarship

The goal of this study was to examine the growing use of neurological and behavioral genetic evidence by criminal defendants in US criminal law. Judicial opinions issued between 2005–12 that discussed the use of neuroscience or behavioral genetics by criminal defendants were identified, coded and analysed. Yet, criminal defendants are increasingly introducing such evidence to challenge defendants’ competency, the effectiveness of defense counsel at trial, and to mitigate punishment.

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, …

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 Role Of Oxidative Stress In The Mechanisms Of Ammonia-Induced Brain Swelling And Tolerance In The Goldfish (Carassius Auratus), David F. Jones Lisser Mr.

Theses and Dissertations (Comprehensive)

Toxic build-ups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). The mechanisms of ammonia-induced brain swelling and tolerance remain elusive, but several studies have suggested a role for reactive oxygen species (ROS), which may damage proteins and lipids in the plasma membrane of astrocytes in the brain. As a result, osmotic gradients across cell membranes may be altered leading to water uptake by astrocytes and swelling. While a role for ROS has been proposed in mammals, no studies have addressed this question in …

Changes In Brain Water Content In The Rainbow Trout (Oncorhynchus Mykiss) And In The Goldfish (Carassius Auratus) Due To High External Ammonia Exposure, Phillip Q.H. Pham-Ho

Theses and Dissertations (Comprehensive)

In fishes, hyperammonemia may occur following feeding or exposure to abnormally high concentrations of environmental ammonia due to sewage effluents, agricultural run-off and in crowded aquaculture pens. Increased internal ammonia can result in hyperactivity, convulsions, coma and death. In mammals, it is also associated with potentially fatal brain edema, in which the accumulation of intracellular water results in swelling, increased intracranical pressure and herniation leading to death. Recently it was shown that rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus) experience brain swelling following exposure to high external ammonia (HEA). However, the mechanism of ammonia-induced brain …

The Contribution Of The Cerebello-Thalamo-Cortical Circuit To The Pathology Of Non-Dopaminergic Responsive Parkinson's Disease Symptoms, Shannon C. Lefaivre

Theses and Dissertations (Comprehensive)

It has been well established that motor symptoms in Parkinson’s disease (PD) are primarily associated with dopaminergic degeneration in the basal ganglia. However, symptoms which respond poorly to dopaminergic replacement, such as tremor, gait, and balance deficits, point to an alternative pathology to dysfunction of the basal ganglia. Over-activity of the cerebellum has been demonstrated in PD, however it is not entirely clear how the cerebellum might be affecting motor symptoms. A lack of consensus exists regarding how cerebellar over-activity might be influencing PD tremor, and whether resting and postural tremor are differentially influenced by cerebellar dysfunction. It is also …

Scalar Short-Term Memory, Tyler D. Bancroft

Theses and Dissertations (Comprehensive)

The location of the brain’s working and short-term memory (WM/STM) “system” is unclear. The existence of a dedicated WM/STM system is itself under debate. Recently, it has been proposed that WM/STM storage relies not on a dedicated system in prefrontal cortex, but rather that it is an emergent function of interaction between attentional and representational systems (e.g., sensory cortex) in the brain. However, mnemonic representations of very simple stimuli have repeatedly been shown to exist in frontal cortex. In this manuscript, I use computational and behavioural methods to demonstrate similarities between the representations of different types of very simple stimuli …

The Effects Of External Focus Of Attention Exercise Rehabilitation On Dual Task Walking In Parkinson's Disease, Eric N. Beck

Theses and Dissertations (Comprehensive)

Parkinson’s disease impairs control of well-learned movements, and therefore, individuals with Parkinson’s disease are forced to walk with greater conscious control. This causes difficulties while walking and completing a secondary task simultaneously (dual tasking), in that distractions from conscious control of walking increase the risk of falls and injury. Although, attention-based exercise may be a potential avenue to decrease the demands associated with walking in Parkinson’s disease. For example, an external focus of attention (on manipulated objects) has been found to recruit the networks that are important for walking with little conscious control (automatic control networks). In contrast, an internal …

The Effects Of Manipulated Somatosensory Input On Simulated Falls During Walking, Sarah Mitchell-Ewart

Theses and Dissertations (Comprehensive)

Previous research has demonstrated that there is a distinct relationship between aging and instability. The somatosensory system plays a significant role in balance control in conjunction with vision and the vestibular system (Qiu et al., 2012). Evidence has shown that manipulation of the mechanoreceptors on the plantar surface of the foot has a direct effect on balance control. By manipulating these receptors with hypothermic anesthesia and vibration, researchers are capable of simulating the effect of sensory modification on healthy individuals, in order to understand the role that plantar-surface sensation has in adapting to perturbation during gait (Perry et al., 2001; …

Sensitivity Of Composite Scores To Amyloid Burden In Preclinical Alzheimer's Disease: Introducing The Z-Scores Of Attention, Verbal Fluency, And Episodic Memory For Nondemented Older Adults Composite Score, Yen Ying Lim, Peter J. Snyder, Robert H. Pietrzak, Albulene Ukiqi, Victor L. Villemagne, David Ames, Olivier Salvado, Pierrick Bourgeat, Ralph N. Martins, Colin L. Masters, Christopher C. Rowe, Paul Maruff

Research outputs 2014 to 2021

Introduction:

Cognitive composite scores developed for preclinical Alzheimer's disease (AD) often consist of multiple cognitive domains as they may provide greater sensitivity to detect β-amyloid (Aβ)-related cognitive decline than episodic memory (EM) composite scores alone. However, this has never been empirically tested. We compared the rate of cognitive decline associated with high Aβ (Aβ+) and very high Aβ (Aβ++) in cognitively normal (CN) older adults on three multidomain cognitive composite scores and one single-domain (EM) composite score.

Methods:

CN older adults (n = 423) underwent Aβ neuroimaging and completed neuropsychological assessments at baseline, and at 18-, 36-, 54-, …