Neuroscience and Neurobiology Commons^™

Mra-Based Evaluation Of Anatomical Variation Of Circle Of Willis In Adult Pakistanis, Rehana Shaikh, Saba Sohail

Department of Radiology

Objective: To determine the frequency and patterns of normal anatomical variation of Circle of Willis on magnetic resonance angiogram in adults without cerebrovascular disease.
Methods: This descriptive cross-sectional study was conducted at the Radiology Department of Dow University of Health Sciences / Civil Hospital, Karachi, from January to December 2016, and comprised patients referred for magnetic resonance imaging of the brain and magnetic resonance angiogram without any clinical or radiological manifestation of cerebrovascular disease, primarily including those with suspected demyelination, infection, epilepsy or metastases. Three-dimensional time-of-flight magnetic resonance angiography was performed. The Circle of Willis was assessed for its completeness …

Treated Hypothyroidism Is Associated With Cerebrovascular Disease But Not Alzheimer's Disease Pathology In Older Adults, Willa D. Brenowitz, Fang Han, Walter A. Kukull, Peter T. Nelson

Pathology and Laboratory Medicine Faculty Publications

Thyroid hormone (TH) disease is common among older adults and is associated with cognitive impairment. However, pathologic correlates are not well understood. We studied pathologic and clinical factors associated with hypothyroidism, the most common form of TH disease, in research subjects seen annually for clinical evaluations at U.S. Alzheimer’s Disease Centers. Thyroid disease and treatment status were assessed during clinician interviews. Among autopsied subjects, there were 555 participants with treated hypothyroidism and 2,146 with no known thyroid disease; hypothyroidism was associated with severe atherosclerosis (OR=1.35 95% CI: 1.02, 1.79) but not Alzheimer’s disease (AD) pathologies (amyloid plaques or neurofibrillary tangles). …

Minocycline Protects Developing Brain Against Ethanol-Induced Damage, Xin Wang, Kai Zhang, Fanmuyi Yang, Zhenhua Ren, Mei Xu, Jacqueline A. Frank, Zun-Ji Ke, Jia Luo

Pharmacology and Nutritional Sciences Faculty Publications

Fetal alcohol spectrum disorders (FASD) are caused by ethanol exposure during the pregnancy and is the leading cause of mental retardation. Ethanol exposure during the development results in the loss of neurons in the developing brain, which may underlie many neurobehavioral deficits associated with FASD. It is important to understand the mechanisms underlying ethanol-induced neuronal loss and develop appropriate therapeutic strategies. One of the potential mechanisms involves neuroimmune activation. Using a third trimester equivalent mouse model of ethanol exposure, we demonstrated that ethanol induced a wide-spread neuroapoptosis, microglial activation, and neuroinflammation in C57BL/6 mice. Minocycline is an antibiotic that inhibits …

Neonatal Stimulation Of Pkc Epsilon Signaling Normalizes Fragile X-Associated Deficits In Pvn Oxytocin Expression And Later-Life Social And Anxiety Behavior, Alexandra E. Marsillo

Dissertations, Theses, and Capstone Projects

Fragile X Syndrome (FXS) is an inherited developmental disorder characterized by disturbances in emotional and social behavior. Our studies have revealed suppressed hippocampal PKCε expression in Fmr1 knockout (KO) mice, the leading model of FXS. To compensate for this deficiency, we stimulated PKCε in neonatal KO mice by administering a selective PKCε activator, dicyclopropyl-linoleic acid (DCP-LA), and studied its effect on ventral hippocampal neurons and a proximal target of the ventral hippocampus, the hypothalamus, which regulates social and emotional behavior. We observed that at postnatal day 18 (P18), vehicle-treated KO mice displayed increased surface localization of the 3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) …

Neural Underpinnings Of Walking Under Cognitive And Sensory Load: A Mobile Brain/Body Imaging Approach, Brenda R. Malcolm

Dissertations, Theses, and Capstone Projects

Dual-task walking studies, in which individuals engage in an attentionally-demanding task while walking, have provided indirect evidence via behavioral and biomechanical measures, of the recruitment of higher-level cortical resources during gait. Additionally, recent EEG and imaging (PET, fNIRS) studies have revealed direct neurophysiological evidence of cortical contributions to steady-state walking. However, there remains a lack of knowledge regarding the underlying neural mechanisms involved in the allocation of cortical resources while walking under increased load. This dissertation presents three experiments designed to provide a greater understanding of the cortical dynamics implicated in processing load (top-down or bottom-up) during locomotion. Furthermore, we …

Biological Signatures Of Emotion Regulation In Children, Sarah Myruski

Dissertations, Theses, and Capstone Projects

Emotion regulation (ER) is a key predictor of positive adjustment throughout the lifespan. Despite decades of research on discrete ER strategy use, ER may be more appropriately measured in terms of the breadth of emotional range, or the degree to which one can flexibly modulate emotional responses. Yet little is known about ER flexibility in childhood. Also, given the crucial role of caregiver support in children’s emotional lives, ER may be most accurately measured in developmentally appropriate and ecologically valid social contexts. Further, few developmental studies have capitalized on the growing evidence base surrounding biological signatures of ER. This study …

Insights Into The Cyclooxygenase Pathway In A Progressive Rat Model Of Parkinson’S Disease Induced By Prostaglandin J2: Protection With Ibuprofen, Chuhyon Corwin

Dissertations, Theses, and Capstone Projects

Parkinson’s disease (PD) is a neurodegenerative disease with aging as a major risk factor. Its defining symptoms are motor deficits that are primarily associated with dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc) in the midbrain. Post-mortem PD brains exhibit abnormal intraneuronal inclusions of α-synuclein and ubiquitinated protein aggregates known as Lewy bodies, a hallmark of PD pathology.

Currently, there is no validated biomarker for PD. Especially the early stage of PD is difficult to detect as the pathology develops progressively. While symptom-managing treatments are available, there is no neuroprotective treatment as of yet, mainly due to the …

Social Influences On Songbird Behavior: From Song Learning To Motion Coordination, Iva Ljubičić

Dissertations, Theses, and Capstone Projects

Social animals learn during development how to integrate successfully into their group. How do social interactions combine to maintain group cohesion? We first review how social environments can influence the development of vocal learners, such as songbirds and humans (Chapter 1). To bypass the complexity of natural social interactions and gain experimental control, we developed Virtual Social Environments, surrounding the bird with videos of manipulated playbacks. This way we were able to design sensory and social scenarios and test how social zebra finches adjust their behavior (Chapters 2 & 3). A serious challenge is that the color output of a …

An Aged Canid With Behavioral Deficits Exhibits Blood And Cerebrospinal Fluid Amyloid Beta Oligomers, Clare Rusbridge, Francisco J. Salguero, Monique Antoinette David, Kiterie M. E. Faller, Jose T. Bras, Rita J. Guerreiro, Angela C. Richard-Londt, Duncan Grainger, Elizabeth Head, Sebastian G. P. Brandner, Brian Summers, John Hardy, Mourad Tayebi

Pharmacology and Nutritional Sciences Faculty Publications

Many of the molecular and pathological features associated with human Alzheimer disease (AD) are mirrored in the naturally occurring age-associated neuropathology in the canine species. In aged dogs with declining learned behavior and memory the severity of cognitive dysfunction parallels the progressive build up and location of Aβ in the brain. The main aim of this work was to study the biological behavior of soluble oligomers isolated from an aged dog with cognitive dysfunction through investigating their interaction with a human cell line and synthetic Aβ peptides. We report that soluble oligomers were specifically detected in the dog's blood and …

Fk506-Binding Protein 12.6/1b, A Negative Regulator Of [Ca2+], Rescues Memory And Restores Genomic Regulation In The Hippocampus Of Aging Rats, John C. Gant, Eric M. Blalock, Kuey-Chu Chen, Inga Kadish, Olivier Thibault, Nada M. Porter, Philip W. Landfield

Pharmacology and Nutritional Sciences Faculty Publications

Hippocampal overexpression of FK506-binding protein 12.6/1b (FKBP1b), a negative regulator of ryanodine receptor Ca²⁺ release, reverses aging-induced memory impairment and neuronal Ca²⁺ dysregulation. Here, we tested the hypothesis that FKBP1b also can protect downstream transcriptional networks from aging-induced dysregulation. We gave hippocampal microinjections of FKBP1b-expressing viral vector to male rats at either 13 months of age (long-term, LT) or 19 months of age (short-term, ST) and tested memory performance in the Morris water maze at 21 months of age. Aged rats treated ST or LT with FKBP1b substantially outperformed age-matched vector controls and performed similarly …

Liposomal Tricurin, A Synergistic Combination Of Curcumin, Epicatechin Gallate And Resveratrol, Repolarizes Tumor-Associated Microglia/Macrophages, And Eliminates Glioblastoma (Gbm) And Gbm Stem Cells, Sumit Mukherjee, Juliet N. E. Baidoo, Samay Sampat, Andrew Manusco, Lovena David, Leah S. Cohen, Shuiqin Zhou, Probal Banerjee

Publications and Research

Glioblastoma (GBM) is a deadly brain tumor with a current mean survival of 12–15 months. Despite being a potent anti-cancer agent, the turmeric ingredient curcumin (C) has limited anti-tumor efficacy in vivo due to its low bioavailability. We have reported earlier a strategy involving the use two other polyphenols, epicatechin gallate (E) from green tea and resveratrol (R) from red grapes at a unique, synergistic molar ratio with C (C:E:R: 4:1:12.5, termed TriCurin) to achieve superior potency against HPV+ tumors than C alone at C:E:R (M): 32:8:100 (termed 32 M+ TriCurin). We have now prepared liposomal TriCurin (TrLp) and demonstrated …

Mechanisms Underlying Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Medial Prefrontal Cortex, Emily K. Stephens, Arielle L. Baker, Allan T. Gulledge

Dartmouth Scholarship

Serotonin (5-HT) selectively excites subpopulations of pyramidal neurons in the neocortex via activation of 5-HT_2A (2A) receptors coupled to G_q subtype G-protein alpha subunits. G_q-mediated excitatory responses have been attributed primarily to suppression of potassium conductances, including those mediated by K_V7 potassium channels (i.e., the M-current), or activation of non-specific cation conductances that underlie calcium-dependent afterdepolarizations (ADPs). However, 2A-dependent excitation of cortical neurons has not been extensively studied, and no consensus exists regarding the underlying ionic effector(s) involved. In layer 5 of the mouse medial prefrontal cortex, we tested potential mechanisms of serotonergic excitation …

Anti-Correlated Cortical Networks Arise From Spontaneous Neuronal Dynamics At Slow Timescales, Nathan X. Kodama, Tianyi Feng, James J. Ullett, Hillel J. Chiel, Siddharth S. Sivakumar, Roberto F. Galán

Faculty Scholarship

In the highly interconnected architectures of the cerebral cortex, recurrent intracortical loops disproportionately outnumber thalamo-cortical inputs. These networks are also capable of generating neuronal activity without feedforward sensory drive. It is unknown, however, what spatiotemporal patterns may be solely attributed to intrinsic connections of the local cortical network. Using high-density microelectrode arrays, here we show that in the isolated, primary somatosensory cortex of mice, neuronal firing fluctuates on timescales from milliseconds to tens of seconds. Slower firing fluctuations reveal two spatially distinct neuronal ensembles, which correspond to superficial and deeper layers. These ensembles are anti-correlated: when one fires more, the …

The Variability Of Neural Responses To Naturalistic Videos Change With Age And Sex, Agustin Petroni, Samantha Cohen, Lei Ai, Nicolas Langer, Simon Henin, Tamara Vanderwal, Michael P. Milham, Lucas C. Parra

Publications and Research

Neural development is generally marked by an increase in the efficiency and diversity of neural processes. In a large sample (n=114) of human children and adults with ages ranging from 5 to 44 yr, we investigated the neural responses to naturalistic video stimuli. Videos from both real-life classroom settings and Hollywood feature films were used to probe different aspects of attention and engagement. For all stimuli, older ages were marked by more variable neural responses. Variability was assessed by the intersubject correlation of evoked electroencephalographic responses. Young males also had less-variable responses than young females. These results were replicated in …

Internal Carotid Artery Stenosis: A Novel Surgical Model For Moyamoya Syndrome, Jill M. Roberts, Michael E. Maniskas, Justin F. Fraser, Gregory J. Bix

Sanders-Brown Center on Aging Faculty Publications

Moyamoya is a cerebrovascular disorder characterized by progressive stenosis of the intracranial internal carotid arteries. There are two forms: Disease and Syndrome, with each characterized by the sub-population it affects. Moyamoya syndrome (MMS) is more prominent in adults in their 20’s-40’s, and is often associated with autoimmune diseases. Currently, there are no surgical models for inducing moyamoya syndrome, so our aim was to develop a new animal model to study this relatively unknown cerebrovascular disease. Here, we demonstrate a new surgical technique termed internal carotid artery stenosis (ICAS), to mimic MMS using micro-coils on the proximal ICA. We tested for …

Collective Adhesion And Displacement Of Retinal Progenitor Cells Upon Extracellular Matrix Substrates Of Transplantable Biomaterials, Ankush Thakur, Shawn Mishra, Juan Pena, Jing Zhou, Stephen Redenti, Robert Majeska, Maribel Vazquez

Publications and Research

Strategies to replace retinal photoreceptors lost to damage or disease rely upon the migration of replacement cells transplanted into sub-retinal spaces. A significant obstacle to the advancement of cell transplantation for retinal repair is the limited migration of transplanted cells into host retina. In this work, we examine the adhesion and displacement responses of retinal progenitor cells on extracellular matrix substrates found in retina as well as widely used in the design and preparation of transplantable scaffolds. The data illustrate that retinal progenitor cells exhibit unique adhesive and displacement dynamics in response to poly-l-lysine, fibronectin, laminin, hyaluronic acid, and Matrigel. …

Effects Of Environmental Conditions On C-Fos Expression In Rat Nucleus Accumbens After Remifentanil, Usman Z. Hamid, Rebecca S. Hofford, Michael T. Bardo

Oswald Research and Creativity Competition

Previous studies have shown that adolescents raised in impoverished conditions are more likely to develop drug abuse in adulthood. In addition, both stress-inducing living conditions (impoverishment/isolation) and drugs of abuse may lead to an increase in the c-fos transcription factor in the reward circuit of the brain, particularly in the nucleus accumbens. The aim of the current study was to quantify the number of c-fos positive cells in the nucleus accumbens of enriched and isolated rats exposed to the opioid remifentanil. Thirty-two male Sprague-Dawley rats were raised in either enriched or isolated conditions for one month, after which they received …

Review: Do The Different Sensory Areas Within The Cat Anterior Ectosylvian Sulcal Cortex Collectively Represent A Network Multisensory Hub?, M. Alex Meredith, Mark T. Wallace, H. Ruth Clemo

Anatomy and Neurobiology Publications

Current theory supports that the numerous functional areas of the cerebral cortex are organized and function as a network. Using connectional databases and computational approaches, the cerebral network has been demonstrated to exhibit a hierarchical structure composed of areas, clusters and, ultimately, hubs. Hubs are highly connected, higher-order regions that also facilitate communication between different sensory modalities. One region computationally identified network hub is the visual area of the Anterior Ectosylvian Sulcal cortex (AESc) of the cat. The Anterior Ectosylvian Visual area (AEV) is but one component of the AESc that also includes the auditory (Field of the Anterior Ectosylvian …

Low Sucrose, Omega-3 Enriched Diet Has Region-Specific Effects On Neuroinflammation And Synaptic Function Markers In A Mouse Model Of Doxorubicin-Based Chemotherapy, Tonya S. Orchard, Monica M. Gaudier-Diaz, Panchita Phuwamongkolwiwat-Chu, Rebecca Andridge, Maryam B. Lustberg, Joshua Bomser, Rachel M. Cole, Martha A. Belury, Courtney A. Devries

Faculty & Staff Scholarship

Chemotherapeutic agents such as doxorubicin may negatively affect long-term brain functioning in cancer survivors; neuroinflammation may play a causal role. Dietary approaches that reduce inflammation, such as lowering sucrose and increasing eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA), may attenuate chemotherapy-induced neuroinflammation and synaptic damage, thereby improving quality of life. Ovariectomized, C57BL/6 mice were assigned to a chemotherapy (9 mg/kg doxorubicin + 90 mg/kg cyclophosphamide) or vehicle two-injection regimen, with injections two and four weeks after starting diets. In Study 1, mice received low sucrose diets with EPA + DHA or No EPA + DHA for four to six …

Analytical Cpg Model Driven By Limb Velocity Input Generates Accurate Temporal Locomotor Dynamics, Sergiy Yakovenko, Anton Sobinov, Valeriya Gritsenko

Faculty & Staff Scholarship

The ability of vertebrates to generate rhythm within their spinal neural networks is essential for walking, running, and other rhythmic behaviors. The central pattern generator (CPG) network responsible for these behaviors is well-characterized with experimental and theoretical studies, and it can be formulated as a nonlinear dynam- ical system. The underlying mechanism responsible for locomotor behavior can be expressed as the process of leaky integration with resetting states generating appropriate phases for changing body velocity. The low-dimensional input to the CPG model generates the bilateral pattern of swing and stance modulation for each limb and is consistent with the desired …

Embodying Functionally Relevant Action Sounds In Patients With Spinal Cord Injury, Mariella Pazzaglia, Giulia Galli, James W. Lewis, Giorgio Scivoletto, Anna Maria Giannini, Marco Molinari

Faculty & Staff Scholarship

Growing evidence indicates that perceptual-motor codes may be associated with and influenced by actual bodily states. Following a spinal cord injury (SCI), for example, individuals exhibit reduced visual sensitivity to biological motion. However, a dearth of direct evidence exists about whether profound alterations in sensorimotor traffic between the body and brain influence audio-motor representations. We tested 20 wheelchair-bound individuals with lower skeletal-level SCI who were unable to feel and move their lower limbs, but have retained upper limb function. In a two-choice, matching-to-sample auditory discrimination task, the participants were asked to determine which of two action sounds matched a sample …

Respiratory Muscle Training Positively Affects Vasomotor Response In Young Healthy Women, Angela Valentina Bisconti, Michela Devoto, Massimo Venturelli, Randall Bryner, Mark Olfert, Paul D. Chantler, F. Esposito

Faculty & Staff Scholarship

Vasomotor response is related to the capacity of the vessel to maintain vascular tone within a narrow range. Two main control mechanisms are involved: the autonomic control of the sympathetic neural drive (global control) and the endothelial smooth cells capacity to respond to mechanical stress by releasing vasoactive factors (peripheral control). The aim of this study was to evaluate the effects of respiratory muscle training (RMT) on vasomotor response, assessed by flow-mediated dilation (FMD) and heart rate variability, in young healthy females. The hypothesis was that RMT could enhance the balance between sympa- thetic and parasympathetic neural drive and reduce …

Maternal Engineered Nanomaterial Inhalation During Gestation Alters The Fetal Transcriptome, P.A. Stapleton, Q.A. Hathaway, C.E. Nichols, A.B. Abukabda, M.V. Pinti, D.L. Shepherd, C.R. Mcbride, J. Yi, V.C. Castranova, J.M Hollander, Timothy Robert Nurkiewicz

Faculty & Staff Scholarship

Background: The integration of engineered nanomaterials (ENM) is well-established and widespread in clinical, commercial, and domestic applications. Cardiovascular dysfunctions have been reported in adult populations after exposure to a variety of ENM. As the diversity of these exposures continues to increase, the fetal ramifications of maternal exposures have yet to be determined. We, and others, have explored the consequences of ENM inhalation during gestation and identified many cardiovascular and metabolic outcomes in the F1 generation. The purpose of these studies was to identify genetic alterations in the F1 generation of Sprague-Dawley rats that result from maternal ENM inhalation during gestation. …

Absolute Lymphocyte And Neutrophil Counts In Neonatal Ischemic Brain Injury, Jessica M. Povroznik, Elizabeth B. Engler-Chiurazzi, Tania Nanavati, Paola Pergami

Faculty & Staff Scholarship

Objectives: This study aimed to identify differences in absolute neutrophils, lymphocytes, and neutrophil-to-lymphocyte ratio between neonates with two forms of ischemic brain injury, hypoxic-ischemic encephalopathy, and acute ischemic stroke, compared to controls. We also aimed to determine whether this neutrophil/lymphocyte response pattern is associated with disease severity or is a consequence of the effects of total-body cooling, an approved treatment for moderate-to-severe hypoxic-ischemic encephalopathy. Methods: A retrospective chart review of 101 neonates with hypoxic-ischemic encephalopathy + total-body cooling (n = 26), hypoxic-ischemic encephalopathy (n=12), acute ischemic stroke (n=15), and transient tachypnea of the newborn (n=48) was conducted; transient tachypnea of …

Tasseography From Jung's Perspective, Avetisian, Elizabeth

CONSCIOUSNESS: Ideas and Research for the Twenty-First Century

Approaching from Jung’s perspective this paper aims to understand how the unconscious communicates through symbolism that may be the basis for synchronicity arising from mantic procedures. A particular ritual of divination called tasseography will be studied whereby the seer interprets patterns in coffee grounds intuitively and by following a standard system of symbolism to foretell the seeker’s future life events or provide answers to seeker’s pressing life questions. The paper will examine various processes involved in the experience of tasseography and its ritual that enable the reader to predict the seeker’s future or bring light to the present or past …

Discerning Suicide In Drug Intoxication Deaths: Paucity And Primacy Of Suicide Notes And Psychiatric History, Ian Rh Rockett, Eric D. Caine, Hilary S. Connery, Gail D'Onofrio, David J. Gunnell, Ted R. Miller, Kurt B. Nolte, Mark S. Kaplan, Nestor D. Kapusta, Christa L. Lilly, Lewis S. Nelson, Sandra L. Putnam, Steven Stack, Peeter Varnik, Lynne R. Webster, Haomiao Jia

Faculty & Staff Scholarship

Objective

A paucity of corroborative psychological and psychiatric evidence may be inhibiting detec- tion of drug intoxication suicides in the United States. We evaluated the relative importance of suicide notes and psychiatric history in the classification of suicide by drug intoxication versus firearm (gunshot wound) plus hanging/suffocation—the other two major, but overtly violent methods.

Methods

This observational multilevel (individual/county), multivariable study employed a general- ized linear mixed model (GLMM) to analyze pooled suicides and undetermined intent deaths, as possible suicides, among the population aged 15 years and older in the 17 states participating in the National Violent Death Reporting System …

Acute Effects Of Diets Rich In Almonds And Walnuts On Endothelial Function, Ravindra Bhardwaj, Harvinder Dod, Manjinder S. Sandhu, Rohil Bedi, Sachin Dod, Gregory Konat, H.K. Chopra, Rakesh Sharma, Abnash C. Jain, Navin Nanda

Faculty & Staff Scholarship

Objective: Omega-3 fatty acids, especially alpha-linolenic acid (ALA), which are present in nuts may reduce cardiovascular disease (CVD) risk, by changing vascular inflammation and improving endothelial dysfunction. The objective of the study was to evaluate the acute effects of two different diets, one containing walnuts and the other almonds on endothelial function.

Methods: Twenty-seven overweight volunteers underwent a randomized 2-period, crossover, controlled intervention study. The subjects were given either walnut or almond diets which varied in monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content. The walnut diet provided 23.1% energy from PUFA and the almond diet provided 7.6% …

Tau Aggregation, Conformational Selection, And Inhibition, Michael R. Holden

Electronic Theses and Dissertations

Tau fibrils are a pathological hallmark of over 20 neurodegenerative disorders, including Alzheimer's disease. There currently is no cure for these diseases and treatments are limited. Once Tau fibrils form in the brain, they propagate down neuronal networks, and this spreading is linked to disease progression. Studying the behavior and structure of Tau monomer and Tau aggregates therefore may give insight into methods by which the spread of Tau fibrils can be inhibited. The structures of the Tau fibrils from different diseases are thought to vary, partially giving rise to the different disease phenotypes. Tau natively binds to microtubules by …

Chickens Play To The Crowd, Cinzia Chiandetti

Animal Sentience

The time was ripe for Marino’s review of chickens’ cognitive capacities. The research community, apart from expressing gratitude for Marino’s work, should now use it to increase public awareness of chickens’ abilities. People’s views on many animals are ill-informed. Scientists need to communicate and engage with the public about the relevance and societal implications of their findings.

Post-Darwin Skepticism And Run-Of-The-Mill Suicide, John Hadley

Animal Sentience

Peña-Guzmán’s depiction of the opponent of animal suicide as a conservative is a straw man. It is possible to accept that animals are self-conscious and reflexive yet still reject the view that they have the mental wherewithal to commit run-of-the-mill suicide. That animal behaviour can be positioned on a continuum of self-destructive behaviour does not establish that animals can intentionally kill themselves.