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Sentience

Daniel Toker

What is a mind? What does it mean to be conscious? And why do the answers matter?

Hosted by neuroscientist Daniel Toker, PhD (@the_brain_scientist), Sentience explores the biggest questions about minds, intelligence, and what it means to be a thinking, feeling being. Through conversations with scientists, philosophers, physicians, historians, entrepreneurs, and other leading thinkers, each episode uncovers ideas that could change how we understand ourselves—and our future.

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  • 18 episodes
  • Avg 1 hr 7 min
  • English

Episodes 18

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  • August 14 · 1 hr 9 min

    18. Do Elephants Have Names? The Hidden Minds of Animals with Mickey Pardo, PhD

    What if we’ve been dramatically underestimating what it’s like to be another animal? In this episode of Sentience, animal cognition researcher Mickey Pardo, PhD takes us inside the minds of other animals—from woodpeckers that track relationships between other birds to elephants that appear to use name-like calls to address one another. We explore how scientists can investigate the private mental lives of animals, what the famous mirror test actually tells us about self-awareness, and why humans have repeatedly moved the goalposts whenever another species demonstrates an ability we once thought was uniquely ours. We also dive into the future of animal communication: could AI uncover hidden patterns in the vocalizations of elephants, dolphins, and whales that humans have completely missed? And if animals have richer inner lives than we've assumed, what does that mean for how we understand intelligence, consciousness, and our relationship with the other minds sharing the planet with us? Chapters/timestamps (00:12) – How can we know what's happening inside an animal's mind? (01:05) – How science changed its view of animal intelligence (02:50) – Jane Goodall and the revolution in animal cognition (06:52) – The surprisingly sophisticated social lives of woodpeckers (13:37) – How scientists can uncover relationships between animals (15:29) – Birds remembering relationships from before they were born (21:59) – Why study elephants? (24:44) – The mirror test: what does it actually prove? (28:28) – What cleaner fish can teach us about intelligence (33:12) – Do elephants have names? (35:08) – How scientists discovered elephant “names” (41:56) – The hidden complexity of animal communication (43:55) – Why humans keep moving the goalposts for intelligence (49:16) – Could AI decode animal communication? (51:37) – Can animals talk about things that aren't happening right now? (54:39) – Dolphins, AI, and the search for animal language (57:04) – What animal communication could teach us about alien intelligence (01:02:58) – What will we get completely wrong about animal minds? (01:07:37) – What other minds can teach us about ourselves (01:08:39) – Rethinking our relationship with sentient animals

  • July 19 · 1 hr 32 min

    17. Bruno Olshausen, PhD on how the brain compresses, sees, and makes sense of the world

    In this episode of Sentience, Bruno Olshausen, PhD, professor at UC Berkeley, tells the story of how he went from wanting to build brain-like robots to uncovering one of neuroscience's most surprising results. Early in his career, he and a collaborator showed that if you train a simple computer model to represent images as efficiently as possible, it spontaneously reinvents the same kind of visual "building blocks" found in real brains—a discovery almost nobody believed at first. Olshausen walks us through why the brain seems to prefer having most of its neurons sit quietly at any given moment, why this looks so different from how modern AI vision systems work, and why brains might not be "efficient" so much as bound by the same physical limits as everything else. We also get into why the brain sends information as sudden spikes rather than smooth signals, and what all of this might mean for building truly autonomous machines. Timestamps(00:00) – Welcome to Sentience and meeting Bruno Olshausen(00:41) – From building robots to studying the brain(03:37) – An early chapter at NASA(05:56) – Why recognizing objects is harder than it sounds(09:45) – Where AI vision and real vision part ways(17:48) – A brief history of "efficient" brains(32:46) – The experiment that surprised everyone(36:04) – Why nobody believed it at first(46:17) – Making sense of uncertainty: how the brain guesses(54:47) – Why most of your neurons are doing nothing right now(01:07:16) – Two very different ways the brain stores memories(01:15:01) – What "efficient" really means for a brain(01:22:33) – Why the brain uses spikes instead of steady signals(01:28:19) – What Bruno's chasing next Books referenced: Sterling, P. & Laughlin, S. Principles of Neural Design. MIT Press. MacKay, D.J.C. Information Theory, Inference, and Learning Algorithms. Cambridge University Press. Core papers referenced: Olshausen, B.A. & Field, D.J. (1996). "Emergence of simple-cell receptive field properties by learning a sparse code for natural images." Nature, 381, 607–609. Barlow, H.B. (1961). "Possible principles underlying the transformation of sensory messages." In Sensory Communication. Rozell, C.J., Johnson, D.H., Baraniuk, R.G., & Olshausen, B.A. (2008). "Sparse coding via thresholding and local competition in neural circuits." Neural Computation, 20(10), 2526–2563.

  • May 9 · 46 min

    16. Yi-Li Wu, PhD on the forgotten global history of anesthesia

    In this episode of Sentience, Yi-Li Wu, PhD, Associate Professor of History and Women's and Gender Studies at the University of Michigan, explores the overlooked history of anesthesia and pain management. We discuss medieval Chinese surgical practices, herbal anesthetics, and the transmission of medical knowledge across centuries and cultures. Wu explains how physicians balanced the therapeutic and toxic effects of powerful plants, why much of this knowledge was passed down orally rather than written, and how modern narratives of scientific discovery often obscure the broader global networks behind medicine. The conversation also explores traumatic injuries, military medicine, and what the history of anesthesia reveals about how humans everywhere have confronted pain, surgery, and healing. Chapters / Timestamps (00:00) – Welcome to Sentience and meeting Yi-Li Wu(01:02) – From women’s history to the history of Chinese medicine(07:18) – Traumatic injuries and the problem of unwritten medical knowledge(10:30) – Discovering a 14th-century Chinese anesthesia recipe(13:36) – Ancient pain management and the legend of Hua Tuo(15:42) – Empirical medicine and how early physicians understood anesthetics(18:03) – Poison, potency, and balancing dangerous medicines(21:40) – Datura, bone setting, and independent discoveries across cultures(26:17) – Surgery, warfare, and what Hua Tuo may really have done(33:03) – Japanese anesthesia, Seishu Hanaoka, and shared medical traditions(37:35) – Why scientific breakthroughs are rarely the work of one person(39:28) – Rethinking the global history of anesthesia(43:49) – Recovering lost medical histories and finishing the book project

  • January 4 · 1 hr 14 min

    15. Osh Agabi on wetware, biological sensing, and the future of living machines

    In this episode of Sentience, Osh Agabi, CEO of Koniku Inc., explores what happens when technology is built not just with silicon, but with living biology. We discuss his journey from growing up in Lagos to leading efforts in “wetware computing,” where engineered biological systems are designed to sense, adapt, and solve problems in the real world. Agabi explains how biological chips can smell their environment, why embodiment and sensing may be essential for intelligence, and why many traditional brain–machine approaches miss something fundamental. He also reflects on failure, engineering rigor, ethics, and what it means to build machines that might one day learn and evolve alongside us. Timestamps (00:00) – Welcome to Sentience and meeting Osh Agabi(10:00) – From robotics in Europe to early machine learning(17:23) – What AI can’t do yet and current limits(19:09) – Building next-generation neural electrode chips(35:35) – Toward embodied systems and artificial “brains”(40:26) – Ambition, rigor, and real-world usefulness(42:17) – The long view of foundational technology(43:14) – Why smell is a powerful sensing problem(47:30) – Turning neurons into real-world sensors(50:38) – Engineering mindset vs. biotech mindset(51:32) – Why optical readouts beat electrical ones(52:05) – Modular biochips, maintenance, and usability(53:06) – Beyond smell and toward richer perception

  • Dec 22, 2025 · 59 min

    14. Joel Frohlich, PhD on brain waves, entropy, and consciousness

    In this episode of Sentience, Joel Frohlich, PhD explores how scientists study consciousness through brain signals. We discuss why familiar brain waves can sometimes mislead us, how ideas from entropy and information theory offer deeper insight into conscious states, and what neurodevelopmental conditions and brain injury reveal about long-held assumptions in neuroscience. Frohlich also shares his work using advanced imaging to study the developing brain before birth, and reflects on what it really means to measure the mind. Timestamps (00:00) – Welcome to Sentience and meeting Joel Frohlich (01:00) – Communicating neuroscience and asking bigger questions (05:20) – Studying consciousness through brain activity (07:45) – Why brain waves can be misleading (11:10) – Consciousness and recovery after severe brain injury (15:10) – What brain waves actually represent (19:20) – How oversimplified brain stories persist (22:00) – Entropy, complexity, and richer measures of consciousness (26:40) – Information, uncertainty, and the structure of neural activity (31:15) – Consciousness as a dynamic process (35:30) – Measuring the developing brain before birth (41:20) – What fetal brain signals can—and can’t—tell us (48:50) – Open questions and future directions in consciousness science (55:00) – Seeing patterns in noise, from brains to astrophotography

  • Oct 21, 2025 · 59 min

    13. Alysson Muotri, PhD on how brain organoids are transforming neuroscience, evolution, and medicine

    In this episode of Sentience, Alysson Muotri, PhD, professor at UC San Diego, discusses how brain organoids—lab-grown neural tissues derived from stem cells—are reshaping neuroscience. He explains how organoids can model early brain development, uncover the roots of neurodevelopmental disorders like autism, and accelerate the search for new treatments. We also explore how these systems shed light on human evolution, the emergence of intelligence, and the ethical questions that come with studying increasingly complex neural models. Chapters / Timestamps (00:00) – Welcome to Sentience (00:24) – Alysson’s journey into stem cell and brain organoid research (03:14) – How organoids model the developing human brain (06:22) – Using organoids to study autism and other neurodevelopmental disorders (09:58) – From lab dish to therapy: translating organoid insights into medicine (13:27) – When organoids begin producing brain-like activity (17:36) – What these systems reveal about intelligence and evolution (21:18) – The ethics of studying increasingly complex neural tissue (26:03) – Biological vs. artificial intelligence: where the lines blur (29:55) – What organoids are teaching us about being human (33:12) – Looking ahead: the future of brain models in science and medicine

  • Oct 8, 2025 · 58 min

    12. Thomas Hartung, PhD on how lab-grown and artificial intelligence can phase out animal testing

    In this episode of Sentience, we talk with Thomas Hartung, PhD, about how organoids and AI are reshaping biomedical science. Hartung explains how AI models can predict the toxicity of chemicals more accurately than animal tests and how organoids—tiny, lab-grown versions of human organs—can stand in for animals in studying disease and drug effects. We explore the concept of organoid intelligence, the ethics of creating brain-like systems, and how these technologies together could make research more humane, efficient, and human-relevant. Timestamps (00:12) – From animal lover to scientist: Thomas’s early journey (03:06) – Replacing a major rabbit test and the origins of modern alternatives( 05:42) – Why AI became the next frontier for toxicology (09:32) – How algorithms can predict chemical safety without animals (13:24) – Thinking in probabilities: a smarter kind of toxicology (16:14) – Designing safer drugs from the start (18:43) – The rise of lab-grown intelligence: what organoids can do (24:01) – From simple cells to living models of the human brain (28:21) – Why brain organoids matter for understanding disease (33:17) – Building connections: assembling mini-brains (36:31) – Organoid intelligence and the idea of biological learning (40:54) – Could organoids ever think? Ethics and embedded responsibility (44:17) – What AI can learn from the brain—and vice versa (48:16) – The road to replacing animal tests: challenges and hope (54:36) – A new era of human-relevant science

  • Sep 25, 2025 · 37 min

    11. Shaolei Ren, PhD on AI’s hidden environmental costs and the path to sustainable computing

    In this episode of Sentience, we speak with Shaolei Ren, PhD, about the hidden environmental footprint of artificial intelligence. From the enormous water and energy demands of data centers to the trade-offs between carbon emissions and cooling needs, Ren explains how his research uncovers these overlooked costs. We discuss geographical load balancing, fairness in resource allocation, brain-inspired computing, and how tech companies can improve transparency. This conversation explores how to build a greener, more equitable future for AI. Timestamps (00:00) – Introduction and Shaolei Ren’s journey into AI and environmentalism (02:10) – The physical reality of AI: data centers, hardware, and energy use (04:10) – Water as the overlooked resource in AI training and cooling (07:59) – Why data centers need cooling and how it drives environmental impact (10:15) – Geographical load balancing: shifting workloads to save resources (13:21) – Trade-offs between carbon footprint and water consumption (15:24) – Algorithms for efficiency and fairness in AI’s environmental impact (17:12) – Defining and measuring fairness across regions (20:37) – How tech companies can improve sustainability and transparency (22:19) – Learning from the brain: energy-efficient, brain-inspired AI (26:06) – Personal use of AI, individual vs. systemic impact, and cost–benefit thinking (29:37) – AI as a tool to fight climate change and optimize renewable energy (30:32) – The future of greener, more intelligent AI systems (34:34) – Public health impacts and power grid considerations (36:35) – Closing thoughts on transparency, user awareness, and a sustainable AI future

  • Apr 12, 2025 · 1 hr 33 min

    10. Barbara Finlay, PhD on how brains develop and evolve

    In this episode, I speak with evolutionary neuroscientist Barbara Finlay, PhD, whose pioneering research has reshaped our understanding of brain evolution. Barbara shares her scientific journey, from her early inspiration in vision science to her groundbreaking discoveries about how brains scale and evolve. We explore how brains self-organize to process sensory information, why humans don't have a uniquely special cortex, and what the evolutionary transition from water to land meant for brain development and consciousness. This conversation dives deep into how evolution shapes neural architecture, uncovering principles that bridge species from sharks to humans, and raises fascinating new questions about consciousness, memory, language, and AI. Whether you're a scientist, student, or simply curious, Barbara’s insights offer a compelling glimpse into the evolutionary story of our own minds. Timestamps: (00:00) – Intro to Barbara Finlay and the premise of the episode (00:32) – Barbara’s early path into neuroscience (08:33) – Introduction to Evo-Devo: how development shapes brain evolution and how evolution shapes brain development (17:20) – Brain scaling laws and how the cortex grows in coordination with the rest of the brain (29:12) – Why the human cortex isn’t special—and what actually makes us unique (36:09) – Language, sociality, and the deeper brain structures that support them (43:12) – Self-organization of the cortex: how brain areas emerge without being hardwired (53:00) – The brain’s hunger for information: from monkeys gaining color vision to human adaptability (59:00) – The limbic system vs. cortex: two distinct computational systems (01:10:00) – Egocentric mapping, the transition from water to land, and the roots of consciousness (01:24:00) – Consciousness, midbrain vs. cortex, and what AI is missing (01:31:00) – Barbara’s current work and reflections on being part of the neuroscience founder generation

  • Apr 2, 2025 · 1 hr 30 min

    9. Glenn Fox, PhD on the science of gratitude

    In this episode of Sentience, neuroscientist Dr. Glenn Fox takes us on a fascinating journey through the science of gratitude. From his pioneering brain-imaging studies on Holocaust survivor testimonies to developing practical frameworks for entrepreneurs, Glenn reveals how gratitude impacts our brains, emotional health, and resilience. We discuss why gratitude is uniquely powerful, especially during difficult times, and how understanding its neural and psychological foundations can transform our personal and professional lives. Tune in for insights into cultivating genuine gratitude—and discover why it's far more profound than simply "feeling happy." You can find Dr. Foxx on Instagram @profGlennFox. Timestamps: (00:00) - Introduction to Dr. Glenn Fox and the neuroscience of gratitude (01:01) - Glenn’s personal journey into studying gratitude (07:43) - Gratitude research: clinical vs. positive psychology perspectives (11:58) - Defining gratitude using the "gift space" model (19:18) - Applying gratitude beyond gift-giving scenarios (32:44) - Differentiating gratitude from other positive emotions like happiness (39:44) - Neuroscience of gratitude: lessons from Holocaust survivor testimonies (54:09) - The role of the mu-opioid system in gratitude and pain relief (1:02:29) - Gratitude’s role in entrepreneurship and managing stress (1:12:23) - Personal reflections on practicing gratitude and creativity (1:20:09) - Current research on stress, challenge, and threat in entrepreneurship (1:26:12) - Final thoughts: Cultivating gratitude through fun and creativity

  • Nov 12, 2024 · 1 hr 5 min

    8. Farah Lubin, PhD on epigenetics and the brain

    In this episode, I sit down with Dr. Farah Lubin, a neuroscientist from the University of Alabama at Birmingham, to explore the fascinating world of epigenetics in the brain. Dr. Lubin shares her groundbreaking research on how gene expression can influence memory formation and neurological disorders like epilepsy. We also discuss how understanding these mechanisms could lead to novel therapies, along with the transformative power of epigenetics in brain science. Follow along as Dr. Lubin walks us through her unique career journey and sheds light on the evolving field of neuroepigenetics. Timestamps: (00:00) - Introduction to Dr. Farah Lubin and her research on epigenetics (06:00) - Epigenetic mechanisms: DNA methylation and histone modifications (09:00) - Epigenetics and brain plasticity in memory and learning (12:00) - The role of DNA methylation in gene expression and memory (18:00) - Epigenetics and the consolidation of long-term fear memories (25:00) - How brain-derived neurotrophic factor (BDNF) is influenced by epigenetics (30:00) - The role of epigenetics in epilepsy development and resilience (35:00) - Methionine supplementation and its potential impact on memory (40:00) - The importance of environmental influences on the epigenome (46:00) - Future directions in epigenetics: new sequencing technologies (52:00) - Funding challenges in neuroscience research and the value of basic science (56:00) - Advice for students interested in neuroscience and epigenetics

  • Nov 7, 2024 · 1 hr 6 min

    7. Gill Livingston, MD on preventing dementia

    In this episode, I chat with Dr. Gill Livingston about her groundbreaking research on dementia. Dr. Livingston has played an important role in uncovering the lifestyle, environmental, and genetic factors that contribute to our risk of developing dementia. Follow her on X @Gill_Livingston for more insights. Timestamps: (00:00) - Introduction to Dr. Gill Livingston and Her Research on Dementia (00:30) - Dr. Livingston's Career Path and Inspiration for Dementia Research (06:35) - The Lancet Commission on Dementia Prevention and Key Findings (09:53) - Understanding Dementia’s Preventability and Main Risk Factors (12:22) - Hearing Loss and Other Key Dementia Risk Factors (22:45) - Blood Pressure, Air Pollution, and Dementia Risk (29:44) - Amyloid Beta and Tau’s Role in Alzheimer’s Disease (36:59) - Cognitive Reserve and the Impact of Education on Dementia Risk (41:12) - Genetics in Dementia: APOE4 and Other Risk Genes (46:24) - The Immune System’s Role in Alzheimer’s and Potential Treatments (50:12) - Policy Implications for Dementia Prevention (01:04:01) - Dr. Livingston’s Ongoing Research

  • Sep 25, 2024 · 1 hr 12 min

    6. Athina Demertzi, PhD on the neuroscience of consciousness

    In this episode, I had the pleasure of speaking with Athina Demertzi, PhD, a neuroscientist at the University of Liège who studies human consciousness, especially in patients with severe brain injuries. We discussed her fascinating work on disorders of consciousness like the vegetative and minimally conscious states, and how brain imaging techniques have advanced our understanding of these conditions. We also talked about some treatments people have proposed for these conditions, including psychedelics. Timestamps: (00:00) - Introduction and Background (01:58) - Defining Disorders of Consciousness: Coma, Vegetative, and Minimally Conscious States (05:13) - Using Neuroimaging to Study Consciousness in Brain-Injured Patients (07:36) - Predicting Recovery from Disorders of Consciousness (09:51) - Auditory and Visual Cortex Communication in Conscious Patients (15:16) - The Role of the Default Mode Network in Consciousness (20:14) - Phase Coherence and Communication Across the Brain (26:34) - Functional vs. Structural Connectivity in Consciousness (28:24) - Theories of Consciousness: Global Workspace, Integrated Information, and Active Inference (35:44) - Body-Brain Interactions in Anesthesia and Unconscious States

  • Aug 30, 2024 · 1 hr 14 min

    5. Stephen Coombes, PhD on neural field theory

    In this episode, I talk with Stephen Coombes, Ph.D. about neural field theory, or the theory of brainwaves. Dr. Coombes is Professor of Applied Mathematics in the School of Mathematical Sciences at the University of Nottingham. We explore the foundations of neural field theory, how it models large-scale brain activity, and its relevance to understanding states of consciousness, visual hallucinations, and working memory. Dr. Coombes shares insights from his journey from theoretical physics to neuroscience, and we discuss the future directions and challenges in this fascinating field of study. Timestamps: (00:00) - Introduction to Neural Field Theory (02:05) - Dr. Stephen Coombes’ Journey to Neuroscience (10:06) - What is Neural Field Theory? (16:22) - Why Model Average Firing Rates? (24:00) - History and Evolution of Neural Field Theory (32:12) - Mean Field Models vs. Neural Mass Models (36:16) - Patterns in Neural Field Theory: Waves, Bumps, and Turing Patterns (44:54) - Neural Field Theory as a Space-Time Model (45:54) - Neural Field Theory and Visual Hallucinations (50:06) - Working Memory and Neural Field Theory (53:18) - Advances in Neural Field Theory (59:53) - Recent Challenges and New Directions (1:06:16) - The Future of Neural Field Theory (1:09:34) - White Matter Plasticity and Its Role in Neuroscience (1:12:28) - Closing Remarks and Resources

  • Jun 14, 2024 · 1 hr 10 min

    4. Jay Skelton, PhD and Andrew Leker on AI for mental health

    In this episode I talk with clinical psychologist Jay Skelton, Ph.D. and software engineer Andrew Leker about Willow. Willow is a new, empathetic AI specifically designed to be a mental health tool (and not a replacement for a licensed therapist). We take a deep dive into how Willow was trained, how strict safety guardrails were put in place, how Willow is already being used in mental health clinics, its privacy, and the future of AI for mental health. This podcast came out of a partnership with Bambu AI. Timestamps: (00:00:00) - Trigger warning for mental health discussions (00:01:17) - My interest in Willow AI (00:02:54) - Andrew Leker introduces himself (00:04:05) - Jay Skelton, Ph.D. introduces himself (00:05:32) - Willow's role in mental health (00:06:44) - Discussing Willow's design as an empathetic and curious agent (00:07:34) - Importance of empathic interaction in mental health support (00:09:04) - Willow's non-judgmental approach (00:09:24) - Shaping Willow's empathetic identity (00:12:16) - Real conversations in Willow's training (00:14:04) - Evidence-based practices in Willow's training (00:16:36) - Willow does not diagnose, just assists (00:17:54) - Safety in Willow's interactions (00:19:00) - Technical safety features in Willow (00:24:33) - Handling suicidal ideation cautiously and safely (00:26:59) - Jay's comfort as a clinical psychologist with deploying Willow (00:30:00) - Willow's deployment in mental health clinics (00:33:24) - AI's availability and affordability (00:36:40) - Willow providing emotional support and guidance (00:39:53) - Willow as a mental health tool (00:45:38) - Privacy and security in Willow (00:51:18) - Willow's potential for improvement over time (00:52:10) - Benefits of Willow's feedback for therapists (00:54:43) - Future applications of AI in mental health (00:57:32) - Empathy and theory of mind in AI development (01:00:54) - Importance of Willow's emotional intelligence (01:07:48) - Positive feedback from patients using Willow

  • May 31, 2024 · 1 hr 10 min

    3. Michael Treanor, PhD on the science of cognitive-behavioral therapy

    In this episode, I talk with Michael Treanor, PhD about the science of cognitive-behavioral therapy, and its foundations in the psychology and neuroscience of learning and memory. You can find out more about Dr. Treanor's clinical practice at https://www.cacenterforanxietytrauma.com/.

  • Mar 5, 2024 · 44 min

    1. Minimally conscious patient meets scientist who woke him up

    Bradley Crehan wasn't regaining consciousness after his brain injury, but then he became the first person in the world to receive an experimental treatment developed at UCLA by Martin Monti, PhD and his colleagues. You can support our research here: https://thebrainscientist.com/donate/

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