Curiosity Weekly – "Is a Lab-Grown 'Brain' Conscious?"

Host: Dr. Samantha Yammine
Guest: Dr. Daniel Toker (UCLA neuroscientist)
Air Date: September 10, 2025
Runtime: ~16 minutes (excluding ads and credits)

Episode Overview

In this kickoff to Curiosity Weekly’s two-part "Brain" series, neuroscientist Dr. Samantha Yammine explores mind-bending questions about the nature of consciousness, especially in relation to lab-grown "mini-brains" (organoids). She’s joined by Dr. Daniel Toker, a UCLA researcher at the intersection of neuroscience, AI, and brain organoid studies. Together, they unpack what consciousness is, how it’s measured in the clinic and the lab, and whether organoids might ever cross the threshold into sentience—with surprising and accessible explanations for listeners of all backgrounds.

Key Discussion Points & Insights

[01:26] Setting the Stage: Why Study the Brain and Consciousness?

• Dr. Yammine’s personal intro: Enthusiasm for neuroscience, briefly mentioning common mistakes (e.g., saying “you too” to a server) to illustrate the brain's “error alarms.”

  • The anterior cingulate cortex (ACC) is highlighted as key for noticing and responding to errors:

    "Next time that happens, you can thank one of my favorite parts of the brain, the anterior cingulate cortex, or ACC for short." – Dr. Yammine (03:06)

  • ACC’s role in anxiety, OCD, and dementia: too sensitive or too quiet error signals can cause clinical symptoms (03:36–04:10).

• Reflecting on different states of consciousness: Sleep, flow, grogginess, and disorders such as epilepsy and coma are connected under the broad banner of “what is consciousness?” (04:11–04:36)

[05:33] What Is Consciousness, and Where Does It Live?

• No “consciousness spot” in the brain:

  “There's not really a single consciousness spot in the brain...there are some highly vulnerable areas...if you damage those...you will become unconscious, or go into a coma. That doesn’t necessarily mean that’s where consciousness lives.”
  – Dr. Daniel Toker (05:43)

• Networks, not centers: Damaging select areas creates bottlenecks, but broader networks drive conscious experience.

[06:09] Measuring and Detecting Consciousness

• Behavioral and technological approaches:
  • Clinically, responsiveness is measured using scales like the Coma Recovery Scale-Revised—but it’s imperfect (07:23–07:41).
  • For unresponsive patients (e.g., locked-in syndrome) MRI is used:

    “Some patients, you can ask them, hey, imagine playing tennis...that area [premotor cortex] will light up...for most vegetative patients, nothing happens. But a small subset...that part of their brain will light up, which tells you that they can hear you and they can do what you’re asking.”
    – Dr. Daniel Toker (06:16–07:17)

[07:41] Lab-Grown Brain Organoids: What Are They?

• Definition and Usefulness:

  “A brain organoid is basically this thing that we grow out of stem cells...we just coax them into becoming brain cells and grow them in a clump...they can model different parts of the brain.”
  – Dr. Daniel Toker (08:04)

  • “Mini-brain” is a misnomer; organoids are “brain-like tissue” but not brains in a dish (08:24).

• Applications:

  • Study brain waves in disease models (e.g., epilepsy)
  • Test response to medications at the cell circuit level, bypassing animal model limitations (08:58–09:25)

• Electrophysiology:

  “Certain types of brain organoids will generate these electric waves that kind of resemble our brain waves...could be really useful for studying things like epilepsy or coma…”
  – Dr. Daniel Toker (08:36)

[09:46] Ethical Boundaries: Could Organoids Be Conscious?

• Ethical grays emerge with added complexity:

  “Things start to get murkier when you give the organoids sensory input...You can have...that paper where organoids learn to play pong...if we're starting to allow them to interact with their environment and they can start learning, that's when I think things get a little murkier.”
  – Dr. Daniel Toker (09:58–10:22)

• Current consensus: Organoids without sensory input or learning remain clearly non-conscious and ethical to experiment on.

[10:22] Artificial Intelligence & Simulations: Modeling Consciousness

• Why use ‘in silico’ or digital models of brains?

  “Most animals can’t really go into a coma...So we can't really model these disorders or diseases....What if we developed a whole brain model that can accurately capture what's happening in these different states..."
  – Dr. Daniel Toker (10:52–11:31)

• Key benefit: AI can pinpoint critical networks (e.g., specific tracts in the basal ganglia driving coma), sometimes outperforming human intuition and validated against brain scans:

  "And the AI was saying, 'Hey, I think this particular [basal ganglia pathway] is the more relevant one to look at.' And...that specific track of connections that the AI was pinpointing did seem to be more selectively damaged in these patients."
  – Dr. Daniel Toker (11:47–12:33)

• Clinical potential:

  "You could just record their EEG, feed it to the AI, the AI can output how awake they are."
  – Dr. Daniel Toker (13:06)

[13:31] Dr. Toker’s Path to Neuroscience

• Origin story:

  "I just was sitting there in class and it just kind of hit me. Oh, my God. All my conscious experience comes from chemical reactions. What? I never stopped thinking about it."
  – Dr. Daniel Toker (13:34)

  • Motivation: curiosity about consciousness, desire to connect high-level measures to the microscopic (cellular/circuit level).

[16:30] Bonus Segment: How Many Senses Do Humans Have?

• Beyond the classic five senses:

  “Close your eyes, reach your arms out wide, and now with your thumb, touch the tip of your nose. Did you get it on the first try? ...that's because most of us have an awareness of how our bodies are positioned in space. But what sense allows us to do that? ...It's a different one called proprioception.”
  – Dr. Samantha Yammine (16:30)

  • Explains proprioception and interoception as “hidden” senses responsible for body position, hunger, heartbeat, etc.
  • Some argue there are as many as 20–30+ senses, depending on scientific definitions. (17:50)
  • Applications: Research in these senses informs prosthetics, pain treatments, and understanding conditions like synesthesia.

Notable Quotes & Memorable Moments

• On the ACC and error detection:

  "They're meant to help us clock mistakes quickly so we can course correct before they become a bigger problem."
  – Dr. Samantha Yammine (04:10)

• On consciousness in organoids:

  "I think if we're starting to allow them to interact with their environment and they can start learning, that's when I think things get a little murkier."
  – Dr. Daniel Toker (10:12)

• On the promise of AI brain models:

  "The AI was saying, 'Hey, I think this particular [basal ganglia] pathway is the more relevant one,' ...and it did actually turn out...that the AI was pinpointing the correct [network]." – Dr. Daniel Toker (12:11–12:33)

Timestamps for Key Segments

• [01:26] – Introduction, the brain's "error alarm," and the role of the ACC
• [04:36] – Consciousness, flow states, sleep, and disorders
• [05:33] – Is there a consciousness “spot” in the brain?
• [06:09] – How do we measure if someone is conscious?
• [07:41] – Brain organoids explained and their scientific value
• [09:46] – Ethical concerns: could organoids be conscious?
• [10:22] – Using AI and computer models to simulate consciousness
• [13:31] – Dr. Toker's motivation and path in neuroscience
• [16:30] – How many senses do we really have? Proprioception and beyond

Episode Tone & Style

• Conversational, approachable, and energetic: Both Dr. Yammine and Dr. Toker bring enthusiasm, making complex neuroscience relatable via analogies, humor, and real-life examples.
• Informative but never condescending: The episode balances depth with accessibility, ensuring listeners understand both the “how” and “why” behind cutting-edge research.

For further learning: Follow Dr. Daniel Toker at @thebrainscientist on Instagram and TikTok.

This episode is essential listening for anyone fascinated by the frontiers of neuroscience, bioethics, and artificial intelligence, offering a thorough yet inviting primer on brain organoids and the mysteries of consciousness.