Square A and square B are exactly the same shade of gray. So, scratch "objective reality" off the list of things you're personally in contact with.
Two amazing videos recently appeared in the prestigious journal Science.
The first is an animation showing the detail in a (glutamatergic) synapse.
The second video, based on hundreds of electron micrographs stitched together, shows the impossible complex ultrastructure of the neuropil — the impenetrable forest surrounding synapses. (Even the great Cajal was blown away!)
The key question is — how much of that fine detail must be modeled to replicate the brain's performance? My confident assertion is that much more is required than is incorporated into current brain-inspired AI models. (Multi-layer convolutional neural nets are just one piece — even when combined with reinforcement learning.)
These are my detailed notes on the many lectures I attend every week at Stanford: neuroscience, psychology, AI, cardiology, and molecular biology. These feature cutting edge research by our faculty, students, and visiting superstars. My WebBrain contains hundreds of archived lecture notes (last updated January, 2020).) To obtain more recent notes, contact me.
Living in Silicon Valley, I'm used to watching Google's self-driving cars dodge me as I ride around town on my electric bike. But, are they conscious?
No (not yet!) But, here I address what it will take to make them conscious — and, why would you bother? Also, what's the difference between machine vision and mammalian visual perception? Led by advances in neuroscience, computer vision researchers are rapidly accelerating (but have quite a ways to go.)
I've been fascinated by the neurobiology of consciousness for fifty years.
How is it possible for neural circuits to produce pain, pleasure, and our entire perceived world?
Consciousness is the master illusion — the engineering product of hundreds of millions of years of evolution.
Except for career excursions into medicine and into computer science, my central interest for decades has been in two questions —
This is an outstanding work by one of the world's top researchers of consciousness. Since the death of William James and the mid-20th century ascent of Watson, Thorndike, and Skinner, consciousness all but disappeared (as a field of study) from American psychology. Europeans, especially the brilliant Stan Dehaene, are leading the current revitalization.
This is a must-read for neuroscientists and psychologists.
In 2010 I gave a presentation at the Bay Area AI Meetup.
Here's the video (thank you, Monica!) This is for a (non-neuroscience) general audience.
In this broad overview I stress the obvious critical role played by consciousness for our survival.
I introduce comparative neuroanatomy and discuss (in broad terms) the phylogeny of consciousness
Consciousness confers a pivotal advantage in a fiercely competitive and changing world.
(See my essay: The Mystery of Consciousness: Introduction.)
Here's what my head-freezer friends have signed up for the minute they die. Agents from Alcor will lop off the head of the deceased and (after some prep) will drop it into a tank of liquid nitrogen for eternity (until the person can be resurrected.) I haven't signed up with Alcor, but ask me again in 2030.
But meanwhile, I'm on the Science Advisory Board of the Brain Preservation Foundation (BPF), which seeks to advance the state of the art by awarding cash prizes for best research. "But, you ask, "are you for real?" The answer is "yes (maybe!)"
Here, neuroscience MD, PhD candidate Andy McKenzie elicits my opinions. In brief: molecular whole brain preservation may be possible by 2040. Resurrection in silicon may not be possible (if ever) until well after 2100. (So, keep eating vegetables and exercising — that's my best longevity advice for now!)
By the way, we just awarded our BPF small mammal cash prize to Robert McIntyre, who spearheaded the team at 21st Century Medicine. If you want to see the state of art, look at his work Aldehyde Stabilized Cryopreservation in Cryobiology.
2018 Update: Robert McIntyre also founded Nectome, a company promoting end-of-life euthanasia to facilitate brain preservation for the purpose of future brain uploading. He had a research collaboration with MIT superstar neuroscientist Ed Boyden that MIT just terminated. Although McIntyre's brain preservation techniques are very real and "cutting edge" as is Boyden's neuroanatomical research, the notion of brain uploading to resurrect consciousness is fanciful science fiction. But, the future is not yet written.
Out in the desert foothills of Tucson in 2010, I interviewed NDE researcher and cardiologist, Pim Van Lommel, who organized the largest study of NDEs thus far.
My view is that the patients studied by Dr. Van Lommel were genuinely conveying their experiences, but their perceptions were hallucinatory.
Dr. Van Lommel believes they were quite real and that the patients were actually seeing events outside their bodies. He believes this requires a fundamental revision of neuroscience and physics. I doubt it.
In 2008 I went to the Amazon on a trip with the Center for Inquiry (CFI). (Normally, I don't go anywhere that can't be reached by bike.)
The world famous Harvard cognitive scientist, Steven Pinker, was our guest lecturer.
This is a photo essay about the trip, Steve, Paul Kurtz (CFI's Founder and leading luminary), and our traveling band of skeptics.
This (seemingly sci-fi) proposal to map every single spike in every neuron was batted around in mid-2012 by Kavli Foundation scientists. I got wind of it shortly thereafter and circulated it around Stanford, where it aroused considerable skepticism
But, one of the neuroscientists who took it seriously was Professor Bill Newsome, a co-chair of our Stanford Neurosciences Institute.
Roll the clock forward to January, 2013. Unbeknowst to us, this proposal had become the centerpiece of President Barack Obama's State of the Union — his ten year moonshot.
Next, roll the clock to April, 2013. Prof. Newsome gets a call from NIH Director Francis Collins asking him to co-chair the working committee to formally draft the proposal. How was I so clairvoyant? A combination of paying close attention and luck.
This is my review of Kevin O'Regan's 2011 book, thus titled.
This is a beautifully written book, which, unfortunately, Oxford Press has overpriced. Similar material (by the author) is, however, freely available online.
Sensorimotor theory (SMT), while generative, has essential flaws.
Nonetheless, the book itself is a clear, delightful introduction to the problems posed by qualia, which "color" everything we know.
In 2009 I reviewed this key paper from Stan Dehaene's group on the neural correlates of consciousness.
His research was conducted on ten human subjects using intracranial electrode arrays (ECoG.)
Electrocorticography presents a rare opportunity to track consciousness in real-time (milliseconds). MRI BOLD signal, developing over seconds, is usually too slow — although it does provide the "big picture."
The article claims that consciousness is a global reverberatory state involving all cortical lobes.
Even better than this paper is Professor Dehaene's 2014 book Consciousness and the Brain which greatly expands our knowledge of the neural mechanisms underlying consciousness.
This is a letter I sent to MIT's Technology Review in 2007 responding to an article by Yale computer scientist David Gelernter: Artificial Intelligence Is Lost in the Woods in TR in July/August 2007..
(In the first epoch of Bob (1965 to 1990), AI was lost in the woods. Now (thanks to the resurgence of neural nets,) it's doing much better.
Some nervous nellies are worried that AI's making too much progress — and that soon it may pose a threat.)
I say "bring it on, baby!" (Autonomous humans are the big threat!)
A brief bio I wrote a decade ago about my life-long interest in the mind/body problem.
Woody Allen would say, "which is it better to have?"
A chapter length autobiography of my interest in the mind/brain and software/computer relationship (downloads as a WORD document.)
I was writing this for a book. My current view is that books are almost obsolete.
Why buy a book when you can read stuff free on the web? (And, the public's attention span is at most a month. As an author, why bother?)
As an old guy, however, all my life I've enjoyed reading a book at bedtime (and actually turning the pages.) I'm now re-reading Kevin Kelly's What Technology Wants. I also love all of Steve Pinker's books.
Another chapter length essay (an early draft) on the power of knowledge.
Yes, intelligence is multi-dimensional — academic, social, emotional, motoric, spiritual , but that's later.)
This is an unsolicited, unpaid testimonial for TheBrain, a software program I use to keep track of everything. This program is so useful, it gets its on monitor in my four monitor set-up.
I've used TheBrain for a decade. A quite handy version is available for free.
By the way, I've repeatedly refused solicitations to carry ads of all sorts on my website.
I take my inspiration from philanthropists Jimmy Wales (Wikipedia founder — Jimmy gave it away!) and from Craig Newmark (Craigslist founder.)
All lines are parallel (including the horizontal ones) in the Cafe Wall Illusion.
Objective reality is out there, but it can't be experienced — ever.
This YouTube of an unfixed brain is a must-watch! Here, Suzanne Stensaas, Professor of Neurobiology (Univ. of Utah) shows us a fresh autopsy brain of a young woman who died of cancer.
Only in this superb, rare video do you see the supreme fragility of the brain. It has the firmness of custard or jello. (Most formalin-fixed brains feel like they're made of rubber — big conceptual error.) The bottom line: forget all high-impact sports!Here, Suzanna Herculano-Houzel tells us how many neurons each of us has. The answer is about eighty six billion. She knows — she was the first one to count them. Sixteen billion in the cerebral cortex. (I don't fully buy her explanation about the evolutionary importance of cooking. But she's right that our brains are high-maintenance organs. They require about 20% of our blood flow and about 20% of our calories.)
British child prodigy Alma Deutscher not only plays violin and piano superbly (here at age 11) but has been composing and orchestrating entire sonatas and operas for years.
Here she reveals the secret that unlocks her creativity: "waving around a skipping rope." Say what?
OK, neuropsychologists — good luck figuring that out! Alma needs to be included in every account that attributes creativity to mere practice. So does child math genius Terry Tao. Practice just shapes and polishes the biological diamond.
In this series Charlie Rose was joined by Nobel Laureate Eric Kandel to interview some of the top U.S. neuroscientists on childhood neural development, depression, social interaction, perception, cognition, emotion, learning, memory, and other topics. (Nov 20, 2017: Charlie Rose's tragic downfall — nonetheless his previous work still stands.)
BTW, how do you get to be age 87 (Dr. Kandel) and be one of the smartest, most productive men alive? I asked him, "What's your secret?" And, he told me about his diet. He eats mainly vegetables (and some fish,) and exercises daily (swimming and tennis.) He also has a great sense of humor and is wonderfully optimistic.
Want to see the talks presented by the world's top neuroscientists, to the world's top neuroscientists — there's a great collection here. Microsoft founder, Paul Allen, funds two of my favorite institutes: 1) the Brain Institute and 2) the Allen Institure for AI (AI2.) Between the two of them, they should be able to crack this pesky mind/brain thing!One of my favorite videos is Terry Sejnowski's talk in 2011. Start at minute 7 or 8. Then watch as he narrates a spectacular reconstruction of a cube 6 microns on a side of hippocampus. (You can see the video Waltz thru the Hippocampus but you'll miss Terry's essential narration.)
QualiaSoup is an anonymous video producer. All his brief videos are outstanding.
In 2010 we celebrated the centennial of one of America's greatest psychologists, philosophers, and intellectuals: William James.
At the close of the 19th century, James was the towering intellectual of America and certainly our preeminent psychologist. He was a great champion of consciousness — the defining characteristic of humanity.
With James' passing in 1910, psychology entered a Dark Age that cast out consciousness as an object of study and even questioned its reality. Fortunately, in the past few decades that insanity has lessened.
Read about William James.
And, here's another excellent bio in the Stanford Encyclopedia.
William James' most important work was his 1200 page the Principles of Psychology published in 1890. Two years later in 1892, he published an abridged version for the classroom called Psychology: The Briefer Course. (The 1200 page work is known as James; the briefer (480 page) summary is known as Jimmy.)
Bask in James' insights and erudition. (He turns a phrase as pleasingly as does his younger brother, novelist Henry James.)
Principles of Psychology is here.
Psychology: The Briefer Course is here.
And here is the first 32 pages.
And, completely here as a 38 mb download.
Here is James' brilliant chapter on Consciousness of the Self.
"A man's Self is the sum total of all he can call his, not only his body and his psychic powers, but his clothes, and his house, his wife and children, his ancestors and friends, his reputation and works, his lands and horses, and yacht and bank-account." (James neglected to mention a "man's website!")
Speaking of William James, this index compiles many links to must-read papers of his as well as to papers by Gordon Allport on personality, Aristotle on memory, Al Bandura on aggression, Binet on intelligence, Cattell on mental testing, Darwin's Descent of Man, George Miller on memory, Plato on the psyche, and others.
Change blindness is a fascinating window into the limits of conscious awareness. Subjective and consensus reality are different, sometimes spectacularly so. The above link shows a Londoner asking for directions. and another at Harvard (This wouldn't happen at MIT!) And another with a basketball team. Also, read the wiki on change blindness.
The above is an extensive collection of stunning optical illusions.
To quote the great anatomist, Purkinje, "Illusions of the senses tell us the truth about perception." The brain constructs the visual world from fleeting images. Occasionally, it gets it wrong — and when it does, it's revelatory!
In speech understanding, the brain combines what we hear with what we see. The McGurk effect shows what happens when lip-reading is combined with hearing..
Our individual, conscious universe is just our own brain's attempt to make sense of the world, as it combines sense data past experiences.
Here's another great set of illusions from Gizmodo.).
Most of our vision is done with a tiny (1 mm) portion of the retina called the fovea , in which cone cells are packed tightly together. Although the fovea is less than 1% of the retina, it takes up over 50% of the visual cortex in the brain.
To create our visual world, then, we must continually shift our gaze by changing our visual fixation about 3 to 4 times per second in visual saccades or jumps. Neuroscientists use eye trackers to determine where and at what the subject is looking from moment to moment. These videos from ISCAN will show you the state of the art: looking close and far; indoors and outdoors.
I love autostereogram. See them above or here: search Google images for autostereograms.
The brain perceives the hidden image by making pixel by pixel comparisons of the depth disparity detected by the right and the left eye. Our visual systems are infinitely more complex than mere cameras.
Psychologist Susan Blackmore studied parapsychology as a wannabe believer for decades. Parapsychology embraces the likes of telepathy, telekinesis, and remote viewing. Unfortunately, the study of consciousness has been tainted by association with it.
The study of consciousness is far too important to be tainted by association with pseudoscience and superstition. Besides, nowadays we have cell phones — telepathy is obsolete!
In the above essay Sue explains Why I have given up (on parapsychology). (The wonderful Paul Kurtz, founder of the Center for Inquiry, edited the volume.) I joined Dr. Kurtz and CFI for a trip to the Amazon with Prof. Steve Pinker..
Pseudoscience is an appropriate context to transition to clinical use of SPECT scans.
My tv viewing — not all of it is high-brow — is immeasurably elevated by PBS's wonderful shows like NOVA and Nature.
But, occasionally — especially during PBS pledge drives— I'll see some shows that look more like cable tv infomercials. One such is Daniel Amen's Change Your Brain, Change Your Age .
I appreciate and greatly approve of psychiatrist Amen's emphasis on brain health measures — physical and mental exercise, nutrition, sleep, freedom from anxiety, depression, stress, toxins, and toxic relationships. These topics deserve his polished and entertaining style. However, the part of the program that makes me wince is his focus on the clinical use of SPECT scans as a means of diagnosing mental disorders.
Spect scans are expensive; they involve radiation; and they have limited diagnostic value.
Excellent critiques of Amen's extensive and lucrative use of SPECT scans and supplements of unproven efficacy have been published.
First is this detailed critique called Brain Scam by Dr. Robert Burton, former Chief of Neurology at Mt. Zion/UCSF.
Second, is this critque by Dr. Harriet Hall in QuackWatch. According to Dr. Hall, Amen sicced his lawyers onto QuackWatch — not exactly the way we like to see truth emerge in the academic world of peer-review and falsifiability.
Amen's zeal for SPECT Scans is understandable from a self-enrichment standpoint. One also assumes that skepticism and falsifiability were not emphasized at Oral Roberts Medical School, where he got his degree.
I agree with his commonsense advice on brain health, but skip the SPECT Scans, unless you have money to burn.
(Note to older readers: a carotid ultrasound was life-changing for me).
And a note to PBS. Every night on NewsHour, you have opponents that debate controversial issues. Viewers expect that level of intellectual honesty from PBS. It'd be easy to include dissenting opinions when running shows like Amen's.
I love this TED video by Josh Klein, who built a vending machine for crows. They are incredibly intelligent tool users. When I backpack, I observe the Clark's Nutcrackers, another of the Corvidae. They can remember thousands of seed caches. Never call someone a bird-brain, unless you mean it as a compliment. Are birds nonconscious robots driven by instinct? Forget it! Check out this snow-boarding crow! Or, this crow using cars to crack nuts.
Check out Ayumu, a young lab chimp, who outperforms college students at a brief numerical video game. Ayumu and the other young chimps all outperform the students at this test of visual memory.
With 200 million fibers, the corpus callosum is a huge cable connecting the two hemispheres of the brain. In this wonderful clip from Scientific American Frontiers, Alan Alda (of MASH fame) interviews famed neuroscientist Michael Gazzaniga as he tests one of his split-brain patients. The results are amazing and informative.
This little girl was developing normally when at age 3 she began to have uncontrollable grand mal seizures. To cure her, neurosurgeons removed her entire right hemisphere! In this five minute YouTube, she and her parents are interviewed on Today at NBC by Ann Curry and Nancy Snyderman.
In this masterfully concise and amusing video, Stanford's Prof. Phil Zimbardo shows how our individual perspectives on time affect our work, health, and well-being. Time influences our personal identities, our relationships, and our world views.
Superb and charmingly illustrated lessons on overcoming our foibles
A brief video on where intelligence is in the brain.
Professor Aron Barbey (University of Illinois, Urbana/Champaign,) who led the research team, narrates it. He shows which voxels light up on fMRI during intelligence tests in men with focal brain damage. His team correlated the imaging with the participants Wechsler Intelligence scores and with their Delis-Kaplan Executive scores. This study appeared in 2012 in Brain and used 182 Vietnam veterans with highly localized brain lesions from penetrating trauma.
As expected, the left frontal, temporal, and parietal cortices predominate — and their connecting fiber tracts.
But note, making the inference that those active brain regions are causing the associated behavior is quite a leap! (Defense lawyers regularly try to sucker juries with that argument. "Look at this scan — his brain made him to do it!"
Stanford's Professor Russ Poldrack articulately warns us against blithely (and most often falsely) making that inference.
Sex works even better than chocolate.