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Machines Like Us

Giulio Tononi

Giulio Tononi is a psychiatrist and neuroscientist who has held faculty positions in Pisa, New York, San Diego and Madison, Wisconsin, where he is Professor of Psychiatry. Dr. Tononi and collaborators have pioneered several complementary approaches to study sleep. These include genomics, proteomics, fruit fly models, rodent models employing multiunit / local field potential recordings in behaving animals, in vivo voltammetry and microscopy, high-density EEG recordings and transcranial magnetic stimulation in humans, and large-scale computer models of sleep and wakefulness. This research has led to a comprehensive hypothesis on the function of sleep, the synaptic homeostasis hypothesis. According to the hypothesis, wakefulness leads to a net increase in synaptic strength, and sleep is necessary to reestablish synaptic homeostasis. The hypothesis has implications for understanding the effects of sleep deprivation and for developing novel diagnostic and therapeutic approaches to sleep disorders and neuropsychiatric disorders.

Another focus of Dr. Tononi's work is the integrated information theory of consciousness: a scientific theory of what consciousness is, how it can be measured, how it is realized in the brain and, of course, why it fades when we fall into dreamless sleep and returns when we dream. The theory is being tested with neuroimaging, transcranial magnetic stimulation, and computer models. In 2005, Dr. Tononi received the NIH Director's Pioneer Award for his work on sleep mechanism and function, and in 2008 he was made the David P. White Chair in Sleep Medicine and is a Distinguished Chair in Consciousness Science. His work has been described as "the only really promising fundamental theory of consciousness," by Christof Koch.

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Giulio Tononi Quotes

Subjective experience is one and the same thing as a system's capacity to integrate information.

Consciousness … does not require language. Nor does it require memory. Or perception of the world, or any action in the world, or emotions, or even attention.

What our brains are good at is being flexible, learning from experience and adapting to different situations.

I would be happy to create a mouse brain. A mouse brain is quite remarkable. And from there, it shouldn't be too hard to scale up to a rat brain, and then a cat or monkey brain.

Strikingly, in the sleep-deprived brain, subsets of neurons go offline in one cortex area but not in another – or even in one part of an area and not in another.

Based on a theory about how consciousness is generated, we expect to see a response that is both integrated and differentiated when the brain is conscious. When there is a loss of consciousness, either due to sleep or anesthesia, the response is radically different. We see a stereotyped burst of activity that remains localized and fades quickly.

One practical application would be a test to help assess how conscious a patient is. We want to know whether a person is really there, and to us, it is important that the method is grounded on a theoretical model of what is required for consciousness.