Discover 3

March 2018^ DISCOVER^47

BRAD BUHR

to. His team discovered that tubulin proteins were among

them, and then found that if a kind of reverse agent were

administered — a microtubule-stabilizing drug — so were

the anesthetic effects. He remains a critic of Hameroff ’s

“speculative” theories, but says his research suggests micro-

tubules might play “some role” in consciousness.

Yet Hameroff remains controversial. Koch, the brain

researcher and consciousness expert, declined to comment,

saying he doesn’t want to be the “eternal critic” everyone

goes to for takedowns of the Hameroff-Penrose theory. But

some are coming around.

“I was always quite skeptical of Stuart’s claims about

microtubules,” says Anthony Hudetz, a neuroscientist in the

anesthesiology department at the University of Michigan.

“But now there is data. And I have to say, I think Stuart

does have some momentum now.”

Hudetz sees microtubules as a good potential mechanism

for explaining anesthesia. “I have the feeling that this whole

microtubule theory has matured actually quite nicely,” he

says. For Hudetz, the key going forward is testing whether

molecular events inside microtubules actually relate to the

quantum events as Hameroff proposes.

And now, two scientists working independently of one

another, yet both openly inspired by Hameroff, are taking

microtubule research to a whole new level.

INSIDE THE NEURON

Anirban Bandyopadhyay summarized his research in a talk

at Hameroff ’s 2016 Science of Consciousness conference.

Six feet tall and slim with dark, black hair and a broad,

joyful smile, Bandyopadhyay enjoys a plum job for a

scientist in his early 40s, leading his own research group

at the National Institute for Materials Science

(NIMS) in Japan. As a physicist, he’s studied

the inner workings of both natural and

artificial brains. To understand brain

function, Bandyopadhyay believes

scientists must understand the work-

ings inside the neuron, including the

microtubule.

The conventional view is that neu-

rons fire when a channel within the

cell membrane opens, flooding the

neuron with positively charged ions.

Once a specific threshold is reached, an

electrical signal travels down the axon —

the nerve fibers within the neuron — and

the neuron fires. Axons are long wires that con-

nect neurons to other cells. And inside each axon is a

bundle of nanowires, including the microtubule.

Bandyopadhyay found that he could apply one of these

specific charges to the microtubule, causing activity to

build up in the neuron. By allowing the current to con-

tinue, he could cause the neuron to fire, or — by cutting

the signal off — stop it from firing altogether.

He says this bundle of nanowire resonates like a guitar

string, firing thousands of times faster than normal activ-

ity in a neuron. The neuron, he thought, contrary to all

current scientific understanding, wasn’t

the essential, or first cause of the human

thought process.

“[Neuroscientists] need to go deeper —

into the microtubule,” he says.

To Bandyopadhyay, modern brain

science’s emphasis on the neuron is

misguided. Brash at times, he refers to

neuroscience as akin to dermatology.

“The neuron is the skin,” he says. “It’s

important, yes, but not everything.”

FRINGE OR FRONTIER?

Bandyopadhyay’s 2013 work on the

microtubule required refitting a special

microscope and contracting with an out-

side firm to create a needle with a

1-by-1-nanometer point — the

smallest ever constructed,

Bandyopadhyay says.

His team used it

to peer inside the

microtubule with

incredible precision.

Bandyopadhyay

inserted the needle

into a rat neuron to

view the microtubule.

As he did, monitors

on one wall in the room

flickered with images from

the tiniest level of animal biol-

ogy. The next set of experiments was

to apply various electrical charges and

watch the “skin” of the neuron as well

as the inside of the microtubule. At first,

nothing happened. But when he began

applying specific energy charges to the

microtubule, it responded, vibrating and

conducting the electricity. This was curi-

ous, and exciting.

A microtubule is composed of many

Anirban

Bandyopadhyay,

a physicist who

studies both

artificial and natural

brains, has been

applying currents to

microtubules to see

how they react.

The neuron, he

thought, contrary to

all current scientific

understanding, wasn’t the

essential, or first cause

of the human thought

process.