See elegance in a worm brain

Designated assistant professor
Graduate school of Science, Nagoya University

Ken NomaVolumeSTOP!

Who has a brain?

Wonderful!!

Today’s menu
- Appetizer Brain

8 elegantthings- Main dish Worm
- Dessert MeThe brain isInput

Process（処理）Outputthe organ inside the head that controls thought, memory,feelings, and activity. (Cambridge dictionary)Neurons are the functional
units of the brain

Neuron 神経細胞
(a type of the cell)Neurons communicate with eachother to process information

Communication

Exciting questions about the brain
How do neurons process information?
処理する

How is the brain formed?
What is the consciousness?
意識The problem
Our brain is too complex

Quiz
How many neurons in our brain?
1. 1000 (thousand)
2. 1000,000 (million)
3. 1000,000,000 (billion)

Quiz
How many neurons in our brain?
1. 1000 (thousand)
2. 1000,000 (million)
3. 1000,000,000 (billion)
4. 100,000,000,000 (100 billion)

1,000,000 times thisBarack Obama attracted 100,000 people(Worldpress.com)

by Chip Somodevilla/Getty.

That’s…
too…
complicated…

Problems of the human brain as a
research subject
Human brain is
1. too complicated
2. hard to see
3. hard to manipulate

What should we do?
We needa hero…

Worm the hero

Today’s menu
- Appetizer Brain- Main dish Worm
- Dessert MeThe worm
Caenorhabdits elegans(C. elegans)
Model organism
Simple and easy!!
Core principle原理

The worm
Caenorhabdits elegans(C. elegans)
Sydney Brenner

1974

Nobel prize in 2002
by nobelprize.org

You are going to receive thisC. elegans(~1 mm)Bacteria(Food)

C. elegans is NOT parasitic NOR harmful.
寄生性Elegance 1
C. elegans is easily maintained（飼育）6/16

Hermaphrodite
雌雄同体

3 days~1000 worms

The worm show
LIVEElegance 2
C. elegans senses and responds to stimuli
（刺激）
Touch

Movement

Input

OutputElegance 3
C. elegans has memory
20℃

20℃

Food

Elegance 3
C. elegans has memory
20℃

20℃

Food

Hedgecock and Russell, PNAS, 1975
Mori and Ohshima, Nature, 1995

Elegance 4
C. elegans has a brain
HeadTailElegance 5
Every C. elegans is the same

302 neurons
Good for experiments!!

Well, C. elegans seems to begood for experiments, but...
Whocares?

Whatcan welearn?

Exciting questions about the brain
How do neurons process information?
How is the brain formed?
What is the consciousness?

Elegance 6
C. elegans is transparent
Live animal

HeadNeurons
You can see neurons and neuronal activities!

Elegance 6
Whole brain activities can be imaged ina freely moving animal
Neuronal activity=What C. elegans
is “thinking”.

Nguyen et al., PNAS, 2016

Neuronal activity

Core principle ofinformation processing

Exciting questions about the brain
How do neurons process information?
How is the brain formed?
What is the consciousness?

The brain is formed,
based on the genome

Genome DNA(Blueprint 設計図)

HOW??

Genes are the functional
units of the genome
Gene(Functional unit)
Genome DNA(Blueprint 設計図)

20,000 genes in C. elegans

Which gene is important for the brain??

Elegance 7
C. elegans is easily manipulated

Elegance 7
C. elegans is easily manipulated
Blueprint
設計図

Forward genetic screen

Gene A

Gene B

Gene C

Important for the brain!

Elegance 7
C. elegans is easily manipulated
Blueprint
設計図

Forward genetic screen

MeGene A

Gene B*not photoshopped
Gene C

Important for the brain!

Example: a gene, unc-13
important for neuronal communicationLIVEElegance 8
Important genes are conserved
保存されているThe blueprint

unc-13https://books.google.co.jp/books/about/Twist_of_Gold.html?id=tJKbQis8xEC&source=kp_cover&redir_esc=y
2018/10/18

https://response.jp/article/img/2018/02/23/306453/1279152.html?from=arrow-next

2018/10/18

Take-home message“Model organisms” are powerful!!
Choose aright tool!!

Dreamstime.com

Today’s menu
- Appetizer Brain- Main dish Worm
- Dessert MeC. elegans genes~20,00036%

Uncharacterized 64%

Peterson et al, Trends in Genetics, 2015

I want to find andcharacterize newgenes!!

Forward genetic screen

0+0=1
Blueprint
設計図
Gene A

Gene A+Gene B

Gene C

Gene B

Well characterizedCombination is challenging
Combination of two genes
C2 = 199,990,000

20,000NEW
Forward genetic screen

I can do it with C. elegans!
8 elegantthings

1. Maintenance

5. Stereotype

2. Sensation

6. Transparency

3. Memory

7. Manipulation

4. Brain

8. Conservation

I hopeyou see elegancein the C. elegans brain

Thanks!

feeling likea worm…

Contact
Kentaro (Ken) Noma
Science building B103
075-789-2501
noma.kentaro@e.mbox.nagoya-u.ac.jp

2012.10.31 @San Diego, USA