March 23rd, 2006



Статьи В.А.Непомнящих
Институт биологии внутренних вод РАН



Архив программы Александра Гордона 2003/январь
Поисковое поведение животных

Интервью «Перспектива для этологии есть до тех пор, пока возникают вопросы»


Физика и философия (zip)

Выводы современной физики, о которых здесь идет речь, во многом изменили представление о мире, унаследованное от прошлого века. Они вызывают переворот в мышлении и потому касаются широкого круга людей. Предлагаемая книга имеет целью помочь подготовить почву для этого переворота.
Мюнхен, 1959 г.

Шаги за горизонт


To See, Brain Assembles Sketchy Images Eyes Feed It

На самом деле глаза не посылают в мозг целостное изображение, падающее на сетчатку. Вместо этого мозг получает порядка дюжины фрагментарных интерпретаций одной и той же картины, которые потом объединяет между собой определенным образом, вовлекая при этом и образы, хранящиеся в памяти.
Данную гипотезу предложили B. Roska and F. Werblin, опубликовав ее в Nature (2001).


“Even though we think we see the world so fully, what we are receiving is really just hints, edges in space and time,” said Frank Werblin, professor of molecular and cell biology in the College of Letters & Science. The brain interprets this sparse information, probably merging it with images from memory, to create the world we know, he said.

In a paper in the March 29 issue of Nature, Werblin and doctoral student Botond Roska provide evidence for between 10 and 12 output channels from the eye to the brain, each carrying a different, stripped-down representation of the visual world.

“These 12 pictures of the world constitute all the information we will ever have about what’s out there, and from these 12 pictures, which are so sparse, we reconstruct the richness of the visual world,” Werblin said. “I’m curious how nature selected these 12 simple movies and how it can be that they are sufficient to provide us with all the information we seem to need.”

Original paper: Nature, March 2001
Vertical interactions across ten parallel, stacked representations in the mammalian retina


The Genome's Black Box
The most intriguing thing about centromeres is that they seem to violate a basic rule of biology.

Human centromeres remain mysterious because their DNA, which is called alpha satellite DNA and makes up 3 to 4 percent of the entire human genome, differs from all the rest. It seems to consist of hundreds of thousands of repetitive segments whose exact order is difficult to determine—so difficult, in fact, that the scientists who sequenced the human genome never even attempted it. Even HHMI investigator David C. Page of the Massachusetts Institute of Technology, who recently sequenced the Y chromosome's masses of repetitive segments, stopped at its centromere. "We only sampled a few bits of DNA within the Y centromere and then gave up because we were unable to interpret it in a biologically interesting way," Page says.

As Willard emphasizes, "We have no idea how these segments operate. We just don't know the code." He hopes to find out, however. So do a growing number of other researchers, including Steven Henikoff, an HHMI investigator at the Fred Hutchinson Cancer Research Center in Seattle, Washington, who studies centromeres primarily in the fruit fly, and Daphne Preuss, an HHMI investigator at the University of Chicago, who works with the model plant Arabidopsis thaliana.