we will find out we are complex programs running on a very complex computers - brains, with structure given and driven by genes.
Roundworm, 1 mm long, - the study of its nervous system offers one of the most promising approaches for understanding the human brain, since it uses much the same working parts but is around a million times less complex.
worm brain, which has just 302 neurons and 8,000 synapses, or neuron-to-neuron connections. These connections are pretty much the same from one individual to another, meaning that in all worms the brain is wired up in essentially the same way.
human brain, a structure with billions of neurons, 100,000 miles of biological wiring and 100 trillion synapses.
which of the worm’s 302 neurons controlled its chemical-tracking behavior. - /understand and control, predict behavior
molecular basis for the sense of smell: there are about a thousand genes, at least in rats, that make odorant receptors, proteins that stud the olfactory nerves’ endings in the nose and respond to specific odors.
The worm C. elegans genome had just been decoded, and Dr. Bargmann was able to identify the worm’s odorant receptor genes. In fact, they have 2,000 of them, twice as many as the rat.
These are the same kind of connections as those made by human neurons. But worms have another kind of connection.
Besides the synapses that mediate electrical signals, there are also so-called gap junctions that allow direct chemical communication between neurons.
The wiring diagram for the gap junctions is quite different from that of the synapses.
this constant rewiring may be a reason why the worm’s behavior cannot be computed from the wiring diagram: the pattern of connections is changing all the time under the influence of the worm’s 250 neuropeptides.
two separate brain neurons wiring diagrams superimposed on each other, but there is a third system that keeps rewiring the wiring diagrams.
This is based on neuropeptides, hormonelike chemicals that are released by neurons to affect other neurons.
The neuropeptides probably help control the brain’s general status, or mood
The worm has 22,000 genes, almost as many as a person, and its brain is a highly complex piece of biological machinery.
What would be required to say that the worm’s nervous system was fully understood?
“You would want to understand a behavior all the way through, and then how the behavior can change,” Dr. Bargmann says.
“You would want to understand a behavior all the way through, and then how the behavior can change,” Dr. Bargmann says.
“That goal is not unattainable,”
great! ....
great article.
No comments:
Post a Comment