Caroni said:Studies in barn owls have revealed that the additional learned circuits that had been assembled during a sensitive period in juvenile birds were turned on and off in the adult through mechanisms distinct from those that turn innate natural circuits on and off (disinhibition versus AMPA/NMDA ratios for the innate and learned circuits, respectively), suggesting that innate and acquired circuit arrangements can be distinguished functionally
Ygggdrasil said:if you were to take a newly born baby and cover its eyes for its entire early childhood, the child's neural circuitry for interpreting visual stimuli would not develop and the child would be blind despite the fact that the child's eyes work perfectly well.
Hi Ygggdrasil. Are you saying that if an animal's eyes were covered in the same way the child's eyes were, the animal would still be able to see?Ygggdrasil said:In many animals, basic instincts and behaviors are encoded in the organism's DNA. The DNA provides instructions for the animal to build specific neural circuits to perform certain behaviors in response to certain stimuli. For example, flies have an escape response triggered by certain stimuli, such as a shadow passing over them. Researchers have identified a specific nerve cell in the fly that controls this response and this nerve cell is the same in all flies of the same species. Artificial stimulation of this nerve cell triggers the escape response. The nematode worm, C. elegans is probably the animal where the neural circuitry for many innate behaviors, as well as the genetic elements controlling the development of the circuitry, is best understood (for example, see http://www.ncbi.nlm.nih.gov/books/NBK20005/).
In humans and other higher mammals, however, the situation is very different. Humans are born with very few innate behaviors and instincts. For example, whereas many animals (insects, fish, reptiles, amphibians, etc.) are fully capable of walking, feeding themselves and even surviving independently after birth, human babies can do practically nothing after birth and cannot survive without a caretaker. The difference here is that the DNA of humans does not specify a wiring diagram for the brain. Rather this wiring diagram is formed in response to the experiences of the individual. For example, if you were to take a newly born baby and cover its eyes for its entire early childhood, the child's neural circuitry for interpreting visual stimuli would not develop and the child would be blind despite the fact that the child's eyes work perfectly well. ...
Sorry, this is a science forum, please read the rules. We don't allow mysticism.John Kari said:Anyways, past life memory can be something that can or can not be explained with DNA?
bassamnfs said:I guess that DNA codes the location information of every cell in relationship to other cells, sort of a 3D map (a blue print) of how to build the body (identical twins have almost identical physical parameters), if my guess is correct do we know what is the mechanism that interprets the code in DNA into coordinations? This is interesting because as I understand ribosome translates the information coded in DNA to proteins and I'm not aware of any other thing that performs similar task but ribosome.
http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1000032Conventionally, the organization of a neural circuit is studied by sparsely labeling its constituent neurons and pooling data from multiple samples. If significant variation exists among circuits, this approach may not answer how each neuron integrates into the circuit's functional organization. An alternative is to solve the complete wiring diagram (connectome) of each instantiation of the circuit, which would enable the identification and characterization of each neuron and its relationship with all others. We obtained six connectomes from the same muscle in adult transgenic mice expressing fluorescent protein in motor axons. Certain quantitative features were found to be common to each connectome, but the branching structure of each axon was unique, including the left and right copies of the same neuron in the same animal. We also found that axonal arbor length is often not minimized, contrary to expectation. Thus mammalian muscle function is implemented with a variety of wiring diagrams that share certain global features but differ substantially in anatomical form, even within a common genetic background.
rootone said:How about instincts such as an antelope fleeing if it senses a predator nearby.
There won't be a specific gene for that, but every antelope will do it, so it must be 'hardwired' in some sense.
If the response to breath when outside the womb was an evolutionary trait, we would all be dead, right? Given a small population of "humans" in the early days, there would not have been enough opportunities to evolve that trait. Logically, the trait to start breathing would have to be an innate ability for the species. Same as the desire to suckle and have a heartbeat.Pythagorean said:Yeah, it's just like anything else that's formed. Some random mutation made a small difference statistically in the population, providing advantage to survival or reproduction. In this case, the random mutation could be in the genes that code for neural organization or individual neuron properties (including 2nd messenger signaling). The random mutation may lead to a slightly different wiring that biases towards a certain input/output relationship (e.g. a muscle reflex that triggers when skin sensors are activated) that reduces infant mortality rates. As time goes by and more mutations occur, eventually another one in some other random aspect of cell organization happens to contribute to that reflex, too, and it becomes even more selected for... one, two, skip a few million years, and you have the palmar grasp reflex.
"is the evolution of physical characteristics via reproduction and selection all there is?"
Too strong of a statement to say it's "all there is". Does it all have a physical correlate? Yes. But it doesn't necissarily have to be limited to DNA-based inheritance if epigenetics carries the information through methylation. In which case, methylation is the physical correlate.
That high level of behavior isn't encoded in DNA; the components of it are. Form is defined by DNA, but function is a property of the relationship between the organism and the environment, both vastly broader subjects than DNA.Andres Pineda said:If the response to breath when outside the womb was an evolutionary trait, we would all be dead, right? Given a small population of "humans" in the early days, there would not have been enough opportunities to evolve that trait. Logically, the trait to start breathing would have to be an innate ability for the species. Same as the desire to suckle and have a heartbeat.
If these types of traits are indeed encoded in the DNA, why can't we insert new traits, such as a memory of how to solve quadratic equations? You can extend that idea to any amount of capabilities.
