“It appears that information is lost in the brain as quickly as it can be “delivered” from the senses. This has fundamental consequences for our understanding of the neural code of the cerebral cortex. Due to the high deletion rate, information about sensory input signals can only be maintained for a few spikes. These new findings therefore indicate that the dynamics of the cerebral cortex are specifically tailored to the processing of brief snapshots of the outside world
Information stored in the activity patterns of cerebral cortex neurons is discarded at the surprisingly high rate of one bit per active neuron per second, scientists from the Max Planck Institute for Dynamics and Self-Organization at the University of Gottingen and the Bernstein Center for…
Brain has two slots for working memory.
Mental version of RAM has an independent module in each hemisphere
Like side-by-side computer RAM cards, the left and the right hemispheres of the brain store information separately, a new study finds. The results help explain why people can remember only a handful of objects at one time, and suggest that people may be able to maximize their cognitive power by delivering information in equal doses to both sides of the brain.
Modern evolutionary biologists believe that, at the genetic level, natural selection is more complex than just a single mutation leading to a single new trait. Most believe that lots of small, sometimes imperceptible changes in the gene pool of a population lead to aggregate changes over time, especially if a new environmental stress selects for the previously-silent mutations. The notion that some mutations that don’t affect an organism but lie dormant until they are selected for or combine with another mutation is called preadaption or cryptic variation, and though biologists have long been writing about it, little empirical evidence exists to support it. That is no longer the case, according to the latest edition of Nature. A group of scientists studied ribozymes, or enzymes made of RNA.
In the new study, Hayden and Wagner evolved ribozymes in test tubes of chemicals, then moved them to a new chemical substrate, a shift analogous to requiring animals to suddenly subsist on a new food source.
The ribozymes that flourished were those that had accumulated specific sets of cryptic mutations in their former environment. Those variations, seemingly irrelevant before, became the basis of newly useful adapation. The researchers were able to measure every change in detail.
Cryptic variation may be critical in the spread of antibiotic resistance, and may also provide insight into the evolution of animals - the authors recommend applying their findings to the classic case of Darwin’s finches. Additionally, the research may prove useful for programmers to create evolving computer systems.
Reconsolidation of memories - is it possible to change our memory of a previous event?
When we consolidate our memories into Long Term Memory, the brain undergoes neuronal changes. Whether they become detached from the hippocampus or not is a whole other debate in the field of memory (which I’ll leave for later). However, is it set in stone? Research is showing that this may not be the case. Memories may be liable to reconsolidation, in which a consolidated memory is conjured back into working memory, through similar contexts, and becomes malleable to other information. One example is a study in which participants learned a set of items in one context, and where then bought back to either a new context or the same context to learn a new set of items. The participants were then brought back a third time to recall items from the first set. Those participants that learned the second set in the same context had significantly more intrusions from items of the second set when recalling items from the first set, than participants in the different context, showing that the memory for items in the first set might have been changed. This gives implications of new methods to treat disorders which are heavily based on memory, such as PTSD.