The tide of memory, turning

Article Abstract:

Virtually all animals learn in one way or another; in humans, learning reaches exquisite complexity. Everything we are hinges on memories of past experience, our learning of language, and the successful performance of tasks and skills. Therefore, it is surprising that so little is known about how the brain manages learning and memory. The physiological basis for memory has long been sought by neuroscientists. Some researchers have turned to long-term potentiation to learn more about the formation of memories. Long-term potentiation are long-lasting changes which result from electrophysiological stimulation of particular neurons. Although the phenomenon has been demonstrated in several regions of the brain, it is most widely studied in the hippocampus, where it was first observed. It is certain that synaptic changes occur during long-term potentiation. Though the synapses, which are the specialized spots of communication between neurons, have clearly demonstrable electrophysiological changes, it is not known if the change results from alterations in the cell sending the signal or changes in the cell receiving the signal. Although in recent years the majority of opinion has favored the receiving cell as the location of change, results from two independent laboratories now suggest that the sending, or presynaptic, cell might be changing. The researchers based their conclusion on a careful statistical analysis called quantum analysis. The sending cell releases neurotransmitter in packets, hence the 'quantum'. While the effects of an individual packet are hardly distinguishable, statistical analysis can show whether the observed potentiation has resulted from the sending cell releasing more packets, or the receiving cell becoming more sensitive to the same number of packets. Researchers found that the sending cell was increasing the number of packets released, and may play a key role in long-term potentiation. It should be mentioned that while most researchers feel long-term potentiation to be a valid model of the changes which occur in memory, there is no real evidence that related phenomena actually take place inside a living person or animal during learning. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, Memory, Hippocampus (Brain), editorial

---

Neuroscience models the brain

Article Abstract:

In the past, computer models of the brain were not taken seriously by scientists interested in understanding brain physiology. These neuroscientists regarded most models as simply naive; the best were viewed as trivial computerized reenactments of what was already known about the brain. Today, however, models are appearing which are generating new hypotheses about brain function, hypotheses which can be experimentally tested in the lab. Allen Selverston of the University of California at San Diego points out that models are one way of deciding which aspects of experimental data are important and which simply represent extraneous information. Terrence Sejnowski of the Salk Institute believes that models do not actually solve problems, but they can provide a means for deciding which aspects of a problem are most likely to yield useful information upon further experimentation. Computerized neural networks, which are completely abstract entities consisting of numerous nodes and even more numerous internode connections, are not thought by neuroscientists to represent how the brain actually performs its tasks. Nonetheless, for researchers trying to understand how a large set of neurons adapts and responds, neural nets provide an opportunity to explore highly parallel information processing in a defined environment. As scientists become more familiar with such systems, they may be able to bring new insights to neurobiological research. (Consumer Summary produced by Reliance Medical Information, Inc.)

Models, Usage, Computers, Digital computers

---

New imaging methods provide a better view into the brain

Article Abstract:

Functional magnetic resonance imaging (fMRI) is undergoing major enhancements. Test methods, such as event-related trials, are improving, and higher magnetic field strengths are being marketed.

Product enhancement, Magnetic resonance imaging

Similar abstracts:

• Abstracts: Laws of calorie counting. Time travelers in the field. Information technology, 2500 B.C
• Abstracts: The elusive goal of machine translation. Talking to Bill. 2001: A Scorecard
• Abstracts: The promise of the mother cell. Growing replacement parts. Code of the code
• Abstracts: Identification of hardening parameters of metals from spherical indentation tests. Determination of friction coefficient by employing the ring compression test
• Abstracts: Neuroscientists track nerve development. Neuroscientists seek answers to brain function and disease. The big easy serves up a feast to visiting neuroscientists

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.