Scientists say they have genetically modified mice to make them smarter.



After using gene implants to create a strain of mice having double the normal amount of a memory protein in their brains, the researchers found that the animals learned significantly faster and remembered longer than their normal counterparts.



Moreover, the added gene prevented the normal decline in memory and learning that occurs with advancing age in both mouse and man.



"This is the first evidence for manipulation of genes producing improvement in a higher function" in animals, said Dr. Larry Squire, a leading memory researcher, at the University of California in San Diego.



The gene-altered mice outshone unmodified rodents in a series of tasks, such as recognizing a Lego piece they had encountered before, learning the location of a hidden underwater platform and recognizing signs that they were about to receive a mild shock.



The mice carried their enhanced intelligence into adulthood, when learning ability and memory naturally taper off, and passed it on to their offspring.



However, specialists pointed out, creating improved memory and learning ability is not the same as boosting intelligence, the complex and hard-to-define ability measured by IQ tests.



You can learn without realizing what your are doing, a new study finds. The process is similar to how other animals learn, scientists suspect.



A distinction is made between declarative learning, which involves the memorization of facts and events, and habit learning, which is a gradual change in behavior arrived at unconsciously through trial and error.



These two types of learning occur in separate areas of the brain. The medial temporal lobe is associated with the formation of new conscious memories, while the basal ganglia are a group of nuclei that are responsible for habitual responses to repeated stimuli.



The implication is that humans have an unconscious ability -- comparable to that in animals -- to mold our behavior in response to a consistent stimulus.



"Habit learning is going on all the time. All of us are acquiring habits, " Squire said. "What this is showing is that habit learning is well-developed in humans, and that it works independent of consciousness."



Controlling the flow of impulses across the synapse is a protein called the NMDA receptor, which acts as a switch for memory formation. When it is stimulated by two adjacent nerve cells -- which would happen if two pieces of information were coming together in an association to be remembered -- the NMDA receptor opens for a fraction of a second, allowing the impulses to jump the synapse easily and create a stored memory.



When humans (or mice) are young, the NMDA gateway stays open slightly longer, providing more time for the mental association to be made and remembered. As people age, that time window narrows, and people store information less easily.