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About 40 percent of the cells in the hippocampus that were tagged during initial memory formation were reactivated, Wiltgen said. There was also reactivation of cells in parts of the brain cortex associated with place learning and in the amygdala, which is important for emotional memory.
When the researchers 'teleport' the rats from one place to another by flipping the light switch from A to B, the rats experience exactly the kind of confusion you feel when you momentarily don't know where you are. "But the mind doesn't actually mix up the maps," she says. "It switches back and forth between the two maps that represent rooms A and B, but it is never in an intermediate position. The brain can 'flip' back and forth between the two different maps, but it is always either or, site A or site B."
May-Britt and Edvard Moser have previously discovered the location of the brain's sense of place, shown how the brain works to make memories distinctively different, and have found that the brain has a mechanism to switch between experiences through the use of senses and images stored as memories. Now the researchers have also shown how the brain switches between individual memories, and how long the brain lingers on the different bits of memory.
So why has evolution equipped us with four or more senses of location?
Moser believes the ability to make a mental map of the environment arose very early in evolution. He explains that all species need to navigate, and that some types of memory may have arisen from brain systems that were actually developed for the brain's sense of location.
"We see that the grid cells that are in each of the modules send signals to the same cells in the hippocampus, which is a very important component of memory," explains Moser. "This is, in a way, the next step in the line of signals in the brain. In practice this means that the location cells send a different code into the hippocampus at the slightest change in the environment in the form of a new pattern of activity. So every tiny change results in a new combination of activity that can be used to encode a new memory, and, with input from the environment, becomes what we call memories
Pattern recognition involves identification of faces, objects, words, melodies, etc. The visual system does more than just interpret forms, contours and colors. Pattern recognition refers to the process of recognizing a set of stimuli arranged in a certain pattern that is characteristic of that set of stimuli. Pattern recognition does not occur instantly, although it does happen automatically and spontaneously. Pattern recognition is an innate ability of animals.
Cognitive dissonance is a term used in modern psychology to describe the feeling of discomfort when simultaneously holding two or more conflicting cognitions: ideas, beliefs, values or emotional reactions. In a state of dissonance, people may sometimes feel "disequilibrium": frustration, hunger, dread, guilt, anger, embarrassment, anxiety, etc.
In the domain of cognitive neuroscience, metacognitive monitoring and control has been viewed as a function of the prefrontal cortex, which receives (monitors) sensory signals from other cortical regions and through feedback loops implements control (see chapters by Schwartz & Bacon and Shimamura, in Dunlosky & Bjork, 2008)
This observation obviously refutes the notion that the hippocampus contains a representation of the fixed environmental structure. But rather than abandoning the spatial mapping view, its discoverers concluded that the hippocampus creates multiple spatial maps based on different ‘reference frames’, in the case of this study, separate maps referred to a starting point or goal. By extension, in an environment with many moveable objects of interest, there presumably could be a very large number of maps for the same space.
Similarly, from this perspective place cells appear to be governed by different ‘reference frames’ when behavioral episodes are defined by a sequence of actions and locations centered on objects independently of their positions within the overall spatial environment. And finally, from this view a ‘trajectory’ can be straightforwardly characterized as the representation of a journey defined by a sequence of locations and behaviors recorded in memory.
"By no means do we claim that the universe is a global brain or a computer," said Dmitri Krioukov, co-author of the paper, published by the Cooperative Association for Internet Data Analysis (CAIDA), based at the San Diego Supercomputer Center (SDSC) at the University of California, San Diego. "But the discovered equivalence between the growth of the universe and complex networks strongly suggests that unexpectedly similar laws govern the dynamics of these very different complex systems.
The structure of the universe and the laws that govern its growth may be more similar than previously thought to the structure and growth of the human brain and other complex networks, such as the Internet or a social network of trust relationships between people, according to a new paper published in the science journal Nature's Scientific Reports.
"Although the overall size and asymmetrical shape of Einstein's brain were normal, the prefrontal, somatosensory, primary motor, parietal, temporal and occipital cortices were extraordinary," said Falk, the Hale G. Smith Professor of Anthropology at Florida State. "These may have provided the neurological underpinnings for some of his visuospatial and mathematical abilities, for instance."
"When subjects are lying in a scanner with nothing to do, which we call the resting state, they naturally cycle between the two networks," Jack said. "This tells us that it's the structure of the adult brain that is driving this, that it's a physiological constraint on cognition."
The finding has bearings on a variety of neuropsychiatric disorders, from anxiety, depression and ADHD to schizophrenia -- all of which are characterized by social dysfunction of some sort, Jack said. "Treatment needs to target a balance between these two networks. At present most rehabilitation, and more broadly most educational efforts of any sort, focus on tuning up the analytic network. Yet, we found more cortex dedicated to the social network."
Perhaps most clearly, the theory makes sense in regards to developmental disabilities such as autism and Williams syndrome. Autism is often characterized by a strong ability to solve visuospatial problems, such as mentally manipulating two and three-dimensional figures, but poor social skills. People with Williams syndrome are very warm and friendly, but perform poorly on visuospatial tests.