Archive for April, 2009

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Neuroscientists decode brain activity important for navigation and spatial memory

April 29, 2009

How many times have you wondered where did I leave my keys?  Activity in your hippocampus and medial temporal lobes encodes the answer.

A new study using high resolution brain imaging has shown that the encoding of memories involves the precise pattern of activity of a very large number of neurons in the human hippocampus.  The hippocampus and surround medial temporal lobes are important parts of the brain for our ability to navigate, form and recall memories, and imagine future experience.  This study found that the pattern of activity can be read like a map to accurately “predict” what environment you are in and your location within the environment.

A group of Neuroscientists at the Welcome Trust Centre for Neuroimaging at University College London led by Dr. Eleanor Maguire have imaged the pattern of activity in the hippocampus and surrounding medial temporal lobe of human subjects while they navigated around a virtual environment.  The researchers asked if there is a reliable pattern of activity in the hippocampus, like a map, that can be read to predict where the subject is in the environment.   The results of this study are “yes” — there is a functional structure to the pattern of activity in the human hippocampus that encodes your location in an environment.
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Mirror neurons reflect more than understanding

April 19, 2009

This blog entry is about one of the most interesting discoveries of the 90’s in Neuroscience — Mirror Neurons — and a recent research paper that adds to their intrigue.  Mirror neurons are found in the premotor cortex, and what has made them so interesting is that they fire both when the individual performs a goal-directed action and when they watch someone else perform the same action.  It is as if the mirror neurons encode an understanding about the intentions of someone else.  For example, when my husband reaches for his coffee cup I understand that he intends to take a drink before he even raises the cup to his lips.  Neuroscientists think it is the mirror neurons that encode the “understanding” when we watch what others are doing.

A recent study suggests that mirror neurons may do more than just reflect understanding others.  A group of Neuroscientists in Tubingen Germany and Parma Italy has shown that mirror neurons may contribute to thinking about how to interact.
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Neural Stem Cells in the Aged Brain

April 12, 2009

Within the last 20 years neuroscientists have shown that new neurons are generated in the brain throughout the lifespan. This finding opened a new area of research aimed at understanding if adult neural stem cells can be used in therapies for neurodegenerative diseases.

A challenge with this approach is that there are fewer neural stem cell in the aged brain and the loss of stem cells occurs at just the time when neurodegenerative diseases are most common. But a new study is providing important information that neural stem from an aged brain still have the capacity to mature into functional neurons.
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New study shows recovery of vision after stroke

April 10, 2009

A group of neuroscientists at the University of Rochester have shown that intensive training can promote recovery after a stoke.  What’s new is that the patients recovered vision after a stroke had damaged their visual cortex.

A stroke to the visual cortex causes a type of blindness called “cortical blindness” — the eyes still send information to the visual part of the brain but because of the stroke the brain can not process the information and the patient can not see.  Often these strokes affect only a part of the visual cortex leaving the person with a perceptual hole where they have no conscious feeling that they can see.   The traditional view is that there is little recovery after this type of stroke.  But Dr. Huxlin and her colleagues have shown that intensive visual training can promote a remarkable amount of recovery.
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