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What Is a Memory?

     



Scientists say there could be a reason why you don’t remember what you ate for breakfast last week but can vividly describe your first day of kindergarten. Emotional meaning attached to a memory makes it stick in a way that everyday details can’t. But memories aren’t just about the past. They help us learn and make decisions about the future. Neuroscientists do not completely understand the physical representation of memories in the brain. Neurons, or brain cells, communicate with each other through electrochemical pathways. An electrical impulse travels down the outgoing branch called an axon, where it stimulates fingers known as dendrites at the end, releasing neurotransmitters. These tiny molecules send messages that incoming branches pick up. The space between these branches is called a synapse.

   The reconstruction of a past experience happens through synchronous firing of neurons involved in the original experience. A memory is not a static entity but a unique pattern of activity that can shift or migrate between different parts of  the brain. It is like a jigsaw puzzle that assembles throughout various areas of the brain, rather than a video clip stored as a whole file. Short-term memories do not “stick” in the synapse, and long-term memories might be distorted when they reassemble.

   One of the most important attributes of memory is our ability to learn. When we learn or recall information, we use memory to retrieve the idea we have learned. Every time you eat, drive a car or read a book, you are remembering learned traits. New technology called optogenetics uses light beams to excite or silence a targeted group of neurons in the brain, helping scientists study and perhaps control memories. It may be possible to open up a pathway to selectively implant memories or erase certain memories altogether. For people with amnesia or severe emotional trauma, that will be a moment worth remembering.

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