In their study, Greenberg, Yap and team set out to explore this process by looking at the gene Fos.įirst described in neuronal cells by Greenberg and colleagues in 1986, Fos is expressed within minutes after a neuron is activated. In order to form memories, the brain must somehow wire an experience into neurons so that when these neurons are reactivated, the initial experience can be recalled. “We think coincident activation of this Fos-mediated circuit is potentially a necessary feature for memory consolidation, for example, during sleep, and also memory recall in the brain.” Circuit orchestration “This mechanism likely allows neurons to better talk to each other so that the next time a memory needs to be recalled, the neurons fire more synchronously,” Yap said. In this way, small groups of disparate neurons may form persistent networks with coordinated activity in response to an experience.
These genes allow neurons to fine-tune inputs from so-called inhibitory interneurons, cells that dampen neuronal excitation. The researchers observed that new experiences activate sparse populations of neurons in the hippocampus that express two genes, Fos and Scg2. The question of how we encode memories that last a lifetime is a fundamental one, and our study gets to the very heart of this phenomenon,” said Greenberg, the HMS Nathan Marsh Pusey Professor of Neurobiology and study corresponding author. “Memory is essential to all aspects of human existence. Michael Greenberg, Blavatnik Institute at HMS The study was led by Lynn Yap, HMS graduate student in neurobiology, and Michael Greenberg, chair of neurobiology in the Blavatnik Institute at HMS.
9, they describe a newly identified mechanism that neurons in the adult mouse hippocampus use to regulate signals they receive from other neurons, in a process that appears critical for memory consolidation and recall. Now, neuroscientists at Harvard Medical School (HMS) have taken a decisive step in the quest to understand the biology of long-term memory and find ways to intervene when memory deficits occur with age or disease. Scientists had discovered where memories are made. Patient H.M.’s condition ultimately revealed that the brain’s ability to create long-term memories is a distinct process that depends on the hippocampus. When he woke up after surgery, he could no longer form new long-term memories, despite retaining normal cognitive abilities, language and short-term working memory. Unfortunately, for patient H.M., so too did time.
In an attempt to treat his debilitating seizures, a surgeon removed portions of his brain, including part of a structure called the hippocampus.
On a late summer day in 1953, a young man who would soon be known as patient H.M.
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