Our ability to form long-term memories depends on cells in the brain making strong connections with each other. Yet while it’s not well understood how those connections are made, lost or changed, the process is known to involve the movement of the AMPA receptor protein to and from those neuronal connections.
Reporting this week in Nature Neuroscience, researchers at the Johns Hopkins School of Medicine have discovered by watching live neurons that the AMPA receptor goes where it needs to be with the help of the 4.1N protein, without which long term memories are not formed.
“This has been a long-standing challenge in the field, trying to see a process that involves a handful of molecules and occurs so quickly, on the order of one-tenth of a second,” says Richard Huganir, Ph.D., professor and director of the Solomon H. Snyder Department of Neuroscience at Johns Hopkins. “We just haven’t had the right tools.” Huganir’s research team spent a year building a new microscope to do the experiments.
Removal of the Amygdala makes you literally fearless:
Although clinical observations suggest that humans with amygdala damage have abnormal fear reactions and a reduced experience of fear [,  and ], these impressions have not been systematically investigated. To address this gap, we conducted a new study in a rare human patient, SM, who has focal bilateral amygdala lesions . To provoke fear in SM, we exposed her to live snakes and spiders, took her on a tour of a haunted house, and showed her emotionally evocative films. On no occasion did SM exhibit fear, and she never endorsed feeling more than minimal levels of fear. Likewise, across a large battery of self-report questionnaires, 3 months of real-life experience sampling, and a life history replete with traumatic events, SM repeatedly demonstrated an absence of overt fear manifestations and an overall impoverished experience of fear. Despite her lack of fear, SM is able to exhibit other basic emotions and experience the respective feelings. The findings support the conclusion that the human amygdala plays a pivotal role in triggering a state of fear and that the absence of such a state precludes the experience of fear itself.
A device that reveals what a person sees by decoding their brain activity could soon be a reality, say researchers who have developed a more sophisticated way to extract visual stimuli from brain signals.
Scientists at the University of California, Berkeley, US, developed a computational model that uses functional MRI (fMRI) data to decode information from an individual's visual cortex – the part of the brain responsible for processing visual stimuli.
“Our research makes substantial advances towards being able to decode mental content from brain activity as measured using fMRI,” Kendrick Kay, a co-author of the study, told New Scientist. “In fact, our results suggest it may soon be possible to reconstruct our visual experiences from brain activity.”