We constantly refer to past experiences stored as memories to guide behavioral decisions in our interactions with the environment. But how memories are formed, stored and then retrieved to assist decision-making remains a mystery. By observing whole-brain activity in live zebrafish, researchers from the RIKEN Brain Science Institute have visualized for the first time how information stored as long-term memory in the cerebral cortex is processed to guide behavioral choices.
The study, published today in the journal Neuron was carried out by Dr. Tazu Aoki and Dr. Hitoshi Okamoto from the Laboratory for Developmental Gene Regulation, a pioneer in the study of how the brain controls behavior in zebrafish.
Some Memories Last a Lifetime While Others Disappear
Memories rehearsed during either sleep or waking can have an impact on memory consolidation and on what is remembered later, suggests a new study.
Advertisement
The mammalian brain is too large to observe the whole neural circuit in action.But using a technique called calcium imaging, Aoki et al. were able to visualize for the first time the activity of the whole zebrafish brain during memory retrieval.
Calcium imaging takes advantage of the fact that calcium ions enter neurons upon neural activation. By introducing a calcium sensitive fluorescent substance in the neural tissue, it becomes possible to trace the calcium influx in neurons and thus visualize neural activity.
The researchers trained transgenic zebrafish expressing a calcium sensitive protein to avoid a mild electric shock using a red LED as cue. By observing the zebrafish brain activity upon presentation of the red LED they were could visualize the process of remembering the learned avoidance behavior.
They observe spot-like neural activity in the dorsal part of the fish telencephalon, which corresponds to the human cortex, upon presentation of the red LED 24 hours after the training session. No activity is observed when the cue is presented 30 minutes after training.
In another experiment, Aoki et al. show that if this region of the brain is removed, the fish are able to learn the avoidance behavior, remember it short-term, but cannot form any long-term memory of it.
"This indicates that short-term and long-term memories are formed and stored in different parts of the brain. We think that short-term memories must be transferred to the cortical region to be consolidated into long-term memories," explains Dr. Aoki.
Source: Eurekalert
Advertisement
The researchers trained transgenic zebrafish expressing a calcium sensitive protein to avoid a mild electric shock using a red LED as cue. By observing the zebrafish brain activity upon presentation of the red LED they were could visualize the process of remembering the learned avoidance behavior.
They observe spot-like neural activity in the dorsal part of the fish telencephalon, which corresponds to the human cortex, upon presentation of the red LED 24 hours after the training session. No activity is observed when the cue is presented 30 minutes after training.
In another experiment, Aoki et al. show that if this region of the brain is removed, the fish are able to learn the avoidance behavior, remember it short-term, but cannot form any long-term memory of it.
"This indicates that short-term and long-term memories are formed and stored in different parts of the brain. We think that short-term memories must be transferred to the cortical region to be consolidated into long-term memories," explains Dr. Aoki.
Source: Eurekalert
Advertisement
Advertisement
|
Advertisement
Latest Research News
By 2050, an anticipated increase from 494 million cases in 2020 to 1.06 billion people with musculoskeletal disabilities is expected.
Experts consulted by GlobalData anticipate a significant overhaul in the Gaucher disease scenario because of forthcoming gene therapies in development.
Within the seven major markets, 12% to 20% of diagnosed prevalent NASH cases present severe liver damage (stage 4 liver fibrosis), denoting cirrhosis.
Memory deficits in individuals with epilepsy, especially cognitive difficulties, might partially stem from the transient impairments caused by these slow waves.
High altitude training exhibits potential benefits for pre-surgery patients, enhancing readiness, stated a new study.