New Worlds: Octopuses can teach us a thing or two

Research on the eight-armed cephalopods has shed new light on how our brains store and recall information.

octopus 88 (photo credit: )
octopus 88
(photo credit: )
One wouldn't think that human brains and those of octopuses have much in common, but Hebrew University researchers maintain that research on the eight-armed cephalopods has shed new light on how our brains store and recall information. Dr. Benny Hochner of the neurobiology department at the Alexander Silberman Institute of Life Sciences explains that octopuses and other cephalopods are the "most intelligent invertebrates" because they have relatively large brains and can be trained for various tasks. Their learning and memory abilities are even comparable in complexity to those of advanced vertebrates. But they are still mollusks lacking a spinal cord and having brains that contain many fewer nerve cells and much simpler anatomical organization than that of vertebrate brains. In a previous study, Hochner discovered that an area in the octopus brain known to be important for learning and memory showed a robust, activity-dependent, long-term synaptic potentiation (LTP) - a process which is strikingly similar to that discovered in vertebrate brains. This process accelerates the transfer of information between nerve cells by enhancing the transmission of electrical signals through a special structure called the synapse for days and even a lifetime. It is believed that in the brain area that stores memories, the synaptic connections between nerve cells that are more active during a specific learning function are strengthened by this activity-induced LTP. One can describe this process as an "engraving of memory traces" in the neuronal networks, says Hochner. In a recent article in Current Biology, Hochner described how he tested these hypotheses and ideas. He blocked the ability of the octopus brain to use LTP during learning by utilizing artificial LTP and electrical stimulation. When LTP was blocked with this technique shortly before training for a specific task, the experimental group of octopi did not remember the task well when tested for long-term memory the day after. Similar results were obtained when sensory information was prevented from getting into the learning and memory area by creating a lesion in a specific part of the brain. These findings support the theory that LTP is indeed important for creating memories. The fact that this was revealed in an invertebrate suggests the process (LTP) is an efficient mechanism for mediation of memory. The research results in the octopuses also shed new light on how memory systems are organized. Even if one accepts that LTP is important for learning and memory, however, Hochner stresses that further research will be required to understand how this cellular process is utilized in other brains for storing memories, and how these memories are recollected. The results can also have implications regarding the organization of learning and memory systems, says Hochner. Memory processes can be divided into a short-term memory of minutes or a few hours and long-term memory that can store important events and facts for days or even a lifetime. Interestingly, his results show that as in mammals, the short and long-term memory in the octopus are segregated into two systems, each in different locations. It is not completely understood how these two systems are interconnected, if at all. However, the organization in the octopus demonstrates a sophistication not yet described in other animals. In the octopus, the short-term and long-term systems are working in parallel, but not independently. This is so because the long-term memory area - in addition to its capacity to store long-term memories - also regulates the rate at which the short-term system acquires short-term memories. This regulatory mechanism is probably useful in cases where faster learning is significant for the octopus's survival. HELPING THE BRIGHTEST The name "Azrieli" is well known for shopping centers and the three geometrical skyscrapers in Tel Aviv. But David Azrieli and the foundation named for him is also known for the Azrieli Fellowships he established for the best and brightest Israeli graduate students. The grants they receive create the conditions for them to focus on their research, and in this way encourage them to remain in Israel. The fellows' research fields are in interdisciplinary and applied sciences, education, architecture and urban planning; they are selected by independent committees comprised of world-class experts to become leaders and "ambassadors" for Israel. They are also judged by their academic merits, leadership qualities and potential for making cutting-edge contributions. Ten new Azrieli Fellows have just been chosen to join the existing cohort, bringing the number to 21. The winners will be announced shortly, and will be officially welcomed into the fellowship program in November. Within the next two years, the foundation intends to support a constant 30 fellows from Israel, and an additional 12 graduate students from abroad, bringing its investment in higher Israeli education to over $1 million a year. The Azrieli Foundation, founded in 1989 and based in Canada, is the only non-Israeli foundation to support graduate studies in Israel in the fields of education and architecture/urban planning. There are few, if any, fellowships or grants in these fields, and none at this level of funding. It is also unusual in that it encourages interdisciplinary research. Fellows are encouraged to attend international and local scientific conferences and to purchase supplies and equipment that will enhance their research, via generous additional funding set aside for these express purposes.