In a provocative new paper, a group of UCLA biologists say that the leading theory for how memory is stored in the brain needs a rethink. But is it really time to throw out the textbooks? In their study, published in Elife, authors Shanping Chen, Diancai Cai, and colleagues examined the formation of synapses, connections between neurons. They used neurons from Aplysia, a sea slug whose rather simple nervous system is popular among learning and memory neuroscientists.
Chen, Cai et al. took two neurons from an Aplysia, one sensory and one motor neuron, and put them together in a dish. When placed together these two neurons spontaneously grow synaptic connections. Repeatedly adding 5HT (serotonin) to the dish caused these connections to strengthen - a primitive form of 'learning' called long-term facilitation (LTF). The number of synaptic connections (called varicosities) between the sensory and the motor neuron increased rapidly after 5HT ...
