Final answer:
Donald Hebb postulated the theory of synaptic plasticity, suggesting that learning occurs through changes in synaptic strength and is the basis of memory storage in the brain. His work laid the foundation for the concept of the engram and was pivotal in advancing our understanding of neuroplasticity.
Step-by-step explanation:
Donald Hebb postulated a theory about synaptic plasticity that has had a profound impact on our understanding of the brain. Hebb's theory is often summarized by the phrase "neurons that fire together, wire together." This means that the simultaneous activation of cells leads to pronounced increases in synaptic strength between those cells. Hence, learning is thought to result from changes in synaptic strength, constituting the synaptic basis of the engram, or the physical embodiment of memory.
The research conducted by Karl Lashley on the search for an engram illustrated the challenges in localizing memory in the brain. Despite lesions in rats' brains, the animals were still able to navigate mazes, suggesting memory might not be stored in just one place but is distributed across the brain. He proposed the equipotentiality hypothesis, which led to further understanding of neuroplasticity - the brain's ability to reorganize itself by forming new neural connections. Studies by other researchers, like Eric Kandel, furthered this understanding by looking into how synaptic functions contribute to memory.
Contemporary research by scientists such as Saeed Nabavi has continued to build on these foundational concepts. Nabavi's work demonstrates the process of creating associations in memory through synaptic changes, reinforcing the idea of synaptic plasticity advanced by Hebb's postulates.