Week 4

These papers are incredibly interesting. What is especially noteworthy is how the two papers take what is apparently the same question and previous research and use near opposite approaches to exploring them. Both take on the question of how a neuron is chosen and encoded to form memory and how to identify these neuron within the distributed neuronal network. Both draw on previous research that showed that Lateral Amygdala neurons that have increased CREB expression, are preferentially recruited for fear memory. Both attempt to understand this recruitment process. However the focus for Yiu is to increase neuronal activity and show this excitation is enough for a retrieval cue for fear memory expression and that neurons are an important part of the memory trace. Contrastly, Han selectively deletes CREB expressing neurons, and uses the memory loss that results as evidence of the neuronal subpopulations relationship to memory formation and expression.

Yiu’s approach is to increase neuronal excitability by overexpressing CREB in random portions of LA neurons. There is an increase in fear memory formation and the more excitable neurons were allocated to creating the fear memory trace. In Han’s figure 2 they make the same findings. However Han is able to counter these findings and produce further, more convincing evidence by deleting the overexpressing CREB neurons and reversing this memory formation, essentially eliminating it. Thus Han uses memory loss as a more substantial piece of evidence for the role of these neurons in memory formation.