Memory of Addiction

The specific neural mechanisms that mediate how drug memories are encoded, consolidated and stored are unknown. In order to address this issue, Hsiang et al. investigated this year which particular LA neurons are critical for encoding and storing a memory of the cocaine cue association in mice. They found that about 10% of LA neurons were recruited during cocaine conditioning using a conditioning place preference (CPP) paradigm. Moreover, neurons with increased levels of cyclic-AMP response binding element (CREB) during training –by means of infection with a viral vector- were preferentially allocated to the cocaine engram; while silencing neurons overexpressing CREB before testing disrupted the expression of the previously acquired cocaine memory. It is worth mentioning that overexpression of CREB results in increased neuronal excitability. From this and other studies, we conclude that LA plays a significant role in assigning biological salience to previously neutral cues, which in turn might posit it as a suitable target for pharmacological intervention. 

Reference:

1.     Hsiang HL, Epp JR et al. (2014) Manipulating a cocaine engram in mice. J. Neuroscience, 2014, 34(42):15115-14127.