Scientists have discovered a previously unknown property of nicotine that helps strengthen the connections between particular types of neurons, potentially aiding in the basic processes of learning and memory.
In their studies, Mansvelder and colleagues found that by activating acetylcholine receptors, nicotine affects a process called "spike-timing-dependent potentiation" that governs changes in strength of signaling connections among neurons. What's more, the researchers traced this effect to nicotine's action on specific kinds of neurons, called GABAergic neurons, in the learning centers. In turn, the effects on GABAergic neurons affected signaling between neurons mediated by the key substance calcium.
For those of you who are not up on synaptic plasticity, calcium is one of the key components in mediating memory formation, helping to fuse new or weak synaptic connections into more permanent signaling pathways. By affecting "spike-timing-dependent potentiation", nicotine may lower the threshold of neural firing intensity needed to produce new synaptic bonds in the memory centers; thus, faster memory production with smaller neural spikes.
While this study hopes to pave the way for new treatments in Alzheimer's and other memory problems, it also goes a long way towards explaining why people with cognitive impairments have a much higher risk of nicotine dependence than others -- because it helps their brain function.
