I keep mine in indirect light, keep it moist at all times. Never overwater. Hope that helps a little. They dont like the heat.

Looks like D. 'Janet Craig.' G, how often do you water? My JC is doing the same.. Soil got way too dry. To be on the safe side, inspect the vase, nearest the top. Check for insects. Dracaena's are usually pest-free, but every so often, D. Corn Plant and D. Janet Craig acquire mealy bug. I'd cut brown leaves, then shower. Even though humidity is high, leaves need cleaning...

That IS very cool! Thanks so much for taking the time to share, WOW!! I like to make mini jungles in pots, and this seems like a grand version of that. Inspirational! I hope someone can recognize what is going on with your plant from the additional pics. I continue to suspect some kind of leaf-rolling caterpillar, w/o the benefit of being able to touch & examine in person. How long ago did you notice this? Has it continued to happen after removing it a first time? Are the last 3 close-ups in chronological order, or of different plants? If the former, what is the amount of time that lapsed between them?

why is the soil cold??? ... they are tropical plants ... they probably dont like that ... its stressed.. probably form you bringing it home .. light levels changing.. perhaps the a/c ... water when a plant needs water.. and if the soil is moist.. then it sounds like it should be ok ... it does need light ... is it near a window??? .. it doesnt look it in the pix ... but maybe you moved it for the pix ... its hard to believe.. that this all happened in one weeks since you bought it.. so im wondering what happened to it before you got it ... which we will never know ... note all the lower scars from old leaves removed.... this is annual and cyclical ... and increased by stress ... so it doesnt bother me all that much that a lower leaf has browned ... just snip it off.. and then when it dries pull whatever is left off the trunk ... but again.. how did it brown in one week??? try not to love it to death.. try to warm the soil a bit.. a sunnier location should help that ... ken