deathly howling at the corner of the room

If you just saw it once out of context you would think my cat calie was talking to poltergeists or god or something, and the cry is horribly disturbing. It normally happens at night when i go to bed she will be laying with me, but about an hour later as i am falling asleep she will wake me with this painful meow. She always goes to the same place, in the master bathroom off from the bedroom, she will jump to the bathtub, then up to the counter, and then she will face the corner there while sitting on the counter and look straight up at the ceiling and let loose with the howl.

When she sees that i wake up she will turn quickly and look at me and start with these pleading meows that i just dont even know what to do with. I tried turning on the sink to a trickle to see if she is begging for water but she just turns back to the corner and pleads more. I inspected the corner many times and there is nothing there. On the other side of that wall is the backyard. I don't feel any breeze going on like if the wall was cracked or something.

Usually i bring her back to bed. If i do she will return to the corner in an hour or so. If i ignore her and dont bring her back to bed, she will usually stop howling after about 10 minutes and then she is calm for the night. So my best option is to ignore her as best as i can.

Also, there is this look she gets in her eyes and movements with her head that i recognize happen at other times. Usually when she is in that 'mood', she is always stubbornly trying to climb to the highest place in the room. And then when she gets high enough, she will begin calling out. I come to her and pick her up and set her down on the ground again. But this routine doesn't seem to accomplish anything at all.

She is currently on tapazole to keep her weight up. But I wasn't warned about any behavioral side effects. So I'm wondering, is this calling she does somehow her way of still looking for a mate at night?? And whatever it is, is there something that can be done or should be done to calm her down?

Could she be hearing things in the wall? I know one year my parents had mice in the wall and it would drive the cats crazy. But we could hear them too.

My first thought is that she hears something in the ceiling. But if she hasn't been spayed, calling for a mate is a huge possibility!

Well, when my cats do this, they are making a little play; they are asking for drama.

Mr. Bond will go out in the hall and wail, as he does when I am away or late. But in this case I'm in bed and he knows it. I call him, saying how much I miss him, and he comes bounding into bed for a cuddle.

I had a Maine Coon mix who loved to hide in the basement, so I could play "Lost Bubby." He wouldn't come out until I came down and searched for him so we could have a big, scenery chewing, reunion.

If you have eliminated medical issues, it could be as simple as her feeling ignored. If she acts like she is in distress, and you come to her rescue, she will once again feel loved.

Obviously, I'm not saying to encourage this behavior at bedtime or at other times when it is annoying. But make a big fuss over her when you have time, and tell her how much you care. See if that changes this behavior.

I had a Maine Coon who did something similar when she was older. She'd sit in the bathtub and yowl, or she would pick a spot far away and yowl like she was lost.

I suspected that because she was old, it was the beginnings of dementia.