Hakini

This is a term in the liturgy. It refers to the goddess as expressed through the Ajna chakra, whose energy is a merging of the energy of Shiva and Shakti, male and female.

more here:
http://www.tantra-kundalini.com/ajna.htm

you can perform the Hakini mudra; it will help with concentration and memory:
http://www.panjokutch.com/Health/mudra/hakiniMudra_1.htm
http://cgullworld.blogspot.com/2007/11/hakini-mudra-for-memory.html