Reddit mentions of MATLAB for Psychologists

Neuroscience is increasingly computational, both in the sense of studying the brain as a computer and in the sense of using a computer to study the brain. Learn to use Matlab - I would recommend either MATLAB for Neuroscientists or MATLAB for Psychologists depending on your ability and interests. Knowing programming and learning techniques early on is incredibly valuable. Volunteer in labs and learn these things, get excellent marks and get stellar recommendations. If you do this you should be fine.

EDIT: MATLAB for Neuroscientists is a bit more technical in nature and will require some exposure to calculus and linear algebra. The more complex bits will also likely require some familiarity with differential equations.

I just finished my Masters and this book helped me enormously with Matlab, which I used to program my dissertation project experiment.

It goes into some depth, but also takes you step-by-step through a few basic psychophysics experiment scripts, so sounds like it'd be right up your street.