A system and method for sensing phase errors in a multiple receiver array use three non-collinear transmitters transmitting first, second, and third signals to a target and receiving corresponding signals reflected from the target using the multiple receiver array. Methods of the invention include administering, an effective amount of GDF-1 alone or in combination with neurotrophin-3, to a patient in need of such treatment such as a person suffering from stroke or traumatic brain injury or a neurodegenerative disease. Disclosed is an approach that uses a single plug-in sensor to detect a variety of electrical events throughout the home. In a preferred exemplary embodiment, only a selected number of pixels are monitored for exposure control as opposed to monitoring the entire pixel array.