In the fictional Battle Tech universe, a neurohelmet is a helmet-like device which the pilot of a battlemech wears in order to provide fine control of balance, as well as containing a display.
The primary function off the neurohelmet is to provide balance information to the battlemech, allowing relatively smooth walking movement, and some degree of recovery in cases of loss of footing. Functionally, this system is attuned to a small number of people (though usually only the primary pilot and his/her assigned technician) and has the ability to identify certain patterns in their brain waves. This allows the neurohelmet to recognize the pilot's reaction to poor balance situations and take automatic action accordingly.
This system also functions as security system for the battlemech. Battlemech security systems use a combination of voice recognition, alpha-wave (brain pattern) recognition, and sometimes an electronic combination lock. When an unauthorized user attempts to start the battlemech, a shock will be administered through the neurohelmet and an alarm will sound.
The display inside the neurohelmet, sometimes referred to as "Circle Vision", has a 360 degree field of view around the battlemech. This is achieved by having two screens, one atop the other. the two screens terminate at the 90 and 180 degree mark. As such, anything directly ahead or behind of the battlemech would be in the center of one of the screens, while objects directly to either side would appear to be split, partially existing on one end of each screen. A similar system is used in battle armor, tanks, and aircraft.
As neurohelmets tend to be heavy, they are supported on either side of the pilot's head by his/her cooling vest. This vest provides padding to prevent chafing. Those neurohelmets manufactured by the Clans tend to be both smaller and lighter.