Neuron involved in<unk>  work multiplicatively, taking the input from several together to form the<unk><unk> . It is this process that allows the complexity of motor control. Instead of simply<unk>  the motion of the limb in which a specific motion is desired, the multiplicative nature of the<unk><unk>  ensures that the positioning of the rest of the body is taken in to consideration. This process allows for motor coordination of flexible bimanual actions as opposed to restricting the individual to unimanual motion. For example, when considering the movement of both arms, the body calls upon<unk><unk>  models for each arm in order to compensate for the mechanical interactions created by both. Location Most<unk><unk>  activity is based in the premotor cortex found in the frontal lobe anterior to the primary motor cortex, however it receives input from a variety of locations in the brain. These incoming signals provide frame of reference information through the individual's senses. Further evidence suggests that the cerebellum and posterior parietal cortex (PPC) also play major functional roles in<unk> . The intrinsic and extrinsic properties of the<unk><unk>  can be shown as products of the PPC. In Brodmann area 7 of the PPC, the positioning of objects with respect to the eyes is represented completely extrinsically with no input from the positioning of the body involved. This opposes the case of other parts of the PPC such as Brodmann area 5 which represents objects in relation to body defined coordinates. Due to the extrinsic and intrinsic properties of motor functioning, it is speculated that these types of signals are both taken multiplicatively to form the<unk><unk> . With input from each area, a three-dimensional representation of the objects in space can be arranged for use by the rest of the motor system. Unsurprisingly lesions in the parietal cortex lead to deficiencies in an individual's spatial movements and coordination and, in some cases, hemineglect. These effects were widely variable from person to person and depending on the location of the lesion further hinting at the complicated nature of<unk>  modulated neurons.<unk>  Modulation One of the key components of<unk>  is the variability in the response amplitude of the action potentials from neurons. This variability, when independent of change in response selectivity, is called<unk>  modulation.<unk>  Modulation takes place in many cortical areas and is believed to be a common mechanism of neuronal computation. It allows for the combination of different sensory and cognitive information. For example, neurons implicated in processing a part of the visual<unk>  see again in the response amplitude due to shifting focus to that part of the<unk>  of vision. Therefore, neurons that are<unk>  modulated can represent multiple types of information. The multi-modal nature of these neurons makes them ideal for specific types of computations, mainly coordinate transformations. This creates the ability to think spatially, the main contributor to physical coordination.<unk>  Process The<unk>  of the neurons involved in the motor<unk><unk>  follow the same<unk>  modulation principles as most of the neurons within the brain. That is to say, when<unk>  is increased, the connections between the neurons firing increase in strength leading to further<unk>  if the neurons continue to receive stimulation. This observation is why repetition of a particular set of motions is what leads to muscle memory. Coordinate Manipulation One of the main results of<unk>  is the cognitive ability to manipulate different coordinate planes that are dealt with daily and adjust limb muscle movements accordingly. A good example of this is moving a pointer across a computer screen with a mouse. Depending on the relative location of the user's head to the computer screen as well as the angle at which the screen is being observed, the user's perspective of the screen will be very different. A mentally mapped grid of the screen appears much larger when the user is closer to the screen as opposed to further away, and it is the brain's ability to keep a consistent mental representation that gives people the ability to function under such dynamic conditions.
Gain-field encoding
Lewis offset
Extraction ratio
Countercurrent distribution
Stabilized images
Spin–lattice relaxation
Independent SAGE
Peak kilovoltage