Editing Penmanship (section)

== Motor control ==

Handwriting requires the [[motor coordination]] of multiple joints in the [[hand]], [[wrist]], [[elbow]], and [[shoulder]] to form letters and to arrange them on the page. Holding the pen and guiding it across paper depends mostly upon sensory information from skin, joints and muscles of the hand and this adjusts movement to changes in the friction between pen and paper.<ref>[[Francesco Lacquaniti|Lacquaniti F.]] (1989). Central representations of human limb movement as revealed by studies of drawing and handwriting. Trends Neurosci. 12(8):287-91. {{doi|10.1016/0166-2236(89)90008-8}} {{PMID|2475946}}.</ref> With practice and familiarity, handwriting becomes highly automated using motor programs stored in [[motor memory]].<ref>van der Plaats RE, van Galen GP. (1990).Effects of spatial and motor demands in handwriting. J Mot Behav. 22(3):361-85. {{PMID|15117665}}.</ref> Compared to other complex motor skills handwriting is far less dependent on a moment-to-moment visual guidance.<ref>Marquardt C, Gentz W, Mai N. (1999). Visual control of automated handwriting movements. Exp Brain Res. 128(1-2):224-8. {{PMID|10473764}}.</ref><ref name="Hepp-Reymond">Hepp-Reymond MC, Chakarov V, Schulte-Mönting J, Huethe F, Kristeva R. (2009).  Role of [[proprioception]] and vision in handwriting. Brain Res Bull. 79(6):365-70. {{PMID|19463909}} {{doi|10.1016/j.brainresbull.2009.05.013}}.</ref>

Research in individuals with complete [[Neuropathy|peripheral deafferentation]] with and without vision of their writing hand finds increase of number of pen touches, increase in number of inversions in velocity, decrease of mean stroke frequency and longer writing movement duration. The changes show that [[cutaneous]] and [[proprioceptive]] feedback play a critical role in updating the motor memories and [[internal model (motor control)|internal models]] that underlie handwriting. In contrast, sight provides only a secondary role in adjusting motor commands.<ref name="Hepp-Reymond"/>