Its interesting also that :
http://www.fireflywiki.org/Firefly/SummerGlau
A prima ballerina (also training in flamenco and tango) born and trained in San Antonio, Texas, Summer Glau made her television debut as the ballerina in the "Angel" episode "Waiting in the Wings", as well as appearances in several commercials. She plays River Tam.
River Tam:
"River - the Strange Little Girl (played by Summer Glau)
A hyper-intelligent child of privilege, River discovered that the Academy in which she'd enrolled was more of a torture center than a school. No one knows yet what The Academy did to her before her brother Simon stole her back, because she's still too traumatized to tell them.
But she and Simon need to keep running—because the Academy wants their experiment back.
River was born with a mind of unparalelled brilliance. While Simon was smart enough to become a gifted doctor in the top 3% of his class at the finest medical institution, River was so bright she corrected her older brother's spelling by the time she was three years old, and even found mathematical errors in his textbooks. Their parents spoiled them and lavished them with luxuries, even signing River up for the most challenging of education programs: The Academy. Simon and his parents thought nothing of it; she was an exceptional child and belonged in an educational institution that could cater to her needs—but after a few months, Simon received a perplexing letter from her. There were misspellings and references to individuals who did not exist, to events which never happened. Simon theorized that the letter was written in some kind of code. His parents refused to take Simon's fears seriously, believing River was just being playful and Simon was irrationally overreacting to River's absence. They were wrong.
While her family thought she was safe, The Academy was actually a scientific installation (likely funded by the Blue Sun corporation). Simon decoded his sister's letters and set out to try to get her back, seeking someone, anyone—even those living in Blackout Zones—who could help him help his sister escape. Money changed hands, and soon thereafter Simon found himself captured by the local federal authorities—his father had to come down to bail him out. Upset that bailing his son out had tarnished his reputation, Gabriel Tam told Simon to give up his ridiculous mission, and Simon cut his ties to his parents by refusing to do so.
So.
Simon made arrangements for stealing River from The Academy, then made his way to Persephone and the Eavesdown Docks slums. There, he met with the people delivering cargo containing his sister in stasis from which she was later awakened on the Firefly Transport Serenity. Blue Sun still considers River their property, and they will stop at nothing to get River back.
Unfortunately, exactly what River is now remains uncertain. River's brain was operated on countless times while The Academy had her in its clutches, and she was treated for all intents and purposes like a laboratory animal. Simon was able to perform diagnostic tests and now knows for certain that, among other things, they cut into her brain multiple times. They even stripped her amygdala, which is a part of the brain used to control emotional responses and 'filter' incoming information. As he describes it: "She feels everything; she can't not." The R. Tam sessions, recorded at The Academy, show River's slow descent into her current state.
Precisely why they did these things to her is unknown. The most likely purpose was to turn her into a sort of assassin or spy. However, since the series was unceremoniously cut short, any answers to the uncertainties of motivation are assumptive. We do know to a degree of what she is capable.
* River has taken a firearm and, after a brief glance to ascertain their position, closed her eyes and killed three men with three shots.
* She has snuck on board a bounty hunter's ship without the bounty hunter's knowledge and thwarted his attempts to take her back to Blue Sun.
* She has shown an aptitude for extraordinary assimilation of knowledge and data recall, empathy, and even what appears to be some form of psychic "reading" ability.
o She has been known to make statements, sometimes cryptic and sometimes direct, which sound as if she can read someone's mind or know of events in a stranger's past which she could not have known.
o She has never shown an indication of being able to predict the future, but she can seem to extrapolate probable outcomes based on past experience and knowledge.
o She can just look at an individual and glean more about their history and personality than some could learn from a person in years of friendship. Sometimes her statements are hard to decipher because she talks in a way that she understands but others have difficulty comprehending.
* And she's a hell of a dancer.
River's state of mind is inconsistent and unpredictable. Simon Tam administers semi-regular treatments of medication that seem to improve her ability to cope with her own mental damage for short periods of time, but these treatments have side-effects which leave her physically ill. When in good spirits, River likes playing with Kaylee and occasional practical jokes with the crew. She's potentially very dangerous, however. She caused damage to Jayne on one occasion, slashing him in the chest with a large knife (but... was she attacking him or the Blue Sun logo on his shirt?). "
And in Terminator, she plays the Terminator reprogrammed to help John. There it is again, the same role.
http://en.wikipedia.org/wiki/Summer_Glau
"Summer Lyn Glau (born July 24, 1981) is an American dancer and actress, known for playing River Tam in the short-lived science fiction series Firefly and follow-up movie Serenity, and for playing Cameron in the series Terminator: The Sarah Connor Chronicles."
http://terminatorwiki.fox.com/page/Summer+Glau?t=anon
"“
I am supposed to look like an innocent teenage girl. I go to school with him, which is really funny,” said Glau. “Cameron can be tough and cold and a Terminator in one breath and then in the next breath, she can be this vulnerable, child-like character, because she is absorbing everything around her for the first time. This reality, and going back in time, and trying to blend into normal society is new for her.”"
"That same year she also appeared in three episodes of the third season of Coppola's The 4400, reprising her role of Tess Doerner already played in one of the second season's episodes in 2005. The part of Tess had been written especially for her after she had to step back from playing the part of Lily Moore because of conflicting schedules with the shooting of Serenity. Summer also got cast as Crystal Burns in the second season of CBS' military drama The Unit. She guest starred in six episodes throughout the season, co-staring with her real-life boyfriend, fellow Texan actor Daniel Wisler, who played her on-screen boyfriend on the show. In 2007 Summer came back as a guest for five episodes on The 4400. She also started working mid-year on a new highly secret project. In late 2007 and after much speculation, it was finally revealed that Summer was going to portray
Cameron Phillips, a terminator allied to the human resistance, in the upcoming film tie-in television series Terminator: The Sarah Connor Chronicles. Most recently, Joss Whedon revealed to the press that he was currently working on the score of a ballet movie
The Serving Girl and that Summer will be playing the lead character."