Enough has been written about the popular music 'revolution' of the 1960s, most of it being the somewhat lurid imaginings of journalists who didn't quite understand what was happening. Suffice to say that the USA's dominance in the field was overturned by an 'invasion' of British beat groups who had taken American music, repackaged it and then took it back to the land of its birth.
It took a couple of years for the Americans to respond and that came in 1965 from The Byrds, formed by two former folk singers Jim McGuinn and Gene Clark. (Jim McGuinn subseqeuntly changed his name to Roger for reasons which remain obscure.) Their first hit was a 'rock' version of Bob Dylan's Mr Tambourine Man which helped to inspire Dylan himself to change direction into this new 'folk rock' style.
"McGuinn developed two innovative and very influential styles of electric guitar playing. The first was "jingle-jangle" – generating ringing arpeggios based on banjo finger picking styles he learned while at the Old Town School of Folk – which was influential in the folk rock genre. The second style was a merging of saxophonist John Coltrane's free-jazz atonalities, which hinted at the droning of the sitar – a style of playing, first heard on the Byrds' 1966 single "Eight Miles High", which was influential in psychedelic rock."
The third video here features new band member Clarence White's famous 'string bender' guitar. Invented by White and drummer Gene Parsons this modified Fender is so famous it gets its own special mention on White's Wiki page.