According to Sumner "the music was loud and heavy, and we felt that Martin had toned it down, especially with the guitars". During their live performances, the group did not interact with the audience; according to Paul Morley, "During a Joy Division set, outside of the songs, you'll be lucky to hear more than two or three words. Hello and goodbye. No introductions, no promotion." Curtis would often perform what became known as his "'dead fly' dance", as if imitating a seizure; his arms would "start flying in [a] semicircular, hypnotic curve". Simon Reynolds noted that Curtis's dancing style was reminiscent of an epileptic fit, and that he was dancing in the manner for some months before he was diagnosed with epilepsy. Live performances became problematic for Joy Division, due to Curtis's condition. Sumner later said, "We didn't have flashing lights, but sometimes a particular drum beat would do something to him. He'd go off in a trance for a bit, then he'd lose it and have an epileptic fit. We'd have to stop the show and carry him off to the dressing room where he'd cry his eyes out because this appalling thing had just happened to him". Sumner wrote that Curtis was inspired by artists such as the Doors, Iggy Pop, David Bowie, Kraftwerk, the Velvet Underground and Neu!. Hook has also related that Curtis was particularly influenced by Iggy Pop's stage persona. The group were inspired by Kraftwerk's "marriage between humans and machines", and the inventiveness of their electronic music. Joy Division played "Trans-Europe Express" through the PA before they went on stage, 'to get a momentum". Bowie's "Berlin Trilogy" elaborated with Brian Eno, influenced them; the "cold austerity" of the synthesisers on the b-sides of "Heroes" and "Low" albums, was a "music looking at the future". Morris cited the "unique style" of Velvet Underground's Maureen Tucker and the motorik drum beats, from Neu! and Can. Morris also credited Siouxsie and the Banshees because their "first drummer Kenny Morris played mostly toms" and "the sound of cymbals was forbidden". Hook said that "Siouxsie and the Banshees were one of our big influences ... The way the guitarist and the drummer played was a really unusual way of playing". Hook drew inspiration from the style of bassist Jean-Jacques Burnel and his early material with the Stranglers; he also credited Carol Kaye and her musical basslines on early 1970s work of the Temptations.