(CNN) -- The man who allegedly assaulted GOP Sen. Rand Paul outside his Kentucky residence pleaded not guilty Thursday to misdemeanor assault in the fourth degree at his arraignment in Bowling Green.
Rene Boucher allegedly tackled Paul, breaking six of his ribs and sustaining bruised lungs. There was no change to the charges and no change in bond.
Doug Stafford, a senior adviser to Paul, told CNN Thursday that Boucher attacked the senator without any prior conversation.
"Last week, Sen. Paul was vigorously assaulted by someone in his neighborhood. This is a serious criminal matter involving serious injury, and is being handled by local and federal authorities," Stafford told CNN in a statement. "As to reports of a longstanding dispute with the attacker, the Pauls have had no conversations with him in many years."
He continued: "The first 'conversation' with the attacker came after Sen. Paul's ribs were broken. This was not a 'fight,' it was a blindside, violent attack by a disturbed person. Anyone claiming otherwise is simply uninformed or seeking media attention."
Boucher's attorney, however, told CNN that Paul has hired a personal injury attorney to file a claim for damages against his client.
When pressed for a motive, attorney Matt Baker told CNN that "we should believe" Jim Skaggs, the developer and neighbor who sold both men their homes. While he did not witness the incident, Skaggs has said Boucher and Paul have been quibbling over lawn maintenance for years.
"It was absolutely and unequivocally not about politics, not about right versus left and not about Democrat versus Republican," Baker said.
Baker added that Boucher has been interviewed by US Capitol Police, who he said were interested in whether the incident was politically motivated. Baker said Boucher cooperated fully and reiterated that Boucher's liberal beliefs have nothing to do with the alleged assault.
"It's a personal dispute between two neighbors," Baker said.
He added: "If (Boucher) had to do it over again, I can assure you that it might have been handled much more diplomatically."
Paul tweeted Wednesday night, "I appreciate all of the support from everyone. A medical update: final report indicates six broken ribs & new X-ray shows a pleural effusion."
He also tweeted, separately, a Breitbart News article and a Washington Examiner article that publishes neighbors' statements disputing Skaggs, saying the issue goes beyond quibbling about their yards.
CNN previously reported that Boucher posted $7,500 bail.
According to the Bowling Green Daily News, Boucher is an anesthesiologist and pain specialist, and Boucher's attorney's statement noted that he and Paul worked together when they "were both practicing physicians."