25 April 2012 Last updated at 07:17 ET 
Breivik has argued he should either be put to death or acquitted
The court is discussing two psychiatric reports that came to opposing views on his sanity.
The court earlier heard more testimony from victims of the Oslo bombing.
Breivik, 33, admits to killing 77 people in Oslo and on Utoeya island but denies criminal responsibility.
'Death or acquittal' The BBC's Lars Bevanger in Oslo says Wednesday's evidence is crucial from Breivik's point of view.
The decision on Breivik's sanity will determine whether he is sent to jail or a psychiatric institution. The five-strong panel of judges will make the ruling at the verdict in July.
Breivik is arguing against the first psychiatric report, which found him legally insane and suffering from paranoid schizophrenia, and in favour of the second, which concluded he was accountable for his actions.
He told the court that the psychiatrists compiling the first study had failed to understand he had deliberately suppressed his emotions to prepare for attacks.
Breivik has said committal to a psychiatric ward would be a fate worse than death and he would do "anything to prevent" it.
Breivik himself has argued he should either be put to death or acquitted.
Our correspondent says most people in Norway who have been following the trial expect Breivik to be found sane, given the way he has conducted himself in court.
If so he could face 21 years in jail, which can be extended if he is thought a continuing danger to society. He would face compulsory psychiatric care if found insane.
Earlier, the court heard more testimony from those injured in the Oslo blast and more forensic evidence of the explosion.
Passer-by Eivind Dahl Thoresen described seeing flames out of the corner of his right eye, lifting his hands to his face and being thrown backwards.
Deafened, he said he tried to help another injured man before noticing he was himself bleeding heavily and lay down, shouting for help.
The prosecution also read a statement on behalf of another blast victim, who lost a limb.
Our correspondent says these are some of the first tales of the many victims of the July attacks and over the next eight and a half weeks of the trial, there are sure to be many more harrowing stories to come.
He says that in a few weeks time there will be 69 more coroner's reports - one for each of the deaths at the Labour Party youth camp on Utoeya island.
Relatives of victims sobbed during the evidence on both Tuesday and Wednesday.
Breivik watched the witnesses without any visible emotion.
On Wednesday he said if anyone should apologise for the killings it should be the ruling Labour Party.
"But instead they continue in the same direction, so the grounds for struggle are unfortunately even more relevant now than before July 22."
Breivik spent the first week of the trial giving his own version of events, saying his plan was to kill as many people as possible.
He says he was defending Norway from multiculturalism.
Anders Behring Breivik says insanity report '80% lies'
Breivik has argued he should either be put to death or acquitted Anders Behring Breivik has told his trial in Oslo that "80%" of a psychiatric report that found him insane in relation to his 77 killings in two attacks last July is "lies".
Breivik has returned to the stand to argue he is sane and should not be committed to a mental institution.The court is discussing two psychiatric reports that came to opposing views on his sanity.
The court earlier heard more testimony from victims of the Oslo bombing.
Breivik, 33, admits to killing 77 people in Oslo and on Utoeya island but denies criminal responsibility.
'Death or acquittal' The BBC's Lars Bevanger in Oslo says Wednesday's evidence is crucial from Breivik's point of view.
The decision on Breivik's sanity will determine whether he is sent to jail or a psychiatric institution. The five-strong panel of judges will make the ruling at the verdict in July.
Breivik is arguing against the first psychiatric report, which found him legally insane and suffering from paranoid schizophrenia, and in favour of the second, which concluded he was accountable for his actions.
He told the court that the psychiatrists compiling the first study had failed to understand he had deliberately suppressed his emotions to prepare for attacks.
Continue reading the main story 
The first of Anders Behring Breivik's surviving victims has given evidence in court. Eivind Dahl Thoresen, a 26-year old-law student, recalled how he was blown over as he walked only metres from the car bomb in Oslo while chatting about the Tour de France with a friend on his mobile phone.
He told the court how he came to be covered in blood. The paramedics who took him away in an ambulance were worried there might be another bomb about to go off. Nine months on, Mr Thoresen still needs crutches and has reduced use of one arm.
Earlier the court heard coroner's reports of those who died in the blast outside the government buildings. The details have been too gruesome for media here to report, but spoke of the extreme violence caused by the bomb. Families of the dead have been listening to all this in court, while Breivik has remained largely motionless and appearing interested yet emotionless throughout.
At the scene
He told the court how he came to be covered in blood. The paramedics who took him away in an ambulance were worried there might be another bomb about to go off. Nine months on, Mr Thoresen still needs crutches and has reduced use of one arm.
Earlier the court heard coroner's reports of those who died in the blast outside the government buildings. The details have been too gruesome for media here to report, but spoke of the extreme violence caused by the bomb. Families of the dead have been listening to all this in court, while Breivik has remained largely motionless and appearing interested yet emotionless throughout.
He said: "It is not me who is described in that report... Everything I presented was entirely logical. I don't see the slightest possibility I will be judged insane."
Our correspondent says this is a key issue for Breivik, who wants to show his actions were motivated by a political ideology.Breivik has said committal to a psychiatric ward would be a fate worse than death and he would do "anything to prevent" it.
Breivik himself has argued he should either be put to death or acquitted.
Our correspondent says most people in Norway who have been following the trial expect Breivik to be found sane, given the way he has conducted himself in court.
If so he could face 21 years in jail, which can be extended if he is thought a continuing danger to society. He would face compulsory psychiatric care if found insane.
Earlier, the court heard more testimony from those injured in the Oslo blast and more forensic evidence of the explosion.
Passer-by Eivind Dahl Thoresen described seeing flames out of the corner of his right eye, lifting his hands to his face and being thrown backwards.
Deafened, he said he tried to help another injured man before noticing he was himself bleeding heavily and lay down, shouting for help.
The prosecution also read a statement on behalf of another blast victim, who lost a limb.
Our correspondent says these are some of the first tales of the many victims of the July attacks and over the next eight and a half weeks of the trial, there are sure to be many more harrowing stories to come.
He says that in a few weeks time there will be 69 more coroner's reports - one for each of the deaths at the Labour Party youth camp on Utoeya island.
Relatives of victims sobbed during the evidence on both Tuesday and Wednesday.
Breivik watched the witnesses without any visible emotion.
On Wednesday he said if anyone should apologise for the killings it should be the ruling Labour Party.
"But instead they continue in the same direction, so the grounds for struggle are unfortunately even more relevant now than before July 22."
Breivik spent the first week of the trial giving his own version of events, saying his plan was to kill as many people as possible.
He says he was defending Norway from multiculturalism.
