UPDATE 4.42pm:  "The phrase 'child killer' ... has a very terrible ring to it. That's what a guilty verdict means for this woman."

As Jayde Poole's defence counsel urged the jury to acquit her of manslaughter, the Bendigo mother sat with her family in court, clutching her father's hand and wiping tears from her cheeks.

Poole is charged with the manslaughter of her five-month-old daughter Bella, who died from heatstroke after being left in a hot car for more than two hours in December 2012.

She has pleaded not guilty to the charge.

During his closing address, defence barrister Shane Gardner said his client accepted moral responsibility for her daughter's death, but argued her actions were not deserving of criminal punishment and urged the jury not to "stamp her as a criminal".

He told the jury Poole had waived her right to silence and a lawyer, and never tried to shift the blame for her daughter's death.

He said Poole's full cooperation with police while in the "throes of acute grief" showed she had nothing to hide.

Mr Gardner argued the act of forgetting was not something done consciously, or deliberately and therefore should not constitute the criminally negligent breach of duty required to find his client guilty of manslaughter. 

He said expert evidence from a researcher into the phenomenon of "forgotten baby syndrome" suggested Poole's mind had played a trick on her, leading her to believe her daughter was safely sleeping in her cot. 

He compared Poole's behaviour to that of a parent who decided to leave its child in the car while playing pokies, or to allow the child to continue sleeping and then forgot to remove it - scenarios he suggested were clear examples of gross negligence.

"What you've got is a tragedy of a woman who forgot," Mr Gardner said.

"This is not a person who contributed to her ability to remember or forget, by any voluntary or discreditable behaviour or intervention, or some selfish pursuit of her own needs.

"This is an accident for which she will exist in a living hell for the rest of her days.

"Not in every case do we as a society need to declare that someone's criminally responsible. I urge you to set her free, set her free in the sense of her legal responsibility because of course you know she'll never be truly free."  

Following the closing addresses, Justice Bernard Bongiorno began his directions to the jury before adjourning the case until tomorrow.

UPDATE 3pm: The prosecution has delivered its closing address in the Supreme Court trial of a Bendigo mother charged with the manslaughter of her infant daughter.

This afternoon, prosecutor Nicholas Papas QC told the jury Jayde Poole was a capable and caring mother who breached her duty of care to her five-month-old daughter Bella with tragic consequences.

He said Poole was distracted by her eldest child during a drive to treat him to takeaway food and failed to do what would be expected of a reasonable mother.

"Human frailty is a standard condition, and all of us make mistakes," Mr Papas told the jury.

"(But) this is not about moral responsibility, this is about criminal responsibility. If your child is in the car on a hot day and you have strapped them in, your duty of care is to take them out, immediately.

"It was such a short trip, how could she forget?"

Mr Papas argued the duty of care was so fundamental that the failure to remove such a young, vulnerable child from the car, for any reason, was a gross breach of duty.

"​​We say, and this is the tragedy of the whole thing, we say that in trying to do a good deed for one child she's breached her duty in relation to the other child in such a serious manner that it meets the test of gross negligence manslaughter."

Mr Papas said while the defence's expert evidence suggesting Poole's brain had been acting on "autopilot" when she failed to remove Bella from the car was interesting, he argued it was only a theory which could not rely on a substantial body of collaborative research.

"He's really working on the edge of established science, he's working on his own, he's theorizing" he said.

More to come.

UPDATE 1.50pm: A researcher into the memory function of parents who have accidentally left children in a car has told a Supreme Court jury Jayde Poole was likely to have been acting "on autopilot" on the night her five-month-old daughter Bella died.

University of South Florida behavioural neuroscience professor David Diamond said the act of Poole driving home would have been so habitual, it would have been controlled by a part of the brain which causes a person to act without thinking about their actions.

Dr Diamond said when that part of the brain was activated, it could suppress the brain's ability to process and remember new information like placing a child in the car.

He said research suggested a poor night's sleep, heightened stress, or a lack of appropriate cues such as a child crying or interacting with the parent, could increase the likelihood someone would act on autopilot.

"In every single case the child is quiet for the entire drive, presumably sleeping, there is no indication that the child is in the car, such as a reminder in the front seat, such as a diaper bag, or a bottle," Dr Diamond said.

"The observation that I would make based on Jayde's deposition is consistent with so many reports in which parents state that they had absolutely no awareness that the child was in the car.

"From a neuroscience perspective, what seems to be happening in this case and in so many other cases is that the brain actually seems to fill in the memory gap.  The brain actually creates an alternative reality that the child must be safe. 

"In the current case what is very clear is that Jayde believed that Bella was safe and sleeping in her bedroom, and so the brain has created, in a sense, a reality to fill in the memory gap."

Under cross examination, Dr Diamond told the court he seemed to be the only person looking at the phenomenon of "forgotten baby syndrome" and conceded it was not a medical condition which indicated any damage or disease in the brain.

More to come.

EARLIER: DAY five of Jayde Poole's Supreme Court manslaughter trial has heard expert evidence from a researcher into "forgotten baby syndrome".

Poole is charged over the death of her five-month-old daughter Bella, who died from heatstroke after being left in a hot car for two hours in December 2012.

This morning, Poole's defence called its only witness, a University of South Florida behavioural neuroscience professor who specialises in research into what is colloquially referred to as "forgotten baby syndrome".

Dr David Diamond, who appeared via video link from the United States of America, said the circumstances of Bella's death were consistent with about 200 known child fatalities from the syndrome worldwide.

He told the court he believed any person was capable of leaving a child in a car.

The court was read a quote from Dr Diamond, taken from an American newspaper article.

"Memory is a machine. It is not flawless," it heard.

"Our conscious mind prioritises things by importance but on a cellular level, our memory does not.

"If you're capable of forgetting your cell phone, you're potentially capable of forgetting your child."

More to come.