Ariel Sharon, the former Israeli prime minister who has been in a coma for seven years, has shown significant signs of brain activity, doctors say.
A team of Israeli and American scientists say new tests showed he responded to external stimuli.
The activity increased when he was being shown pictures of his family and played a recording of his son's voice.
The 84-year-old has been in a coma since 2006, when he suffered a massive stroke.
Since then, he has been in a vegetative state, connected to a respirator.
The doctors at Soroka Hospital in Beersheba said that during tests, "significant brain activity was observed... indicating appropriate processing of these stimulations."
While the responses did not mean Mr Sharon was likely to fully regain consciousness, doctors said they were "encouraging".
Alon Friedman, a neurological director at Israel's Soroka Medical Centre in Beersheba, said the findings suggested that even in Mr Sharon's comatose state, "he might be listening, and some important information goes into his brain and is being processed".
Mr Sharon was a storied military officer who fought in three wars before entering politics.
He was admired by many Israelis as a great military leader, but reviled by Palestinians.
He was elected prime minister in 2001, pledging to achieve "security and true peace", and served until his stroke in 2006.
In 2005, he unilaterally withdrew Israeli troops and settlers from Gaza.
Mr Sharon was a keen promoter of the expansion of the building and expansion of settlements in the occupied territories. He also initiated the construction of the separation barrier along the border and inside the West Bank.
But late in his career, despite fierce opposition in Israel, he ordered Jewish settlers to leave Gaza and four settlements in the West Bank.
As defence minister, Mr Sharon masterminded Israel's invasion of Lebanon in 1982. During the invasion, Lebanese Christian militiamen allied to Israel massacred hundreds of Palestinians in two refugee camps under Israeli control.