[8] During the subsequent dissection of the monkeys, it was discovered that significant cortical remapping had occurred, suggesting that being forced to use limbs with no sensory input had triggered changes in their brains' organization.

He took a job as a research assistant in a neurology lab to gain more understanding of the nervous system and became involved in deafferentation experiments with monkeys.

Deafferentation is a surgical procedure in which the spinal cord is opened up and the sensory nerves cut so that these impulses do not reach the brain.

Norman Doidge writes that Taub wondered whether the reason the monkeys abandoned use of the deafferented limbs was simply that they were still able to use their good ones.

[12] Alex Pacheco (born 1958) was a graduate student at George Washington University when he volunteered in May 1981 to work as a research assistant in Taub's lab.

He worked on an anti-whaling ship for the Sea Shepherd Conservation Society, joined the Hunt Saboteurs Association in England, and when he returned to the United States to study political science at George Washington, he teamed up with Ingrid Newkirk, a local poundmaster, to form People for the Ethical Treatment of Animals in March 1980.

[13] Pacheco writes that 12 of the 17 monkeys had had one or both arms deafferented, while according to the Laboratory Primate Newsletter 10 had undergone deafferentation, the seven others acting as the control group.

[14] The researchers had named the monkeys Chester, Paul, Billy, Hard Times, Domitian, Nero, Titus, Big Boy, Augustus, Allen, Montaigne, Sisyphus, Charlie, Brooks, Hayden, Adidas, and Sarah.

He showed them in July to animal rights activists, including Cleveland Amory, who gave him money for a better camera and some walkie-talkies, so that a look-out outside could alert him if visitors arrived unexpectedly.

One local veterinarian, Richard Weitzman, agreed that the lab was very dirty, but said the monkeys seemed well fed and "in pretty good health".

[2] Pacheco reported the situation to the Montgomery County police, who raided the laboratory on September 11, 1981, under Maryland's Prevention of Cruelty to Animals law.

[2] The police removed the monkeys from the lab to the basement of a house in Rockville owned by Lori Kenealy of the local humane society.

In the meantime, Taub's lawyers went to court and demanded their return, and ten days after the raid a judge granted the request.

Five days later the monkeys were suddenly returned, this time with Spanish moss in their cages after a holiday in Florida, according to the activists.

During Taub's vacation that August, which lasted over two weeks, on seven different days in which the animals were supposed to have been fed and the cage area cleaned, the two caretakers failed to show up for work.

Taub estimated the probability of seven absences in that 2.5-week period at seven in a trillion based on the previous 14 months of attendance records from the workers.

[16] Norman Doidge wrote in 2007 that, according to Taub, the monkeys in the photographs had been placed in positions that were not part of the laboratory procedure, a claim Pacheco denied.

[17] As for the dirt, Taub said "monkey rooms are dirty places," and that it was normal in laboratories for fecal matter to lie on the floor and food to drop through the cage bottoms into waste trays.

[15] Based on the OPRR investigation, NIH suspended the remaining funding for the experiments, over $200,000 (equivalent to $670,000 in 2023),[18] because of violations of its animal care guidelines.

"Based on these observations," they wrote, "it would appear that fractures, dislocations, lacerations, punctures, contusions, and abrasions with accompanying infection, acute and chronic inflammation, and necrosis are not the inevitable consequences of deafferentation.

"[11] After the appeal, according to Doidge writing in 2007, 67 professional societies made representations on Taub's behalf, and the NIH reversed its decision not to fund his research.[20][why?]

In 1991 neuroscientist David Hubel, referring to both the Silver Spring monkeys case and a PETA film about the University of Pennsylvania's head injury clinic in 1984, said the science was sound, that the people involved were not cruel, and that at the time there was a "laxness of standards" in animal care that, he wrote, would hardly be conceivable today.

The judge—District Court Judge Stanley Klavan—found Taub guilty of six counts of cruelty to animals for failing to provide adequate veterinary care in respect of six of the monkeys and acquitted him of the other 11 charges against him.

After three weeks at the Montgomery County Circuit Court, a jury acquitted him of five of the convictions, and upheld the sixth charge of inadequate veterinary care of Nero, whose wounds were such that an NIH veterinarian later amputated his deafferented arm.

The sixth charge was set aside on appeal, when the court ruled that Maryland's Prevention of Cruelty to Animals law did not apply to federally funded laboratories.

PETA also hired Tom Vice, a consultant veterinarian associated with the non-profit Primarily Primates to assess Billy, one of the monkeys set to be euthanized by Tulane.

Billy had two disabled arms, extensive pressure wounds, diaper rashes, bone infections, and kidney damage from antibiotic use.

"[26] After the court denied custody to PETA, two of the monkeys, Titus and Allen, were kept for the National Institutes of Health at a Tulane University primate center, where they were later euthanized.

Brainmapping studies were conducted on the remaining monkeys on July 6, 1990, three days after PETA's application for custody was rejected.

[29] Based in part on his work with the Silver Spring monkeys, Taub went on to develop novel physical therapy techniques to help stroke victims, and those with other forms of brain injury, regain the use of affected limbs.