April 2025 — Monkeys subjected to brain lesions, prolonged captivity, and distressing testing—using taxpayer dollars
Many Australians are shocked to learn that primate experimentation is still taking place in their own backyard. A recently published study (Feizpour et al., 2024) has revealed deeply concerning details about invasive brain research carried out on macaques at Monash University.
The study—funded by the Australian Research Council through its Centre of Excellence for Integrative Brain Function—explored the role of the frontopolar cortex, a brain region involved in decision-making. But to do so, researchers inflicted deliberate brain damage on four macaques. These intelligent, social animals were surgically mutilated, subjected to prolonged periods of captivity, and forced to perform repetitive cognitive tasks under distressing conditions.
What the Research Involved
Researchers performed bilateral frontopolar cortex lesions, a highly invasive procedure requiring the removal of part of the skull and brain tissue. After the surgery, the monkeys were given just two weeks to recover before returning to intense cognitive testing. While general anaesthesia was used during surgery, the study fails to clarify whether adequate pain relief was provided beyond the first day—despite the clear likelihood of prolonged suffering from such invasive procedures.
Safe, affordable pain management was available. Yet the incomplete reporting raises the grim possibility that these animals may have endured significant and unnecessary pain throughout recovery. Headaches and other post-operative symptoms in nonhuman primates are difficult to detect and easy to overlook.
There was also inconsistent information about infection prevention after the day of surgery, adding further risk to the monkeys’ welfare.
Distress Beyond Surgery
The suffering didn’t end with the surgery. The macaques were housed in sterile research facilities, far from the complex and stimulating environments they need to thrive. During testing, they were placed in restrictive cages and required to complete repetitive cognitive tasks using a touchscreen interface. These tasks were likely conducted under food restriction, as rewards for correct responses were banana-flavoured pellets—an indication their daily food was contingent on test performance.
A macaque in their cage being fed and macaques with their infants in caging at Monash University’s primate breeding and research facility at Gippsland (released under Freedom of Information request by AFSA).
AFSA Primate Campaign Consultant, Robyn Kirby said
The repeated training these monkeys had to suffer, failing their tasks and their isolation from other monkeys, would likely have caused extreme psychological stress, frustration, and anxiety.
Testing Procedures in Detail
The monkeys were first trained on a “Go” task requiring them to release a switch and select a matching image within a very short time frame (1300 milliseconds). A second “Stop” task required them to inhibit their actions when shown a red cross, a challenging behaviour even for humans. Once baseline data was collected, the monkeys underwent the damaging brain surgery. After only two weeks of recovery, testing resumed for another 15 sessions to assess the effects of the lesions on decision-making performance.
These animals were never referred to by name—only as M157, M51, M62, and M71. Their fate after the experiment remains unknown. Given standard practices in primate research, it is likely they were subjected to further procedures or euthanised once deemed no longer useful.
AFSA asks “Were These Experiments Justified?”
In addition to the four macaques, 58 human volunteers also performed computerised versions of the same tasks. However, the scientific gain from comparing these species was minimal, given that the role of the frontopolar cortex in decision-making was already well understood.
AFSA consulted Professor Jan Lauwereyns, a bioethicist and former primate researcher from Kyushu University in Japan who commented:
“This detailed lesion study is an unremarkable achievement—equivalent to a colouring exercise in a drawing where the contours are already known.”
Given the high level of suffering inflicted and the lack of meaningful scientific advancement, AFSA questions how such research was approved, and why taxpayer funding continues to support it.
AFSA calls for:
• An end to primate research in Australia
• A government funded purpose-built sanctuary for primates used in Australian research
• A redirection of funding away from primate research to non-animal human-relevant methods.
Further information about primate experimentation in Australia here
What you can do to make a difference here ‘What you can do’
ENDS
AFSA: 1800 486 263
Email: info@animalfreesci.org.au
Reference:
Feizpour, A. et al. The role of frontopolar cortex in adjusting the balance between response execution and action inhibition in anthropoids. Progress in Neurobiology (2024)
All images on this page taken from Monash University’s Standard Operating Procedures released under FOI to AFSA.