Study results indicate brain structures outside the hippocampus may support face recognition

June 24, 2014 by Bob Yirka report
The hippocampus is a region of the brain largely responsible for memory formation. Credit: Salk Institute

(Medical Xpress)—A team of neuroscientists and psychologists with members from several universities in the U.S. has found that people with damage to their hippocampus are still able to recognize faces, even when they cannot recognize other objects. In their paper published in Proceedings of the National Academy of Sciences, the team describes five experiments they conducted with volunteer patients that had experienced damage to their hippocampus and what the group found as a result.

Scientists are still struggling to understand how is stored in the human brain—some suggest each memory is stored in a single neuron, while others insist memories are spread across groups of neurons or even brain regions. The researchers in this latest study have found evidence that supports the latter view.

To gain a better understanding of how memory is stored, the researchers focused on the hippocampus, the part of the brain where most memory is believed to be held. They conducted five experiments, each involving with damage to that part of their brain. The first experiment involved giving 10 patients the standard Recognition and Memory Test for Words and for facial recognition. The second involved six patients from the first experiment, they were asked to try to remember faces presented in black and white or color photographs of male faces along with others of buildings and words. The third experiment involved the same six patients repeating the second experiment only with fewer faces to remember and for shorter amounts of time. The fourth experiment involved the same patients who were asked to study pictures of famous people and then to take a . The final experiment was a remake of the third experiment except the interval between photograph viewing and testing was shorter.

In analyzing the results of all five experiments, the researchers were able to see that many patients with hippocampus damage were able to recognize , at least for a short time, despite damage that should have prevented them from doing so—in most cases they were unable to recognize common objects. This, the team suggests, likely indicates that one or more brain structures outside of the are involved in face recognition which implies that at least some types of memory in general are indeed spread across brain structures. That means, they add, that damage to individual neurons likely will not cause memory loss.

Explore further: Study indicates visual adaptation enhanced by sleep and may be tied to memory

More information: When recognition memory is independent of hippocampal function, Christine N. Smith, PNAS, doi: 10.1073/pnas.1409878111 .

Hippocampal damage has been thought to result in broad memory impairment. Recent studies in humans, however, have raised the possibility that recognition memory for faces might be spared. In five experiments we investigated face recognition in patients with hippocampal lesions (H) or large medial temporal lobe (MTL) lesions, including patients where neurohistological information was available. Recognition of novel faces was unequivocally intact in H patients but only at a short retention interval. Recognition memory for words, buildings, inverted faces, and famous faces was impaired. For MTL patients, recognition memory was impaired for all materials and across all retention intervals. These results indicate that structures other than the hippocampus, perhaps the perirhinal cortex, can support face recognition memory in H patients under some conditions. The fact that the faces were novel when recognition memory was intact does not fully account for our findings. We propose that the role of the hippocampus in recognition memory is related to how recognition decisions are accomplished. In typical recognition tasks, participants proceed by forming an association between a study item and the study list, and the recognition decision is later made based on whether participants believe the item was on the study list. We suggest that face recognition is an exception to this principle and that, at short retention intervals, participants can make their recognition decisions without making explicit reference to the study list. Important features of faces that might make face recognition exceptional are that they are processed holistically and are difficult to verbally label.

Related Stories

What happened when? How the brain stores memories by time

March 12, 2014

(Medical Xpress)—Before I left the house this morning, I let the cat out and started the dishwasher. Or was that yesterday? Very often, our memories must distinguish not just what happened and where, but when an event occurred—and ...

How our brains store recent memories, cell by single cell

June 16, 2014

Confirming what neurocomputational theorists have long suspected, researchers at the Dignity Health Barrow Neurological Institute in Phoenix, Ariz. and University of California, San Diego School of Medicine report that the ...

Recommended for you

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

No cable spaghetti in the brain

November 24, 2015

Our brain is a mysterious machine. Billions of nerve cells are connected such that they store information as efficiently as books are stored in a well-organized library. To this date, many details remain unclear, for instance ...

Neurons encoding hand shapes identified in human brain

November 23, 2015

Neural prosthetic devices, which include small electrode arrays implanted in the brain, can allow paralyzed patients to control the movement of a robotic limb, whether that limb is attached to the individual or not. In May ...

Wireless sensor enables study of traumatic brain injury

November 23, 2015

A new system that uses a wireless implant has been shown to record for the first time how brain tissue deforms when subjected to the kind of shock that causes blast-induced trauma commonly seen in combat veterans.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.