Posts tagged psychology
Posts tagged psychology
Even with today’s technology, it still takes both a male and a female to make a baby. But is it important for both parents to raise that child? Many studies have outlined the value of a mother, but few have clearly defined the importance of a father, until now. New findings from the Research Institute of the McGill University Health Centre (RI-MUHC) show that the absence of a father during critical growth periods, leads to impaired social and behavioural abilities in adults. This research, which was conducted using mice, was published today in the journal Cerebral Cortex. It is the first study to link father absenteeism with social attributes and to correlate these with physical changes in the brain.
“Although we used mice, the findings are extremely relevant to humans,” says senior author Dr. Gabriella Gobbi, a researcher of the Mental Illness and Addiction Axis at the RI-MUHC and an associate professor at the Faculty of Medicine at McGill University. “We used California mice which, like in some human populations, are monogamous and raise their offspring together.”
“Because we can control their environment, we can equalize factors that differ between them,” adds first author, Francis Bambico, a former student of Dr. Gobbi at McGill and now a post-doc at the Centre for Addiction and Mental Health (CAMH) in Toronto. “Mice studies in the laboratory may therefore be clearer to interpret than human ones, where it is impossible to control all the influences during development.”
Dr. Gobbi and her colleagues compared the social behaviour and brain anatomy of mice that had been raised with both parents to those that had been raised only by their mothers. Mice raised without a father had abnormal social interactions and were more aggressive than counterparts raised with both parents. These effects were stronger for female offspring than for their brothers. Females raised without fathers also had a greater sensitivity to the stimulant drug, amphetamine.
“The behavioural deficits we observed are consistent with human studies of children raised without a father,” says Dr. Gobbi, who is also a psychiatrist at the MUHC. “These children have been shown to have an increased risk for deviant behaviour and in particular, girls have been shown to be at risk for substance abuse. This suggests that these mice are a good model for understanding how these effects arise in humans.”
In pups deprived of fathers, Dr. Gobbi’s team also identified defects in the mouse prefrontal cortex, a part of the brain that helps control social and cognitive activity, which is linked to the behaviourial deficits.
“This is the first time research findings have shown that paternal deprivation during development affects the neurobiology of the offspring,” says Dr. Gobbi. These results should incite researchers to look more deeply into the role of fathers during critical stages of growth and suggest that both parents are important in children’s mental health development.
After capturing the first brain images of two alert, unrestrained dogs last year, researchers at Emory University have confirmed their methods and results by replicating them in an experiment involving 13 dogs.
The research, published by the Public Library of Science One (PLOS One), showed that most of the dogs had a positive response in the caudate region of the brain when given a hand signal indicating they would receive a food treat, as compared to a different hand signal for “no treat.”
“Our experiment last year was really a proof of concept, demonstrating that dogs could be trained to undergo successful functional Magnetic Resonance Imaging (fMRI),” says the lead researcher Gregory Berns, director of Emory’s Center for Neuropolicy. “Now we’ve shown that the initial study wasn’t a fluke: Canine fMRI is reliable and can be done with minimal stress to the dogs. We have laid the foundation for exploring the neural biology and cognitive processes of man’s best, and oldest, friend.”
Co-authors of the paper include Andrew Brooks, a post-doctoral fellow at the Center for Neuropolicy, and Mark Spivak, a dog trainer and the owner of Comprehensive Pet Therapy.
Both the initial experiment and the more recent one involved training the dogs to acclimatize to an fMRI machine. The task requires dogs to cooperatively enter the small enclosure of the fMRI scanner and remain completely motionless despite the noise and vibration of the machine.
Only those dogs that willingly cooperated were involved in the experiments. The canine subjects were given harmless fMRI brain scans while they watched a human giving hand signals that the dogs had been trained to understand. One signal indicated that the dog would receive a hot dog for a treat. The other hand signal meant that the dog would not receive a hot dog.
The most recent experiment involved the original two dogs, plus 11 additional ones, of varying breeds. Eight out of the 13 showed the positive caudate response for the hand signal indicating they were going to receive a hot dog.
The caudate sits above the brain stem in mammals and has the highest concentration of dopamine receptors, which are implicated in motivation and pleasure, among other neurological processes.
“We know that in humans, the caudate region is associated with decision-making, motivation and processing emotions,” Berns says.
As a point of reference, the researchers compared the results to a similar experiment Berns had led 10 years previously involving humans, in which the subjects pressed a button when a light appeared, to get a squirt of fruit juice.
Eleven of 17 humans involved in that experiment showed a positive response in the caudate region that was similar to the positive response of the dogs. “Our findings suggest that the caudate region of the canine brain behaves similarly to the caudate of the human brain, under similar circumstances,” Berns says.
Six of the dogs involved in the experiment had been specially bred and trained to assist disabled people as companion animals, and two of the dogs (including one of the service dogs) had worked as therapy dogs, used to help alleviate stress in people in hospitals or nursing homes. All of the service/therapy dogs showed a greater level of positive caudate activation for the hot dog signal, compared to the other dogs.
“We don’t know if the service dogs and therapy dogs showed this difference because of genetics, or because of the environment in which they were raised, but we hope to find out in future experiments,” Berns says. “This may be the first hint of how the brains of dogs with different temperaments and personalities differ.”
He adds: “I don’t think it was because they liked hot dogs more. I saw no evidence of that. None of the dogs turned down the hot dogs.”
One limitation of the experiments is the small number of subjects and the selectivity of the dogs involved, since only certain dogs can be trained to do the experiments, Berns says.
“We’re expanding our cohort to include more dogs and more breeds,” Berns says. “As the dogs get more accustomed to the process, we can conduct more complicated experiments.”
Plans call for comparing how the canine brain responds to hand signals coming from the dog’s owner, a stranger and a computer. Another experiment already under way is looking at the neural response of dogs when they are exposed to scents of members of their households, both humans and other dogs, and unfamiliar humans and dogs.
“Ultimately, our goal is to map out canine cognitive processes,” says Berns, who recently published a book entitled “How Dogs Love Us: A Neuroscientist and His Adopted Dog Decode the Canine Brain.”
Even in an increasingly technical era, the role of dogs has not diminished, Berns says. In addition to being popular pets, he notes that dogs are important in the U.S. military, in search-and-rescue missions, as assistants for the disabled and as therapeutic stress relievers for hospital patients and others.
“Dogs have been a part of human society for longer than any other animal,” Berns says. He cites a genetic analysis recently published in Science suggesting that the domestication of dogs goes back 18,000 to 32,000 years, preceding the development of agriculture some 10,000 years ago.
“Most neuroscience studies on animals are conducted to serve as models for human disease and brain functions,” Berns says. “We’re not studying canine cognition to serve as a model for humans, but what we learn about the dog brain may also help us understand more about how our own brains evolved.”
In a new paper published in the current issue of Neuron, McLean Hospital and Harvard Medical School researchers report that increased activity in the medial prefrontal cortex (mPFC) of the brain is linked to decreased activity in the amygdala, the portion of the brain used in the creation of memories of events that scared those exposed.
According to author Vadim Bolshakov, PhD, director of the Cellular Neurobiology Laboratory at McLean and professor at Harvard Medical School, this finding is significant in that it could lead to better methods to prevent PTSD.
"A single exposure to something traumatic or scary can be enough to create a fear memory—causing someone to expect and be afraid in similar situations in the future," said Bolshakov. "What we’re seeing is that we may one day be able to prevent those fear memories."
Bolshakov and his colleagues tested their theory using animal models. Dividing the mice into two groups, some were taught to fear an auditory stimulus while in others fear memory was extinguished Increased activation of mPFC in extinguished animals led to inhibition of the amygdala and significant decreases in fear responses.
"For example, if a sound ended with an extremely loud shriek, a subject would come to expect that scary noise at the end of the sound," explained Bolshakov. "What we found was when we suppressed the fear memory by decreasing activity in the amygdala, the subjects were not afraid of the end of the auditory stimulus any longer."
Bolshakov notes that this work could have serious implications for the treatment of a number of conditions including PTSD.
"While there is still a great deal of research that needs to be done before our work can be translated to clinical trials, what we are showing has the potential to ensure that individuals exposed to trauma were not haunted by the conditions surrounding their initial stressor."
Fear, at the right level, can increase alertness and protect against dangers. Disproportionate fear, on the other hand, can disrupt the sensory perception, be disabling, reduce happiness and therefore become a danger in itself. Anxiety disorders are therefore a psychiatric condition that should not be underestimated. In these disorders, the fear is so strong that there is tremendous psychological strain and living a normal life appears to be impossible. Researchers at the MedUni Vienna have now found a possible explanation as to how social phobias and fear can be triggered in the brain: a missing inhibitory connection or missing “brake” in the brain.
Inside the brain, the amygdala and the orbitofrontal cortex in the frontal lobe form an important control circuit for regulating the emotions. This control circuit is termed the brain’s emotional control centre. Whereas in healthy subjects, this circuit has “negative feedback” and “calmness” was identified, scientists used functional magnetic resonance imaging (MRI) on people with social phobias and found the opposite to be true: an important inhibitory connection is different in these patients, which may explain why they are unable to control their fears.
In collaboration with the Centre for Medical Physics and Biomedical Technology and the University Department of Psychiatry and Psychotherapy at the MedUni Vienna, the research team lead by Christian Windischberger was also able to discover through its recent study at the MedUni Vienna’s High Field MR Centre of Excellence how the areas of the brain that are involved with processing emotions are able to influence each other.
The study participants were shown a series of “emotional faces” while undergoing functional magnetic resonance imaging. fMRI is a non-invasive method which uses radio waves and magnetic fields to measure changes in the levels of oxygen in the blood and therefore neuronal activity in individual regions of the brain. An analysis method developed at University College London was used to provide new perspectives on the data obtained.
Breaking the circle of fear
When emotional facial expressions were shown - from laughing to crying, from happiness to anger - neuronal activity was triggered in the brain. The result: on a purely external basis, the test subjects looked no different, but the healthy subjects were kept calm thanks to their automatic “brake”, despite the emotional nature of the images. For the social phobics, on the other hand, the photographs put their brains into “overdrive”, triggering very strong neuronal activity. This was demonstrated very clearly using the new analysis method: “We have the opportunity not only to localise brain activity and compare it between groups, but we can now also make statements regarding functional connections within the brain. In psychiatric conditions especially, we can assume that there are not complete failures of these connections going on, but rather imbalances in complex regulatory processes,” says Ronald Sladky, the study’s primary author.
This better understanding of the neuronal mechanisms involved will now be used to develop new approaches to treatment. The aim is to understand what effect medications and psycho-therapeutic support have on the networks involved in order to help patients break out of their circles of fear.
Attention, parents: The messier your child gets while playing with food in the high chair, the more he or she is learning.
Researchers at the University of Iowa studied how 16-month-old children learn words for nonsolid objects, from oatmeal to glue. Previous research has shown that toddlers learn more readily about solid objects because they can easily identify them due to their unchanging size and shape. But oozy, gooey, runny stuff? Not so much.
New research shows that changes if you put toddlers in a setting they know well. In those instances, word learning increases, because children at that age are “used to seeing nonsolid things in this context, when they’re eating,” says Larissa Samuelson, associate professor in psychology at the UI who has worked for years on how children learn to associate words with objects. “And, if you expose them to these things when they’re in a highchair, they do better. They’re familiar with the setting and that helps them remember and use what they already know about nonsolids.”
In a paper published in the journal Developmental Science, Samuelson and her team at the UI tested their idea by exposing 16-month-olds to 14 nonsolid objects, mostly food and drinks such as applesauce, pudding, juice, and soup. They presented the items and gave them made-up words, such as “dax” or “kiv.” A minute later, they asked the children to identify the same food in different sizes or shapes. The task required the youngsters to go beyond relying simply on shape and size and to explore what the substances were made of to make the correct identification and word choice.
Not surprisingly, many children gleefully dove into this task by poking, prodding, touching, feeling, eating—and yes, throwing—the nonsolids in order to understand what they were and make the correct association with the hypothetical names. The toddlers who interacted the most with the foods—parents, interpret as you want—were more likely to correctly identify them by their texture and name them, the study determined. For example, imagine you were a 16-month-old gazing at a cup of milk and a cup of glue. How would you tell the difference by simply looking?
“It’s the material that makes many nonsolids,” Samuelson notes, “and how children name them.”
The setting matters, too, it seems. Children in a high chair were more apt to identify and name the food than those in other venues, such as seated at a table, the researchers found.
“It turns out that being in a high chair makes it more likely you’ll get messy, because kids know they can get messy there,” says Samuelson, the senior author on the paper.
The authors say the exercise shows how children’s behavior, environment (or setting), and exploration help them acquire an early vocabulary—learning that is linked to better later cognitive development and functioning.
“It may look like your child is playing in the high chair, throwing things on the ground, and they may be doing that, but they are getting information out of (those actions),” Samuelson contends. “And, it turns out, they can use that information later. That’s what the high chair did. Playing with these foods there actually helped these children in the lab, and they learned the names better.”
“It’s not about words you know, but words you’re going to learn,” Samuelson adds.
A single dose of the hormone oxytocin, delivered via nasal spray, has been shown to enhance brain activity while processing social information in children with autism spectrum disorders, Yale School of Medicine researchers report in a new study published in the Dec. 2 issue of Proceedings of the National Academy of Sciences.
“This is the first study to evaluate the impact of oxytocin on brain function in children with autism spectrum disorders,” said first author Ilanit Gordon, a Yale Child Study Center adjunct assistant professor, whose colleagues on the study included senior author Kevin Pelphrey, the Harris Professor in the Child Study Center, and director of the Center for Translational Developmental Neuroscience at Yale.
Gordon, Pelphrey, and their colleagues conducted a double-blind, placebo-controlled study of 17 children and adolescents with autism spectrum disorders. The participants, between the ages of 8 and 16.5, were randomly given either oxytocin spray or a placebo nasal spray during a task involving social judgments. Oxytocin is naturally occurring hormone produced in the brain and throughout the body.
“We found that brain centers associated with reward and emotion recognition responded more during social tasks when children received oxytocin instead of the placebo,” said Gordon. “Oxytocin temporarily normalized brain regions responsible for the social deficits seen in children with autism.”
Gordon said oxytocin facilitated social attunement, a process that makes the brain regions involved in social behavior and social cognition activate more for social stimuli (such as faces) and activate less for non-social stimuli (such as cars).
“Our results are particularly important considering the urgent need for treatments to target social dysfunction in autism spectrum disorders,” Gordon added.
Exposure to air pollution appears to increase the risk for autism among people who carry a genetic disposition for the neurodevelopmental disorder, according to newly published research led by scientists at the Keck School of Medicine of the University of Southern California (USC).
"Our research shows that children with both the risk genotype and exposure to high air pollutant levels were at increased risk of autism spectrum disorder compared to those without the risk genotype and lower air pollution exposure," said the study’s first author, Heather E. Volk, Ph.D., M.P.H., assistant professor of research in preventive medicine and pediatrics at the Keck School of Medicine of USC and principal investigator at The Saban Research Institute of Children’s Hospital Los Angeles.
The study, “Autism spectrum disorder: Interaction of air pollution with the MET receptor tyrosine kinase gene,” is scheduled to appear in the January 2014 edition of Epidemiology.
Autism spectrum disorder (ASD) is a lifelong neurodevelopmental disability characterized by problems with social interaction, communication and repetitive behaviors. The Centers for Disease Control and Prevention estimates that one in 88 children in the United States has an ASD.
ASD is highly heritable, suggesting that genetics are an important contributing factor, but many questions about its causes remain. There currently is no cure for the disorder.
"Although gene-environment interactions are widely believed to contribute to autism risk, this is the first demonstration of a specific interaction between a well-established genetic risk factor and an environmental factor that independently contribute to autism risk," said Daniel B. Campbell, Ph.D., assistant professor of psychiatry and the behavioral sciences at the Keck School of Medicine of USC and the study’s senior author. "The MET gene variant has been associated with autism in multiple studies, controls expression of MET protein in both the brain and the immune system, and predicts altered brain structure and function. It will be important to replicate this finding and to determine the mechanisms by which these genetic and environmental factors interact to increase the risk for autism."
Independent studies by Volk and Campbell have previously reported associations between autism and air pollution exposure and between autism and a variant in the MET gene. The current study suggests that air pollution exposure and the genetic variant interact to augment the risk of ASD.
Campbell and Volk’s team studied 408 children between 2 and 5 years of age from the Childhood Autism Risks From Genetics and the Environment Study, a population-based, case-control study of preschool children from California. Of those, 252 met the criteria for autism or autism spectrum disorder. Air pollution exposure was determined based on the past residences of the children and their mothers, local traffic-related sources, and regional air quality measures. MET genotype was determined through blood sampling.
Campbell and Volk continue to study the interaction of air pollution exposure and the MET genotype in mothers during pregnancy.
A new brain connectivity study from Penn Medicine published today in the Proceedings of National Academy of Sciences found striking differences in the neural wiring of men and women that’s lending credence to some commonly-held beliefs about their behavior.
In one of the largest studies looking at the “connectomes” of the sexes, Ragini Verma, PhD, an associate professor in the department of Radiology at the Perelman School of Medicine at the University of Pennsylvania, and colleagues found greater neural connectivity from front to back and within one hemisphere in males, suggesting their brains are structured to facilitate connectivity between perception and coordinated action. In contrast, in females, the wiring goes between the left and right hemispheres, suggesting that they facilitate communication between the analytical and intuition.
“These maps show us a stark difference—and complementarity—in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others,” said Verma.
For instance, on average, men are more likely better at learning and performing a single task at hand, like cycling or navigating directions, whereas women have superior memory and social cognition skills, making them more equipped for multitasking and creating solutions that work for a group. They have a mentalistic approach, so to speak.
Past studies have shown sex differences in the brain, but the neural wiring connecting regions across the whole brain that have been tied to such cognitive skills has never been fully shown in a large population.
In the study, Verma and colleagues, including co-authors Ruben C. Gur, PhD, a professor of psychology in the department of Psychiatry, and Raquel E. Gur, MD, PhD, professor of Psychiatry, Neurology and Radiology, investigated the gender-specific differences in brain connectivity during the course of development in 949 individuals (521 females and 428 males) aged 8 to 22 years using diffusion tensor imaging (DTI). DTI is water-based imaging technique that can trace and highlight the fiber pathways connecting the different regions of the brain, laying the foundation for a structural connectome or network of the whole brain.
This sample of youths was studied as part of the Philadelphia Neurodevelopmental Cohort, a National Institute of Mental Health-funded collaboration between the University of Pennsylvania Brain Behavior Laboratory and the Center for Applied Genomics at the Children’s Hospital of Philadelphia.
The brain is a roadmap of neural pathways linking many networks that help us process information and react accordingly, with behavior controlled by several of these sub-networks working in conjunction.
In the study, the researchers found that females displayed greater connectivity in the supratentorial region, which contains the cerebrum, the largest part of the brain, between the left and right hemispheres. Males, on the other hand, displayed greater connectivity within each hemisphere.
By contrast, the opposite prevailed in the cerebellum, the part of the brain that plays a major role in motor control, where males displayed greater inter-hemispheric connectivity and females displayed greater intra-hemispheric connectivity.
These connections likely give men an efficient system for coordinated action, where the cerebellum and cortex participate in bridging between perceptual experiences in the back of the brain, and action, in the front of the brain, according to the authors. The female connections likely facilitate integration of the analytic and sequential processing modes of the left hemisphere with the spatial, intuitive information processing modes of the right side.
The authors observed only a few gender differences in the connectivity in children younger than 13 years, but the differences were more pronounced in adolescents aged 14 to 17 years and young adults older than 17.
The findings were also consistent with a Penn behavior study, of which this imaging study was a subset of, that demonstrated pronounced sexual differences. Females outperformed males on attention, word and face memory, and social cognition tests. Males performed better on spatial processing and sensorimotor speed. Those differences were most pronounced in the 12 to 14 age range.
“It’s quite striking how complementary the brains of women and men really are,” said Dr. Ruben Gur. “Detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neurological disorders, which are often sex related.”
Next steps are to quantify how an individual’s neural connections are different from the population; identify which neural connections are gender specific and common in both; and to see if findings from functional magnetic resonance imaging (fMRI) studies fall in line with the connectome data.
Using a video game in which people navigate through a virtual town delivering objects to specific locations, a team of neuroscientists from the University of Pennsylvania and Freiburg University has discovered how brain cells that encode spatial information form “geotags” for specific memories and are activated immediately before those memories are recalled.
Their work shows how spatial information is incorporated into memories and why remembering an experience can quickly bring to mind other events that happened in the same place.
"These findings provide the first direct neural evidence for the idea that the human memory system tags memories with information about where and when they were formed and that the act of recall involves the reinstatement of these tags," said Michael Kahana, professor of psychology in Penn’s School of Arts and Sciences.
The study was led by Kahana and professor Andreas Schulze-Bonhage of Freiberg. Jonathan F. Miller, Alec Solway, Max Merkow and Sean M. Polyn, all members of Kahana’s lab, and Markus Neufang, Armin Brandt, Michael Trippel, Irina Mader and Stefan Hefft, all members of Schulze-Bonhage’s lab, contributed to the study. They also collaborated with Drexel University’s Joshua Jacobs.
Their study was published in the journal Science.
Kahana and his colleagues have long conducted research with epilepsy patients who have electrodes implanted in their brains as part of their treatment. The electrodes directly capture electrical activity from throughout the brain while the patients participate in experiments from their hospital beds.
As with earlier spatial memory experiments conducted by Kahana’s group, this study involved playing a simple video game on a bedside computer. The game in this experiment involved making deliveries to stores in a virtual city. The participants were first given a period where they were allowed to freely explore the city and learn the stores’ locations. When the game began, participants were only instructed where their next stop was, without being told what they were delivering. After they reached their destination, the game would reveal the item that had been delivered, and then give the participant their next stop.
After 13 deliveries, the screen went blank and participants were asked to remember and name as many of the items they had delivered in the order they came to mind.
This allowed the researchers to correlate the neural activation associated with the formation of spatial memories (the locations of the stores) and the recall of episodic memories: (the list of items that had been delivered).
“A challenge in studying memory in naturalistic settings is that we cannot create a realistic experience where the experimenter retains control over and can measure every aspect of what the participant does and sees. Virtual reality solves that problem,” Kahana said. “Having these patients play our games allows us to record every action they take in the game and to measure the responses of neurons both during spatial navigation and then later during verbal recall.”
By asking participants to recall the items they delivered instead of the stores they visited, the researchers could test whether their spatial memory systems were being activated even when episodic memories were being accessed. The map-like nature of the neurons associated with spatial memory made this comparison possible.
"During navigation, neurons in the hippocampus and neighboring regions can often represent the patient’s virtual location within the town, kind of like a brain GPS device," Kahana said. "These so-called ‘place cells’ are perhaps the most striking example of a neuron that encodes an abstract cognitive representation."
Using the brain recordings generated while the participants navigated the city, the researchers were able to develop a neural map that corresponded to the city’s layout. As participants passed by a particular store, the researchers correlated their spatial memory of that location with the pattern of place cell activation recorded. To avoid confounding the episodic memories of the items delivered with the spatial memory of a store’s location, the researchers excluded trips that were directly to or from that store when placing it on the neural map.
With maps of place cell activations in hand, the researchers were able to cross- reference each participant’s spatial memories as they accessed their episodic memories of the delivered items. The researchers found that the neurons associated with a particular region of the map activated immediately before a participant named the item that was delivered to a store in that region.
“This means that if we were given just the place cell activations of a participant,” Kahana said, “we could predict, with better than chance accuracy, the item he or she was recalling. And while we cannot distinguish whether these spatial memories are actually helping the participants access their episodic memories or are just coming along for the ride, we’re seeing that this place cell activation plays a role in the memory retrieval processes.”
Earlier neuroscience research in both human and animal cognition had suggested the hippocampus has two distinct roles: the role of cartographer, tracking
location information for spatial memory, and the role of scribe, recording events for episodic memory. This experiment provides further evidence that these roles are intertwined.
“Our finding that spontaneous recall of a memory activates its neural geotag suggests that spatial and episodic memory functions of the hippocampus are intimately related and may reflect a common functional architecture,” Kahana said.
Scientists have long suspected that corvids – the family of birds including ravens, crows and magpies – are highly intelligent. Now, Tübingen neurobiologists Lena Veit und Professor Andreas Nieder have demonstrated how the brains of crows produce intelligent behavior when the birds have to make strategic decisions. Their results are published in the latest edition of Nature Communications.
Crows are no bird-brains. Behavioral biologists have even called them “feathered primates” because the birds make and use tools, are able to remember large numbers of feeding sites, and plan their social behavior according to what other members of their group do. This high level of intelligence might seem surprising because birds’ brains are constructed in a fundamentally different way from those of mammals, including primates – which are usually used to investigate these behaviors.
The Tübingen researchers are the first to investigate the brain physiology of crows’ intelligent behavior. They trained crows to carry out memory tests on a computer. The crows were shown an image and had to remember it. Shortly afterwards, they had to select one of two test images on a touchscreen with their beaks based on a switching behavioral rules. One of the test images was identical to the first image, the other different. Sometimes the rule of the game was to select the same image, and sometimes it was to select the different one. The crows were able to carry out both tasks and to switch between them as appropriate. That demonstrates a high level of concentration and mental flexibility which few animal species can manage – and which is an effort even for humans.
The crows were quickly able to carry out these tasks even when given new sets of images. The researchers observed neuronal activity in the nidopallium caudolaterale, a brain region associated with the highest levels of cognition in birds. One group of nerve cells responded exclusively when the crows had to choose the same image – while another group of cells always responded when they were operating on the “different image” rule. By observing this cell activity, the researchers were often able to predict which rule the crow was following even before it made its choice.
The study published in Nature Communications provides valuable insights into the parallel evolution of intelligent behavior. “Many functions are realized differently in birds because a long evolutionary history separates us from these direct descendants of the dinosaurs,” says Lena Veit. “This means that bird brains can show us an alternative solution out of how intelligent behavior is produced with a different anatomy.” Crows and primates have different brains, but the cells regulating decision-making are very similar. They represent a general principle which has re-emerged throughout the history of evolution. “Just as we can draw valid conclusions on aerodynamics from a comparison of the very differently constructed wings of birds and bats, here we are able to draw conclusions about how the brain works by investigating the functional similarities and differences of the relevant brain areas in avian and mammalian brains,” says Professor Andreas Nieder.