Greetings from Boston where the 21st annual meeting of the Cognitive Neuroscience Society is underway. Saturday and Sunday were packed with symposia, lectures and more than 400 posters. Here are just a few of the highlights.
The bilingual brain has been a hot topic at the meeting this year, particularly as researchers grapple with the benefits and challenges of language learning. In news that will make many college language majors happy, a group of researchers led by Harriet Wood Bowden of the University of Tennessee-Knoxville have demonstrated that years of language study alter a person’s brain processing to be more like a native speaker’s brain. They found that native English speaking students with about seven semesters of study in Spanish show very similar brain activation to native speakers when processing spoken Spanish grammar. The study used electroencephalography, or EEG, in which electrodes are placed along the scalp to pick up and measure the electrical activity of neurons in the brain below. By contrast, students who have more recently begun studying Spanish show markedly different processing of these elements of the language. The study focused on the recognition of noun-adjective agreement, particularly in gender and number.
Accents, however, can remain harder to master. Columbia University researchers worked with native Spanish speakers to study the difficulties encountered in hearing and reproducing English vowel sounds that are not used in Spanish. The research focused on the distinction between the extended o sound in “dock” and the soft u sound in “duck,” which is not part of spoken Spanish. The scientists used electroencephalograms to measure the brain responses to these vowel sounds in native-English and native-Spanish speakers. The Spanish speakers responded just like English speakers to the “dock” vowel sound, but not to the “duck,” sound, which was harder for the former group to identify. The finding is part of a larger body of research hinting at the possibility that vowel sounds like the o in dock that are produced on the periphery of the vocal tract are easier to perceive than the soft u sound produced in the middle of the vocal tract. By identifying these kinds of preferences, the researchers hope to better train language-learners to attune to sounds beyond their native tongue’s typical repertoire.
Birth control does not appear to effect cognition, according to Lena Ficco and colleagues of the University of Massachusetts Amherst. In one of the few neuroendocrinological studies presented, Ficco investigated whether contraception containing ethinyl estradiol changed the mental map-making or verbal abilities of women who had been taking this form of birth control for several years. Both verbal and navigation tasks are supported by estrogen. But because ethinyl estradiol suppresses estrogen, Ficco wondered whether there might be cognitive costs in taking contraception. Instead she observed no differences between women on these pills and a control group of non-pill-using women during the low-estrogen phase of their menstrual cycle. In future, Ficco hopes to assess whether length of pill use in an older population relates to any cognitive changes.
Researchers at Notre Dame University have some preliminary evidence that alcohol can set your body’s internal alarm clock. It can, in fact, make a relaxing Sunday morning seem like a manic Monday. The group wanted to investigate how alcohol, a physiological stressor, would alter the body’s cortisol awakening response, in which a flood of the stress hormone cortisol peaks as a person wakes up. Earlier work has demonstrated that this response is tied to psychological stress, prompting earlier rising on weekdays or during other anxious time periods. The Notre Dame group found that college students who consumed about four drinks on a weekend evening would awaken the next morning with significantly higher cortisol levels than non-drinkers. In fact, the researchers suggest that the stress-inducing effect is similar to that produced by cortisol levels on a weekday.
Finally, researchers have worked out a new nuance of the sound-induced flash illusion. In this illusion, an individual will either see a flash of light and hear two beeps or see two flashes and hear one beep. The curious thing is that people will report seeing two flashes if they hear two beeps, and just one flash if they heard one beep. Scientists at the University of Milan-Bicocca in Italy decided to replicate this illusion with a slight twist. Instead of actually flashing lights, they asked their subjects to keep their eyes closed and then used magnetic fields to change the electric currents surrounding neurons and stimulate the occipital lobe (a technique called transcranial magnetic stimulation). This stimulation triggered phosphenes, or the sensation of a flash of light—albeit without any actual light flashing. Because of how these phantom flashes are induced directly in the visual system, this approach enabled the researchers to time the stimuli and response to decipher whether this illusion depended on visual processing shortly after encountering a flash or beep. Indeed, they found that their subjects would report seeing two phosphenes after the researchers had induced just one flash with two auditory beeps, provided the stimuli were presented within relatively short succession. This suggests that the experiences in the brain’s early visual cortex can be modulated by sound. Lead author Silvia Convento explains that this kind of sensory overlap likely reflects brain organization that was beneficial to our ancestors. Even if it introduces some errors, the linkage would allow our brains gather and organize information from the environment more rapidly.
The lectures and symposia thus far have brought together a nice mix of history and hypotheses. Jon Kaas, who studies the organization of the mammalian brain at Vanderbilt University, for example, presented some of his ongoing work mapping the possible “sub-regions” of the motor cortex. The idea was inspired in part by research done in 2009 by neuroscientist Michael Graziano at Princeton University, who demonstrated that by stimulating a specific location on the motor cortex of an anaesthetized monkey, the animal would carry out a behavior such as bringing its hand to its mouth. Kaas has since investigated this and similar behaviors —including grasping, reaching, and climbing behaviors— in several primate species, including galagos, squirrel monkeys and owl monkeys. His findings have led him to the conclusion that the motor cortex may be divided into functional sub-regions with a specific active purpose, that direct movement across the body, and that the organization of these sub-regions could be consistent across primates.
In a totally different vein, a symposium on developmental cognitive neuroscience reflected on how lessons in this field could potentially guide policy on education and the justice system. For example, Margaret Sheridan of Harvard University reviewed the most recent published findings from the Romanian Orphanage Study, which reveal how extreme deprivation brutally inhibits mental development. This research complements ongoing study of the cognitive struggles of children growing up in poverty. On a more positive note, there are interventions that could help these children close the gap. Neuropsychologist Helen Neville of the University of Oregon discussed how her group has succeeded in training young children to improve their attention skills, often through simple and fun activities that ask children to concentrate and ignore distractions.
One of the most moving moments of the conference was in the opening keynote address by MIT neuroscientist Suzanne Corkin. Corkin spoke about the legacy of H.M., a patient who underwent a procedure to prevent epileptic seizures that left him unable to form new memories. Corkin, who spent decades studying H.M., discussed how he helped illuminate the distinctions between different memory forms and where they are located in the brain (to learn more about H.M., check out the May/June issue of Scientific American Mind). But Corkin also discussed the man behind the initials, describing his gentle and remarkably upbeat disposition, given that he was repeatedly confronting a confusing, context-free present. Her talk included a poignant and powerful audio recording of Corkin and H.M. chatting in 1992. In the excerpt, H.M. professes to “not mind” all of the tests and studies, saying simply, “I figure what’s wrong about me helps you help others.”