At the Developmental Cognitive Neuroscience Laboratory, we are broadly interested in the origins of cognitive abilities and how they change over the course of the lifespan. We investigate the behavioral and neural correlates of spatial computation, navigation, memory, and symbolic thinking. Our aim is to understand the core foundations of human intelligence and to uncover new methods to assess and improve disrupted cognitive function in neurodevelopmental or neurodegenerative disorders.
Since the opening of the lab in the summer of 2017, we published two papers, one showing the comparative origins of hippocampal coding of spatial memory and the other demonstrating a case of impaired spatial conceptual understanding in a genetic neurodevelopmental disorder.
1. Representation of environmental shape in the hippocampus of domestic chicks
The hippocampus plays an important role in spatial mapping across various vertebrate species. However, the understanding of avian hippocampus at the neuronal level is limited. To investigate the comparative function of the hippocampus in early development, we tested neuronal representation of environmental shape in 6-day-old chicks. Neurons in the mammalian hippocampus are highly influenced by environmental shape when representation spatial location. If there are functional similarities across birds and mammals in spatial mapping, and if those functions are innately specified, we would find that neurons in the chick hippocampus also represent environmental shape.
34 male domestic chicks were trained to forage for mealworms in two square-shaped chambers connected by a door that they had to walk through to get a mealworm. After the fifth day of training, chicks were assigned into one of four experimental groups. The baseline group was a control condition to measure baseline hippocampal activity. Chicks assigned to this group remained in the base arena where they received four worms randomly placed in the environment with a 1-min interval between each worm. The second group was exposed twice to a novel square-shaped arena. The third group was exposed twice to a novel rectangular experimental arena. The fourth group was exposed to both the square and rectangular arenas. Under these conditions, chicks went from the familiar base arena to the experimental arena and back twice, receiving four worms total.
Neural activation was measured by c-Fos expression using immunohistochemistry. Chicks (in the fourth group) who were exposed to both a square and a rectangular arena had a significantly higher number of activated hippocampal neurons than those exposed twice to just the square or just the rectangle.
These results provide evidence that the avian hippocampus, from shortly after birth, distinguishes between enclosures of different geometric shapes and creates distinct representation of those environments. This converges with findings from rodents and demonstrates similarities between the mammalian and avian hippocampus, not only at the anatomical level but also at the neuronal level.
2. What gestures reveal about cognitive deficits in Williams Syndrome
Williams Syndrome (WS) is a genetic developmental disorder involving severe spatial impairments and relatively spared social communication abilities. In order to investigate how WS subjects communicate spatial information in a social situation, we examined the interaction between gestures and language in a simple verbal narrative task.
11 individuals with WS and 22 individuals with typical development participated in this study. Typical subjects consisted of the chronological age-matched (CA) group or the mental age-matched (MA) group, according to the results of standardized assessments. All participants watched a short, animated cartoon without any dialogue. After watching the video clip, they were asked to recount the story to their parent. Their narrative retelling was videotaped and analyzed offline on the language and gestures produced. First, we found that WS subjects produced gestures far more often than typical subjects, particularly preceding or in place of the corresponding verbal expression.
Furthermore, when looking at the semantic content of these compensatory gestures, almost 60% of gestures used by WS subjects contained spatial information (e.g., mimicking spatial movement or trajectory), which was significantly higher than both typical groups.
Gestures are a window into the spatial cognitive processes, a means of communicating spatial information, and a tool that people use in service of spatial thinking and speaking. We interpret the WS subjects’ compensatory use of gestures to be indicative of an interaction between their difficulty in conceptualizing spatial relationships into symbolic language and their motivation to communicate despite their difficulty.
- Mayer, U., Bhushan, R., Vallortigara, G., & Lee, S. A. (2017). Representation of environmental shape in the hippocampal formation of the domestic chick (Gallus gallus), Brain Structure and Function, doi: 10.1007/s00429-017-1537-5.
- Mastrogiuseppe, M., Bordignon, A., & Lee, S. A. (2017). What gestures reveal about cognitive deficits in Williams Syndrome. Developmental Neuropsychology, 42, 470-481.