Browsing by Author "Nankoo, Jean-François"
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ItemCerebellar tDCS alters the perception of optic flow(2021) Nankoo, Jean-François; Madan, Christopher R.; Medina, Omar; Makepeace, Tyler; Striemer, ChristopherStudies have shown that the cerebellar vermis is involved in the perception of motion. However, it is unclear how the cerebellum influences motion perception. tDCS is a non-invasive brain stimulation technique that can reduce (through cathodal stimulation) or increase neuronal excitability (through anodal stimulation). To explore the nature of the cerebellar involvement on large-field global motion perception (i.e., optic flow-like motion), we applied tDCS on the cerebellar midline while participants performed an optic flow motion discrimination task. Our results show that anodal tDCS improves discrimination threshold for optic flow perception, but only for left-right motion in contrast to up-down motion discrimination. This result was evident within the first 10 min of stimulation and was also found post-stimulation. Cathodal stimulation did not have any significant effects on performance in any direction. The results show that discrimination of optic flow can be improved with tDCS of the cerebellar midline and provide further support for the role of the human midline cerebellum in the perception of optic flow. ItemSpatial navigation in corn snakes(2018) Shahab, Aaizah; Nankoo, Jean-FrançoisResearch has shown that a variety of organisms encode the geometry of their environment to re-establish orientation (i.e., reorientation). This has been shown in species ranging from rats to bees, and has been shown to be an automatic process. This automatic process of encoding geometry has been taken as evidence for a geometric module in the brain of these species. However, it is currently not known whether reptiles also use geometry to reorient. This study will investigate the use of geometric cues for reorientation in a corn snake. The snake will be trained to locate a goal in a corner of a rectangular arena. At each corner, a unique landmark will be available. Once the snake has learned to locate the target corner, it will attempt to relocate the corner in the absence of the landmarks. If the snake has encoded the geometry of the arena during training, it should be able to locate the goal, and will make rotational errors (i.e., mistaking the diagonally opposite corner for the correct corner). This rotational error would provide evidence that the snake has encoded the geometry even though it was trained to rely on the landmarks during training. This would provide support for the existence of a geometric module in the snake’s brain, and potentially in the general reptilian brain as well.