IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Coding for running speed and computing displacement in the mammalian brain's GPS
Autor/es:
EMILIO KROPFF
Reunión:
Conferencia; ISCB Latin America; 2016
Resumen:
Keynote speaker.The last decades have witnessed major discoveries concerning the brain mechanisms through which mammals compute their own location and orient in space. Hippocampal place cells provide maps that describe the position of the animal within a known environment, including a rich contextual description. Entorhinal grid cells provide instead a spatial map that is applied to all environments and is not altered by contextual variations. For this reason grid cells have been proposed to be the framework for an egocentric representation of location, where position is computed independently of contextual cues and based only on the animal's knowledge of its own movements. To achieve this, grid cells should receive information about orientation and speed of instantaneous movements. While neurons coding for the head orientation have been described in the entorhinal cortex, the entorhinal speed code has remained elusive for almost a decade. We present the Flintstone car, a new behavioral paradigm that allows the precise control of rat running speed. Using this device we have discovered a new functional entorhinal cell type: the speed cell. These neurons code for running speed in an instantaneous and linear way. The code is context-independent, allowing running speed to be decoded from the activity of a handful of speed cells even across environments. In addition, we found speed cells to be slightly ahead in time with respect to the actual running speed (~80 ms on average) and, consistently, we found grid cells to be ahead in time with respect to the actual position. Taken together, these observations point to entorhinal speed cells as a key component in the dynamic representation of self-location.