RESUMO
While isolated motor actions can be correlated with activities of neuronal networks, an unresolved problem is how the brain assembles these activities into organized behaviors like action sequences. Using brain-wide calcium imaging in Caenorhabditis elegans, we show that a large proportion of neurons across the brain share information by engaging in coordinated, dynamical network activity. This brain state evolves on a cycle, each segment of which recruits the activities of different neuronal sub-populations and can be explicitly mapped, on a single trial basis, to the animals' major motor commands. This organization defines the assembly of motor commands into a string of run-and-turn action sequence cycles, including decisions between alternative behaviors. These dynamics serve as a robust scaffold for action selection in response to sensory input. This study shows that the coordination of neuronal activity patterns into global brain dynamics underlies the high-level organization of behavior.
Assuntos
Caenorhabditis elegans/citologia , Caenorhabditis elegans/fisiologia , Animais , Encéfalo/citologia , Encéfalo/fisiologia , Fenômenos Eletrofisiológicos , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Rede Nervosa , Células Receptoras Sensoriais/citologia , Células Receptoras Sensoriais/fisiologia , Transdução de SinaisRESUMO
High-speed, large-scale three-dimensional (3D) imaging of neuronal activity poses a major challenge in neuroscience. Here we demonstrate simultaneous functional imaging of neuronal activity at single-neuron resolution in an entire Caenorhabditis elegans and in larval zebrafish brain. Our technique captures the dynamics of spiking neurons in volumes of â¼700 µm × 700 µm × 200 µm at 20 Hz. Its simplicity makes it an attractive tool for high-speed volumetric calcium imaging.
Assuntos
Cálcio/metabolismo , Imageamento Tridimensional/métodos , Microscopia/métodos , Neurônios/fisiologia , Animais , Caenorhabditis elegans , Sinalização do Cálcio , Larva/ultraestrutura , Microscopia de Fluorescência/métodos , Peixe-ZebraRESUMO
Recent efforts in neuroscience research have been aimed at obtaining detailed anatomical neuronal wiring maps as well as information on how neurons in these networks engage in dynamic activities. Although the entire connectivity map of the nervous system of Caenorhabditis elegans has been known for more than 25 years, this knowledge has not been sufficient to predict all functional connections underlying behavior. To approach this goal, we developed a two-photon technique for brain-wide calcium imaging in C. elegans, using wide-field temporal focusing (WF-TeFo). Pivotal to our results was the use of a nuclear-localized, genetically encoded calcium indicator, NLS-GCaMP5K, that permits unambiguous discrimination of individual neurons within the densely packed head ganglia of C. elegans. We demonstrate near-simultaneous recording of activity of up to 70% of all head neurons. In combination with a lab-on-a-chip device for stimulus delivery, this method provides an enabling platform for establishing functional maps of neuronal networks.