title: Reverse correlation of rapid calcium signals in the zebrafish optic tectum in vivo.
abstract: Reverse correlation techniques provide a quantitative means of computing neuronal input/output relationships. Until now these methods have been limited to electrically recorded responses since unprocessed optical signals generally lack necessary temporal characteristics. We sought to overcome this barrier since combining reverse correlation with calcium imaging would afford a powerful alternative to current methods of measuring response properties of neurons non-invasively in vivo. We labeled zebrafish optic tecta with a calcium indicator and measured responses to a whole-field random flicker light stimulus. Although calcium signals exhibited slow decay kinetics, we could use computational modeling to show that the positive differential of these traces extracts high frequency information. Experimentally, we found that calcium signals processed in this way were synchronous with simultaneously measured synaptic responses and could be used with reverse correlation to determine temporal filters of neurons in the zebrafish optic tectum. These findings demonstrate that calcium responses to physiological stimulation can be processed to obtain rapid signal information and consequently to determine linear filter properties in vivo.
authors.affiliation: Program in Neuroscience, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA. ramdya@fas.harvard.edu
authors.forename: Pavan
authors.initials: P
authors.lastname: Ramdya
authors.forename: Bettina
authors.initials: B
authors.lastname: Reiter
authors.forename: Florian
authors.initials: F
authors.lastname: Engert
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D003952:Diagnostic Imaging; D005074:Evoked Potentials, Visual / Q000502:physiology*; D008959:Models, Neurological; D009474:Neurons / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D013477:Superior Colliculi / Q000378:metabolism*; D015027:Zebrafish