Fig. 1.

Dramatic increase in dendritic calcium in awake rats. (A) Schematic diagram of experimental design. Left, “periscope” fiberoptic imaging device attached to rat cortex. Tension and EMG of upper hindlimb muscles were measured in response to an air-puff to the hindlimb. Middle, head mount allowing application of drugs with simultaneous imaging of the somatosensory cortex. Right, schematic diagram showing the light path for collecting fluorescence changes from populations of L5 pyramidal neuron dendrites (blue arrow, excitation at 475 nm; green arrow, emission at 520 nm). (B) Dendritic Ca²⁺ fluorescence changes recorded under anesthesia (AN, black), in awake state (AW) with hindlimb movement (red) and without movement (blue). Signals were evoked by air-puff stimulation (50-ms, dashed line) to contralateral hindlimb. The data are shown as averages (20 trials for AN, 11 trials for AW with movement, 16 trials for AW without movement). The areas of the slow components are highlighted. (C) Summary of dendritic Ca²⁺ signals in anesthetized (AN) and awake (AW) states (n = 6 rats). pFC, peak amplitude of fast component and aSC, area of slow component (see also Fig. S1 for pSC, peak amplitude of slow component; dSC, duration of slow component). All statistics show significant differences (P < 0.05), except pFC between movement and no movement in the awake state (NS, no significant difference). Dashed lines show SEM. (D) Example of single, simultaneous recording of dendritic Ca²⁺ signals, electromyogram (EMG) and tension of hindlimb in awake state.