Fig. 1.
Synchronous corticostriatal slow wave. (A) Schematic drawings of coronal brain sections illustrating the placement of electrodes in three cortical areas (mot, motor; cin, cingulate; sen, somatosensory) and of MSNs. Numbers indicate distance to bregma in millimeters (50). lMSN, rostrolateral MSN; cMSN, caudal MSN; mMSN, rostromedial MSN. (B) The Vm of an mMSN recorded simultaneously with the LFP in three cortical areas. (C) Relative power spectra of the Vm and LFPs (1) and the corresponding MSN-LFP cross-amplitude (2), coherence (3), and phase (4) spectra, for a 2-min recording including the epoch shown in B. Spectra exhibit a dominant peak at ≈1 Hz, which is the frequency shared by UP–DOWN state transitions and cortical slow waves. The gray area encompasses the frequencies where cross-amplitude reached significance. Phase spectra show a lineal change in phase angle within the frequency range of synchronous activity. A positive phase difference means that cortical LFP preceded MSN Vm. Thin lines in C4 are confidence intervals. (D) Coherence was high for every MSN-LFP pair. However, PLS detected one statistically significant linear association accounting for 92% of the cross-block variance (P < 0.0001), related to different connectivity strengths of striatal regions with the motor cortex LFP (** in D1; see also Fig. S3). (1) One-way ANOVAs performed within each striatal region showed that mMSNs were preferentially associated with the cingulate LFP (*, P < 0.01 vs. motor or sensory cortex). (2) Coherence between motor cortex and MSNs increased linearly with distance of MSN from midline (regression ANOVA, P < 0.001, r = 0.68).