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A beta2-frequency (20–30 Hz) oscillation in nonsynaptic networks of somatosensory cortex

Roopun et al. 10.1073/pnas.0607443103.

Supporting Figures

Files in this Data Supplement:

Supporting Figure 4
Supporting Figure 5




Fig. 4. Firing patterns of deep cortical neurons during beta2 oscillations. (A) Response to depolarizing current injection in the absence of kainate in three layer V/VI neurons: layer V intrinsically bursting neuron (LV IB, rmp = -70 mV), layer V fast-spiking neuron (LV FS, rmp = -62 mV) and layer VI regular-spiking neuron (LVI, rmp = -75 mV). Peak positivity of each period of the concurrent field recording for FS cell is indicated by dots. Note occasional periods are not accompanied by spiking in this neuron, and note the single period where a spike doublet was generated. (B) Spontaneous activity patterns for each cell during kainate-induced beta2 population oscillations. LV IB amp = -58 mV, LV FS amp = -55 mV, LVI amp = -70 mV. Corresponding firing patterns for neurons in the network model also are shown. (Scale bars: A, 200 ms; B, 100 ms; 20 mV.)





Fig. 5. Beta2 frequency rhythms are relatively insensitive to the main synaptic excitatory and inhibitory inputs. (A) Effects of blockade of the main glutamatergic synaptic responses in cortex abolishes superficial layer gamma rhythms but does not abolish beta2 rhythms. Data shown are mean power spectra from 60-s epochs of data (n = 6). All spectra were taken from LIV to illustrate the selective effects on concurrently generated gamma and beta2 rhythms. Control spectra are shown in black, and spectra taken in the presence of each drug are shown in red. The a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist SYM2206 (20 mM) did not significantly alter the power of beta2 population rhythms (P > 0.05) but abolished the spectral peak in the gamma band. The NMDA receptor blocker d-AP5 (50 mM) abolished the spectral peak in the gamma band but significantly increased the peak power in the beta2 band (P < 0.05). (B) Effects of blockade of the main GABAergic synaptic responses in cortex. Partial blockade of GABAA receptors with gabazine (250 nM) abolished the spectral peak in the gamma band but doubled the peak in the beta2 band (red line). Complete blockade of GABAB receptors with CGP55845 (10 mM) had no significant effect on peak power in either the gamma or beta2 bands (P > 0.05).

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