Article Figures & Data
Figures
- Fig. 1.
Power distribution of sensorimotor EEG recorded continuously for 2 hr during sleep in the echidna. Sample A, Indicated on the power distribution plots and expanded below is from sleep; sample B is from waking.
- Fig. 2.
Location of recorded neurons in the echidna, cat, and dog. Filled circles indicate units that increased variability in sleep in the echidna or in REM sleep in the cat and dog, relative to QW.
- Fig. 3.
Unit discharge of a representative neuron recorded in the nucleus reticularis pontis oralis of the echidna during waking and sleep. Note irregularity of neuronal discharge during sleep. EEG, EMG–ECG (electromyogram–electrocardiogram) unit, pulse output of window discriminator triggered by neuron. Duration of recordings is 30 sec.
- Fig. 4.
Instantaneous compressed rate plots of representative units recorded in nucleus reticularis pontis oralis of the cat, dog, and echidna. Each point represents the discharge rate for the previous interspike interval. In cat QW and non-REM sleep, the discharge rate is low and relatively regular. The rate increases and becomes highly variable during REM sleep. A similar pattern can be seen in a unit recorded in the dog. In the echidna, sleep is characterized by variable unit discharge rates.
- Fig. 5.
QW variance of the number of neuronal action potentials in consecutive 10 sec epochs plotted against sleep variance. Echidna units are plotted with REM sleep and non-REM sleep values in the cat (A) and dog (B). Note that the majority of the points representing echidna sleep fall between those of cat or dog units recorded in REM sleep and non-REM sleep.
- Fig. 6.
Rate histogram and cross-correlogram of discharge in a pair of cat reticularis pontis oralis units recorded during REM sleep (top), compared with a pair of echidna reticularis pontis oralis units recorded during sleep (bottom). Counts per second on y-axis on left. Cross-correlograms of each pair computed at 50 msec binwidth are shown atright. Unit pairs in both the cat and echidna were recorded from adjacent microwires on a single bundle of 32 μm microwires. Whereas most cat and dog units fire synchronously and are cross-correlated during REM sleep (Siegel et al., 1981), none of the echidna unit pairs was cross-correlated in sleep.
