Firing rates recorded in wild-type and beta2-/- retinal neurons using a multielectrode array. For each movie, dots represent the positions of electrodes in the multielectrode array on which discreet units were recorded. The maximum extent of the array is 480 um. The size of each dot in every frame represents the average firing rate recorded over 500 ms on that electrode. The movie plays five times as fast as real time and represents five minutes of recording. Only electrodes in which unambiguous units could be isolated from each other are illustrated. If multiple units were recorded on the same electrode, units were randomly eliminated so only one unit was portrayed on each electrode.

At postnatal days 4 (P4), firing rates in wild-type (WT) retina are highly correlated among neighboring neurons, and waves of activity periodically propagate across the array. In contrast, in P4 beta2-/- retina (lacking the beta2 subunit of the nicotinic ACh receptor) the firing rates are not significantly correlated among neighboring neurons, and waves of activity are not observed. At the age of P10, however, there is no significant difference in spontaneous activity patterns between WT and beta2-/- retinas.

[McLaughlin et al, Neuron 2003]

Spontaneous waves in a neonate mouse retina. An acutely isolated retina from a P3 mouse was incubated in fura-2AM and the decreases in fluorescence associated with spontaneus depolarization-induced increases in [Ca2+]i in neurons of the ganglion cell layer were monitored in real time. The total field of view is 2mm². Under control conditions, waves are initiated in random locations throughout the retina and propagate over finite distances.

[Singer et al, J Neuroscience 2001]

The same retinal preparation as in the clip above after a 10min exposure to 2.5 uM FPL-64176. Note that waves are still initiated in random locations, but each wave propagates over the entire imaged field.

[Singer et al, J Neuroscience 2001]

Example of a retina simulation representing a point in parameter space of the proposed mesoscopic model of the developing retina.

[Butts et al, J Neuroscience 1999; Feller et al, Neuron 1997]

A movie of spontaneous wave domains. The first frame is a fluorescence image of the ganglion cell layer of a fura-2 stained retina. The total field is over 1mm². Next, a movie of the data summarized in the first frame is shown. Increases in [Ca2+]i correspond to cells going dark.

[Feller et al, Science 1996]

Waves can be elicited by a short pressure ejection of artificial cerebral spinal fluid containing K+. The first frame is a fluorescence image of a fura-2 stained retina at a lower magnification than the first segment (the total field is over 4mm²). The white spot shows the location of the micropipette tip. Following the fluorescent image, a local depolarization induced by the pressure ejection and an elicited wave traveling down and toward the left are shown. A second puff, 20 seconds after the first, evoked only a local depolarization since it occurred within the refractory period of the tissue. By this method, we could determine the area of tissue that is directly depolarized by the pressure ejection of K+. Note that spontaneous waves also occur during the sequence.

[Feller et al, Science 1996]

Waves can be elicited by pressure ejection of 200M nicotine. The first frame is a fluorescence image of a fura-2 stained retina. The total field is 0.25 mm2, which is a higher magnification view than in the previous clips. The fura-2 labeled cell bodies can be seen clearly. The white circle shows the location of the micropipette tip. The elicited wave travels upward from the region of the pipette and then circles around to the center of the frame.

[Feller et al, Science 272, 1996]