Discharge patterns of principal cells and interneurones in lateral geniculate nucleus of rat

Abstract

SUMMARY1. The cells of the lateral geniculate nucleus of the rat are classified into one of two distinct groups on the basis of their responses to a single shock to optic nerve or visual cortex. The distinctive difference between these two groups is that the P cells (87 % of all cells) responded with short bursts of 1-5 spikes, whereas the I cells (13 %) responded with long bursts of about 10 spikes. Both groups give recurring bursts at intervals of 100 msec or more for a total duration of up to about 5 sec.2. The majority of P cells (75 %) have a lower threshold for late firing than for early firing. The majority of I cells (62 %) have about the same threshold and all I cells have very low thresholds.3. To stimulation of the optic nerve the mean latency of the first spikes of all P cells is 4-4 msec. The mean latency of the first spikes of all I cells is 5*8 msec. The latency of the earliest spike in an I cell is 0(9 msec longer than the earliest spike in a P cell.4. To stimulation of the visual cortex the latency of the earliest spike in an I cell is 1-0 msec longer than the earliest spike in a P cell. Most P cells (78 %) respond with either very short latency (less than 1X7 msec) or with a wave form characteristic of antidromic invasion or both. No I cell has either of these characterstics.5. It is concluded that P cells are principal cells projecting to visual cortex and that I cells are interneurones.

A Four Group Classification of the Rat Superior Collicular Cells Responding to Optic Nerve Stimulation

“…of the OX-latency was calculated for 43 P-cells (BURKE and SEFTON, 1966a) of the lateral geniculate nucleus (LGN) from records obtained in a previous study (FuKuDA, 1973). The data are depicted in Fig.…”

On the excitatory post‐synaptic potential evoked by stimulation of the optic tract in the rat lateral geniculate nucleus.

“…Differently from ventral l.g.n. cells, dorsal neurones show a period of decreased excitability following stimulation of the optic nerve (Burke & Sefton, 1966a;Hale & Sefton, 1978; Sumitomo, Sugitani, Fukuda & Iwama, 1979).…”

A Further Study on Fast and Slow Principal Cells of Rat Lateral Geniculate Body: An Analysis of Flash-Evoked Responses

“…These findings seem to provide a further support for the classification of P-cells into the fast and slow types. principal cells; fast and slow P-cells; lateral geniculate body; rat Principal cells (P-cells) of the rat lateral geniculate body (LGB) are known to respond to single shock stimulation of the optic pathway with the following dis charge pattern: first, a single spike discharge is elicited with latencies less than 10 msec and then, more than 160 msec later, it is followed by recurring bursts of grouped discharges (Burke and Sefton 1966a;Fukuda and Iwama 1972;Fukuda 1973).…”

“…These findings seem to provide a further support for the classification of P-cells into the fast and slow types. principal cells; fast and slow P-cells; lateral geniculate body; rat Principal cells (P-cells) of the rat lateral geniculate body (LGB) are known to respond to single shock stimulation of the optic pathway with the following dis charge pattern: first, a single spike discharge is elicited with latencies less than 10 msec and then, more than 160 msec later, it is followed by recurring bursts of grouped discharges (Burke and Sefton 1966a;Fukuda and Iwama 1972;Fukuda 1973).Designating the short-latency discharge as the initial spike (IS) and the later occurring grouped discharges as the late discharges (LDs) with the distinc tion of LD1, LD2 and so on, in the order of appearance, Fukuda (1973) made detailed studies on how the IS-latency was distributed in many P-cells and on how it was related to the LD1 _-and LD2-latencies. The most essential points of his…”