Oscillations of the spontaneous slow-wave sleep rhythm in lateral geniculate nucleus relay neurons of behaving cats

184

101

1. Hyperpolarizing potentials evoked by electrical stimulation of the optic tract were studied in projection cells of the rat dorsal lateral geniculate nucleus (LGN) in vitro. In the same cells the effects of gamma-amino butyric acid (GABA), baclofen and acetylcholine (ACh) were also investigated. 2. In the majority of cells a short- (SHP) (34 ms) and a long-lasting (LHP) (240 ms) hyperpolarizing potential could be recorded in the presence and in the absence of a preceding EPSP. They were blocked by tetrodotoxin (1 microM) and were more sensitive than the monosynaptic EPSP to a low-Ca2+-high-Mg2+ solution. 3. The SHP was associated with a marked decrease (75%) in input resistance, was blocked by bicuculline (1-100 microM) and its reversal potential (-67 mV) was dependent on the extracellular Cl- concentration. 4. The LHP was associated with a smaller decrease (45%) in input resistance and its reversal potential (-76 mV) was dependent on the extracellular K+ concentration. It was increased by bicuculline (100% at 50 microM) and nipecotic acid (30% at 10 microM), blocked by Ba2+ (1 mM), and unaffected by eserine (1-10 microM), neostigmine (1-10 microM) or by recording with EGTA-filled electrodes. In the presence of bicuculline, a single LHP was able to evoke, as a rebound response, a low-threshold Ca2+ spike that was, however, not followed by another LHP (or any other long-lasting hyperpolarization). 5. Ionophoretic applications of GABA evoked in the same cell a Cl- -dependent hyperpolarization (reversal potential: -65 mV) and/or depolarization, both of which were associated with a marked decrease (91%) in input resistance and abolished by bicuculline. GABA was also able to evoke a bicuculline-insensitive, K+-dependent hyperpolarization that had a reversal potential of -75 mV and was associated with a smaller decrease (43%) in input resistance. 6. Baclofen, applied by ionophoresis, pressure ejection or in the perfusion medium (1-100 microM), produced a hyperpolarization that had a reversal potential of -79 mV and was associated with a decrease (45%) in input resistance. 7. In the majority of cells (thirty-seven out of forty) ACh evoked a slow depolarization and only in three cells a hyperpolarization which had a reversal potential of -80 mV.(ABSTRACT TRUNCATED AT 400 WORDS)

Section: Crunelli and Othersmentioning

confidence: 89%

“…5 of Andersen & Sears, 1964;Fig. 1 of Roy et al 1984;Fourment, Hirsch & Marc, 1985). In both A and B the intensity of stimulation was adjusted so that in the control experiments no EPSP could be evoked although in B the block of the SHP revealed a clear, though small, EPSP preceding the LHP.…”

Section: Crunelli and Othersmentioning

confidence: 99%

Cl‐ ‐ and K+‐dependent inhibitory postsynaptic potentials evoked by interneurones of the rat lateral geniculate nucleus.

Crunelli

Haby

Jassik-Gerschenfeld

et al. 1988

184

101

“…are indeed similar to those described in the l.g.n. and in other thalamic nuclei of the cat and guinea-pig both in vitro and in vivo (Jahnsen & Llinas, 1984 a;Deschenes et al 1984;Fourment, Hirsch & Marc, 1985). The role played by such potentials in the responsiveness of dorsal as opposed to ventral cells to electrical stimulation of the optic tract is discussed in detail in the following paper (Crunelli et al 1987).…”

Section: Discussionmentioning

confidence: 99%

The ventral and dorsal lateral geniculate nucleus of the rat: intracellular recordings in vitro.

Crunelli

Leresche

et al. 1987

102

SUMMARY1. The membrane properties and the electrotonic structure of neurones in the ventral and dorsal lateral geniculate nucleus (l.g.n.) of the rat were studied using an in vitro slice preparation.2. Following electrophysiological characterization, horseradish peroxidase (HRP) was injected intrasomatically and the morphological features of impaled cells were characteristic of principal neurones of the rat ventral and dorsal l.g.n.3. Neurones in the ventral l.g.n. had a higher input resistance but similar membrane time constants (X0) and resting potentials than cells in the dorsal l.g.n.4. Using a simple neuronal model, the electrotonic length (L) and the dendritic to somatic conductance ratio (p) were calculated and found to be similar for cells in both divisions of the l.g.n. The mean value of L (0 7) and p (1P5) suggest that both groups of neurones are electrotonically compact.5. The width and after-hyperpolarization of directly evoked action potentials, but not their threshold or their amplitude, were different between cells of the ventral and dorsal l.g.n.6. At potentials more negative than -55 mV, a slow rising and falling potential could be evoked in each neurone (n = 310) of the dorsal l.g.n. but only in three cells of the ventral l.g.n. (n = 94). The electrophysiological and pharmacological properties of this potential were identical with those of the low-threshold Ca2+-dependent potential observed in other thalamic nuclei.7. These results indicate that some of the passive and active membrane properties of ventral and dorsal l.g.n. neurones are different. The implications of these findings for the control of the integrative capability and the response of 1.g.n. neurones to visual stimulation are discussed.

“…Low-frequency membrane potential oscillations of thalamocortical (TC) cells and their often associated rhythmic burst firing play a major role in physiological functions (references in Andersen & Andersson, 1968;Purpura, 1970;Lamarre, Filion & Cordeau, 1971;Fourment, Hirsch & Marc, 1985;Steriade & Llina's, 1988) as well as in pathological conditions (Gloor & Fariello, 1988;Lenz, Tasker, Kwan, Dostrovsky & Murphy, 1988;Buzsaki, Smith, Berger, Fisher & Gage, 1990). These oscillatory activities have been mainly regarded as involving sensory and cortical excitatory drives as well as inhibitory postsynaptic potentials originating from the rhythmic recruitment of thalamic inhibitory cells, thus stressing the role of both intra-and extra-thalamic inputs in the mechanism responsible for their generation (Burke & Sefton, 1966;Andersen & Andersson, 1968;Purpura, 1970;Gloor & Fariello, 1988;Steriade & Llinas, 1988;Sumitomo, Takahashi, Kayama & Ogawa, 1988;Buzsaki et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Low‐frequency oscillatory activities intrinsic to rat and cat thalamocortical cells.

Leresche

Lightowler

Soltész

et al. 1991

227

108

SUMMARY1. Low-frequency membrane potential oscillations recorded intracellularly from thalamocortical (TC) cells of the rat and cat dorsal lateral geniculate nucleus (dLGN) and of the rat ventrobasal nucleus (VB) maintained in vitro were investigated. On the basis of their electrophysiological and pharmacological properties, four types of activity were distinguished and named: the pacemaker oscillations, the spindle-like oscillations, the 'very slow' oscillations and the 'N-methyl-D-aspartate' (NMDA) oscillations.2. The pacemaker oscillations (95 out of 173 cells) consisted of rhythmic, largeamplitude (10-30 mV) depolarizations which occurred at a frequency of 1-8+ 03 Hz (range, 0 5-2 9 Hz) and could often give rise to single or a burst of action potentials. Pacemaker oscillations were observed when the membrane potential was moved negative to -55 and positive to -80 mV, but in a given cell the upper and lower limits of this voltage range were separated by only 13 1+0-5 mV. Above -45 mV tonic firing consisting of single action potentials was seen in the cells showing this or the other types of low-frequency oscillations.3. The spindle-like oscillations were observed in thirty-nine (out of 173) TC cells and consisted of rhythmic (2-1 +0 3 Hz), large-amplitude depolarizations (and often associated burst firing) similar to the pacemaker oscillations but occurring in discrete periods every 5-25 s and lasting for 1-5-28 s. The spindle-like oscillations were observed when the membrane potential was moved negative to -55 and positive to -80 mV and in two cells they were transformed into continuous pacemaker oscillations by depolarization of the membrane potential to -60 mV.4. Pacemaker and spindle-like oscillations were unaffected by tetrodotoxin (TTX) or by selective blockade of NMDA, non-NMDA, GABAA, GABAB, nicotinic, muscarinic, a-and fl-noradrenergic receptors. 6. The 'NMDA' oscillations were observed only in a 'Mg2"-free' medium (0 mmMg2+, 2-4 mM-Ca2+; 64 out of 72 cells) and consisted of large-amplitude (10-25 mV) depolarizations that did not occur at regular intervals and were intermixed with smaller depolarizations present on the baseline and on the falling phase of the larger ones. The 'NMDA' oscillations were voltage dependent (observed in the range from -60 to -85 mV), insensitive to TTX and had a frequency of 1-4 Hz. Application of selective NMDA receptor antagonists reversibly transformed the NMDA into the pacemaker or the spindle-like oscillations while blockade of non-NMDA receptors as well as the other receptors mentioned above (paragraph 4) had no effect on the 'NMDA' oscillations. 7. The pacemaker, the spindle-like and the 'very slow' oscillations were never observed in electrophysiologically identified rat and cat dLGN interneurones (n = 12). Similarly, in a 'Mg2+-free' medium, interneurones in the dLGN and cells in the ventral lateral geniculate nucleus did not show the 'NMDA' oscillations but only slow, small-amplitude (< 4 mV) depolarizations that were reversibly abolished by DL-2-amino-5-phosp...