EurekaMag.com logo
+ Site Statistics
References:
47,893,527
Abstracts:
28,296,643
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrophysiological properties of neurons recorded intracellularly in slices of the pigeon optic tectum


, : Electrophysiological properties of neurons recorded intracellularly in slices of the pigeon optic tectum. Neuroscience 23(1): 305-318

The electrical properties of pigeon's optic tectum neurons located in the non-retinorecipient region of layer II have been studied in in vitro slice preparations by using intracellular recordings. As judged from the somatodendritic characteristics of cells intracelluarlly labeled with horseradish peroxidase recordings were obtained from pyramidal neurons, the main morphological type, as well as from ganglion cells. When stimulated with depolarizing current pulses of 300-500 ms duration, three distinct modes of firing were observed. Most neurons (Type I) responded with a continuous firing of fast action potentials whose frequency rate increased regularly when current strength was raised. Another group of cells (Type II) also exhibited sustained firing. However, in Type II cells, grouped discharges formed by 2-6 fast action potentials per group fired in rapid succesion were elicited within a certain range of current intensity. Finally, another group of cells (Type III) responded at all intensities tested by a short train of fast action potentials only at the onset of the current step. At current strength close to threshold the spike undershoot of type I neurons was followed by a slow hyperpolarizing after potential while the spike undershoot of Type II cells was followed by a hump-like depolarization and a slow hyperpolarizing afterpotential. In Type II cells, we have also observed a pronounced increase of the hyperpolarizing afterpotential after a grouped discharge. Type III cells were characterized by a small amplitude and short duration hyperpolarizing afterpotential, barely visible in most of them. In Type I and II cells the slow hyperpolarizing after potential was blocked by replacing Ca2+ and Mg2+ or Cd2+ in the saline. These results support the idea that in these two types of neurons the slow hyperpolarizing afterpotential is primarily caused by a Ca2+-dependent K+ conductance. Furthermore, blocking the slow hyperpolarizing afterpotential provoked a pronounced increase of the firing frequency of Type I cells. In Type II cells blockade of the slow hyperpolarizing afterpotential had a greater effect on firing behavior: i.e. when Ca2+ was replaced with Mg2+ or Cd2+, Type II neurons exhibited repetitively fired action potentials at high frequency but were incapable of discharging repetivive grouped discharges. These observations indicate that the Ca2+-depenent K+ conductance involved in the generation of the slow hyperpolarizing afterpotential is the main modulator of the firing behavior of both types of cells. On the contrary, in Type III cells removal of Ca2+ from the bath had no either on the firing frequency or in the duration of the train of spikes. The present study also demonstrates that pigeon's tectal neurons are capable of generating action potentials corresponding not only to those arising from a sodium conductance but also to those arising from a low threshold calcium conductance.

Accession: 005349741

PMID: 2825075

DOI: 10.1016/0306-4522(87)90291-0

Download PDF Full Text: Electrophysiological properties of neurons recorded intracellularly in slices of the pigeon optic tectum


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Vandermaelen, C.P.; Aghajanian, G.K., 1983: Electrophysiological and pharmacological characterization of serotonergic dorsal raphe neurons recorded extracellularly and intracellularly in rat brain slices. Extracellular and intracellular recordings were made from dorsal raphe (DR) neurons in frontal rat brain slices maintained in vitro. A population of neurons was found which displayed electrophysiological and pharmacological characteristics of sero...

Hu, C.H.a; Wang, B., 1996: Effects of glutamate, acetylcholine on the electric activity of neurons located in sublayer II- in pigeon optic tectum slices. Journal of Neurochemistry 67(SUPPL ): S6

Woody, C.D.; Gruen, E., 1978: Characterization of electrophysiological properties of intracellularly recorded neurons in the neocortex of awake cats: a comparison of the response to injected current in spike overshoot and undershoot neurons. Intracellular recordings were obtained from 212 neurons of the coronal pericruciate cortex of 7 awake, untrained cats. Glass microelectrodes, filled with K+ citrate alone or K+ citrate with either cyclic GMP or 5'-GMP were used for recording...

Lewald, J.; Doerrscheidt, G.J.achim, 1998: Spatial-tuning properties of auditory neurons in the optic tectum of the pigeon. We studied the auditory neurons in the optic tectum of the unanesthetized pigeon, using single-unit recordings and acoustic free-field stimulation. Most units showed spatial tuning, with best areas located in the contralateral hemifield. All units...

Hardy O.; Audinat E.; Jassik Gerschenfeld D., 1986: Electrophysiological properties of pigeons optic tectum neurons in vitro. Neuroscience Letters Supplement (26): S347

White, C.A.; Esguerra, M.; Sur, M., 1992: Electrophysiological properties of developing neurons recorded in slices of ferret LGN. Society for Neuroscience Abstracts 18(1-2): 923

Bilge, M., 1971: Electrophysiological investigations on the pigeon's optic tectum. Quarterly Journal of Experimental Physiology and Cognate Medical Sciences 56(4): 242-249

Mercuri, N.B.; Calabresi, P.; Bonci, A.; Pisani, A.; Vagnozzi, R.; Bernardi, G., 1995: The electrophysiological effects of monoamino oxidase inhibitors on rat dopaminergic neurons intracellularly recorded in vitro. Society for Neuroscience Abstracts 21(1-3): 1140

Bagnoli P.; Brunelli M.; Zavagno E., 1979: Habituation and sensitization in the optic tectum neurons of the pigeon. Neuroscience Letters SUPPL(3): S289

Bagnoli P.; Francesconi W.; Pellegrino M., 1981: Contrast sensitivity of neurons in pigeon optic tectum. An analysis of contrast sensitivity of neurons in the optic tectum of intact and wulst-ablated pigeons was carried out using moving light bars. Changes of contrast from 0.1-89%, obtained with different bar luminances, induced increases of response...