What is tonic activation?
a form of arousal mediated by the reticular formation and identified as tonic because of its persistent effect.
What is tonic activation of neurons?
Generally speaking, tonic firing refers to a sustained response, which activates during the course of the stimulus; while phasic firing refers to a transient response with one or few action potentials at the onset of stimulus followed by accommodation.
What does tonic inhibition mean?
This form of neurotransmission is known as tonic inhibition. Tonic inhibition is usually thought to reduce the excitability of all neurons, but here we show that it can selectively modulate the excitability of different types of neurons.
What is tonic conductance?
Tonic GABAA conductance was calculated as the difference between the baseline conductance (1/Ri) and the conductance in the presence of a GABAA receptor antagonist (gGABA) or exogenous GABA (ΔgGABA). Synaptic GABAA conductance in response to electric stimulation (PSG, Fig.
What is an example of a tonic receptor?
Nociceptors. The receptors for pain are called nociceptors. It is the best example of the tonic receptor. Nociceptors are the free nerve endings.
What is tonic control?
Tonic Control permits the activity of the organ system to be modulated (either up or down). This is like the volume control on a radio which enables you to make the sound louder or softer by turning a single knob.
What does tonic mean in physiology?
Tonic in physiology refers to a physiological response which is slow and may be graded. This term is typically used in opposition to a fast response.
What is tonic GABA?
Tonic GABA(A) receptor-mediated currents were present in pyramidal cells and interneurons in layer V-VI of temporal neocortex and granule cells in the dentate gyrus. These tonic currents have cell type-specific pharmacologies, opening up the possibility of targeted therapeutics.
What is tonic and phasic dopamine?
Behaviorally relevant stimuli are proposed to cause short-term activation of dopamine cell firing to trigger the phasic component of dopamine release. In contrast, tonic dopamine release is proposed to regulate the intensity of the phasic dopamine response through its effect on extracellular dopamine levels.
What is GABA mediated inhibition?
Phasic inhibition consists of fast GABAA-mediated inhibitory postsynaptic potentials (IPSPs) regulating point to point communication between neurons. In physiological conditions it exerts a powerful control on cell excitability and network oscillations thought to be associated with high cognitive functions.
What is phasic and tonic inhibition?
Phasic inhibition is mediated by the fast activation of synaptic GABAARs from synaptically released GABA. Tonic inhibition depends on the sustained activation of peri- and extrasynaptic GABAARs by ambient GABA in the extracellular space.
What is Extrasynaptic transmission?
Extrasynaptic transmission is a unifying term for a wide variety of cellular processes, in which outside of synaptic terminals transmitter substances activate extrasynaptic receptors.
What is Neural inhibition?
In physiology, inhibition refers to a process whereby neural activity patterns are suppressed, blocked or restricted in both space and time. In the mammalian brain, inhibition is predominantly realised by inhibitory interneurons which release gamma amino butyric acid (GABA), the principle inhibitory neurotransmitter.
What inhibits the firing of neurons?
Rapid and precise signal transmission between the majority of nerve cells (neurons) in the mammalian central nervous system (CNS) is mediated by two major modes of neurotransmission: excitation by glutamic acid and inhibition by γ-aminobutyric acid (GABA).
What triggers inhibition of a neuron?
Feedback inhibition occurs when excitatory principal neurons synapse onto inhibitory interneurons, which project back to the principal neurons and inhibit them (negative-feedback loop). Feedforward inhibition occurs when axons synapse directly onto inhibitory interneurons, inhibiting downstream principal neurons.