Almost every essay in this book contains "pearls" of Arendt's tonically subversive thinking, and many of her observations push readers to think harder about the language in which political activity is conducted.
|
|
Tonically active neurons are cholinergic interneurons that fire during the entire duration of the stimulus and fire at about 0.5–3 impulses per second. Phasic neurons are the opposite and only fire an action potential when movement occurs.
|
|
Calponin is a calcium binding protein. Calponin tonically inhibits the ATPase activity of myosin in smooth muscle. Phosphorylation of calponin by a protein kinase, which is dependent upon calcium binding to calmodulin, releases the calponin's inhibition of the smooth muscle ATPase.
|
|
Most of the dendritic spines on the medium spiny neurons synapse with cortical afferents and their axons project numerous collaterals to other neurons.Czubayko and Plenz, 2002 The cholinergic interneurons of the primate, are very different from those of non-primates. These are said to be tonically active.Kimura et al.
|
|
Caldesmon is a protein that in humans is encoded by the CALD1 gene. Caldesmon is a calmodulin binding protein. Like calponin, caldesmon tonically inhibits the ATPase activity of myosin in smooth muscle. This gene encodes a calmodulin- and actin-binding protein that plays an essential role in the regulation of smooth muscle and nonmuscle contraction.
|
|
The indirect pathway also receives excitatory input from various brain regions. Indirect pathway medium spiny neurons project to the external segment of the globus pallidus (GPe). Like the GPi, the GPe is a tonically active inhibitory nucleus. The GPe projects to the excitatory subthalamic nucleus (STN), which in turn projects to the GPi and SNr.
|
|
Both GAD67 and GAD65 are present in all types of synapses within the human nervous system. This includes dendrodendritic, axosomatic, and axodendritic synapses. Preliminary evidence suggests that GAD65 is dominant in the visual and neuroendocrine systems, which undergo more phasic changes. It is also believed that GAD67 is present at higher amounts in tonically active neurons.
|
|
Hair plates function as proprioceptors. The sensory neurons innervating the hair plate may respond phasically to hair movements (rapidly adapting) or tonically to maintained deflections (slowly adapting). Thus, hair plates can encode the position and movement of an adjoining body segment. Hair plate neurons project to the insect central nervous system, where they form synapses with multiple postsynaptic partners.
|
|
In some neurological disorders, the pupil does not react to light, but it does react to accommodation. This is called “light-near dissociation”. In Adie syndrome, damage involving the ciliary ganglion manifests light-near dissociation and a tonically dilated pupil (usually on the same side). Other causes of light-near dissociation involve damage to the brainstem, where a tonic pupil is not produced.
|
|
Evidence for the role of the endocannabinoid system in food-seeking behavior comes from a variety of cannabinoid studies. Emerging data suggests that THC acts via CB1 receptors in the hypothalamic nuclei to directly increase appetite. It is thought that hypothalamic neurons tonically produce endocannabinoids that work to tightly regulate hunger. The amount of endocannabinoids produced is inversely correlated with the amount of leptin in the blood.
|
|
The glomerulus is made up of the mossy fibre terminal, granule cell dendrites, the Golgi terminal and is enclosed by a glial coat. The Golgi cell acts by altering the mossy fibre - granule cell synapse. The Golgi cells use GABA as their transmitter. The basal level of GABA produces a postsynaptic leak conductance by tonically activating alpha 6-containing GABA-A receptors on the granule cell.
|
|
Along with various types of movement, the putamen also affects reinforcement learning and implicit learning. Reinforcement learning is interacting with the environment and catering actions to maximize the outcome. Implicit learning is a passive process where people are exposed to information and acquire knowledge through exposure. Although the exact mechanisms are not known, it is clear that dopamine and tonically active neurons play a key role here.
|
|
They are innervated by proprioreceptors that detect the stretch in extensor muscles when the flexors are contracted. They then fire phasically or tonically. It then excites the motor neurons in the fast extensor muscles while directly exciting an inhibitory neuron that prevents contractions in the FF muscles. The hair cells detect the resulting movement caused by the tail flip when activated, they would fire and excite the fast extensor motor neurons.
|
|
Direct and indirect striatopallidal pathways: Glutamatergic pathways are red, dopaminergic are magenta and GABAergic pathways are blue. STN: Subthalamic Nucleus SNr: Substantia Nigra pars reticulata SNc: Substantia Nigra pars compacta GPe: External globus pallidus The GPi acts to tonically inhibit the ventral lateral nucleus and ventral anterior nucleus of the thalamus. As these two nuclei are needed for movement planning, this inhibition restricts movement initiation and prevents unwanted movements.
|
|
Neural pathways in the basal ganglia in the cortico-basal ganglia- thalamo-cortical loop, are seen as controlling different aspects of behaviour. This regulation is enabled by the dopamine pathways. It has been proposed that the dopamine system of pathways is the overall organiser of the neural pathways that are seen to be parallels of the dopamine pathways. Dopamine is provided both tonically and phasically in response to the needs of the neural pathways.
|
|
Image showing the sphincter in a female, and demonstrating its action to prevent urination. This is the primary muscle for maintaining continence of urine, a function shared with the external urethral sphincter which is under voluntary control. It prevents urine leakage as the muscle is tonically contracted via sympathetic fibers traveling through the inferior hypogastric plexus and vesical nervous plexus. Specifically, it is controlled by the hypogastric nerve, predominantly via the alpha-1 receptor.
|
|
Cardiovascular targets of the sympathetic nervous system includes both blood vessels and the heart. Even at resting levels of blood pressure, arterial baroreceptor discharge activates NTS neurons. Some of these NTS neurons are tonically activated by this resting blood pressure and thus activate excitatory fibers to the nucleus ambiguus and Dorsal nucleus of vagus nerve to regulate the parasympathetic nervous system. These parasympathetic neurons send axons to the heart and parasympathetic activity slows cardiac pacemaking and thus heart rate.
|
|
Smooth muscle may contract phasically with rapid contraction and relaxation, or tonically with slow and sustained contraction. The reproductive, digestive, respiratory, and urinary tracts, skin, eye, and vasculature all contain this tonic muscle type. This type of smooth muscle can maintain force for prolonged time with only little energy utilization. There are differences in the myosin heavy and light chains that also correlate with these differences in contractile patterns and kinetics of contraction between tonic and phasic smooth muscle.
|
|
The direct pathway is involved in facilitation of wanted movements. The projections from dopamine D1 receptor containing medium spiny neurons in the caudate nucleus and putamen synapse onto tonically active GABAergic cells in the substantia nigra pars reticulata and the internal segment of the globus pallidus (GPi) which then project to the thalamus. Because the striatonigral / striatoentopeduncular and nigrothalamic pathways are inhibitory, activation of the direct pathway creates an overall net excitatory on the thalamus and on movement generated by the motor cortex.
|
|
The Lithuanian prosodic system is characterized by free accent and distinctive quantity. Its accentuation is sometimes described as a simple tone system, often called pitch accent.Phonetic invariance and phonological stability: Lithuanian pitch accents Grzegorz Dogil & Gregor Möhler, 1998 In lexical words, one syllable will be tonically prominent. A heavy syllable—that is, a syllable containing a long vowel, diphthong, or a sonorant coda—may have one of two tones, falling tone (or acute tone) or rising tone (or circumflex tone).
|
|
Possible causes of opsoclonus include neuroblastoma and encephalitis in children, and breast, lung, or ovarian cancer in adults. Other considerations include multiple sclerosis, toxins, medication effects (e.g. Serotonin Syndrome), celiac disease, certain infections (West Nile virus, Lyme disease), non-Hodgkin lymphoma, and renal adenocarcinoma. It can also be caused by a lesion in the omnipause neurons which tonically inhibit initiation of saccadic eye movement (until signaled by the superior colliculus) by blocking paramedian pontine reticular formation (PPRF) burst neurons in the pons.
|
|
Here during the attack tonic muscular contraction may occur, leading to increase in muscle tone which may affect the extensor muscles or the flexor muscles symmetrically or asymmetrically. If the patient is standing, the head may be drawn backward and the trunk may arch. This may lead to retropulsion, which may cause eyelids to twitch rapidly, eyes may jerk upwards or the patients head may rock back and forth slowly, as if nodding. The head may tonically draw to one or another side.
|
|
As a further example of the melody's baroque characteristics, the bridge contains an implied but unfulfilled tonicisation of VI. In addition, over the coda, the recurring four-bar instrumental passage is partly shifted to a parallel minor, through the use of the more classically oriented Am chord, rather than its major equivalent as before. Following the instrumental coda, the song ends with the strings playing a tonically ambiguous cadence, which Everett describes as an unexpected "diminished fourth away from tonic".
|
|
For emotionally salient information to be remembered, the perceived stress must be induced before encoding, and retrieval must follow shortly afterwards. In contrast, for emotionally charged stimuli to be forgotten, the stressful exposure must be after encoding and retrieval must follow after a longer delay. If stressful information is relatable to a person, the event more prone to be stored in permanent memory. When a person is under stress, the sympathetic system will shift to a constantly (tonically) active state.
|
|
The striatum also contains interneurons that are classified into nitrergic neurons (due to use of nitric oxide as a neurotransmitter), tonically active cholinergic interneurons, parvalbumin-expressing neurons and calretinin-expressing neurons. The dorsal striatum receives significant glutamatergic inputs from the cortex, as well as dopaminergic inputs from the substantia nigra pars compacta. The dorsal striatum is generally considered to be involved in sensorimotor activities. The ventral striatum receives glutamatergic inputs from the limbic areas as well as dopaminergic inputs from the VTA, via the mesolimbic pathway.
|
|
The indirect pathway is involved in suppressing unwanted movement. The projections from dopamine D2 receptor containing medium spiny neurons in the caudate nucleus and putamen synapse onto tonically active GABAergic cells in the external segment of the globus pallidus (GPe) which then projects to the substantia nigra pars reticulata via the excitatory subthalmic nucleus (STN). Because the striatopallidal and nigrothalamic pathways are inhibitory but the subthalamic to nigra pathway is excitatory, activation of the indirect pathway creates an overall net inhibitory effect on the thalamus and on movement by the motor cortex.
|
|
Long term depression (LTD) at the PF-PC synapse is hypothesized to have significant functional consequences for learning the behavioral CR in EBC (Ito, 1984). For example, as a result of training, INP cells discharge prior to CR execution and fire in a pattern of increased frequency of response that predicts the temporal form of the behavioral CR (McCormick & Thompson, 1984). This pattern of activity clearly indicates that the INP is capable a generating a conditioned response. Purkinje cells of the cerebellar cortex tonically inhibit deep nuclear cells.
|
|
The LGI receives its sensory input from the hair-like projections found on the edge of the tail fan. The sensory information is sent from bipolar receptors connected to the hair that are directionally sensitive. The path of the signal varies from here depending on the strength of the input. In the beta pathway, the signal can then pass a chemical synapse, the information is sent to a sensory interneuron (SI) of either type A (which fires phasically in response to input) or type C, (which fire tonically).
|
|
Adie syndrome, also known as Holmes-Adie syndrome, is a neurological disorder characterized by a tonically dilated pupil that reacts slowly to light but shows a more definite response to accommodation (i.e., light-near dissociation). It is frequently seen in females with absent knee or ankle jerks and impaired sweating. The syndrome is caused by damage to the postganglionic fibers of the parasympathetic innervation of the eye, usually by a viral or bacterial infection that causes inflammation, and affects the pupil of the eye and the autonomic nervous system.
|
|
The muscle helps maintain continence of urine along with the internal urethral sphincter which is under control of the autonomic nervous system. The external sphincter muscle prevents urine leakage as the muscle is tonically contracted via somatic fibers that originate in Onuf's nucleus and pass through sacral spinal nerves S2-S4 then the pudendal nerve to synapse on the muscle. Voiding urine begins with voluntary relaxation of the external urethral sphincter. This is facilitated by inhibition of the somatic neurons in Onuf's nucleus via signals arising in the pontine micturition center and traveling through the descending reticulospinal tracts.
|
|
This sustained phase has been attributed to certain myosin crossbridges, termed latch-bridges, that are cycling very slowly, notably slowing the progression to the cycle stage whereby dephosphorylated myosin detaches from the actin, thereby maintaining the force at low energy costs. This phenomenon is of great value especially for tonically active smooth muscle. Isolated preparations of vascular and visceral smooth muscle contract with depolarizing high potassium balanced saline generating a certain amount of contractile force. The same preparation stimulated in normal balanced saline with an agonist such as endothelin or serotonin will generate more contractile force.
|
|
Although the structure and function is basically the same in smooth muscle cells in different organs, their specific effects or end-functions differ. The contractile function of vascular smooth muscle regulates the lumenal diameter of the small arteries- arterioles called resistance vessels, thereby contributing significantly to setting the level of blood pressure and blood flow to vascular beds. Smooth muscle contracts slowly and may maintain the contraction (tonically) for prolonged periods in blood vessels, bronchioles, and some sphincters. Activating arteriole smooth muscle can decrease the lumenal diameter 1/3 of resting so it drastically alters blood flow and resistance.
|
|
The muscle helps maintain continence of urine along with the internal urethral sphincter which is under control of the autonomic nervous system. The external sphincter muscle prevents urine leakage as the muscle is tonically contracted via somatic fibers that originate in Onuf's nucleus and pass through sacral spinal nerves S2-S4 then the pudendal nerve to synapse on the muscle. Voiding urine begins with voluntary relaxation of the external urethral sphincter. This is facilitated by inhibition of the somatic neurons in Onuf's nucleus via signals arising in the pontine micturition center and traveling through the descending reticulospinal tracts.
|
|
The direct pathway within the basal ganglia receives excitatory input from the cortex, thalamus, and other brain regions. In the direct pathway, medium spiny neurons project to the internal division of the globus pallidus (GPi) or the substantia nigra pars reticula (SNpr or SNr). These nuclei project to the deep layer of the superior colliculus and control fast eye movements (saccades), and also project to the ventral thalamus, which in turn projects to upper motor neurons in the primary motor cortex (precentral gyrus). The SNr and GPi outputs are both tonically active inhibitory nuclei and are thus constantly inhibiting the thalamus (and thus motor cortex).
|
|
The structure of the otolith organs enables them to sense both static displacements, as would be caused by tilting the head relative to the gravitational axis, and transient displacements caused by translational movements of the head. The mass of the otolithic membrane relative to the surrounding endolymph, as well as the membrane's physical uncoupling from the underlying macula, means that hair bundle displacement will occur transiently in response to linear accelerations, and tonically in response to tilting of the head. Prior to tiliting, the axon has a high firing rate, which increases or decreases depending on the direction of tilt. When the head is returned to its original position, the firing level returns to baseline value.
|
|
The basal ganglia functions to tonically inhibit movement, mainly in the absence of motor cortex command, via GABAergic inhibition of the ventral lateral nucleus and ventral anterior nucleus of the thalamus, as well as the superior colliculus and mesopontine tegmentum of the brain stem. When movement is required, the cerebral cortex sends commands to the striatum, which directly inhibits the medial globus pallidus and substantia nigra pars reticulata, decreasing thalamus and brainstem inhibition. As the pathway from the striatum to the medial globus pallidus is monosynaptic (containing one synapse), it is called the direct pathway. The indirect pathway, which contains the GPe and the subthalamic nucleus, functions to modulate the effects of the direct pathway.
|
|
Eye movements are evoked by activity in the deep layers of the SC. During fixation, neurons near the front edge — the foveal zone — are tonically active. During smooth pursuit, neurons a small distance from the front edge are activated, leading to small eye movements. For saccades, neurons are activated in a region that represents the point to which the saccade will be directed. Just prior to a saccade, activity rapidly builds up at the target location and decreases in other parts of the SC. The coding is rather broad, so that for any given saccade the activity profile forms a "hill" that encompasses a substantial fraction of the collicular map: The location of the peak of this "hill" represents the saccade target.
|
|
Like other members of the RING-between-RING (RBR) family of E3 ligases, parkin possesses two RING finger domains and an in-between-RING (IBR) region. RING1 forms the binding site for E2 Ub-conjugating enzyme while RING2 contains the catalytic cysteine residue (Cys431) that cleaves Ub off E2 and transiently binds it to E3 via a thioester bond. Ub transfer is aided by neighbouring residues histidine His433, which accepts a proton from Cys431 to activate it, and glutamate Glu444, which is involved in autoubiquitination. Together these form the catalytic triad, whose assembly is required for parkin activation. Parkin also contains an N-terminal Ub-like domain (Ubl) for specific substrate recognition, a unique RING0 domain and a repressor (REP) region that tonically suppresses ligase activity. Under resting conditions, the tightly coiled conformation of parkin renders it inactive, as access to the catalytic RING2 residue is sterically blocked by RING0, while the E2 binding domain on RING1 is occluded by Ubl and REP.
|
|
TRPV1 antagonists have shown efficacy in reducing nociception from inflammatory and neuropathic pain models in rats. This provides evidence that TRPV1 is capsaicin's sole receptor In humans, drugs acting at TRPV1 receptors could be used to treat neuropathic pain associated with multiple sclerosis, chemotherapy, or amputation, as well as pain associated with the inflammatory response of damaged tissue, such as in osteoarthritis. These drugs can affect body temperature (hyperthermia) which is a challenge to therapeutic application. For example, a transient temperature gain (~1 °C for a duration of approximately 40 minutes, reverting to baseline by 40 minutes) was measured in rats with the application of TRPV1 antagonist AMG9810. The role of TRPV1 in the regulation of body temperature has emerged in the last few years. Based on a number of TRPV-selective antagonists' causing a mild increase in body temperature (hyperthermia), it was proposed that TRPV1 is tonically active in vivo and regulates body temperature by telling the body to "cool itself down".
|
|