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Neurons
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
It has been estimated that approximately 20% of the synaptic contacts in the brain are inhibitory. Note that a single-line diagram of neuronal connections as in Figure 7.3 should be interpreted in terms of neuron types rather than literally. Thus, in Figure 7.3a, the incoming excitation may excite a given excitatory neuron, but the inhibitory neuron excited by this incoming excitation may inhibit other excitatory neurons of the same type as the given excitatory neuron. Similarly, in Figure 7.3b, the output of the excitatory neuron excites an inhibitory interneuron, which may then inhibit other excitatory neurons of the same type. In center-surround-inhibition, an excited neuron is surrounded by inhibited neurons of the same type. In lateral inhibition, the inhibited neurons are located mainly laterally with respect to the excited neuron of the same type. Examples of these types of inhibition are given in connection with Figure 12.14.
Physiology of Hearing
Published in James R. Tysome, Rahul G. Kanegaonkar, Hearing, 2015
Other cells appear better suited to encode intensity and have a dynamic range considerably in excess of that found in any individual auditory nerve fibre; clearly, cells at this stage are summing information from many auditory nerve fibres. Some cells show strong lateral inhibition, analogous to that seen in the visual system and not to be confused with two-tone suppression, a non-neural phenomenon seen in the auditory nerve.
Physiology of the nervous system
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2015
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The mechanisms involved in the modification of input into the relay nuclei may be presynaptic, postsynaptic or both. Interneurons are important for pre- and postsynaptic inhibition, producing lateral or afferent inhibition. This is particularly important in the visual and auditory systems. Functionally, lateral inhibition is important for spatial discrimination and the ability to localize stimuli.
Non-linguistic auditory speech processing
Published in International Journal of Audiology, 2023
Robert H. Margolis, Aparna Rao, Richard H. Wilson, George L. Saly
Models of speech perception (e.g. Klatt 1979; Cole and Jakimik 1980; Blomberg et al. 1986; Poeppel et al. 2009) represent the derivation of meaning from auditory speech as a series of processes that begins with the spectro-temporal analysis of the speech waveform. Models disagree on the relative importance of spectral and temporal analysis to speech perception. Searle et al. (1980) suggested that the speech-perception process begins with analysing the input signal into 1/3 octave bands. The 1/3 octave bandwidth would provide the necessary spectral information and an adequately fast time constant to encode the important temporal properties of the signal. Scott (1980), on the other hand, emphasised the importance of the temporal analysis of the waveform for encoding the necessary information to derive meaning from the signal. Elhilali et al. (2003) hypothesised a three-stage process for the peripheral spectro-temporal analysis, composed of (a) a temporally-varying spatial pattern on the basilar membrane; (b) a temporally-varying pattern of inner hair cell intra-cellular potentials; and (c) a spectral sharpening mechanism mediated by lateral inhibition. This acoustic analysis of the input signal is a non-linguistic process performed by the auditory periphery. The importance of this peripheral analysis was stated cogently by Galbraith et al. (2004):
Updated review on the link between cortical spreading depression and headache disorders
Published in Expert Review of Neurotherapeutics, 2021
Doga Vuralli, Hulya Karatas, Muge Yemisci, Hayrunnisa Bolay
Though CSD propagates through limited gyri in intact human brain, still, it may cause a small depolarized cortical focus, adequate to alter the cortico-thalamic drive on thalamic relay nuclei and TRN. Cessation of cortical neuronal firing during CSD would reduce excitatory drive from cortex to the thalamus, resulting in decreased GABAergic output from TRN to thalamic relay nuclei and enhanced transmission of sensory input from thalamic relay nuclei to the cortex. This might be the mechanism underlying sensory hyperresponsivity, reduced sensory discrimination and reduced lateral inhibition in migraine. For instance, pulvinar nucleus of thalamus is an integration area for multiple sensory modalities [164] and is connected to multiple functional brain networks such as default mode, somato-motor, fronto-opercular, and cingulo-opercular networks [77]. CSD may lead to a dysfunction in the thalamocortical network and change the interplay between the cortical areas such as sensorimotor cortex or visual cortex and the pulvinar and may cause synchronous or sequential multisensory symptoms. Impairment in multiple sensory and cognitive domains accompanying migraine headache can be related to the dysfunction of the thalamocortical circuit and task negative and task positive functional brain networks. We also assume that thalamocortical dysfunction leading to the activation of the trigeminal pain nucleus through central pathways could also play a role in the development of lateralized headache in migraine.
Agmatine as a potential therapeutic intervention in bipolar depression: the preclinical landscape
Published in Expert Opinion on Therapeutic Targets, 2019
Devon Watts, Bianca Pfaffenseller, Bianca Wollenhaupt-Aguiar, Luiza Paul Géa, Taiane De Azevedo Cardoso, Flavio Kapczinski
For instance, there has been a recent interest in potential deficits in somatostatin positive GABA interneurons in the context of mood disorders [118]. In both the neocortex and hippocampus, somatostatin positive interneurons are involved in feedback mediation and lateral inhibition. Interestingly, aCREB-regulated transcription coactivator 1 (CRTC1) deficient mice show increased agmatinase, an agmatine-degrading enzyme, in the PFC, and hippocampus, as well as increased number of agmatinase expressing parvalbumin and somatostatin-positive GABAergic interneurons. Exogenous administration of agmatine has been shown to lead to a rapid antidepressant-like effect within this model, suggesting that an agmatine deficit, secondary to increased agmatinase presence, may be related to depressive phenotypes [61].