scholarly journals Bilateral auditory processing studied by selective cold-deactivation of cricket hearing organs

2019 ◽  
Author(s):  
Xinyang Zhang ◽  
Berthold Hedwig
Keyword(s):  
Auditory Processing ◽  
Reciprocal Inhibition ◽  
Excitatory Input ◽  
Intracellular Recordings ◽  
Afferent Activity ◽  
Acoustic Stimuli ◽  
Hearing Organ ◽  
Inhibitory Coupling ◽  
Sound Pulses

ABSTRACTWe studied bilateral processing in the auditory ON neurons of crickets using reversible cold-deactivation of the hearing organs by means of Peltier elements. Intracellular recordings of the neurons’ activity in response to acoustic stimuli were obtained, while either the ipsilateral or the contralateral hearing organ was cold-deactivated. Afferent activity was abolished at a temperature of about 10°C. In ON1 contralateral inhibition has no effect on the latency and amplitude of the phasic onset activity, it enhances the decline of the onset activity and decreases the subsequent tonic spiking response to acoustic stimuli. As a consequence the phasic onset activity becomes more salient and reciprocal inhibition may support the detection of sound pulses. Contralateral inhibition had a significant impact on the tonic ON1 response, in line with its presumed function to enhance the bilateral auditory contrast. In ON2, experiments confirmed a bilateral excitatory input, with the ipsilateral input dominating the response, and no inhibitory coupling between the ON2 neurons.

Neuromodulatory Feedback to the Inferior Colliculus

2018 ◽  
pp. 576-610 ◽  
Author(s):  
Laura Hurley
Keyword(s):  
Inferior Colliculus ◽  
Auditory System ◽  
Auditory Processing ◽  
Internal State ◽  
Brain Regions ◽  
Auditory Information ◽  
Situational Variables ◽  
Acoustic Stimuli ◽  
Functionally Diverse ◽  
Behavioral Information

The inferior colliculus (IC) receives prominent projections from centralized neuromodulatory systems. These systems include extra-auditory clusters of cholinergic, dopaminergic, noradrenergic, and serotonergic neurons. Although these modulatory sites are not explicitly part of the auditory system, they receive projections from primary auditory regions and are responsive to acoustic stimuli. This bidirectional influence suggests the existence of auditory-modulatory feedback loops. A characteristic of neuromodulatory centers is that they integrate inputs from anatomically widespread and functionally diverse sets of brain regions. This connectivity gives neuromodulatory systems the potential to import information into the auditory system on situational variables that accompany acoustic stimuli, such as context, internal state, or experience. Once released, neuromodulators functionally reconfigure auditory circuitry through a variety of receptors expressed by auditory neurons. In addition to shaping ascending auditory information, neuromodulation within the IC influences behaviors that arise subcortically, such as prepulse inhibition of the startle response. Neuromodulatory systems therefore provide a route for integrative behavioral information to access auditory processing from its earliest levels.

Organization of Binocular Pathways: Modeling and Data Related to Rivalry

1991 ◽  
Vol 3 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Sidney R. Lehky ◽  
Randolph Blake
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Binocular Rivalry ◽  
Striate Cortex ◽  
Reciprocal Inhibition ◽  
Lateral Geniculate ◽  
Layer 4 ◽  
Inhibitory Coupling ◽  
Binocular Matching

It is proposed that inputs to binocular cells are gated by reciprocal inhibition between neurons located either in the lateral geniculate nucleus or in layer 4 of striate cortex. The strength of inhibitory coupling in the gating circuitry is modulated by layer 6 neurons, which are the outputs of binocular matching circuitry. If binocular inputs are matched, the inhibition is modulated to be weak, leading to fused vision, whereas if the binocular inputs are unmatched, inhibition is modulated to be strong, leading to rivalrous oscillations. These proposals are buttressed by psychophysical experiments measuring the strength of adaptational aftereffects following exposure to an adapting stimulus visible only intermittently during binocular rivalry.

Computer simulations of the effects of different synaptic input systems on motor unit recruitment

1993 ◽  
Vol 70 (5) ◽  
pp. 1827-1840 ◽  
Author(s):  
C. J. Heckman ◽  
M. D. Binder
Keyword(s):  
Motor Unit ◽  
Computer Simulations ◽  
Synaptic Input ◽  
Reciprocal Inhibition ◽  
Excitatory Input ◽  
Medial Gastrocnemius ◽  
Synaptic Inputs ◽  
Monte Carlo Techniques ◽  
Recruitment Order ◽  
Random Variance

1. The effects of four different synaptic input systems on the recruitment order within a mammalian motoneuron pool were investigated using computer simulations. The synaptic inputs and motor unit properties in the model were based as closely as possible on the available experimental data for the cat medial gastrocnemius pool and muscle. Monte Carlo techniques were employed to add random variance to the motor unit thresholds and forces and to sample the resulting recruitment orders. 2. The effects of the synaptic inputs on recruitment order depended on how they modified the range of recruitment thresholds established by differences in the intrinsic current thresholds of the motoneurons. Application of a uniform synaptic input to the pool (i.e., distributed equally to all motoneurons) resulted in a recruitment sequence that was quite stable even with the addition of large amounts of random variance. With 50% added random variance, the recruitment reversals did not exceed 8%. 3. The simulated monosynaptic input from homonymous Ia afferent fibers generated a twofold expansion of the range of recruitment thresholds beyond that attributed to the differences in the intrinsic current thresholds. The Ia input generated a small reduction in the number of recruitment reversals due to random variance (6% reversals at 50% random variance). The simulated monosynaptic vestibulospinal input generated a twofold compression of the range of recruitment thresholds that exerted a modest increase in the number of recruitment reversals (12% reversals at 50% random variance). 4. In comparison with the modest effects of the two monosynaptic inputs, the simulated oligosynpatic rubrospinal excitatory input exerted a nine-fold compression in the recruitment threshold range that resulted in a recruitment sequence that was highly sensitive to random variance. With 50% added random variance, the sequence became nearly random (40% reversals). 5. Reciprocal Ia inhibition was simulated by a uniform distribution within the pool, but its effects on recruitment order were highly dependent on the distribution of the excitatory input. Reciprocal inhibition exerted only minor effects on recruitment order when combined with the Ia or vestibulospinal inputs. However, when the excitatory drive was supplied by the rubrospinal input, even small amounts of reciprocal inhibition were sufficient to completely reverse the normal recruitment sequence. 6. The simulated monosynaptic Ia input was highly effective in compensating for the disruptive effects of rubrospinal excitation on recruitment order. Even a small Ia bias combined with the rubrospinal excitation was sufficient to halve the effects of random variance and to restore the normal recruitment sequence in the presence of rather large amounts of reciprocal inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)

Cortical auditory evoked potentials with different acoustic stimuli: Evidence of differences and similarities in coding in auditory processing disorders

2021 ◽  
pp. 110944
Author(s):  
Pamela Papile Lunardelo ◽  
Marisa Tomoe Hebihara Fukuda ◽  
Patricia Aparecida Zuanetti ◽  
Ângela Cristina Pontes-Fernandes ◽  
Marita Iannazzo Ferretti ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Auditory Processing ◽  
Auditory Evoked Potentials ◽  
Auditory Processing Disorders ◽  
Acoustic Stimuli ◽  
Cortical Auditory Evoked Potentials

scholarly journals A novel coding mechanism for social vocalizations in the lateral amygdala

2012 ◽  
Vol 107 (4) ◽  
pp. 1047-1057 ◽  
Author(s):  
Marie A. Gadziola ◽  
Jasmine M. S. Grimsley ◽  
Sharad J. Shanbhag ◽  
Jeffrey J. Wenstrup
Keyword(s):  
Auditory Processing ◽  
Response Duration ◽  
Spike Rate ◽  
Acoustic Stimuli ◽  
Big Brown Bats ◽  
The Social ◽  
General Functioning ◽  
Persistent Firing ◽  
Duration Information ◽  
Lateral Nucleus

The amygdala plays a central role in evaluating the significance of acoustic signals and coordinating the appropriate behavioral responses. To understand how amygdalar responses modulate auditory processing and drive emotional expression, we assessed how neurons respond to and encode information that is carried within complex acoustic stimuli. We characterized responses of single neurons in the lateral nucleus of the amygdala to social vocalizations and synthetic acoustic stimuli in awake big brown bats. Neurons typically responded to most of the social vocalizations presented (mean = nine of 11 vocalizations) but differentially modulated both firing rate and response duration. Surprisingly, response duration provided substantially more information about vocalizations than did spike rate. In most neurons, variation in response duration depended, in part, on persistent excitatory discharge that extended beyond stimulus duration. Information in persistent firing duration was significantly greater than in spike rate, and the majority of neurons displayed more information in persistent firing, which was more likely to be observed in response to aggressive vocalizations (64%) than appeasement vocalizations (25%), suggesting that persistent firing may relate to the behavioral context of vocalizations. These findings suggest that the amygdala uses a novel coding strategy for discriminating among vocalizations and underscore the importance of persistent firing in the general functioning of the amygdala.

Intrinsic Circuitry of the Superior Colliculus: Pharmacophysiological Identification of Horizontally Oriented Inhibitory Interneurons

1998 ◽  
Vol 79 (3) ◽  
pp. 1597-1602 ◽  
Author(s):  
M. Alex Meredith ◽  
Ary S. Ramoa
Keyword(s):  
Superior Colliculus ◽  
Excitatory Amino Acid ◽  
Reciprocal Inhibition ◽  
Excitatory Input ◽  
Inhibitory Interneurons ◽  
Local Circuit ◽  
Physiological Evidence ◽  
Spontaneous Action ◽  
Potential Activity

Meredith, M. Alex and Ary S. Ramoa. Intrinsic circuitry of the superior colliculus: pharmacophysiological identification of horizontally oriented inhibitory interneurons. J. Neurophysiol. 79: 1597–1602, 1998. Much of what is known about the organization of the superior colliculus is based on the arrangement of its external connections. Consequently, there is little information regarding pathways that remain intrinsic to it, even though recent data suggest that a horizontally oriented local circuit may mediate the functional reciprocity among fixation and saccade-related neurons. Therefore, the present experiments sought physiological evidence for neurons intrinsic to the superior colliculus that might participate in a horizontally oriented local circuit. Parasagittal slices of the ferret superior colliculus were prepared for in vitro recording, and 125 intermediate/deep layer neurons were examined in response to electrical stimulation rostral or caudal to the recording site. A substantial proportion (37%) of neurons responded with a prolonged period (means = 59.3 ± 30 ms) of poststimulus suppression of spontaneous action potential activity. Of the suppressed neurons, most (53%) were disinhibited when the excitatory amino acid receptor antagonists d-2-amino-5-phosphonovaleric acid (d-APV) and 6-nitro-7 sulphamoylbeno[f]-quinoxaline-2,3-dione (NBQX) were administered, indicating that excitatory input to inhibitory interneurons was blocked. Of the neurons that received inputs from inhibitory interneurons, all had their suppressive responses decreased or eliminated by the γ-aminobutyric acid antagonist, bicuculline. Finally, severing the superficial layers from the slice had no effect on intermediate layer responses to intrinsic stimulation. These data provide physiological evidence for the presence of horizontally oriented inhibitory interneurons in the superior colliculus. Furthermore, these findings are consistent with the hypothesis that an intrinsic circuit, routed through interneurons, might account for the reciprocal inhibition observed among fixation and saccade-related neurons.

Cholinergic contribution to excitation in a spinal locomotor central pattern generator in Xenopus embryos

1995 ◽  
Vol 73 (3) ◽  
pp. 1013-1019 ◽  
Author(s):  
R. Perrins ◽  
A. Roberts
Keyword(s):  
Spinal Cord ◽  
Central Pattern Generator ◽  
Excitatory Amino Acid ◽  
Pattern Generator ◽  
Excitatory Input ◽  
Intracellular Recordings ◽  
Electrical Excitation ◽  
Spinal Interneurons ◽  
Xenopus Embryos ◽  
Spike Firing

1. We have investigated whether in Xenopus embryos, spinal interneurons of the central pattern generator (CPG) receive cholinergic or electrical excitatory input during swimming. The functions of cholinergic excitation during swimming were also investigated. 2. Intracellular recordings were made from rhythmically active presumed premotor interneurons in the dorsal third of the spinal cord. After locally blocking inhibitory potentials with 2 microM strychnine and 40 microM bicuculline, the reliability of spike firing and the amplitude of fast, on-cycle, excitatory postsynaptic potentials (EPSPs) underlying the single on-cycle spikes were measured during fictive swimming. 3. The nicotinic antagonists d-tubocurarine and dihydro-beta-erythroidine (DH beta E, both 10 microM) reversibly reduced the reliability of the spike firing during swimming and reduced the amplitude of the on-cycle EPSP by 16%. DH beta E also reduced the EPSP amplitude in spinalized embryos by 22%. These results indicate that interneurons receive rhythmic cholinergic excitation from a source within the spinal cord. 4. Combined applications of nicotinic and excitatory amino acid (EAA) antagonists or cadmium (Cd2+, 100-200 microM) resulted in complete block of the fast EPSP, suggesting that interneurons do not receive electrical excitation. 5. The nicotinic antagonists mecamylamine and d-tubocurarine (both 5 microM) reduced the duration of episodes of fictive swimming recorded from the ventral roots, in spinal embryos. When applied in the middle of a long episode, d-tubocurarine decreased the swimming frequency, ruling out an effect on the initiation pathway. The cholinesterase inhibitor eserine (10 microM) increased the duration of swimming episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of input from the Forewing Stretch Receptors on Motoneurones in Flying Locusts

1990 ◽  
Vol 151 (1) ◽  
pp. 317-340 ◽  
Author(s):  
K. G. PEARSON ◽  
J. M. RAMIREZ
Keyword(s):  
Membrane Potential ◽  
Excitatory Input ◽  
Cycle Period ◽  
Strongly Correlated ◽  
Intracellular Recordings ◽  
Wingbeat Frequency ◽  
Potential Oscillations ◽  
Stretch Receptors ◽  
Membrane Potential Oscillations ◽  
Stimulation Of

1. Previous studies on the forewing stretch receptors (FSRs) of locusts have suggested that feedback from these receptors during flight contributes to the excitation of depressor motoneurones and reduces the duration of depolarizations in elevator motoneurones. We have investigated these proposals by measuring the timing of FSR activity relative to depressor activity and by examining the effects of stimulating the FSRs on the membrane potential oscillations in flight motoneurones. 2. Activity in the FSRs was recorded in tethered intact animals flying in a windstream and in preparations that allowed intracellular recordings from motoneurones during flight activity. The timing of FSR activity was similar in both preparations. In most animals we observed that at normal wingbeat frequencies (about 20 Hz) the activity in the FSRs commenced after the onset of activity in the wing depressor muscles. As wingbeat frequency declined there was a progressive advance of FSR activity relative to depressor activity. Most of the spikes in each burst of FSR activity occurred during the time that the membrane potential in depressor motoneurones was repolarizing. 3. Electrical stimulation of the FSRs timed to follow the onset of depressor activity slowed the rate of repolarization, decreased the peak hyperpolarization and increased the rate of the following depolarization in depressor motoneurones. In elevator motoneurones, the same pattern of FSR stimulation produced an additional excitatory input during the depolarization phase and, at low wingbeat frequencies, reduced the duration of the peak depolarizations. The reduction in the duration of the peak depolarization in elevator motoneurones was not strongly correlated to the reduction in cycle period. 4. We propose that the primary reason why input from the FSRs increases wingbeat frequency is because this input reduces the degree of hyperpolarization in depressor neurones and thus promotes an earlier onset of the next depolarization in these neurones.

Changes in the Estimated Time Course of the Motoneuron Afterhyperpolarization Induced by Tendon Vibration

2010 ◽  
Vol 104 (6) ◽  
pp. 3240-3249 ◽  
Author(s):  
Christopher W. MacDonell ◽  
Tanya D. Ivanova ◽  
S. Jayne Garland
Keyword(s):  
Achilles Tendon ◽  
Time Constant ◽  
Time Course ◽  
Motor Units ◽  
Reciprocal Inhibition ◽  
Excitatory Input ◽  
Motor Unit Action Potential ◽  
Inhibitory Input ◽  
Tendon Vibration ◽  
Single Motor Units

Group Ia afferents are activated vigorously with high-frequency tendon vibration and provide excitatory input to the agonist muscle and inhibitory input to the antagonist muscle group via inhibitory interneurons. The purpose of this experiment was to determine whether the afterhyperpolarization (AHP) time course in humans is altered in response to tendon vibration. The AHP time course is estimated using the interval death rate (IDR) analysis, a transform of the motor unit action potential train. Single motor units from tibialis anterior (TA) were recorded as subjects held low force dorsiflexor contractions for 600 s with and without vibration. The vibratory stimulus was superimposed on the low force contraction either to the tendon of the TA or the antagonist Achilles tendon. During TA tendon vibration, the time course of the AHP, as expressed by its time constant (τ), decreased from 35.5 ms in the previbration control condition to 31.3 ms during the vibration ( P = 0.003) and returned to 36.3 ms after the vibration was removed ( P = 0.002). The AHP τ during vibration of the antagonist Achilles tendon (38.6 ms) was greater than the previbration control condition (33.6 ms; P = 0.001). It is speculated that the reduction in AHP time constant with TA vibration may have resulted alone or in combination with a modulation of motoneuron gain, an alteration of persistent inward currents and/or the restructuring of synaptic noise. A decrease in firing probability, possibly reflecting Ia reciprocal inhibition, may have been responsible for the larger AHP time constant.

ADAPTIVE MODIFICATIONS IN THE FLIGHT SYSTEM OF THE LOCUST AFTER THE REMOVAL OF WING PROPRIOCEPTORS

1991 ◽  
Vol 157 (1) ◽  
pp. 313-333 ◽  
Author(s):  
ANSGAR BÜSCHGES ◽  
KEIR G. PEARSON
Keyword(s):  
Normal Values ◽  
Locusta Migratoria ◽  
Motor Pattern ◽  
Afferent Input ◽  
Excitatory Input ◽  
Time Dependent ◽  
Intracellular Recordings ◽  
Wingbeat Frequency ◽  
Flight System ◽  
Flight Motor

Previous investigations on the flight system of the locust have found that removal of the wing tegulae in mature locusts (Locusta migratoria) results in an immediate change in the flight motor pattern: the wingbeat frequency (WBF) decreases, the interval between the activity of the depressor and the elevator muscles (the D-E interval) increases, and the phase of the elevator activity in the depressor cycle increases. Here we report the results of a detailed quantitative analysis of these changes. We also examined the flight motor pattern for up to 14 days after removal of the tegulae and found that the changes caused by this operation were not permanent. Beginning on the first day after the operation there was a time-dependent recovery of the WBF, the D-E interval and the phase towards their normal values. In about 80% of the experimental animals the flight motor pattern recovered almost completely. Intracellular recordings from elevator motoneurones showed that this recovery was associated with changes in the pattern of excitatory input to these motoneurones. The modification of activity in elevator motoneurones was dependent on afferent input since complete deafferentation of recovered animals resulted in a motor pattern similar to that following deafferentation of normal animals.

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