Central Control of an Insect Sensory Interneurone

1970 ◽  
Vol 53 (1) ◽  
pp. 137-145 ◽  
Author(s):  
J. M. McKAY
Keyword(s):  
Feedback Loop ◽  
Sensory Input ◽  
Sine Wave ◽  
Feedback Stabilization ◽  
Inhibitory Input ◽  
Stimulus Amplitude ◽  
Response Level ◽  
Directional Information ◽  
Prothoracic Ganglion ◽  
High Stimulus

1. The T fibre habituates little to a series of sine-wave pulses, and recovery is complete within 10 min. 2. Both response level and rate of habituation are increased when the posterior thoracic ganglia are disconnected from the prothoracic ganglion. This indicates that response level and rate of habituation are maintained at a low level in the intact animal by an inhibitory input or inputs to the prothoracic ganglion, which arise within the pterothorax. These inputs are entirely central in origin, and are independent of extratympanal sensory input. 3. The function of the posterior branch of the T fibre to the posterior thorax may be to initiate a feedback loop which is completed by the input from the posterior thorax. It is suggested that such feedback stabilization of the response level would reduce loss of directional information at high stimulus amplitude, preserve discrimination at high stimulus repetition rates and reduce habituation. The implications of these findings for a warning neurone system are discussed.

Phase resetting of spontaneously beating embryonic ventricular heart cell aggregates

1986 ◽  
Vol 251 (6) ◽  
pp. H1298-H1305 ◽  
Author(s):  
M. R. Guevara ◽  
A. Shrier ◽  
L. Glass
Keyword(s):  
Action Potentials ◽  
High Amplitude ◽  
Heart Cell ◽  
Cell Aggregates ◽  
Embryonic Chick ◽  
Phase Resetting ◽  
Stimulus Amplitude ◽  
High Stimulus ◽  
Very High ◽  
Spontaneous Rhythm

The influence of isolated 20-ms duration current pulses on the spontaneous rhythm of embryonic chick ventricular heart cell aggregates was studied. A pulse could either delay or advance the time of occurrence of the next action potential, depending on whether it fell early or late in the cycle. As the stimulus amplitude was increased, the transition from delay to advance occurred over a narrower range of coupling intervals. At low-stimulus amplitudes the transition from delay to advance occurred in a smooth continuous fashion; at medium-stimulus amplitudes the transition was discontinuous; at high-stimulus amplitudes graded action potentials were seen. It was impossible to annihilate spontaneous activity in aggregates with a single stimulus. The phase-resetting response to hyperpolarizing pulses was qualitatively the reverse of that produced by depolarizing pulses. A very high-amplitude depolarizing or hyperpolarizing pulse could produce rapid repetitive activity. Theoretical aspects of these phenomena are discussed.

Binaural processing of sound pressure level in the inferior colliculus

1987 ◽  
Vol 57 (4) ◽  
pp. 1130-1147 ◽  
Author(s):  
M. N. Semple ◽  
L. M. Kitzes
Keyword(s):  
Inferior Colliculus ◽  
Sound Pressure ◽  
Spatial Information ◽  
Discharge Rate ◽  
Excitatory Input ◽  
Central Nucleus ◽  
Intensity Difference ◽  
Inhibitory Input ◽  
Directional Information ◽  
Discharge Rates

The central auditory system could encode information about the location of a high-frequency sound source by comparing the sound pressure levels at the ears. Two potential computations are the interaural intensity difference (IID) and the average binaural intensity (ABI). In this study of the central nucleus of the inferior colliculus (ICC) of the anesthetized gerbil, we demonstrate that responses of 85% of the 97 single units in our sample were jointly influenced by IID and ABI. For a given ABI, discharge rate of most units is a sigmoidal function of IID, and peak rates occur at IIDs favoring the contralateral ear. Most commonly, successive increments of ABI cause successive shifts of the IID functions toward IIDs favoring the ipsilateral ear. Neurons displaying this behavior include many that would conventionally be classified EI (receiving predominantly excitatory input arising from one ear and inhibitory input from the other), many that would be classified EE (receiving predominantly excitatory input arising from each ear), and all that are responsive only to contralateral stimulation. The IID sensitivity of a very few EI neurons is unaffected by ABI, except near threshold. Such units could provide directional information that is independent of source intensity. A few EE neurons are very sensitive to ABI, but are minimally sensitive to IID. Nevertheless, our data indicate that responses of most EE units in ICC are strongly dominated by excitation of contralateral origin. For some units, discharge rate is nonmonotonically related to IID and is maximal when the stimuli at the two ears are of comparable sound pressure. This preference for zero IID is common for all binaural levels. Many EI neurons respond nonmonotonically to ABI. Discharge rates are greater for IIDs representative of contralateral space and are maximal at a single best ABI. For a subset of these neurons, the influence arising from the ipsilateral ear is comprised of a mixture of excitation and inhibition. As a consequence, discharge rates are nonmonotonically related not only to ABI but also to IID. This dual nonmonotonicity creates a clear focus of peak response at a particular ABI/IID combination. Because of their mixed monaural influences, such units would be ascribed to different classes of the conventional (EE/EI) binaural classification scheme depending on the binaural level presented. Several response classes were identified in this study, and each might contribute differently to the encoding of spatial information.(ABSTRACT TRUNCATED AT 400 WORDS)

The Auditory System of Homorocoryphus (Tettigonioidea, Orthoptera)

1969 ◽  
Vol 51 (3) ◽  
pp. 787-802 ◽  
Author(s):  
J. M. McKAY
Keyword(s):  
Auditory System ◽  
High Frequency ◽  
Warning System ◽  
Inhibitory Effect ◽  
Behavioural Response ◽  
Inhibitory Input ◽  
Phasic Response ◽  
Directional Information ◽  
High Frequency Sound ◽  
Song Frequency

1. The responses of the auditory interneurones indicate that the tettigoniid ear discriminates frequencies. 2. The T fibre receives strong ipsilateral and weak contralateral excitatory inputs and a strong contralateral inhibitory input, from the tympanic nerves. These inputs are frequency-sensitive, the response being greatest at 30 kcyc./sec. and above. Responsiveness is low in the region of 15 kcyc./sec., which is the dominant song frequency. 3. At 30 kcyc./sec. the T fibre is most sensitive to amplitude increments, and conveys maximal directional information. Both the T fibre and the ear (as judged by the compound potential in the tympanic nerve) respond to steps of 2 dB. The directionality of the ear is enhanced by the contralateral inhibitory connexions of the T fibre. At 15 kcyc./sec. directionality is poor, but is present at 10 kcyc./sec. 4. The T fibre is inhibited by continuous sounds, including the species song. The extent of the inhibitory effect varies with the amplitude of the continuous sound. This may assist in explaining the ‘phasic’ response of the T fibre. There is little habituation to repetitive stimuli. 5. A small interneurone seen in split connectives gives a ‘tonic’ response to song and to continuous sound. It may inhibit the T fibre. Two other auditory fibres are occasionally recorded in the connectives. 6. The T fibre has all the properties required of a warning system responding to pulsed high-frequency sound, and it responds well to bat cries. There is, however, no evidence that it mediates a behavioural response.

An Acridid Auditory Interneurone

1969 ◽  
Vol 51 (1) ◽  
pp. 247-260
Author(s):  
C. H. FRASER ROWELL ◽  
J. M. McKAY
Keyword(s):  
Complete Recovery ◽  
Significant Negative Correlation ◽  
Slight Reduction ◽  
Central Control ◽  
Response Decrement ◽  
Descending Inhibition ◽  
Response Level ◽  
Short Pulses ◽  
Prothoracic Ganglion ◽  
Central Lesions

1. The alpha neurone habituates to repetitive short (40 msec.) or long (2-3 sec.) pulses of sound. The response decrement to 10 short pulses at 1/sec. is exponential. Twenty-five minutes is required for complete recovery to 20 short pulses at 1/sec. No dishabituation followed various changes in stimulus repetition. 2. The C.N.S. affects both response level and habituation. In 13% of all animals the neurone was completely inhibited by the head ganglia and was disinhibited by decapitation. Progressive lesions reveal strong inhibition by the head ganglia, and possibly weaker inhibition by the abdominal chain; the prothoracic ganglion has no apparent effect. 3. Removal of the head ganglia almost halves the habituation rate; further removal of the abdominal chain may give a further slight reduction; the prothoracic ganglion has no effect. 4. There is a significant negative correlation between response level and habituation. This could be partially explained if the absolute response decrement is independent of response level. The remaining decrease in habituation observed suggests either a further link between response level and habituation at the synapse, or possibly independent central control of both. Central control affects habituation more than response level. 5. Spontaneous variation in response level is unaffected by the various central lesions. It thus arises in the posterior thoracic ganglia, and not as descending inhibition or excitation from higher centres. 6. These findings are related to the animal's biology and to previous work.

Gating of Afferent Input by a Central Pattern Generator

1999 ◽  
Vol 81 (2) ◽  
pp. 950-953 ◽  
Author(s):  
Ralph A. DiCaprio
Keyword(s):  
Central Pattern Generator ◽  
Sensory Input ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Afferent Input ◽  
Inhibitory Input ◽  
Cycle Period ◽  
Intracellular Recordings ◽  
Afferent Fibers ◽  
Sufficient Magnitude

Gating of afferent input by a central pattern generator. Intracellular recordings from the sole proprioceptor (the oval organ) in the crab ventilatory system show that the nonspiking afferent fibers from this organ receive a cyclic hyperpolarizing inhibition in phase with the ventilatory motor pattern. Although depolarizing and hyperpolarizing current pulses injected into a single afferent will reset the ventilatory motor pattern, the inhibitory input is of sufficient magnitude to block afferent input to the ventilatory central pattern generator (CPG) for ∼50% of the cycle period. It is proposed that this inhibitory input serves to gate sensory input to the ventilatory CPG to provide an unambiguous input to the ventilatory CPG.

Auxin-induced nanoclustering of membrane signaling complexes underlies cell polarity establishment in Arabidopsis

2019 ◽  
Author(s):  
Xue Pan ◽  
Linjing Fang ◽  
Jianfeng Liu ◽  
Betul Senay-Aras ◽  
Wenwei Lin ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Polarity ◽  
Feedback Loop ◽  
Cortical Microtubule ◽  
Cell Polarization ◽  
Feedback Stabilization ◽  
Cell Surface Receptor ◽  
List Type ◽  
Pavement Cells ◽  
Polarity Establishment

AbstractCell polarity is fundamental to the development of both eukaryotic and prokaryotic organisms, yet the mechanism of its establishment remains poorly understood. Here we show that signal-activated nanoclustering of membrane proteins and a cytoskeleton-based feedback loop provide an important mechanism for the establishment of cell polarity. The phytohormone auxin promoted sterol-dependent nanoclustering of cell surface transmembrane receptor-like kinase 1 (TMK1) to initiate cell polarity during the morphogenesis of Arabidopsis puzzle piece-shaped leaf pavement cells (PC). Auxin-triggered nanoclustering of TMK1 stabilized flotillin-associated ordered nanodomains, which were essential for auxin-mediated formation of ROP6 GTPase nanoclusters that act downstream TMK1 to promote cortical microtubule ordering. Mathematical modeling further demonstrated the essential role of this auxin-mediated stabilization of TMK1 and ROP6 nanoclusters, and predicted the additional requirement of ROP6-dependent cortical microtubules for further stabilization of TMK1-sterol nanodomains and the polarization of PC. This prediction was experimentally validated by genetic and biochemical data. Our studies reveal a new paradigm for polarity establishment: A diffusive signal triggers cell polarization by activating cell surface receptor-mediated lateral segregation of signaling components and a cytoskeleton-mediated positive feedback loop of nanodomain stabilization.HighlightsSterols are required for cell polarity in Arabidopsis leaf epidermal cellsAuxin promotes lipid ordering and polar distribution of ordered lipid nanodomains at the plasma membrane (PM)Auxin stabilizes sterol-dependent nanoclustering of transmembrane kinase (TMK1), a PM auxin signal transducerAuxin-induced TMK1 nanoclustering is required but insufficient for cell polarizationMicrotubule-based feedback stabilization of the auxin-induced TMK1 nanodomains can generate cell polarity

scholarly journals Feed-forward information and zero-lag synchronization in the sensory thalamocortical circuit are modulated during stimulus perception

2019 ◽  
Vol 116 (15) ◽  
pp. 7513-7522 ◽  
Author(s):  
Adrià Tauste Campo ◽  
Yuriria Vázquez ◽  
Manuel Álvarez ◽  
Antonio Zainos ◽  
Román Rossi-Pool ◽  
...  
Keyword(s):  
Information Flow ◽  
Tactile Stimulus ◽  
Functional Information ◽  
Stimulus Amplitude ◽  
Lag Synchronization ◽  
Directional Information ◽  
Feed Forward ◽  
Somatosensory Thalamus ◽  
Stimulus Perception ◽  
Ventral Posterolateral Nucleus

The direction of functional information flow in the sensory thalamocortical circuit may play a role in stimulus perception, but, surprisingly, this process is poorly understood. We addressed this problem by evaluating a directional information measure between simultaneously recorded neurons from somatosensory thalamus (ventral posterolateral nucleus, VPL) and somatosensory cortex (S1) sharing the same cutaneous receptive field while monkeys judged the presence or absence of a tactile stimulus. During stimulus presence, feed-forward information (VPL → S1) increased as a function of the stimulus amplitude, while pure feed-back information (S1 → VPL) was unaffected. In parallel, zero-lag interaction emerged with increasing stimulus amplitude, reflecting externally driven thalamocortical synchronization during stimulus processing. Furthermore, VPL → S1 information decreased during error trials. Also, VPL → S1 and zero-lag interaction decreased when monkeys were not required to report the stimulus presence. These findings provide evidence that both the direction of information flow and the instant synchronization in the sensory thalamocortical circuit play a role in stimulus perception.

Direction selectivity in a model of the starburst amacrine cell

2004 ◽  
Vol 21 (4) ◽  
pp. 611-625 ◽  
Author(s):  
JOHN J. TUKKER ◽  
W. ROWLAND TAYLOR ◽  
ROBERT G. SMITH
Keyword(s):  
Amacrine Cell ◽  
Dendritic Tree ◽  
Sine Wave ◽  
Direction Selectivity ◽  
Membrane Properties ◽  
Calcium Signal ◽  
Inhibitory Input ◽  
Excitatory Postsynaptic Potential ◽  
Global Signal ◽  
Starburst Amacrine Cell

The starburst amacrine cell (SBAC), found in all mammalian retinas, is thought to provide the directional inhibitory input recorded in On–Off direction-selective ganglion cells (DSGCs). While voltage recordings from the somas of SBACs have not shown robust direction selectivity (DS), the dendritic tips of these cells display direction-selective calcium signals, even when γ-aminobutyric acid (GABAa,c) channels are blocked, implying that inhibition is not necessary to generate DS. This suggested that the distinctive morphology of the SBAC could generate a DS signal at the dendritic tips, where most of its synaptic output is located. To explore this possibility, we constructed a compartmental model incorporating realistic morphological structure, passive membrane properties, and excitatory inputs. We found robust DS at the dendritic tips but not at the soma. Two-spot apparent motion and annulus radial motion produced weak DS, but thin bars produced robust DS. For these stimuli, DS was caused by the interaction of a local synaptic input signal with a temporally delayed “global” signal, that is, an excitatory postsynaptic potential (EPSP) that spread from the activated inputs into the soma and throughout the dendritic tree. In the preferred direction the signals in the dendritic tips coincided, allowing summation, whereas in the null direction the local signal preceded the global signal, preventing summation. Sine-wave grating stimuli produced the greatest amount of DS, especially at high velocities and low spatial frequencies. The sine-wave DS responses could be accounted for by a simple mathematical model, which summed phase-shifted signals from soma and dendritic tip. By testing different artificial morphologies, we discovered DS was relatively independent of the morphological details, but depended on having a sufficient number of inputs at the distal tips and a limited electrotonic isolation. Adding voltage-gated calcium channels to the model showed that their threshold effect can amplify DS in the intracellular calcium signal.

scholarly journals Single-neuron interactions between the somatosensory thalamo-cortical circuits during perception

2018 ◽  
Author(s):  
Adrià Tauste Campo ◽  
Yuriria Vázquez ◽  
Manuel Álvarez ◽  
Antonio Zainos ◽  
Román Rossi-Pool ◽  
...  
Keyword(s):  
Single Neuron ◽  
Detection Task ◽  
Cortical Circuits ◽  
Task Context ◽  
Stimulus Amplitude ◽  
Significant Stimulus ◽  
Somatosensory Thalamus ◽  
Stimulus Perception ◽  
High Stimulus ◽  
Bidirectional Interactions

SUMMARYSensory thalamo-cortical interactions are key components of the neuronal chains associated with stimulus perception, but surprisingly, they are poorly understood. We addressed this problem by evaluating a directional measure between simultaneously recorded neurons from somatosensory thalamus (VPL) and somatosensory cortex (S1) sharing the same cutaneous receptive field, while monkeys judged the presence or absence of a tactile stimulus. During the stimulus-presence, feedforward (VPL→S1) interactions increased, while pure feedback (S1→VPL) interactions were unaffected. Remarkably, bidirectional interactions (VPL↔S1) emerged with high stimulus amplitude, establishing a functional thalamo-cortical loop. Furthermore, feedforward interactions were modulated by task context and error trials. Additionally, significant stimulus modulations were found on intra-cortical (S1→S1) interactions, but not on intra-thalamic (VPL→VPL) interactions. Thus, these results show the directionality of the information flow between the thalamo-cortical circuits during tactile perception. We suggest that these interactions may contribute to stimulus perception during the detection task used here.

Angiotensin II Activates a Nitric-Oxide-Driven Inhibitory Feedback in the Rat Paraventricular Nucleus

2003 ◽  
Vol 89 (3) ◽  
pp. 1238-1244 ◽  
Author(s):  
Kevin J. Latchford ◽  
Alastair V. Ferguson
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Nitric Oxide Synthase ◽  
Paraventricular Nucleus ◽  
Negative Feedback ◽  
Feedback Loop ◽  
Inhibitory Input ◽  
Negative Feedback Loop ◽  
Magnocellular Neurons ◽  
Oxide Synthase

The hypothalamic paraventricular nucleus (PVN) has been shown to play major obligatory roles in autonomic and neuroendocrine regulation. Angiotensin II (ANG) acts as a neurotransmitter regulating the excitability of magnocellular neurons in this nucleus. We report here that ANG also activates a nitric-oxide-mediated negative feedback loop in the PVN that acts to regulate the functional output of magnocellular neurons. Thus in addition to its depolarizing actions on magnocellular neurons, ANG application results in an increase in the frequency of inhibitory postsynaptic potentials in a population of these neurons without effect on the amplitude of these events. ANG was also without significant effect on the mean frequency or amplitude of mini synaptic currents analyzed in voltage-clamp experiments. This increase in inhibitory input after ANG can be abolished by the nitric oxide synthase inhibitor Nω-nitro-l-arginine methylester, demonstrating a requisite role for nitric oxide in the activation of this pathway. The depolarization of magnocellular neurons that show increased inhibitory postsynaptic potential (IPSP) frequency in response to ANG is significantly smaller than that observed in neurons in which IPSPs frequency was unaffected (3.2 ± 1.1 vs. 8.0 ± 0.5mV, P < 0.05). Correspondingly, after nitric oxide synthase inhibition, the depolarizing effects of ANG on magnocellular neurons are augmented (2.0 ± 0.7 vs. 6.7 ± 0.7mV, P < 0.05). The depolarization was also enhanced in the presence of the GABAergic antagonist bicuculline (1.9 ± 1.2 vs. 11.9 ± 2.3, P < 0.001). These data demonstrate that there exists within the PVN an intrinsic negative feedback loop that modulates neuronal excitability in response to peptidergic excitation.

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