Distal Versus Proximal Inhibitory Shaping of Feedback Excitation in the Electrosensory Lateral Line Lobe: Implications for Sensory Filtering

1998 ◽  
Vol 80 (6) ◽  
pp. 3214-3232 ◽  
Author(s):  
Neil J. Berman ◽  
Leonard Maler

Berman, Neil J. and Leonard Maler. Distal versus proximal inhibitory shaping of feedback excitation in the electrosensory lateral line lobe: implications for sensory filtering. J. Neurophysiol. 80: 3214–3232, 1998. The inhibition controlling the indirect descending feedback (parallel fibers originating from cerebellar granule cells in the eminentia posterior pars granularis) to electrosensory lateral line lobe (ELL) pyramidal cells was studied using intracellular recording techniques in vitro. Parallel fibers (PF) contact stellate cells and dendrites of ventral molecular layer (VML) GABAergic interneurons. Stellate cells provide local input to pyramidal cell distal dendrites, whereas VML cells contact their somata and proximal dendrites. Single-pulse stimulation of PF evoked graded excitatory postsynaptic potentials (EPSPs) that were blocked by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and N-methyl-d-aspartate (NMDA) antagonists. The EPSPs peaked at 6.4 ± 1.8 ms (mean ± SE; n = 11) but took >50 ms to decay completely. Tetanic stimulation (100 ms, 100 Hz) produced a depolarizing wave with individual EPSPs superimposed. The absolute amplitude of the individual EPSPs decreased during the train. Spike rates, established by injected current, mostly were increased, but in some cells were decreased, by tetanic stimulation. Global application of a γ-aminobutyric acid-A (GABAA) antagonist to the recorded cell's soma and apical dendritic region increased the EPSP peak and decay phase amplitudes. Tetanic stimulation always increased current-evoked spike rates after GABAA blockade during, and for several hundred milliseconds after, the stimulus. Application of a GABAB antagonist did not have any significant effects on the PF-evoked response. This, and the lack of any long hyperpolarizing inhibitory postsynaptic potentials, suggests that VML and stellate cell inhibition does not involve GABAB receptors. Focal GABAA antagonist applications to the dorsal molecular layer (DML) and pyramidal cell layer (PCL) had contrasting effects on PF-evoked EPSPs. DML GABAA blockade significantly increased the EPSP peak amplitude but not the decay phase of the EPSP, whereas PCL GABAA-blockade significantly increased the decay phase, but not the EPSP peak, amplitude. The order of antagonist application did not affect the outcome. On the basis of the known circuitry of the ELL, we conclude that the distal inhibition originated from GABAergic molecular layer stellate cells and the proximal inhibition originated from GABAergic cells of the ventral molecular layer (VML cells). Computer modeling of distal and proximal inhibition suggests that intrinsic differences in IPSP dynamics between the distal and proximal sites may be amplified by voltage-dependent NMDA receptor and persistent sodium currents. We propose that the different time courses of stellate cell and VML cell inhibition allows them to act as low- and high-pass filters respectively on indirect descending feedback to ELL pyramidal cells.

1999 ◽  
Vol 202 (10) ◽  
pp. 1255-1265 ◽  
Author(s):  
R.W. Turner ◽  
L. Maler

Oscillatory and burst discharge is recognized as a key element of signal processing from the level of receptor to cortical output cells in most sensory systems. The relevance of this activity for electrosensory processing has become increasingly apparent for cells in the electrosensory lateral line lobe (ELL) of gymnotiform weakly electric fish. Burst discharge by ELL pyramidal cells can be recorded in vivo and has been directly associated with feature extraction of electrosensory input. In vivo recordings have also shown that pyramidal cells are differentially tuned to the frequency of amplitude modulations across three ELL topographic maps of electroreceptor distribution. Pyramidal cell recordings in vitro reveal two forms of oscillatory discharge with properties consistent with pyramidal cell frequency tuning in vivo. One is a slow oscillation of spike discharge arising from local circuit interactions that exhibits marked changes in several properties across the sensory maps. The second is a fast, intrinsic form of burst discharge that incorporates a newly recognized interaction between somatic and dendritic membranes. These findings suggest that a differential regulation of oscillatory discharge properties across sensory maps may underlie frequency tuning in the ELL and influence feature extraction in vivo.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martina Francesca Rizza ◽  
Francesca Locatelli ◽  
Stefano Masoli ◽  
Diana Sánchez-Ponce ◽  
Alberto Muñoz ◽  
...  

AbstractThe functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear. We have measured stellate cells electroresponsiveness and their activation by parallel fiber bursts. Stellate cells showed intrinsic pacemaking, along with characteristic responses to depolarization and hyperpolarization, and showed a marked short-term facilitation during repetitive parallel fiber transmission. Spikes were emitted after a lag and only at high frequency, making stellate cells to operate as delay-high-pass filters. A detailed computational model summarizing these physiological properties allowed to explore different functional configurations of the parallel fiber—stellate cell—Purkinje cell circuit. Simulations showed that, following parallel fiber stimulation, Purkinje cells almost linearly increased their response with input frequency, but such an increase was inhibited by stellate cells, which leveled the Purkinje cell gain curve to its 4 Hz value. When reciprocal inhibitory connections between stellate cells were activated, the control of stellate cells over Purkinje cell discharge was maintained only at very high frequencies. These simulations thus predict a new role for stellate cells, which could endow the molecular layer with low-pass and band-pass filtering properties regulating Purkinje cell gain and, along with this, also burst delay and the burst-pause responses pattern.


2020 ◽  
Author(s):  
Martina Francesca Rizza ◽  
Francesca Locatelli ◽  
Stefano Masoli ◽  
Diana Sánchez Ponce ◽  
Alberto Muñoz ◽  
...  

AbstractThe functional properties of cerebellar stellate cells and the way they regulate molecular layer activity are still unclear. We have measured stellate cells electroresponsiveness and their activation by parallel fiber bursts. Stellate cells showed intrinsic pacemaking, along with characteristic responses to depolarization and hyperpolarization, and showed a marked short-term facilitation during repetitive parallel fiber transmission. Spikes were emitted after a lag and only at high frequency, making stellate cells to operate as delay-high-pass filters. A detailed computational model summarizing these physiological properties allowed to explore different functional configurations of the parallel fiber – stellate cell – Purkinje cell circuit. Simulations showed that, following parallel fiber stimulation, Purkinje cells almost linearly increased their response with input frequency but such an increase was inhibited by stellate cells, which leveled the Purkinje cell gain curve to its 4 Hz value. When reciprocal inhibitory connections between stellate cells were activated, the control of stellate cells over Purkinje cell discharge was maintained only at very high frequencies. These simulations thus predict a new role for stellate cells, which could endow the molecular layer with low-pass and band-pass filtering properties regulating Purkinje cell gain and, along with this, also burst delay and the burst-pause responses pattern.


2002 ◽  
Vol 87 (3) ◽  
pp. 1404-1414 ◽  
Author(s):  
Katherine L. Perkins

Whole cell voltage-clamp recording and focal application of the neurotransmitter γ-aminobutyric acid (GABA) were used to investigate the ability of exogenous GABA applied to different locations within the guinea pig hippocampal slice to trigger a giant GABA-mediated postsynaptic current (GPSC) in pyramidal cells. A GPSC reflects the synchronous release of GABA from a group of interneurons. Recordings were done in the presence of 4-aminopyridine (4-AP) and blockers of ionotropic glutamatergic synaptic transmission. Spontaneous GPSCs occurred rhythmically in pyramidal cells under these conditions. Brief focal pressure application of GABA (500 μM; 30–200 ms) to CA3 stratum lacunosum-moleculare (SLM) or to the border between CA3 s. radiatum (SR) and SLM triggered an “all-or-none” GPSC in CA3 and CA1 pyramidal cells that looked like the spontaneous GPSCs. During the refractory period following a spontaneous GPSC, application of GABA could not trigger a GPSC. Both spontaneous GPSCs and GPSCs triggered by exogenous GABA were blocked by suppressing synaptic transmission with high Mg2+/low Ca2+bath solution. On the other hand, focal application of GABA to CA3 s. oriens (SO) or to proximal SR did not trigger a GPSC in the CA3 pyramidal cell; instead it produced a graded response. Focal application of GABA to regions other than CA3 was also tested. Focal application of GABA to CA1 SLM always triggered a GPSC in the CA3 pyramidal cell. Focal application of GABA within the outer two-thirds of the dentate molecular layer often elicited a GPSC in the CA3 pyramidal cell. In contrast, focal application of GABA to CA1 SO, to CA1 SR, or to the hilus elicited no current response in the CA3 pyramidal cell. These data indicate that the GPSC recorded in pyramidal cells that was triggered by focal GABA application resulted from the synchronous synaptic release of GABA from activated interneurons rather than from the binding of exogenous GABA to receptors on the pyramidal cell. Furthermore, the “all-or-none” nature of the response to SLM GABA applications of different durations indicates that the exogenous GABA was exciting (directly or indirectly) some members of a network of interneurons, which in turn recruited the rest of the network, rather than individually activating each interneuron that contributed to the GPSC. Interestingly, the effective sites of GABA application—CA3 SLM, CA1 SLM, and the outer two-thirds of the dentate molecular layer—are also the sites which receive direct innervation from the entorhinal cortex in an intact animal.


1998 ◽  
Vol 79 (4) ◽  
pp. 1839-1857 ◽  
Author(s):  
J. Bastian

Bastian, J. Plasticity in an electrosensory system. III. Contrasting properties of spatially segregated dendritic inputs. J. Neurophysiol. 79: 1839–1857, 1998. Efferent neurons of the first-order electrosensory processing center of the brain, the electrosensory lateral line lobe (ELL), receive electroreceptor afferent input as well as feedback inputs descending from higher centers. These ELL efferents, pyramidal cells, adaptively filter predictable patterns of sensory input while preserving sensitivity to novel stimuli. The filter mechanism involves integration of centrally generated predictive inputs with the afferent inputs being canceled. The predictive inputs, referred to as “negative image” inputs, terminate on pyramidal cell apical dendrites and generate responses that are opposite those resulting from the predictable afference, hence integration of these signals results in attenuation of pyramidal cell responses. The system also shows a robust form of plasticity; the pyramidal cells learn, with a time course of a few minutes, to cancel new patterns of repetitive inputs. This is accomplished by adjusting the strength of excitatory and inhibitory apical dendritic inputs according to an anti-Hebbian learning rule. This study focuses on the properties of two separate pathways that convey descending information to pyramidal cell apical dendrites. One pathway terminates proximally, nearer to the pyramidal cell body, whereas the other terminates distally. Recordings of ELL evoked potentials, extracellular pyramidal cell spike responses, and intracellularly recorded synaptic potentials show that the pyramidal cells respond oppositely to moderate-frequency (> ∼8 Hz) single pulse stimulation or repeated (1/s) tetanic activation of these two pathways. Repetitive activation of the proximally terminating pathway results in highly facilitating responses due to potentiation of pyramidal cell excitatory postsynaptic potentials (EPSPs). These same stimuli applied to the distally terminating pathway result in a reduction of pyramidal cell responses due to depression of EPSPs and potentiation of inhibitatory postsynaptic potentials (IPSPs). Anti-Hebbian plasticity was demonstrated by pairing tetanic stimulation of either pathway with changes in the postsynaptic cell's membrane potential. After stabilization of the response potentiation due to tetanic stimulation of the proximally terminating pathway, paired postsynaptic hyperpolarization resulted in further increases in spike responses and additional potentiation of pyramidal cell EPSPs. Paired postsynaptic depolarization reduced subsequent responses to the tetanus, depressed EPSP amplitudes, and, in many cases, potentiated IPSPs. The same pattern of plasticity was observed when postsynaptic hyper- or depolarization was paired with tetanic stimulation of the distally terminating pathway except that the plasticity was superimposed on the depressed pyramidal cell responses resulting from stimulating this pathway alone. Modulation of a postsynaptic form of synaptic depression is proposed to account for the anti-Hebbian plasticity associated with both pathways.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Yoshiyuki Kubota ◽  
Satoru Kondo ◽  
Masaki Nomura ◽  
Sayuri Hatada ◽  
Noboru Yamaguchi ◽  
...  

Inhibitory interneurons target precise membrane regions on pyramidal cells, but differences in their functional effects on somata, dendrites and spines remain unclear. We analyzed inhibitory synaptic events induced by cortical, fast-spiking (FS) basket cells which innervate dendritic shafts and spines as well as pyramidal cell somata. Serial electron micrograph (EMg) reconstructions showed that somatic synapses were larger than dendritic contacts. Simulations with precise anatomical and physiological data reveal functional differences between different innervation styles. FS cell soma-targeting synapses initiate a strong, global inhibition, those on shafts inhibit more restricted dendritic zones, while synapses on spines may mediate a strictly local veto. Thus, FS cell synapses of different sizes and sites provide functionally diverse forms of pyramidal cell inhibition.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
David C Rowland ◽  
Horst A Obenhaus ◽  
Emilie R Skytøen ◽  
Qiangwei Zhang ◽  
Cliff G Kentros ◽  
...  

Layer II of the medial entorhinal cortex (MEC) contains two principal cell types: pyramidal cells and stellate cells. Accumulating evidence suggests that these two cell types have distinct molecular profiles, physiological properties, and connectivity. The observations hint at a fundamental functional difference between the two cell populations but conclusions have been mixed. Here, we used a tTA-based transgenic mouse line to drive expression of ArchT, an optogenetic silencer, specifically in stellate cells. We were able to optogenetically identify stellate cells and characterize their firing properties in freely moving mice. The stellate cell population included cells from a range of functional cell classes. Roughly one in four of the tagged cells were grid cells, suggesting that stellate cells contribute not only to path-integration-based representation of self-location but also have other functions. The data support observations suggesting that grid cells are not the sole determinant of place cell firing.


2013 ◽  
Vol 110 (10) ◽  
pp. 2257-2274 ◽  
Author(s):  
N. H. Barmack ◽  
V. Yakhnitsa

Cerebellar Purkinje cells are excited by two afferent pathways: climbing and mossy fibers. Climbing fibers evoke large “complex spikes” (CSs) that discharge at low frequencies. Mossy fibers synapse on granule cells whose parallel fibers excite Purkinje cells and may contribute to the genesis of “simple spikes” (SSs). Both afferent systems convey vestibular information to folia 9c–10. After making a unilateral labyrinthectomy (UL) in mice, we tested how the discharge of CSs and SSs was changed by the loss of primary vestibular afferent mossy fibers during sinusoidal roll tilt. We recorded from cells identified by juxtacellular neurobiotin labeling. The UL preferentially reduced vestibular modulation of CSs and SSs in folia 8–10 contralateral to the UL. The effects of a UL on Purkinje cell discharge were similar in folia 9c–10, to which vestibular primary afferents project, and in folia 8–9a, to which they do not project, suggesting that vestibular primary afferent mossy fibers were not responsible for the UL-induced alteration of SS discharge. UL also induced reduced vestibular modulation of stellate cell discharge contralateral to the UL. We attribute the decreased modulation to reduced vestibular modulation of climbing fibers. In summary, climbing fibers modulate CSs directly and SSs indirectly through activation of stellate cells. Whereas vestibular primary afferent mossy fibers cannot account for the modulated discharge of SSs or stellate cells, the nonspecific excitation of Purkinje cells by parallel fibers may set an operating point about which the discharges of SSs are sculpted by climbing fibers.


1986 ◽  
Vol 56 (6) ◽  
pp. 1626-1649 ◽  
Author(s):  
J. M. Shen ◽  
A. R. Kriegstein

The dorsal and medial telencephalon of reptiles consists of a simple trilaminar cortex. The turtle dorsal cortex has been identified as a favorable physiological preparation that may bear a phylogenetic relationship to mammalian neocortex. While anatomical studies have likened the reptilian medial cortical region to mammalian hippocampus, its physiological properties have not been explored. We therefore used intracellular and extracellular recording techniques to examine the cellular and synaptic physiology of turtle "hippocampal" or medial cortex. Turtle medial cortex contains two principal classes of neurons, pyramidal cells and stellate neurons. Recordings with Lucifer yellow CH (LY)-filled microelectrodes allowed us to correlate the physiological properties of medial cortical neurons with their cellular morphology. Pyramidal neurons were situated in a single cellular layer and had spiny apical dendrites extending into the molecular layer. These cells fired relatively long-duration action potentials (APs) and showed frequency adaptation to suprathreshold current pulse injections. Stellate cells were usually found in the subcellular and molecular layers and had aspiny dendrites. In contrast to pyramidal cells, they fired brief APs and displayed no frequency adaptation. A discrete population of cells in the dorsal portion of medial cortex (DMC) was capable of bursting endogenously or in response to synaptic activation. Bursts usually contained an underlying slow depolarization and often occurred at regular intervals. Intracellular LY injections confirmed that these cells were pyramidal in morphology. Electrical stimulation of afferent fibers revealed that pyramidal cells and stellate neurons differed in their synaptic responses. In ventral medial cortex (VMC), afferent stimulation evoked a multiphasic response in most pyramidal cells, whereas stellate cells were synaptically excited. Orthodromic activation of DMC bursting cells resulted in a powerful excitation--often a short burst--and subsequent inhibition. Stellate neurons in DMC also had a biphasic synaptic response consisting of both an early excitation and a late inhibition. Experiments using intracellular chloride (Cl-) injection or focal bicuculline application suggested that part of the inhibitory component of the pyramidal cell synaptic response was dependent on a gamma-aminobutyric acid (GABA)-mediated increase in Cl- conductance. These results correlated with our immunohistochemical studies that revealed the presence of GABAergic neurons in medial cortex.(ABSTRACT TRUNCATED AT 400 WORDS)


1996 ◽  
Vol 76 (4) ◽  
pp. 2497-2507 ◽  
Author(s):  
J. Bastian

1. This report summarizes studies of the changes in postsynaptic potentials that occur as pyramidal cells within the primary electrosensory processing nucleus learn to reject repetitive patterns of afferent input. The rejection mechanism employs "negative image inputs" that oppose or cancel electroreceptor afferent inputs or patterns of pyramidal hyperpolarization or depolarization caused by intracellular current injection. Feedback pathways carrying descending electrosensory as well as other types of information provide the negative image inputs. This study focuses on the role of a directly descending projection from a second-order electrosensory nucleus the nucleus praeeminentialis (nP), which provides excitatory and inhibitory inputs to the apical dendrites of electrosensory lateral line lobe (ELL) pyramidal cells. 2. Electrical stimulation of the pathway linking the nP to the ELL was used to activate descending inputs to the pyramidal cells. Pyramidal cell activity was typically increased due to stimulation of this pathway. Tetanic stimulation of the descending pathway paired with either electrosensory stimuli that inhibited pyramidal cells, or hyperpolarizing current injection, increased the excitation provided by subsequent stimulation of this pathway. Pairing tetanic stimulation with excitatory electrosensory stimuli or depolarizing current injection had the opposite effect. Subsequent activation of the descending pathway inhibited pyramidal cells. 3. Intracellular recordings showed that the increased firing of pyramidal cells evoked by stimulation of the descending pathway following tetanic stimulation paired with postsynaptic hyperpolarization resulted from larger amplitude and longer-duration excitatory postsynaptic potentials (EPSPs). The shift in the effect of activity in this descending pathway to providing net inhibitory input to the pyramidal cells after paired presynaptic activity and postsynaptic depolarization probably results from the potentiation of inhibitory postsynaptic potentials (IPSPs). The EPSP and IPSPs evoked by activity in this descending pathway can be continuously adjusted in amplitude, thereby counterbalancing patterns of pyramidal cell excitation and inhibition received from the periphery with the result that repetitive patterns of afferent activity are strongly attenuated.


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