Contribution of morphology and membrane resistance to integration of fast synaptic signals in two thalamic cell types

Perreault, Marie−Claude; Raastad, Morten

doi:10.1113/jphysiol.2006.113043

Cited by 18 publications

(19 citation statements)

References 55 publications

(85 reference statements)

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“…This is similar to procedures used in several investigations of single neurons in other systems (e.g. Spruston & Johnston, 1992; Briska et al 2003; Perreault & Raastad, 2006). In general, there are two ways in which unblocked, voltage‐gated conductances could influence the estimates.…”

Section: Discussionmentioning

confidence: 79%

“…An important point concerns the problems introduced by including an incorrect value for R s in the subsequent computer modelling. In the ideal case, computer modelling would require either full compensation or independent knowledge of R s , as even relatively small errors in R s can lead to large errors in the estimates for R i (Perreault & Raastad, 2006). In a previous study we found that accurate estimation of R s in whole‐cell recordings at the axon terminal is non‐trivial (Oltedal et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…An alternative strategy is to include R s as a free parameter in the direct fitting of the current responses of the morphological models. In their comparison of voltage‐clamp and current‐clamp recording, Perreault & Raastad (2006) concluded that when R s was included as a free parameter, voltage‐clamp recording resulted in a more accurate parameter estimation than current‐clamp recording. In our study, we included R s as a free parameter in the direct fitting and subsequent bootstrap analysis suggested that all four fitted parameters ( R i , C m , R m and R s ) were well constrained (cf.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Passive membrane properties and electrotonic signal processing in retinal rod bipolar cells

Oltedal

Veruki

Hartveit

2009

The Journal of Physiology

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Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Passive membrane properties and electrotonic signal processing in retinal rod bipolar cells

Oltedal

Veruki

Hartveit

2009

The Journal of Physiology

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“…Most previous models focus on aspects of passive signal propagation in INs [33]–[35]. To our knowledge, the only currently available model that includes a variety of the active mechanisms in INs was primarily developed in order to study the mechanisms behind the rebound bursts [36], whereas other properties such as dendritic conductances and the relationship between somatic current injections and action potentials frequency (hereby referred to as the I/O curve) were not taken into account.…”

Section: Introductionmentioning

confidence: 99%

A Multi-Compartment Model for Interneurons in the Dorsal Lateral Geniculate Nucleus

et al. 2011

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GABAergic interneurons (INs) in the dorsal lateral geniculate nucleus (dLGN) shape the information flow from retina to cortex, presumably by controlling the number of visually evoked spikes in geniculate thalamocortical (TC) neurons, and refining their receptive field. The INs exhibit a rich variety of firing patterns: Depolarizing current injections to the soma may induce tonic firing, periodic bursting or an initial burst followed by tonic spiking, sometimes with prominent spike-time adaptation. When released from hyperpolarization, some INs elicit rebound bursts, while others return more passively to the resting potential. A full mechanistic understanding that explains the function of the dLGN on the basis of neuronal morphology, physiology and circuitry is currently lacking. One way to approach such an understanding is by developing a detailed mathematical model of the involved cells and their interactions. Limitations of the previous models for the INs of the dLGN region prevent an accurate representation of the conceptual framework needed to understand the computational properties of this region. We here present a detailed compartmental model of INs using, for the first time, a morphological reconstruction and a set of active dendritic conductances constrained by experimental somatic recordings from INs under several different current-clamp conditions. The model makes a number of experimentally testable predictions about the role of specific mechanisms for the firing properties observed in these neurons. In addition to accounting for the significant features of all experimental traces, it quantitatively reproduces the experimental recordings of the action-potential- firing frequency as a function of injected current. We show how and why relative differences in conductance values, rather than differences in ion channel composition, could account for the distinct differences between the responses observed in two different neurons, suggesting that INs may be individually tuned to optimize network operation under different input conditions.

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“…Given the diverse roles of the interneuron dendrites, we expect that active dendritic conductances will be crucial for understanding the function of the LGN interneurons. By including dendritic ion-channels, we will go beyond previous modelling efforts, which typically use the simplification that the dendrites are passive (Zhu et al, 1999;Briska et al, 2003;Perreault & Raastad, 2006). The presence and kinetics of specific ion-channels will be deduced partly from previous literature (Zhu et al, 1999;Zhu & Heggelund, 2001;Acuna-Goycolea et al, 2007), and partly from our new experiments, including whole-cell voltage-clamp, and calcium imaging.…”

Section: Introductionmentioning

confidence: 99%

Kongsberg Vision Meeting 2009

Baraas¹,

Einevoll²

2009

SJOVS

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In Old World primates, the three cone photoreceptor classes provide the starting point for trichromatic vision. These cone classes are characterized by differences in spectral sensitivity, in density with respect to distance from the fovea, and in relative abundance across individuals (Hofer et al., 2005). How neural signals originating from the cones lead to colour perception is still not understood. For example, there is controversy over the chromatic structure of the receptive fields of the midget class of retinal ganglion cells, which give rise to the parvocellular visual pathway. To distinguish colours, the responses of different cone types must be compared. It is uncertain if the centres and surrounds of midget ganglion cell receptive fields are composed of inputs from only one cone type, or from cone mixtures. These options lead to different colour-coding schemes in the retina, and thus dictate how colour must be processed downstream. To solve this and other problems concerning visual perception, it would be useful to have a way to directly map the cone fields that initially define every receptive field.The main impediments to achieving this goal have been the inability to resolve and stimulate individual cones in the living retina. To begin to overcome these difficulties, we used an adaptive optics scanning laser ophthalmoscope (AOSLO) to visualize and stimulate the cones in vivo in the macaque (Roorda et al., 2002; Arathorn et al., 2007). We made extracellular recordings in the lateral geniculate nucleus to map the cones providing excitatory input to single parvocellular neurons, and assessed the efficacy of each cone's input for eliciting responses (Sincich et al., 2009). We found that parvocellular neurons can be mapped reliably by this method, and that the probability of evoking a spike with each stimulus flash varied considerably from cone to cone. This variability appeared to have two sources: a high sensitivity to the position of stimuli relative to each cone, and more variation in the synaptic weighting of cones than would be predicted if each class had a characteristic weight. For receptive field centres comprised of multiple cones, we also found that stimulation of just one of these cones leads to geniculate transmission with high probability. This result suggests that activation of a single cone within a large receptive field is sufficient for perception.Although our studies are at an early stage, cone imaging with an AOSLO, performed in conjunction with traditional electrophysiology, is a promising way to study the inputs to the visual system at the elemental level of the single cone. Receptive fields recorded at any level of the visual system can then be mapped by what they are truly made of -cone fields.

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Contribution of morphology and membrane resistance to integration of fast synaptic signals in two thalamic cell types

Cited by 18 publications

References 55 publications

Passive membrane properties and electrotonic signal processing in retinal rod bipolar cells

Passive membrane properties and electrotonic signal processing in retinal rod bipolar cells

A Multi-Compartment Model for Interneurons in the Dorsal Lateral Geniculate Nucleus

Kongsberg Vision Meeting 2009

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