A sensory brain map for each behavior?

Metzner, Walter; Juranek, Jenifer

doi:10.1073/pnas.94.26.14798

Cited by 89 publications

(76 citation statements)

References 38 publications

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“…Previous studies have shown important differences in tuning between pyramidal cells of the different segments (Shumway, 1989a): pyramidal cells of the CMS/CLS/LS segments are tuned to low, mid, and high frequencies, respectively. This suggests a specific function for each segment, which has been partially verified through behavioural experiments (Metzner and Juranek, 1997). The mechanisms underlying differential tuning across the segments are still unclear.…”

Section: Pyramidal Cell Frequency Tuningmentioning

confidence: 76%

“…This burst mechanism has been shown to be controlled by a variety of intrinsic membrane conductances including persistent sodium currents and high-threshold potassium channels (Ellis et al, 2007b;Fernandez et al, 2005a;Mehaffey et al, 2006;Noonan et al, 2003;Rashid et al, 2001a,b). As channel densities have been shown to vary across the different tuberous maps (Deng et al, 2005;Smith et al, 2006), they may contribute to map-specific computations including frequency selectivity (Metzner and Juranek, 1997;Shumway, 1989a). Furthermore, synaptic input from feedback pathways can have a significant impact on burst firing (Bastian and Nguyenkim, 2001;Chacron and Bastian, 2008;Chacron et al, 2005a;Mehaffey et al, 2007Mehaffey et al, , 2008a.…”

Section: Regulation Of Pyramidal Cell Burstingmentioning

confidence: 99%

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Ionic and neuromodulatory regulation of burst discharge controls frequency tuning

Mehaffey

Ellis

Krahe

et al. 2008

Journal of Physiology-Paris

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Sensory neurons encode natural stimuli by changes in firing rate or by generating specific firing patterns, such as bursts. Many neural computations rely on the fact that neurons can be tuned to specific stimulus frequencies. It is thus important to understand the mechanisms underlying frequency tuning. In the electrosensory system of the weakly electric fish, Apteronotus leptorhynchus, the primary processing of behaviourally relevant sensory signals occurs in pyramidal neurons of the electrosensory lateral line lobe (ELL). These cells encode low frequency prey stimuli with bursts of spikes and high frequency communication signals with single spikes. We describe here how bursting in pyramidal neurons can be regulated by intrinsic conductances in a cell subtype specific fashion across the sensory maps found within the ELL, thereby regulating their frequency tuning. Further, the neuromodulatory regulation of such conductances within individual cells and the consequences to frequency tuning are highlighted. Such alterations in the tuning of the pyramidal neurons may allow weakly electric fish to preferentially select for certain stimuli under various behaviourally relevant circumstances.

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Section: Pyramidal Cell Frequency Tuningmentioning

confidence: 76%

Section: Regulation Of Pyramidal Cell Burstingmentioning

confidence: 99%

Ionic and neuromodulatory regulation of burst discharge controls frequency tuning

Mehaffey

Ellis

Krahe

et al. 2008

Journal of Physiology-Paris

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“…These make synaptic contact unto pyramidal cells within the hindbrain electrosensory lateral line lobe (ELL) which is composed of three parallel maps of the body surface (Shumway 1989;Krahe et al 2008) that are essential for proper sensory processing of natural stimuli (Metzner and Juranek 1997). The physiological responses of pyramidal cells within the three maps show important differences and have been well characterized both in vivo (Bastian et al 2002;Chacron et al 2003;Bastian et al 2004;Chacron et al 2005a, c;Chacron 2006;Chacron et al 2007;Chacron and Bastian 2008;Chacron et al 2009;Toporikova and Chacron 2009;Avila Akerberg et al 2010) and in vitro (Berman and Maler 1999;Oswald et al 2004;Ellis et al 2007a, b;Oswald et al 2007;Mehaffey et al 2008a, b).…”

Section: Introductionmentioning

confidence: 99%

In vivo conditions influence the coding of stimulus features by bursts of action potentials

Akerberg

Chacron

2011

J Comput Neurosci

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The functional role of burst firing (i.e. the firing of packets of action potentials followed by quiescence) in sensory processing is still under debate. Should bursts be considered as unitary events that signal the presence of a particular feature in the sensory environment or is information about stimulus attributes contained within their temporal structure? We compared the coding of stimulus attributes by bursts in vivo and in vitro of electrosensory pyramidal neurons in weakly electric fish by computing correlations between burst and stimulus attributes. Our results show that, while these correlations were strong in magnitude and significant in vitro, they were actually much weaker in magnitude if at all significant in vivo. We used a mathematical model of pyramidal neuron activity in vivo and showed that such a model could reproduce the correlations seen in vitro, thereby suggesting that differences in burst coding were not due to differences in bursting seen in vivo and in vitro. We next tested whether variability in the baseline (i.e. without stimulation) activity of ELL pyramidal neurons could account for these differences. To do so, we injected noise into our model whose intensity was calibrated to mimic baseline activity variability as quantified by the coefficient of variation. We found that this noise caused significant decreases in the magnitude of correlations between burst and stimulus attributes and could account for differences between in vitro and in vivo conditions. We then tested this prediction experimentally by directly injecting noise in vitro through the recording electrode. Our results show that this caused a lowering in magnitude of the correlations between burst and stimulus attributes in vitro and gave rise to values that were quantitatively similar to those seen under in vivo conditions.While it is expected that noise in the form of baseline activity variability will lower correlations between burst and stimulus attributes, our results show that such variability can account for differences seen in vivo. Thus, the high variability seen under in vivo conditions has profound consequences on the coding of information by bursts in ELL pyramidal neurons. In particular, our results support the viewpoint that bursts serve as a detector of particular stimulus features but do not carry detailed information about such features in their structure.

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“…The ensemble of premotor neurons encoding identity and location of an external object and triggering an innate response to that object has been referred to in the ethological literature as a "command releasing system" (Ewert, 1987). Such a system may be exclusively dedicated to a particular behavior, although it is debated whether this is a general feature of CNS organization (Metzner and Juranek, 1997;Edwards et al, 1999;Kupfermann and Weiss, 2001;Sewards and Sewards, 2002).…”

Section: Introductionmentioning

confidence: 99%

Visual Prey Capture in Larval Zebrafish Is Controlled by Identified Reticulospinal Neurons Downstream of the Tectum

Gahtan¹,

Tanger²,

Baier³

2005

J. Neurosci.

310

335

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Many vertebrates are efficient hunters and recognize their prey by innate neural mechanisms. During prey capture, the internal representation of the prey's location must be constantly updated and made available to premotor neurons that convey the information to spinal motor circuits. We studied the neural substrate of this specialized visuomotor system using high-speed video recordings of larval zebrafish and laser ablations of candidate brain structures. Seven-day-old zebrafish oriented toward, chased, and consumed paramecia with high accuracy. Lesions of the retinotectal neuropil primarily abolished orienting movements toward the prey. Wild-type fish tested in darkness, as well as blind mutants, were impaired similarly to tectum-ablated animals, suggesting that prey capture is mainly visually mediated. To trace the pathway further, we examined the role of two pairs of identified reticulospinal neurons, MeLc and MeLr, located in the nucleus of the medial longitudinal fasciculus of the tegmentum. These two neurons extend dendrites into the ipsilateral tectum and project axons into the spinal cord. Ablating MeLc and MeLr bilaterally impaired prey capture but spared several other behaviors. Ablating different sets of reticulospinal neurons did not impair prey capture, suggesting a selective function of MeLr and MeLc in this behavior. Ablating MeLc and MeLr neurons unilaterally in conjunction with the contralateral tectum also mostly abolished prey capture, but ablating them together with the ipsilateral tectum had a much smaller effect. These results suggest that MeLc and MeLr function in series with the tectum, as part of a circuit that coordinates prey capture movements.

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A sensory brain map for each behavior?

Cited by 89 publications

References 38 publications

Ionic and neuromodulatory regulation of burst discharge controls frequency tuning

Ionic and neuromodulatory regulation of burst discharge controls frequency tuning

In vivo conditions influence the coding of stimulus features by bursts of action potentials

Visual Prey Capture in Larval Zebrafish Is Controlled by Identified Reticulospinal Neurons Downstream of the Tectum

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