Sparse but specific temporal coding by spikes in an insect sensory-motor ocellar pathway

Simmons, Peter; Steveninck, Rob R. de Ruyter van

doi:10.1242/jeb.043547

Cited by 6 publications

(1 citation statement)

References 75 publications

(97 reference statements)

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“…However, it was also assumed that cricket auditory neurons detected bat calls using a rate code (Nolen and Hoy, 1984 ), but later shown that bursting is the reliable code (Marsat and Pollack, 2006 ). Indeed, within the time frame of a single wing beat, the deviation neuron in the locust, DNI, uses the timing of spikes to reliably transmit information regarding changes in pitch (Simmons and van Steveninck, 2010 ), which presumably aids course deviation correction during flight by responding to changes in the horizon. Within the DCMD spike train there may exist timing information that plays a pivotal role in the control of rhythmical motor output.…”

Section: Introductionmentioning

confidence: 99%

Burst Firing in a Motion-Sensitive Neural Pathway Correlates with Expansion Properties of Looming Objects that Evoke Avoidance Behaviors

McMillan

Gray

2015

Front. Integr. Neurosci.

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The locust visual system contains a well-defined motion-sensitive pathway that transfers visual input to motor centers involved in predator evasion and collision avoidance. One interneuron in this pathway, the descending contralateral movement detector (DCMD), is typically described as using rate coding; edge expansion of approaching objects causes an increased rate of neuronal firing that peaks after a certain retinal threshold angle is exceeded. However, evidence of intrinsic DCMD bursting properties combined with observable oscillations in mean firing rates and tight clustering of spikes in raw traces, suggest that bursting may be important for motion detection. Sensory neuron bursting provides important timing information about dynamic stimuli in many model systems, yet no studies have rigorously investigated if bursting occurs in the locust DCMD during object approach. We presented repetitions of 30 looming stimuli known to generate behavioral responses to each of 20 locusts in order to identify and quantify putative bursting activity in the DCMD. Overall, we found a bimodal distribution of inter-spike intervals (ISI) with peaks of more frequent and shorter ISIs occurring from 1–8 ms and longer less frequent ISIs occurring from 40–50 ms. Subsequent analysis identified bursts and isolated single spikes from the responses. Bursting frequency increased in the latter phase of an approach and peaked at the time of collision, while isolated spiking was predominant during the beginning of stimulus approach. We also found that the majority of inter-burst intervals (IBIs) occurred at 40–50 ms (or 20–25 bursts/s). Bursting also occurred across varied stimulus parameters and suggests that burst timing may be a key component of looming detection. Our findings suggest that the DCMD uses two modes of coding to transmit information about looming stimuli and that these modes change dynamically with a changing stimulus at a behaviorally-relevant time.

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Section: Introductionmentioning

confidence: 99%

Burst Firing in a Motion-Sensitive Neural Pathway Correlates with Expansion Properties of Looming Objects that Evoke Avoidance Behaviors

McMillan

Gray

2015

Front. Integr. Neurosci.

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The effects of temperature on signalling in ocellar neurons of the desert locust, Schistocerca gregaria

Simmons

2011

J Comp Physiol A

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In Schistocerca gregaria ocellar pathways, large second-order L-neurons use graded potentials to communicate signals from the ocellar retina to third-order neurons in the protocerebrum. A third-order neuron, DNI, converts graded potentials into axonal spikes that have been shown in experiments at room temperature to be sparse and precisely timed. I investigated effects of temperature changes that a locust normally experiences on these signals. With increased temperature, response latency decreases and frequency responses of the neurons increase. Both the graded potential responses in the two types of neuron and the spikes in DNI report greater detail about a fluctuating light stimulus. Over a rise from 22 to 35°C the power spectrum of the L-neuron response encompasses higher frequencies and its information capacity increases from about 600 to 1,700 bits/s. DNI generates spikes more often during a repeated stimulus but at all temperatures it reports rapid decreases in light rather than providing a continual measure of light intensity. Information rate carried by spike trains increases from about 50 to 185 bits/s. At warmer temperatures, increased performance by ocellar interneurons may contribute to improved aerobatic performance by delivering spikes earlier and in response to smaller, faster light stimuli.

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The organization of honeybee ocelli: Regional specializations and rhabdom arrangements

Ribi

Warrant

Zeil

2011

Arthropod Structure & Development

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Sparse but specific temporal coding by spikes in an insect sensory-motor ocellar pathway

Cited by 6 publications

References 75 publications

Burst Firing in a Motion-Sensitive Neural Pathway Correlates with Expansion Properties of Looming Objects that Evoke Avoidance Behaviors

Burst Firing in a Motion-Sensitive Neural Pathway Correlates with Expansion Properties of Looming Objects that Evoke Avoidance Behaviors

The effects of temperature on signalling in ocellar neurons of the desert locust, Schistocerca gregaria

The organization of honeybee ocelli: Regional specializations and rhabdom arrangements

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