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H CH6: flight in locusts H locust flight H flight system H sensory integration during flight H summary PART 3: MOTOR STRATEGIES #14: FLIGHT IN LOCUSTS II
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H CH6: flight in locusts H locust flight H flight system H sensory integration during flight H summary PART 3: MOTOR STRATEGIES #14: FLIGHT IN LOCUSTS II
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H IN301 & IN501... 2 of the known parts of the pattern generator CELLULAR ORGANIZATION
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H how does proprioceptive feedback work ?... so far... H it can influence average pattern frequency H it has no “essential” role in pattern generation H experiment... H wingbeat imposed on 1 forewing H how does sensory feedback from this wing influence flight rhythm of the other 3 wings ? H observed that wings phase lock to imposed frequencies... proprioception does CPG PROPRIOCEPTIVE FEEDBACK
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H what are the roles of the 3 types of receptors ? H synaptic connections CPG interneurons H stimulate wing hinge receptor fires wing depressor neuron H inhibits elevator H stimulate campaniform opposite effect H proprioceptors can initiate & maintain flight rhythm PROPRIOCEPTIVE FEEDBACK
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H tegulae ?... H neurons in phase with elevator motor neurons H neurons excite IN566 H IN566 excites elevator motor neuron PROPRIOCEPTIVE FEEDBACK
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H tegulae ?... H stimulation of afferent neurons resets flight rhythm PROPRIOCEPTIVE FEEDBACK
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H wing proprioceptors are elements of the CPG: 1.phasically active ~ wingbeat cycle 2.activation initiate, entrain & maintain oscillation 3.deafferentation reduces operation of CPG 4.reset CPG when stimulated PROPRIOCEPTIVE FEEDBACK
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H how do wing proprioceptors flight... 2 main inputs 1.wing depression excites tegulae H excites elevator motor neurons 2.wing elevation excites wing hinge stretch H excites depressor motor neurons H inhibits wing elevator motor neurons PROPRIOCEPTIVE FEEDBACK
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H why is CPG control so complicated ? 1.stable core oscillating circuit, and 2.sensitive to sensory appropriate to situation H central rhythm generator integrated with sensory normal flight pattern PROPRIOCEPTIVE FEEDBACK
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H course control ? H must make rapid steering adjustment ~ wind SENSORY INTEGRATION DURING FLIGHT
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H uses 3 different sensory systems... exteroceptors 1.compound eyes 2.ocelli (simple eyes) 3.wind-sensitive hairs SENSORY INTEGRATION DURING FLIGHT
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H uses 3 different sensory systems... exteroceptors 1.compound eyes... 3D but H complex H ~ slow (100 ms thorax ~ 2 wingbeat cycles) 2.ocelli (simple eyes) 3.wind-sensitive hairs H simple H ~ fast SENSORY INTEGRATION DURING FLIGHT
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H uses 3 different sensory systems... exteroceptors 1.compound eyes... 3D but complex & slow 2.ocelli (simple eyes)... pitch & roll, fast 3.wind-sensitive hairs... yaw & pitch, fast SENSORY INTEGRATION DURING FLIGHT
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H uses 3 different sensory systems... exteroceptors 1.compound eyes... 3D but complex & slow 2.ocelli (simple eyes)... pitch & roll, fast 3.wind-sensitive hairs... yaw & pitch, fast H 2 sensorimotor pathways 1.slow head position, steering by legs & abdomen SENSORY INTEGRATION DURING FLIGHT
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H uses 3 different sensory systems... exteroceptors 1.compound eyes... 3D but complex & slow 2.ocelli (simple eyes)... pitch & roll, fast 3.wind-sensitive hairs... yaw & pitch, fast H 2 sensorimotor pathways 1.slow head position, steering by legs & abdomen 2.fast thorax, course deviation information SENSORY INTEGRATION DURING FLIGHT
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons (DDNs) H DNI – ipsilateral ocellus H DNM – medial ocellus H DNC – contralateral ocellus DEVIATION-DETECTING INTERNEURONS
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons (DDNs) H DNI – ipsilateral ocellus H DNM – medial ocellus H DNC – contralateral ocellus H respond to different deviations ~ movement detectors* DEVIATION-DETECTING INTERNEURONS
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons (DDNs) H DNI – ipsilateral ocellus H DNM – medial ocellus H DNC – contralateral ocellus H respond to different deviations ~ movement detectors* H relay to thoracic ganglia DEVIATION-DETECTING INTERNEURONS
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons H DNC – contralateral ocellus* H relay to thoracic ganglia H integrated with H air current stimuli hairs H visual stimuli eyes DEVIATION-DETECTING INTERNEURONS
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons (DDNs) H respond to different deviations ~ movement detectors* H integrated with air current stimulus to hairs* and eyes H hair signals ocelli signals DEVIATION-DETECTING INTERNEURONS
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H ocelli (simple eyes)... detect horizon deviation H 3 pairs of deviation-detecting neurons (DDNs) H respond to different deviations ~ movement detectors * H integrated with air current stimulus to hairs* and eyes H hair signals ocelli signals H ocelli signals hair signals H multimodal input critical... feature detector neurons DEVIATION-DETECTING INTERNEURONS
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H DDNs integrated into thoracic circuitry via thoracic interneurons (TINs) H only works during flight H influenced by the CPG H phase-gated = signal at appropriate phase of of cycle course control H... but not part of the CPG H TINs integrate sensory with phase-locked CPG FLIGHT CONTROL CIRCUITRY
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H locusts have 2 pairs of wings @ thorax H beat @ 20 Hz, 7 ms offset cycles H 10 pairs of muscles / wing: 4 depressors, 6 elevators H driven by 1-5 neurons / muscle H isolated thoracic circuitry rhythmic motor output H central pattern generator... influenced by proprioceptive sensory feedback H 3 types of sensilla: wing hinge, tegula, campaniform H activation rhythmic motor output, part of CPG H CPG = central oscillating core + sensory feedback SUMMARY
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H CPG = central oscillating core + sensory feedback H 3 primary exteroceptor types on head flight H activate descending neurons, deviation-detecting neurons (DDNs) are 1 type H multimodal DDNs detect flight deviations H DDNs thoracic interneurons (TINs) H TIN motor neurons via interneurons H tonic sensory signal phasic signal by CPG gating H course control during flight H CPG rhythms (1) wingbeat & (2) sensory signal SUMMARY
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