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PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II. exam I motor strategies mate calling in crickets song production by s song recognition by s sender-receiver matching summary. PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II. exam I motor strategies
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PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II • exam I • motor strategies • mate calling in crickets • song production by s • song recognition by s • sender-receiver matching • summary
PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II • exam I • motor strategies • mate calling in crickets • song production by s • song recognition by s • sender-receiver matching • summary
SONG PRODUCTION BY s • recall… oscillogram • cycles • carrier frequency (CF) • = 5 kHz • ~ 5 k file teeth / s • pulses • = syllables • 1 stridulation • chirps & trills • sequences
SONG RECOGNITION & LOCALIZATION • recall… tracheal tubes = insect “lungs” • connect tympanum outside via spiracles • sound via 2 routes • direct • indirect • tracheal tube • resonates @ 5 kHz • = carrier frequency CF
SONG RECOGNITION & LOCALIZATION • tracheal tubes amplify signal from inside ? ... somehow • mechanism called pressure-difference receiver • sound locator • how ? • distances... • wave period ~ 7 cm • legs ~ 1 cm apart (cannot resolve) • indirect ~ 3.5 cm
SONG RECOGNITION & LOCALIZATION • @ left tympanum... • sound from left peaks + troughs amplify (A) • sound from right peaks – troughs cancel (B) • signal strength ~ tympanum movement • tuned to CF of call • sound zigzag walking behavior ?
SONG RECOGNITION & LOCALIZATION • sound zigzag walking behavior ?
SONG RECOGNITION & LOCALIZATION • sound zigzag walking behavior ? 120° ? 60° MIN 60° MAX 120° ?
SONG RECOGNITION & LOCALIZATION • sound zigzag walking behavior ? 120° ? 60° MIN 60° MAX 120° ZIGZAG
SONG RECOGNITION & LOCALIZATION • sound zigzag walking behavior ? • behavior does not maximum sensory input* 120° ? 60° MIN 60° MAX 120° ZIGZAG ... CNS
NEURAL PROCESSING OF SONG • how does CNS sharpen the directional sensitivity ?
NEURAL PROCESSING OF SONG • how does CNS sharpen the directional sensitivity ? • s prefer • 5 kHz song • @ 30 pulses / s • tracking above & below 30 pulses / s • how is this sound feature recognized ?
NEURAL PROCESSING OF SONG • sensory neurons (aud. n. ) aud. neuropile (proth. g.) • sharply tuned to signal • ipsilateral connection • omega () neurons • 2 (1 on each side) • inhibit eachother • ipsilateral excited • contralateral inhibited • = reciprocal inhibition • accentuate L / R signal
NEURAL PROCESSING OF SONG • neurons do not show 30 pulse / s preference • other candidates... • large prothoracic neurons brain • ascending neurons (ANs) • excited by auditory receptor neurons • sensitive to 5 kHz sound • directional sensitivity ~ • inhibited by contralateral neurons • what is their function ?
NEURAL PROCESSING OF SONG • crickets walking on spherical treadmill (A) • intracellular recording from L & R AN-1 neurons (B) (dye-filled)
NEURAL PROCESSING OF SONG • tracking (orientation ~ speaker) (C) • AN-1 firing rates... (D) • call left, a > a' firing, track left • call right, b < b' firing, track right • call left, c hyperpolarized (inhibited), track right
NEURAL PROCESSING OF SONG • tracking (orientation ~ speaker) (C) • AN-1 firing rates... (D) • call left, a > a' firing, track left • call right, b < b' firing, track right • call left, c hyperpolarized (inhibited), track right • directional information transmitted by AN-1... play a role in positive phonotaxis • call song detectors ? • no 30 pulse / s preferences
NEURAL PROCESSING OF SONG • AN-1 brain neurons • brain neuron classes 1 & 2 (BNC-1, 2) • overlapping projections • AN-1 & BNC-1 • BNC-1 & 2 • coordinated firing with • AN-1 • song
NEURAL PROCESSING OF SONG • BNC-1 & 2 do not copy signals as do & AN-1 • BNC-1 & 2 do show syllable preferences • BNC-1 low-pass filters (fire ~ rate < 30 / s) • BNC-2 high-pass filters (fire ~ rate > 30 / s) • BNC-2 band-pass filters (fire ~ 30 / s)
NEURAL PROCESSING OF SONG • organization of auditory system • logical AND gate (additive signals) BNC-2 BNC-2 BNC-1
SENDER – RECEIVER MATCHING • genetic basis of song species specificity • interbred 2 related & sympatric (co-existing) species • Teleogryllus commodus (T.c.) CF = 3.5 kHz • Teleogryllus oceanicus (T.o.) CF = 5 kHz • other qualitative differences as well To x To Tc x Tc Tc x To To x Tc
SENDER – RECEIVER MATCHING • hybrid s show intermediate song (A) • dosage-dependent (next slide...) • hybrid s prefer songs of their brothers (B) • F1 >reciprocal F1 & > either P To x To Tc x Tc Tc x To To x Tc
SENDER – RECEIVER MATCHING • dosage-dependent genetic basis song and preference s s s s s prefer
SUMMARY • song • 3 song types: call, courtship, aggressive • structure: carrier frequency, syllables (pulses), chirps or trills, sequences • song by stridulation: rubbing scraper & file • neural basis for song • generator in thoracic ganglia • triggered by descending neurons from brain
SUMMARY • reception • attracted by 5 kHz CF & 30 syllables / s rate • ears (in knees) filter sound • directionally sensitive to CF • neural basis for song reception • auditory neurons AN-1 BNC-1&2 2 • & AN-1 sharpen signal • BNC-1 (low pass) + BNC-2 (high pass) BNC-2 (band pass), sensitive to 30 syllables / s • genetic basis to sender-receiver matching