H exam I H motor strategies H mate calling in crickets H song production by  s H song recognition by  s H sender-receiver matching H summary PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II

H exam I H motor strategies H mate calling in crickets H song production by  s H song recognition by  s H sender-receiver matching H summary PART 3: MOTOR STRATEGIES #12: MATE CALLING IN CRICKETS II

H recall… oscillogram H cycles H carrier frequency (CF) H = 5 kHz H ~ 5 k file teeth / s H pulses H = syllables H 1 stridulation H chirps & trills H sequences SONG PRODUCTION BY  s

H recall… tracheal tubes = insect “lungs” H connect tympanum  outside via spiracles H sound via 2 routes H direct H indirect H tracheal tube H 5 kHz H = carrier frequency CF SONG RECOGNITION & LOCALIZATION

H tracheal tubes amplify signal from inside ?... somehow H mechanism called pressure-difference receiver H sound locator H how ? H distances... H wave period ~ 7 cm H legs ~ 1 cm apart (cannot resolve) H indirect ~ 3.5 cm SONG RECOGNITION & LOCALIZATION

left tympanum... H sound from left  peaks + troughs amplify (A) H sound from right  peaks – troughs cancel (B) H signal strength ~ tympanum movement H tuned to CF of  call H sound  zigzag walking behavior ? SONG RECOGNITION & LOCALIZATION

H sound  zigzag walking behavior ? SONG RECOGNITION & LOCALIZATION

60° MAX 120° ? 60° MIN H sound  zigzag walking behavior ? SONG RECOGNITION & LOCALIZATION

60° MAX 120° ? 60° MIN H sound  zigzag walking behavior ? 120° ZIGZAG    SONG RECOGNITION & LOCALIZATION

60° MAX 120° ? 60° MIN H sound  zigzag walking behavior ? H behavior does not  maximum sensory input* 120° ZIGZAG... CNS SONG RECOGNITION & LOCALIZATION

H how does CNS sharpen the directional sensitivity ? NEURAL PROCESSING OF SONG

H how does CNS sharpen the directional sensitivity ? H  s prefer H 5 kHz song 30 pulses / s H tracking  above & below 30 pulses / s H how is this sound feature recognized ? NEURAL PROCESSING OF SONG

H sensory neurons (aud. n. )  aud. neuropile (proth. g.) H sharply tuned to signal H ipsilateral connection H  omega (  ) neurons H 2 (1 on each side) H inhibit eachother H ipsilateral excited H contralateral inhibited H = reciprocal inhibition H  accentuate L / R signal NEURAL PROCESSING OF SONG

H  neurons do not show 30 pulse / s preference H other candidates... H large prothoracic neurons  brain H ascending neurons (ANs) H excited by auditory receptor neurons H sensitive to 5 kHz sound H directional sensitivity ~  H inhibited by contralateral  neurons H what is their function ? NEURAL PROCESSING OF SONG

H crickets walking on spherical treadmill (A) H intracellular recording from L & R AN-1 neurons (B) (dye-filled) NEURAL PROCESSING OF SONG

H tracking (orientation ~ speaker) (C) H AN-1 firing rates... (D) H call left, a > a' firing, track left H call right, b < b' firing, track right H call left, c hyperpolarized (inhibited), track right NEURAL PROCESSING OF SONG

H tracking (orientation ~ speaker) (C) H AN-1 firing rates... (D) H call left, a > a' firing, track left H call right, b < b' firing, track right H call left, c hyperpolarized (inhibited), track right H directional information transmitted by AN-1... play a role in  positive phonotaxis H call song detectors ? H no 30 pulse / s preferences NEURAL PROCESSING OF SONG

H AN-1  brain neurons H brain neuron classes 1 & 2 (BNC-1, 2) H overlapping projections H AN-1 & BNC-1 H BNC-1 & 2 H coordinated firing with H AN-1 H song NEURAL PROCESSING OF SONG

H BNC-1 & 2 do not copy signals as do  & AN-1 H BNC-1 & 2 do show syllable preferences H BNC-1  low-pass filters (fire ~  rate < 30 / s) H BNC-2  high-pass filters (fire ~  rate > 30 / s) H BNC-2  band-pass filters (fire ~ 30 / s) NEURAL PROCESSING OF SONG

H organization of auditory system H logical AND gate (additive signals) BNC-2 BNC-1 BNC-2 NEURAL PROCESSING OF SONG

H genetic basis of song species specificity H interbred 2 related & sympatric (co-existing) species H Teleogryllus commodus ( T.c. ) CF = 3.5 kHz H Teleogryllus oceanicus ( T.o. ) CF = 5 kHz H other qualitative differences as well To  x To  Tc  x Tc  Tc  x To  To  x Tc  SENDER – RECEIVER MATCHING

H hybrid  s show intermediate song (A) H dosage-dependent (next slide...) H hybrid  s prefer songs of their brothers (B) H F 1 > reciprocal F 1 & > either P To  x To  Tc  x Tc  Tc  x To  To  x Tc  SENDER – RECEIVER MATCHING

H dosage-dependent genetic basis song and preference   s prefer  s s s s s s s s SENDER – RECEIVER MATCHING

H song H 3 song types: call, courtship, aggressive H structure: carrier frequency, syllables (pulses), chirps or trills, sequences H  song by stridulation: rubbing scraper & file H neural basis for song H generator in thoracic ganglia H triggered by descending neurons from brain SUMMARY

H reception H  attracted by 5 kHz CF & 30 syllables / s rate H ears (in knees) filter sound H directionally sensitive to CF H neural basis for song reception H auditory neurons    AN-1  BNC-1&2  2 H  & AN-1 sharpen signal H BNC-1 (low pass) + BNC-2 (high pass)  BNC-2 (band pass), sensitive to 30 syllables / s H genetic basis to sender-receiver matching SUMMARY