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1711 Optical measurement of spatiotemporal response change in rat auditory cortex caused by reversible cerebral ischemia
S192 1709
ONE OF V O C O - A U D I T O R Y
NUCLEI OF ZEBRA FINCH BRAIN (MAN) IS CLOSELY RELATED TO
THE PATTERN D I S C R I M I N A T I O N
OF THEIR SONGS.
MASAOMAEKAWA
Dept. of Physiol., Dokkyo U n i v e r s i t y School 9 f M e d i g i n e j _
AND NOZOMU SAITO ,
M__ibu,_TQchigi,
321C02Japan~
The learned songs of male zebra finches includes CF components of harmonic structure and FM component.
The combination
of each harmonic
of CF component
differs
individual finch and most finches can discriminate the combination pattern. that neurons harmonics, components.
in MAN, one of v o c o - a u d i t o r y
in addition,
nuclei,
that they were sensitive
discriminated
nucleus,
HVc.
We examined
the combination of CF
to temporal combination
These features of sensitivity were frequently
another major voco-auditory
among
of CF and FM
found in MAN, but never in
The different contribution of each nucleus
to song recognition will be discussed.
1 710
LESION OF A FOREBRAIN NUCLEUS (LMAN) IN THE ZEBRA FINCH SONG CONTROL SYSTEM DISRUPTS D I S C R I M I N A T I O N OF H A R M O N I C - A L T E R E D SONG SYLLABLES. KAZUO OKANOYA I°2, MASAO M A E K A W A 2, AND NOZOMU SAITO 2, IBird Control Lab., Natl. Aqric. Res. Cntr., Kannondai, Tsukuba 305 Japan and ZDept. Physiol., Dokkyo Univ., School of Medicine, Mibu, Tochiqi, 321-02 Japan.
Zebra finch songs are individually distinctive in their acoustical compositions. Relative a m p l i t u d e of each harmonic in song syllables is one of such features and neurons in a forebrain song nucleus, IMAN, are shown to be sensitive to the harmonic c o n s t i t u t e of song syllables (Maekawa et. al., in this volume). To examine the role of IMAN in p e r c e i v i n g harmonic structures of song, 5 m a l e Zebra finches received bilateral lesion of IMAN and their auditory d i s c r i m i n a t i o n was compared with that of 3 control birds. The birds were trained, by operant techniques, to peck a response key w h e n a song syllable with a m i s s i n g 3rd harmonic (Go-stimulus) was presented, and not to peck when the original, not altered song syllable (Nogo-stimulus) was presented. The reaction times for Nogo and Go stimuli were s i g n i f i c a n t l y different in control birds but not so in the i M A N - l e s i o n e d birds. Results are in agreement with the electro-physiological data and suggest IMAN might govern the perception of harmonic structures of song in Zebra finches.
1711
O P T I C A L M E A S U R E M E N T OF S P A T I O T E M P O R A L R E S P O N S E C H A N G E IN RAT AUDITORY CORTEX CAUSED BY R E V E R S I B L E C E R E B R A L I S C H E M I A . J U N S E I HORIKAWA, IKUO T A N I G U C H I , T O S H I H I K O KUROIWA*, HIROTO I C H I K I * , AND MASAHIRO NASU, D e p a r t m e n t of Neurophysiology and *Department of Pathology, Medical Research Institute, Tokyo Medical and Dental University, Kanda-surugadai 2-3-10, Tokyo 101, Japan. Cerebral infarction was studied in rats subjected to reversible focal cerebral ischemia caused by the occlusion of the common carotid arteries (CCAs), under N e m b u t a l anesthesia. Neural activities of the auditory cortex stained with a voltage-sensitive dye RH795, were recorded optically with a 12 x 12 photodiode array. The spatio-temporal neural activities of auditory cortex in response to tone-burst stimuli were m e a s u r e d before, during and after the occlusion of CCAs. The CCA occlusion caused an immediate suppression of the responses in the whole auditory cortex. They never appeared during the occlusion for 2030 min. The responses began to recover 30 rain after the t-ecirculation of the CCAs, and after 60-90 min their amplitudes reached to 60-100% of those before the occlusion. Two features were noted in the response recovery: (1) the fast excitatory component was significantly recovered but the late excitatory component was not, and (2) there was an areal difference in the response recovery within the auditory cortex. These results indicate t h a t the recovery of the responses after the cerebral ischemia is not uniform within the auditory cortex, in the time course and spatial locations.
ONE OF V O C O - A U D I T O R Y
NUCLEI OF ZEBRA FINCH BRAIN (MAN) IS CLOSELY RELATED TO
THE PATTERN D I S C R I M I N A T I O N
OF THEIR SONGS.
MASAOMAEKAWA
Dept. of Physiol., Dokkyo U n i v e r s i t y School 9 f M e d i g i n e j _
AND NOZOMU SAITO ,
M__ibu,_TQchigi,
321C02Japan~
The learned songs of male zebra finches includes CF components of harmonic structure and FM component.
The combination
of each harmonic
of CF component
differs
individual finch and most finches can discriminate the combination pattern. that neurons harmonics, components.
in MAN, one of v o c o - a u d i t o r y
in addition,
nuclei,
that they were sensitive
discriminated
nucleus,
HVc.
We examined
the combination of CF
to temporal combination
These features of sensitivity were frequently
another major voco-auditory
among
of CF and FM
found in MAN, but never in
The different contribution of each nucleus
to song recognition will be discussed.
1 710
LESION OF A FOREBRAIN NUCLEUS (LMAN) IN THE ZEBRA FINCH SONG CONTROL SYSTEM DISRUPTS D I S C R I M I N A T I O N OF H A R M O N I C - A L T E R E D SONG SYLLABLES. KAZUO OKANOYA I°2, MASAO M A E K A W A 2, AND NOZOMU SAITO 2, IBird Control Lab., Natl. Aqric. Res. Cntr., Kannondai, Tsukuba 305 Japan and ZDept. Physiol., Dokkyo Univ., School of Medicine, Mibu, Tochiqi, 321-02 Japan.
Zebra finch songs are individually distinctive in their acoustical compositions. Relative a m p l i t u d e of each harmonic in song syllables is one of such features and neurons in a forebrain song nucleus, IMAN, are shown to be sensitive to the harmonic c o n s t i t u t e of song syllables (Maekawa et. al., in this volume). To examine the role of IMAN in p e r c e i v i n g harmonic structures of song, 5 m a l e Zebra finches received bilateral lesion of IMAN and their auditory d i s c r i m i n a t i o n was compared with that of 3 control birds. The birds were trained, by operant techniques, to peck a response key w h e n a song syllable with a m i s s i n g 3rd harmonic (Go-stimulus) was presented, and not to peck when the original, not altered song syllable (Nogo-stimulus) was presented. The reaction times for Nogo and Go stimuli were s i g n i f i c a n t l y different in control birds but not so in the i M A N - l e s i o n e d birds. Results are in agreement with the electro-physiological data and suggest IMAN might govern the perception of harmonic structures of song in Zebra finches.
1711
O P T I C A L M E A S U R E M E N T OF S P A T I O T E M P O R A L R E S P O N S E C H A N G E IN RAT AUDITORY CORTEX CAUSED BY R E V E R S I B L E C E R E B R A L I S C H E M I A . J U N S E I HORIKAWA, IKUO T A N I G U C H I , T O S H I H I K O KUROIWA*, HIROTO I C H I K I * , AND MASAHIRO NASU, D e p a r t m e n t of Neurophysiology and *Department of Pathology, Medical Research Institute, Tokyo Medical and Dental University, Kanda-surugadai 2-3-10, Tokyo 101, Japan. Cerebral infarction was studied in rats subjected to reversible focal cerebral ischemia caused by the occlusion of the common carotid arteries (CCAs), under N e m b u t a l anesthesia. Neural activities of the auditory cortex stained with a voltage-sensitive dye RH795, were recorded optically with a 12 x 12 photodiode array. The spatio-temporal neural activities of auditory cortex in response to tone-burst stimuli were m e a s u r e d before, during and after the occlusion of CCAs. The CCA occlusion caused an immediate suppression of the responses in the whole auditory cortex. They never appeared during the occlusion for 2030 min. The responses began to recover 30 rain after the t-ecirculation of the CCAs, and after 60-90 min their amplitudes reached to 60-100% of those before the occlusion. Two features were noted in the response recovery: (1) the fast excitatory component was significantly recovered but the late excitatory component was not, and (2) there was an areal difference in the response recovery within the auditory cortex. These results indicate t h a t the recovery of the responses after the cerebral ischemia is not uniform within the auditory cortex, in the time course and spatial locations.