Detailed neuroanatomical studies of model species are necessary to facilitate comparative experim... more Detailed neuroanatomical studies of model species are necessary to facilitate comparative experiments which test hypotheses relevant to brain evolution and function. Butterflyfishes (Chaetodontidae) boast numerous sympatric species that differ in social behavior, aggression and feeding ecology. However, the ability to test hypotheses relevant to brain function in this family is hindered by the lack of detailed neural descriptions. The cytoarchitecture of the telencephalon in the monogamous and territorial multiband butterflyfish, Chaetodon multicinctus, was determined with Nissl-stained serial sections and an immunohistochemical analysis of arginine vasotocin (AVT), serotonin, substance P and tyrosine hydroxylase. The ventral telencephalon was similar to that of other perciform fishes studied, with one major difference. A previously undescribed postcommissural region, the cuneate nucleus, was identified and putatively assigned to the ventral telencephalon. While the function of this...
Olfactory stimuli are detected by over 1,000 odorant receptors in mice, with each receptor being ... more Olfactory stimuli are detected by over 1,000 odorant receptors in mice, with each receptor being mapped to specific glomeruli in the olfactory bulb. The trace amine-associated receptors (TAARs) are a small family of evolutionarily conserved olfactory receptors whose contribution to olfaction remains enigmatic. Here, we show that a majority of the TAARs are mapped to a discrete subset of glomeruli in the dorsal olfactory bulb of the mouse. This TAAR projection is distinct from the previously described class I and class II domains, and is formed by a sensory neuron population that is restricted to express TAAR genes prior to choice. We also show that the dorsal TAAR glomeruli are selectively activated by amines at low concentrations. Our data uncover a hard-wired, parallel input stream in the main olfactory pathway that is specialized for the detection of volatile amines.
Sound production that is mediated by intrinsic or extrinsic swim bladder musculature has evolved ... more Sound production that is mediated by intrinsic or extrinsic swim bladder musculature has evolved multiple times in teleost fishes. Sonic muscles must contract rapidly and synchronously to compress the gas-filled bladder with sufficient velocity to produce sound. Muscle modifications that may promote rapid contraction include small fiber diameter, elaborate sarcoplasmic reticulum (SR), triads at the A-I boundary, and cores of sarcoplasm. The diversity of innervation patterns indicate that sonic muscles have independently evolved from different trunk muscle precursors. The analysis of sonic motor pathways in distantly related fishes is required to determine the relationships between sonic muscle evolution and function in acoustic signaling. We examined the ultrastructure of sonic and adjacent hypaxial muscle fibers and the distribution of sonic motor neurons in the coral reef Pyramid Butterflyfish (Chaetodontidae: Hemitaurichthys polylepis) that produces sound by contraction of extrinsic sonic muscles near the anterior swim bladder. Relative to adjacent hypaxial fibers, sonic muscle fibers were sparsely arranged among the endomysium, smaller in cross-section, had longer sarcomeres, a more elaborate SR, wider t-tubules, and more radially arranged myofibrils. Both sonic and non-sonic muscle fibers possessed triads at the Z-line, lacked sarcoplasmic cores, and had mitochondria among the myofibrils and concentrated within the peripheral sarcoplasm. Sonic muscles of this derived eutelost possess features convergent with other distant vocal taxa (other euteleosts and non-euteleosts): small fiber diameter, a well-developed SR, and radial myofibrils. In contrast with some sonic fishes, however, Pyramid Butterflyfish sonic muscles lack sarcoplasmic cores and A-I triads. Retrograde nerve label experiments show that sonic muscle is innervated by central and ventrolateral motor neurons associated with spinal nerves 1-3. This restricted distribution of sonic motor neurons in the spinal cord differs from many euteleosts and likely reflects the embryological origin of sonic muscles from hypaxial trunk precursors rather than occipital somites.
Detailed neuroanatomical studies of model species are necessary to facilitate comparative experim... more Detailed neuroanatomical studies of model species are necessary to facilitate comparative experiments which test hypotheses relevant to brain evolution and function. Butterflyfishes (Chaetodontidae) boast numerous sympatric species that differ in social behavior, aggression and feeding ecology. However, the ability to test hypotheses relevant to brain function in this family is hindered by the lack of detailed neural descriptions. The cytoarchitecture of the telencephalon in the monogamous and territorial multiband butterflyfish, Chaetodon multicinctus, was determined with Nissl-stained serial sections and an immunohistochemical analysis of arginine vasotocin (AVT), serotonin, substance P and tyrosine hydroxylase. The ventral telencephalon was similar to that of other perciform fishes studied, with one major difference. A previously undescribed postcommissural region, the cuneate nucleus, was identified and putatively assigned to the ventral telencephalon. While the function of this...
Olfactory stimuli are detected by over 1,000 odorant receptors in mice, with each receptor being ... more Olfactory stimuli are detected by over 1,000 odorant receptors in mice, with each receptor being mapped to specific glomeruli in the olfactory bulb. The trace amine-associated receptors (TAARs) are a small family of evolutionarily conserved olfactory receptors whose contribution to olfaction remains enigmatic. Here, we show that a majority of the TAARs are mapped to a discrete subset of glomeruli in the dorsal olfactory bulb of the mouse. This TAAR projection is distinct from the previously described class I and class II domains, and is formed by a sensory neuron population that is restricted to express TAAR genes prior to choice. We also show that the dorsal TAAR glomeruli are selectively activated by amines at low concentrations. Our data uncover a hard-wired, parallel input stream in the main olfactory pathway that is specialized for the detection of volatile amines.
Sound production that is mediated by intrinsic or extrinsic swim bladder musculature has evolved ... more Sound production that is mediated by intrinsic or extrinsic swim bladder musculature has evolved multiple times in teleost fishes. Sonic muscles must contract rapidly and synchronously to compress the gas-filled bladder with sufficient velocity to produce sound. Muscle modifications that may promote rapid contraction include small fiber diameter, elaborate sarcoplasmic reticulum (SR), triads at the A-I boundary, and cores of sarcoplasm. The diversity of innervation patterns indicate that sonic muscles have independently evolved from different trunk muscle precursors. The analysis of sonic motor pathways in distantly related fishes is required to determine the relationships between sonic muscle evolution and function in acoustic signaling. We examined the ultrastructure of sonic and adjacent hypaxial muscle fibers and the distribution of sonic motor neurons in the coral reef Pyramid Butterflyfish (Chaetodontidae: Hemitaurichthys polylepis) that produces sound by contraction of extrinsic sonic muscles near the anterior swim bladder. Relative to adjacent hypaxial fibers, sonic muscle fibers were sparsely arranged among the endomysium, smaller in cross-section, had longer sarcomeres, a more elaborate SR, wider t-tubules, and more radially arranged myofibrils. Both sonic and non-sonic muscle fibers possessed triads at the Z-line, lacked sarcoplasmic cores, and had mitochondria among the myofibrils and concentrated within the peripheral sarcoplasm. Sonic muscles of this derived eutelost possess features convergent with other distant vocal taxa (other euteleosts and non-euteleosts): small fiber diameter, a well-developed SR, and radial myofibrils. In contrast with some sonic fishes, however, Pyramid Butterflyfish sonic muscles lack sarcoplasmic cores and A-I triads. Retrograde nerve label experiments show that sonic muscle is innervated by central and ventrolateral motor neurons associated with spinal nerves 1-3. This restricted distribution of sonic motor neurons in the spinal cord differs from many euteleosts and likely reflects the embryological origin of sonic muscles from hypaxial trunk precursors rather than occipital somites.
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