Song system
Encyclopedia
A song system, also known as a song control system (SCS), is a series of discrete brain nuclei involved in the production and learning of song in songbird
s. It was first observed by Fernando Nottebohm
in 1976 in a paper titled "Central control of song in the canary, Serinus canarius", published in the Journal of Comparative Neurology.
studies in the zebra finch
, the song system can be broken into two general pathways. The direct/descending motor pathway is both necessary and sufficient for normal song production, while the anterior forebrain pathway (AFP)is necessary for song learning but not production. Juvenile birds who have not yet fully learned their songs and that have lesions of the AFP never learn to make normal songs. Adult birds who experience these same lesions continue to sing normally for some time. The song system is sexually dimorphic
in many species of songbirds, especially in species in which the male primarily sings.
. The song system is the first neural circuit in which it was conclusively demonstrated that newly generated neurons are incorporated in to the brains of adults vertebrates. Some seasonally-breeding songbird brains vary in volume, neuron
number, and density depending on the time of year, and these changes in the brain are driven by changes in circulating levels of testosterone
.
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
s. It was first observed by Fernando Nottebohm
Fernando Nottebohm
Dr Fernando Nottebohm is a neuroscientist and is the Dorothea L. Leonhardt Professor at Rockefeller University as well as being head of the Laboratory of Animal Behavior and director of the Field Research Center for Ecology and Ethology....
in 1976 in a paper titled "Central control of song in the canary, Serinus canarius", published in the Journal of Comparative Neurology.
Operation
Based on lesionLesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
studies in the zebra finch
Zebra Finch
The Zebra Finch, Taeniopygia guttata, is the most common and familiar estrildid finch of Central Australia and ranges over most of the continent, avoiding only the cool moist south and the tropical far north. It also can be found natively in Indonesia and East Timor...
, the song system can be broken into two general pathways. The direct/descending motor pathway is both necessary and sufficient for normal song production, while the anterior forebrain pathway (AFP)is necessary for song learning but not production. Juvenile birds who have not yet fully learned their songs and that have lesions of the AFP never learn to make normal songs. Adult birds who experience these same lesions continue to sing normally for some time. The song system is sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in many species of songbirds, especially in species in which the male primarily sings.
System model
The song system has emerged as leading model of adult neural plasticitySynaptic plasticity
In neuroscience, synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength in response to either use or disuse of transmission over synaptic pathways. Plastic change also results from the alteration of the number of receptors located on a synapse...
. The song system is the first neural circuit in which it was conclusively demonstrated that newly generated neurons are incorporated in to the brains of adults vertebrates. Some seasonally-breeding songbird brains vary in volume, neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
number, and density depending on the time of year, and these changes in the brain are driven by changes in circulating levels of testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
.