PMC:6610326 / 12881-14273
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/6610326","sourcedb":"PMC","sourceid":"6610326","source_url":"https://www.ncbi.nlm.nih.gov/pmc/6610326","text":"In the spinal cord, MNs are organized into columns (Table 1) based on the location of their target muscle [reviewed in Matise and Sharma (2013) and Stifani (2014)]. Within each column, the MNs innervating each muscle are clustered into motor pools, each containing of 20–300 cells depending on the muscle (Bryan et al., 1972; McHanwell and Biscoe, 1981). α-MNs located in the spinal cord are archetypal MNs that innervate extrafusal muscle fibers, thus creating force to move the skeleton (Table 2). In contrast, γ-MNs innervate intrafusal fibers, which modulate the sensitivity of muscle spindles to stretch (Table 2) (Hunt and Kuffler, 1951; Kuffler et al., 1951; Kanning et al., 2010). β-MNs are not as well characterized as α-MNs but they innervate both intrafusal and extrafusal muscle fibers (Bessou et al., 1965). Both α and γ-MNs have large dendritic trees but γ-MNs have fewer large dendrites than α-MNs (7–11) and they also branch less (Westbury, 1982). The somas of γ-MNs are smaller than those of α-MNs and they also possess thinner axons, which reflects their slower conduction velocity (\u003c55 m/s in γ-MN vs. ∼70–90 m/s in α-MNs in cats) (Table 2) (Westbury, 1982). γ-MNs receive only indirect sensory inputs. Therefore, γ-MNs do not directly participate in spinal reflexes (Eccles et al., 1960; Stifani, 2014), but they contribute to the modulation of muscle contraction instead.","tracks":[{"project":"2_test","denotations":[{"id":"31316328-5015999-38515311","span":{"begin":320,"end":324},"obj":"5015999"},{"id":"31316328-6115428-38515312","span":{"begin":348,"end":352},"obj":"6115428"},{"id":"31316328-14832775-38515313","span":{"begin":638,"end":642},"obj":"14832775"},{"id":"31316328-14784872-38515314","span":{"begin":660,"end":664},"obj":"14784872"},{"id":"31316328-20367447-38515315","span":{"begin":682,"end":686},"obj":"20367447"},{"id":"31316328-4221243-38515316","span":{"begin":814,"end":818},"obj":"4221243"},{"id":"31316328-7108785-38515317","span":{"begin":957,"end":961},"obj":"7108785"},{"id":"31316328-7108785-38515318","span":{"begin":1171,"end":1175},"obj":"7108785"},{"id":"31316328-13725574-38515319","span":{"begin":1302,"end":1306},"obj":"13725574"}],"attributes":[{"subj":"31316328-5015999-38515311","pred":"source","obj":"2_test"},{"subj":"31316328-6115428-38515312","pred":"source","obj":"2_test"},{"subj":"31316328-14832775-38515313","pred":"source","obj":"2_test"},{"subj":"31316328-14784872-38515314","pred":"source","obj":"2_test"},{"subj":"31316328-20367447-38515315","pred":"source","obj":"2_test"},{"subj":"31316328-4221243-38515316","pred":"source","obj":"2_test"},{"subj":"31316328-7108785-38515317","pred":"source","obj":"2_test"},{"subj":"31316328-7108785-38515318","pred":"source","obj":"2_test"},{"subj":"31316328-13725574-38515319","pred":"source","obj":"2_test"}]},{"project":"0_colil","denotations":[{"id":"31316328-5015999-630768","span":{"begin":320,"end":324},"obj":"5015999"},{"id":"31316328-6115428-630769","span":{"begin":348,"end":352},"obj":"6115428"},{"id":"31316328-14832775-630770","span":{"begin":638,"end":642},"obj":"14832775"},{"id":"31316328-14784872-630771","span":{"begin":660,"end":664},"obj":"14784872"},{"id":"31316328-20367447-630772","span":{"begin":682,"end":686},"obj":"20367447"},{"id":"31316328-4221243-630773","span":{"begin":814,"end":818},"obj":"4221243"},{"id":"31316328-7108785-630774","span":{"begin":957,"end":961},"obj":"7108785"},{"id":"31316328-7108785-630775","span":{"begin":1171,"end":1175},"obj":"7108785"},{"id":"31316328-13725574-630776","span":{"begin":1302,"end":1306},"obj":"13725574"}],"attributes":[{"subj":"31316328-5015999-630768","pred":"source","obj":"0_colil"},{"subj":"31316328-6115428-630769","pred":"source","obj":"0_colil"},{"subj":"31316328-14832775-630770","pred":"source","obj":"0_colil"},{"subj":"31316328-14784872-630771","pred":"source","obj":"0_colil"},{"subj":"31316328-20367447-630772","pred":"source","obj":"0_colil"},{"subj":"31316328-4221243-630773","pred":"source","obj":"0_colil"},{"subj":"31316328-7108785-630774","pred":"source","obj":"0_colil"},{"subj":"31316328-7108785-630775","pred":"source","obj":"0_colil"},{"subj":"31316328-13725574-630776","pred":"source","obj":"0_colil"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"2_test","color":"#ece893","default":true},{"id":"0_colil","color":"#ce93ec"}]}]}}