In the past, Walking or locomotion has been thought to be controlled by only the brain, and the spinal cord was merely a connector between the brain and the motor structure. The brain does control the voluntary muscle movement, but it works in conjunction with the spinal cord. It is now accepted that the motor patterns and rhythms governing locomotion in mammals are controlled by an area of the spinal cord known as the Central Pattern Generator (CPG) (Kiehn, 2006).
The neural circuits in the CPG get activated by a signal through the descending locomotor commands coming from neurons in the brainstem and midbrain. After that, the neurons in the CPG take over producing the rhythm and pattern for muscle contraction (Kiehn, 2006). The CPG contains six different classes of interneuron populations which include V0, V1, V2a, V2b, V3, and dI6 populations, and they are all unique to each other. These interneurons will form a complex neural circuit that send direct and indirect signals or inputs to motor neurons (MN) (Hinckley et al., …show more content…
Superoxide dismutase 1 (SOD1) is a gene that has been linked to familial ALS (FALS); it results in the formation of free radicals inside the cell that disrupt cellular functions. Astrocytes are one of the cells affected by free radicals; the free radicals disrupt the glutamate receptor on the cell membrane of astrocytes. It will prevent the astrocytes from taking up and recycling the glutamate at the synapse. When glutamate binds to receptors on the MN, it causes a cascade of reactions which results in the uptake of Ca+2 ions. The excess Ca+2 ions causes organelles inside MN to malfunction resulting in apoptosis (Foran and Trotti, 2009). Astrocytes from FALS patients cultured with healthy MN resulted in the death of at least 50% of the MN compared to a control that contained healthy astrocytes and MN. (Haidet-phillips et al.,
The neural circuits in the CPG get activated by a signal through the descending locomotor commands coming from neurons in the brainstem and midbrain. After that, the neurons in the CPG take over producing the rhythm and pattern for muscle contraction (Kiehn, 2006). The CPG contains six different classes of interneuron populations which include V0, V1, V2a, V2b, V3, and dI6 populations, and they are all unique to each other. These interneurons will form a complex neural circuit that send direct and indirect signals or inputs to motor neurons (MN) (Hinckley et al., …show more content…
Superoxide dismutase 1 (SOD1) is a gene that has been linked to familial ALS (FALS); it results in the formation of free radicals inside the cell that disrupt cellular functions. Astrocytes are one of the cells affected by free radicals; the free radicals disrupt the glutamate receptor on the cell membrane of astrocytes. It will prevent the astrocytes from taking up and recycling the glutamate at the synapse. When glutamate binds to receptors on the MN, it causes a cascade of reactions which results in the uptake of Ca+2 ions. The excess Ca+2 ions causes organelles inside MN to malfunction resulting in apoptosis (Foran and Trotti, 2009). Astrocytes from FALS patients cultured with healthy MN resulted in the death of at least 50% of the MN compared to a control that contained healthy astrocytes and MN. (Haidet-phillips et al.,