On 2014 Dec 30, MARK WEST commented:

Comment on “Striatal firing rate reflects head movement velocity” by Namsoo Kim, Joseph W. Barter, Tatyana Sukharnikova and Henry H. Yin

We read the experiments conducted by Kim et al. with enthusiasm. We feel that it is important to comment on previous studies that demonstrated a direct relationship between striatal activity and movement velocity, which Kim et al. support. Originally demonstrated in the nonhuman primate (DeLong, 1973), several studies in rodents have shown relationships between firing rates of dorsolateral striatal neurons and movement velocity. Kim et al. find that both putative dorsal striatal projection neurons and putative fast-spiking interneurons fire during head movements and exhibit a firing rate relationship with the velocity of head movement. Given our previous demonstration of firing rate correlations with head movement velocity in the subpopulation of dorsolateral striatal projection neurons selectively related to head movement (Pederson et al., 1997; Tang et al., 2007), it is interesting that firing of putative striatal interneurons also exhibits a relationship to movement velocity (although not subjected to sensorimotor examination of the entire body by Kim et al). We want to add information regarding dorsolateral striatal projection neurons, over half of which fire selectively in relation to activity of single body parts (Carelli and West, 1991; Cho and West, 1997), as revealed by sensorimotor examination of the entire body. These neurons exhibit movement properties which may have been outside the scope of the authors’ study. First, movement-related firing patterns are not limited to neurons phasically related to head movements, as they are found throughout the dorsolateral striatum containing single body part neurons. For instance, we have also demonstrated similar properties in neurons phasically related to vibrissae movement (Carelli and West, 1991), forelimb movement (Carelli et al, 1997) or tongue movement (Mittler et al., 1994; Tang et al., 2008). Second, each single body part neuron exhibits a preferred direction of movement. Third, though velocity of movement is a major predictor of firing rate change for many single body part neurons, not all these neurons are sensitive to velocity and some may be sensitive to one or a combination of several movement-related characteristics (e.g., movement length, movement position, etc). References: Carelli RM, West MO (1991) Representation of body by single neurons in the dorsolateral striatum of the awake, unrestrained rat. J Comp Neurol 309:231 249. Carelli RM, Wolske M, West MO (1997) Loss of lever press-related firing of rat striatal forelimb neurons after repeated sessions in a lever pressing task. J Neurosci 17: 1804-1814. Cho J, West MO (1997) Distributions of single neurons related to body parts in the lateral striatum of the rat. Brain Res 756:241-6. DeLong, MR (1973) Putamen: Activity of Single Units during Slow and Rapid Arm Movements, Science 179:1240-1242. Mittler T, Cho J, Peoples LL, West MO (1994) Representation of the body in the lateral striatum of the freely moving rat: Single neurons related to licking, Exp Brain Res 98:163-167. Pederson CL, Wolske M, Peoples LL, West MO (1997) Firing rate dependent effect of cocaine on single neurons of the rat lateral striatum. Brain Res 760:261-5. Tang C, Pawlak AP, Prokopenko V, West MO (2007) Changes in activity of the striatum during formation of a motor habit. Eur J Neurosci 25:1212-1227. Tang CC, Root DH, Duke DC, Zhu Y, Teixeria K, Ma S, Barker DJ, West MO (2009) Decreased firing of striatal neurons related to licking during acquisition and overtraining of a licking task. J Neurosci 29(44):13952-13961.

On 2014 Dec 30, MARK WEST commented:

Comment on “Striatal firing rate reflects head movement velocity” by Namsoo Kim, Joseph W. Barter, Tatyana Sukharnikova and Henry H. Yin

We read the experiments conducted by Kim et al. with enthusiasm. We feel that it is important to comment on previous studies that demonstrated a direct relationship between striatal activity and movement velocity, which Kim et al. support. Originally demonstrated in the nonhuman primate (DeLong, 1973), several studies in rodents have shown relationships between firing rates of dorsolateral striatal neurons and movement velocity. Kim et al. find that both putative dorsal striatal projection neurons and putative fast-spiking interneurons fire during head movements and exhibit a firing rate relationship with the velocity of head movement. Given our previous demonstration of firing rate correlations with head movement velocity in the subpopulation of dorsolateral striatal projection neurons selectively related to head movement (Pederson et al., 1997; Tang et al., 2007), it is interesting that firing of putative striatal interneurons also exhibits a relationship to movement velocity (although not subjected to sensorimotor examination of the entire body by Kim et al). We want to add information regarding dorsolateral striatal projection neurons, over half of which fire selectively in relation to activity of single body parts (Carelli and West, 1991; Cho and West, 1997), as revealed by sensorimotor examination of the entire body. These neurons exhibit movement properties which may have been outside the scope of the authors’ study. First, movement-related firing patterns are not limited to neurons phasically related to head movements, as they are found throughout the dorsolateral striatum containing single body part neurons. For instance, we have also demonstrated similar properties in neurons phasically related to vibrissae movement (Carelli and West, 1991), forelimb movement (Carelli et al, 1997) or tongue movement (Mittler et al., 1994; Tang et al., 2008). Second, each single body part neuron exhibits a preferred direction of movement. Third, though velocity of movement is a major predictor of firing rate change for many single body part neurons, not all these neurons are sensitive to velocity and some may be sensitive to one or a combination of several movement-related characteristics (e.g., movement length, movement position, etc). References: Carelli RM, West MO (1991) Representation of body by single neurons in the dorsolateral striatum of the awake, unrestrained rat. J Comp Neurol 309:231 249. Carelli RM, Wolske M, West MO (1997) Loss of lever press-related firing of rat striatal forelimb neurons after repeated sessions in a lever pressing task. J Neurosci 17: 1804-1814. Cho J, West MO (1997) Distributions of single neurons related to body parts in the lateral striatum of the rat. Brain Res 756:241-6. DeLong, MR (1973) Putamen: Activity of Single Units during Slow and Rapid Arm Movements, Science 179:1240-1242. Mittler T, Cho J, Peoples LL, West MO (1994) Representation of the body in the lateral striatum of the freely moving rat: Single neurons related to licking, Exp Brain Res 98:163-167. Pederson CL, Wolske M, Peoples LL, West MO (1997) Firing rate dependent effect of cocaine on single neurons of the rat lateral striatum. Brain Res 760:261-5. Tang C, Pawlak AP, Prokopenko V, West MO (2007) Changes in activity of the striatum during formation of a motor habit. Eur J Neurosci 25:1212-1227. Tang CC, Root DH, Duke DC, Zhu Y, Teixeria K, Ma S, Barker DJ, West MO (2009) Decreased firing of striatal neurons related to licking during acquisition and overtraining of a licking task. J Neurosci 29(44):13952-13961.