Biomedical subjects

Yoshiya Matsuzaka

Publications and source records attributed to Yoshiya Matsuzaka.

4 recordsLinked to original sources

PubMed2006

Skill representation in the primary motor cortex after long-term practice.

The acquisition of motor skills can lead to profound changes in the functional organization of the primary motor cortex (M1). For example, performance of movement sequences after prolonged practice is associated with an expansion of the effector representation in M1. Paradoxically, there is little evidence that the activity of M1 neurons reflects acquired skills, especially sequences of movements. We examined the activity of M1 neurons during skilled movement sequences in macaques trained to successively hit targets on a monitor. The targets appeared either pseudorandomly (Random mode) or in one of two repeating sequences (Repeating mode). With practice, response times for repeating sequences substantially declined and the monkeys performed the task predictively. Highly trained animals retained the acquired skill after long gaps in practice. After >2 yr of training, 40% of M1 neurons were differentially active during the two task modes. Variations in movement kinematics did not fully explain the task-dependent modulation of neuron activity. Differentially active neurons were more strongly influenced by task mode than by kinematics. Our results suggest that practice sculpts the response properties of M1 neurons. M1 may be a site of storage for the internal representation of skilled sequential movements.

Animals↗

PubMed2005

Prefrontal cortical cells projecting to the supplementary eye field and presupplementary motor area in the monkey.

We examined the location and spatial distribution of prefrontal cortical (PF) cells projecting to the supplementary eye field (SEF) and presupplementary motor area (pre-SMA) using a double retrograde-labeling technique in monkeys (Macaca fuscata). The SEF and pre-SMA were physiologically identified based on the findings of intracortical microstimulation and single cell recordings. Two fluorescent tracers, diamidino yellow and fast blue, were injected into the SEF and pre-SMA of each monkey. Retrogradely labeled cells in the PF were plotted with an automated plotting system. The cells projecting to the SEF and pre-SMA were mainly distributed in the upper and lower banks of the principal sulcus (area 46), with little overlap. Cells projecting to the SEF, but not to the pre-SMA, were observed in areas 8a, 8b, 9, 12, and 45. These findings suggest that the SEF and pre-SMA receive different sets of information from the PF cells.

Action Potentials↗

PubMed2004

Cingulate cortical cells projecting to monkey frontal eye field and primary motor cortex.

We compared the distribution of cingulate cortical cells projecting to the frontal eye field (FEF) and primary motor cortex (MI) using a multiple retrograde labeling technique. Two fluorescent tracers were injected into physiologically identified FEF and MI in each monkey. The location of cells projecting to the forelimb area of MI served to identify the rostral (CMAr) and caudal (CMAc) cingulate motor areas. We found two foci of cells projecting to the FEF: rostral (CEFr) and caudal (CEFc) cingulate eye field. The CEFr was located rostral to the CMAr, while the CEFc was located rostro-ventral to the CMAc. Cells projecting to the FEF and MI scarcely overlapped, indicating that each area receives different sets of information from the cingulate cortex.

Amidines↗

PubMed2002

Reward-based planning of motor selection in the rostral cingulate motor area.

The cingulate motor areas, located in the banks of the cingulate sulcus, constitute a portion of the cingulate cortex of primates. We here present experimental evidence showing that the rostral cingulate motor area (CMAr), but not the caudal one (CMAc) is crucial for the selection of future movements based on reward information. After muscimol injection into the CMAr, monkeys were impaired in selecting movements appropriately on the basis of the amount of reward obtained by performing correct movements. Furthermore, four types of cells in the CMAr were found to reflect a process intervening between detection of reward alteration and selection of a future movement. Each type of cell seems to be involved in responding to the quality of the reward, and to relay that information to change planned movements, and prepare a new movement.

Animals↗