Neuronal activity in the primate premotor, supplementary, and precentral motor cortex during visually guided and internally determined sequential movements

Abstract

1. Single-cell activity was recorded from three different motor areas in the cerebral cortex: the primary motor cortex (MI), supplementary motor area (SMA), and premotor cortex (PM). 2. Three monkeys (Macaca fuscata) were trained to perform a sequential motor task in two different conditions. In one condition (visually triggered task, VT), they reached to and touched three pads placed in a front panel by following lights illuminated individually from behind the pads. In the other condition (internally guided task, IT), they had to remember a predetermined sequence and press the three pads without visual guidance. In a transitional phase between the two conditions, the animals learned to memorize the correct sequence. Auditory instruction signals (tones of different frequencies) told the animal which mode it was in. After the instruction signals, the animals waited for a visual signal that triggered the first movement. 3. Neuronal activity was analyzed during three defined periods: delay period, premovement period, and movement period. Statistical comparisons were made to detect differences between the two behavioral modes with respect to the activity in each period. 4. Most, if not all, of MI neurons exhibited similar activity during the delay, premovement, and movement periods, regardless of whether the sequential motor task was visually guided or internally determined. 5. More than one-half of the SMA neurons were preferentially or exclusively active in relation to IT during both the premovement (55%) and movement (65%) periods. In contrast, PM neurons were more active (55% and 64% during the premovement and movement periods) in VT. 6. During the instructed-delay period, a majority of SMA neurons exhibited preferential or exclusive relation to IT whereas the activity in PM neurons was observed equally in different modes. 7. Two types of neurons exhibiting properties of special interest were observed. Sequence-specific neurons (active in a particular sequence only) were more common in SMA, whereas transition-specific neurons (active only at the transitional phase) were more common in PM. 8. Although a strict functional dichotomy is not acceptable, these observations support a hypothesis that the SMA is more related to IT, whereas PM is more involved in VT. 9. Some indications pointing to a functional subdivision of PM are obtained.

Altered resting‐state functional connectivity of the putamen and internal globus pallidus is related to speech impairment in Parkinson's disease

“…Compared to habitual (internally cued) speech, measures of speech function and intelligibility improve when PD subjects are prompted (externally cued) to speak more loudly, clearly, or slowly (Dromey & Ramig, 1998; Ho, Bradshaw, Iansek, & Alfredson, 1999; Sapir, 2014; Tjaden, Sussman, & Wilding, 2014). As motor preparatory activity in PMd is biased toward the planning and execution of movements that are externally cued (Halsband, Matsuzaka, & Tanji, 1994; Halsband & Passingham, 1982; Lu, Arai, Tsai, & Ziemann, 2012; Mushiake, Inase, & Tanji, 1991), increased connectivity with GPi could reflect a mechanism for compensatory reliance on external cues during speech production in PD.…”

Reversible inactivation of macaque dorsomedial frontal cortex: effects on saccades and fixations

“…This conclusion is supported by studies of reaching arm movements, another behavior in which DMFC is involved. Mushiake et al (1991) recorded from DMFC neurons during visually-guided reaches or remembered sequences of reaches and found preferential modulation during the latter. Also, Tanji and Shima (1994) reported that many DMFC neurons fire only for arm movements that occur at a particular point in a sequence and not for identical movements that occur singly or at other points in the sequence.…”

Comparison of neuronal activity in the supplementary motor area and primary motor cortex

“…In the second report [71], SMA neurons were found to be differentially active depending on whether the animal were prepared to move a single hand or both hands. In the third report [50], a group of SMA neurons exhibited selective activity depending upon whether the monkeys were prepared to perform sequential button-press movement under visual guidance or based on memorized information. Thus, the SMA seem to be more involved in preparatory processes than the MI, during a number of different behavioral paradigm.…”