Monkey primary motor and premotor cortex: single-cell activity related to prior information about direction and extent of an intended movement

1989 ◽  
Vol 61 (3) ◽  
pp. 534-549 ◽  
Author(s):  
A. Riehle ◽  
J. Requin
Keyword(s):  
Reaction Time ◽  
Single Cell ◽  
Prior Information ◽  
Movement Time ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Visual Signal ◽  
Movement Direction ◽  
Wrist Flexion ◽  
Movement Parameters

1. This study was devoted to the neuronal processes underlying the construction of the motor program. Two monkeys were trained in a choice reaction time task to perform precise wrist flexion and extension movements of small and large extent. During a trial, the first visual signal, the preparatory signal (PS), informed the animal completely, partially, or not at all about direction and/or extent of the forthcoming movement. After a constant waiting period, a second visual signal, the response signal (RS), was illuminated calling for execution of the requested movement. 2. Reaction time (RT) and movement time (MT) measurements during the training as well as the recording sessions revealed that providing prior information about movement parameters strongly affected RT, but only slightly affected MT. Reaction time decreased in relation to the amount (number of movement parameters precued) and the type of prior information. Providing information about movement direction shortened RT much more than providing information about movement extent. Behavioral data support a parametric conception of motor programming, i.e., that the programming of the different movement parameters results from assembling separate processes of different duration. These results are compatible with the model in which programming processes are serially and hierachically ordered, movement direction being processed before movement extent. 3. Single-cell recording techniques were used to study neuronal activity of the primary motor (MI) and the premotor (PM) cortex, contralateral to the active arm. The activity of 155 neurons of MI and 158 neurons of PM was recorded during performance of the task. Of these 313 neurons, only 14 neurons did not change their activity during execution of the task. Two hundred and seven neurons whose activity changes were related to movement direction and/or movement extent have been selected for the further study. They were classified into three main groups: 1) execution-related neurons (49 in MI, 27 in PM), 2) preparation- and execution-related neurons (48 in MI, 54 in PM), and 3) preparation-related neurons (8 in MI, 21 in PM). 4. Directionally selective, execution-related neurons were found to be more frequently located within MI (81/105, 77.1%) than within PM (55/102, 53.9%), whereas directionally selective, preparation-related neurons appeared tobe more frequently located within PM (47/102, 46.1%) than within MI (24/105, 22.9%).(ABSTRACT TRUNCATED AT 400 WORDS)

Synchronization patterns suggest different functional organization in parietal reach region and dorsal premotor cortex

2014 ◽  
Vol 112 (12) ◽  
pp. 3138-3153 ◽  
Author(s):  
Shubhodeep Chakrabarti ◽  
Pablo Martinez-Vazquez ◽  
Alexander Gail
Keyword(s):  
Single Cell ◽  
Functional Organization ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Striking Similarity ◽  
Dorsal Premotor Cortex ◽  
Functional Roles ◽  
Neural Ensembles ◽  
Cognitive States ◽  
Cross Correlation Analysis

The parietal reach region (PRR) and dorsal premotor cortex (PMd) form part of the fronto-parietal reach network. While neural selectivity profiles of single-cell activity in these areas can be remarkably similar, other data suggest that both areas serve different computational functions in visually guided reaching. Here we test the hypothesis that different neural functional organizations characterized by different neural synchronization patterns might be underlying the putatively different functional roles. We use cross-correlation analysis on single-unit activity (SUA) and multiunit activity (MUA) to determine the prevalence of synchronized neural ensembles within each area. First, we reliably find synchronization in PRR but not in PMd. Second, we demonstrate that synchronization in PRR is present in different cognitive states, including “idle” states prior to task-relevant instructions and without neural tuning. Third, we show that local field potentials (LFPs) in PRR but not PMd are characterized by an increased power and spike field coherence in the beta frequency range (12–30 Hz), further indicating stronger synchrony in PRR compared with PMd. Finally, we show that neurons with similar tuning properties tend to be correlated in their random spike rate fluctuations in PRR but not in PMd. Our data support the idea that PRR and PMd, despite striking similarity in single-cell tuning properties, are characterized by unequal local functional organization, which likely reflects different network architectures to support different functional roles within the fronto-parietal reach network.

Signs of muscle thixotropy during human ballistic wrist joint movements

2005 ◽  
Vol 99 (5) ◽  
pp. 1922-1929 ◽  
Author(s):  
H. W. Axelson
Keyword(s):  
Reaction Time ◽  
Peak Velocity ◽  
Wrist Joint ◽  
Movement Time ◽  
Surface Emg ◽  
Motor Reaction ◽  
Wrist Flexion ◽  
Electromechanical Delay ◽  
Motor Reaction Time ◽  
Ballistic Movements

A study was conducted on healthy subjects to determine whether voluntary ballistic wrist flexion movements are influenced by immediately preceding conditioning of the forearm muscles. Single rapid wrist flexion movements were made in response to an auditory “Go” signal. Rectified surface EMG was recorded from wrist flexors and extensors, and joint position was measured by a goniometer. The movements were preceded (2–3 s) by four different conditioning routines: 40-s rest (Rest), 10-s voluntary alternating wrist joint flexion and extension movements (Osc), and 10 s of 25° weak isometric wrist extensor (Ext) or flexor contractions (Flex). When subjects made ballistic movements after Osc compared with Rest, peak velocity was higher ( P = 0.02) and movement time shorter ( P = 0.06), but there was no difference ( P = 0.83) in motor reaction time (time between the onset of the first agonist burst and movement onset). If the movements were preceded by Ext compared with Flex, motor reaction time was longer ( P = 0.01), indicating a longer electromechanical delay. There were no indications that postconditioning differences in agonist or antagonist muscle activity could explain the results. It was also demonstrated that, after Rest, peak velocity was lower ( P < 0.01) for the first than for the second of a series of repetitive ballistic movements. The observations corresponded to results from passive experiments in which the median nerve was electrically stimulated. In conclusion, history-dependent (thixotropic) changes in skeletal muscle resistance seem to have implications for voluntary ballistic wrist movements. The study also provided evidence that muscle conditioning influences the central nervous reaction time preceding ballistic contractions.

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

1991 ◽  
Vol 66 (3) ◽  
pp. 705-718 ◽  
Author(s):  
H. Mushiake ◽  
M. Inase ◽  
J. Tanji
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Motor Task ◽  
Delay Period ◽  
Visual Signal ◽  
Visually Guided ◽  
Transitional Phase

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.

Reaching Movements With Similar Hand Paths but Different Arm Orientations. II. Activity of Individual Cells in Dorsal Premotor Cortex and Parietal Area 5

1997 ◽  
Vol 78 (5) ◽  
pp. 2413-2426 ◽  
Author(s):  
Stephen H. Scott ◽  
Lauren E. Sergio ◽  
John F. Kalaska
Keyword(s):  
Neuronal Activity ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Reaching Movements ◽  
Movement Direction ◽  
Dorsal Premotor Cortex ◽  
Cortical Areas ◽  
Parietal Area ◽  
Area 5 ◽  
Interaction Term

Scott, Stephen H., Lauren E. Sergio, and John F. Kalaska. Reaching movements with similar hand paths but different arm orientations. II. Activity of individual cells in dorsal premotor cortex and parietal area 5. J. Neurophysiol. 78: 2413–2426, 1997. Neuronal activity in primary motor cortex (MI) is altered when monkeys make reaching movements along similar handpaths at shoulder level with two different arm orientations, either in the natural orientation with the elbow positioned below the level of the shoulder and hand or in an abducted orientation with the elbow abducted nearly to shoulder level. The present study examines to what degree two other cortical areas, the dorsal premotor (PMd) and parietal area 5, also show modulation of cell activity related to arm geometry during reaching. The activity of most (89%) of the 207 cells in PMd recorded while monkeys made reaching movements showed a statistically significant change in activity between orientations [analysis of variation (ANOVA), P < 0.01]. A common effect of arm orientation on cell activity was a change in the overall level of discharge either before, during, and/or after movement (67%, ANOVA, task main effect, P < 0.01). Many cells (76%) showed a statistical change in their response to movement direction (ANOVA, task × direction interaction term, P < 0.01), including changes in dynamic range and changes in the preferred direction of cells that were directionally tuned in both arm orientations. Overall, these effects were similar qualitatively but not as strong quantitatively as those observed in MI. A sample of cells was recorded in area 5 of one monkey. Most (95%) of the 79 area 5 cells showed a change in activity when reaching movements were performed using different arm orientations (ANOVA, P < 0.01). As in PMd and MI, many area 5 cells (56, 71%) showed changes in their tonic discharge before, during, and/or after movement, and 70 cells (89%) showed changes in their response to movement direction (ANOVA, task × direction interaction term, P < 0.01). The observed changes in neuronal activity related to posture and movement in MI, PMd and area 5 demonstrate that single-cell activity in these cortical areas is not simply related to the spatial attributes of hand trajectory but is also strongly influenced by attributes of movement related to arm geometry.

Rule Activity Related to Spatial and Numerical Magnitudes: Comparison of Prefrontal, Premotor, and Cingulate Motor Cortices

2014 ◽  
Vol 26 (5) ◽  
pp. 1000-1012 ◽  
Author(s):  
Anne-Kathrin Eiselt ◽  
Andreas Nieder
Keyword(s):  
Motor Cortex ◽  
Single Cell ◽  
Frontal Lobe ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Dorsal Premotor Cortex ◽  
Single Cell Activity ◽  
Numerical Magnitudes ◽  
Abstract Level

In everyday situations, quantitative rules, such as “greater than/less than,” need to be applied to a multitude of magnitude comparisons, be they sensory, spatial, temporal, or numerical. We have previously shown that rules applied to different magnitudes are encoded in the lateral PFC. To investigate if and how other frontal lobe areas also contribute to the encoding of quantitative rules applied to multiple magnitudes, we trained monkeys to switch between “greater than/less than” rules applied to either line lengths (spatial magnitudes) or dot numerosities (discrete numerical magnitudes). We recorded single-cell activity from the dorsal premotor cortex (dPMC) and cingulate motor cortex (CMA) and compared it with PFC activity. We found the largest proportion of quantitative rule-selective cells in PFC (24% of randomly selected cells), whereas neurons in dPMC and CMA rarely encoded the rule (6% of the cells). In addition, rule selectivity of individual cells was highest in PFC neurons compared with dPMC and CMA neurons. Rule-selective neurons that simultaneously represented the “greater than/less than” rules applied to line lengths and numerosities (“rule generalists”) were exclusively present in PFC. In dPMC and CMA, however, neurons primarily encoded rules applied to only one of the two magnitude types (“rule specialists”). Our data suggest a special involvement of PFC in representing quantitative rules at an abstract level, both in terms of the proportion of neurons engaged and the coding capacities.

Prior Information in Motor and Premotor Cortex: Activity During the Delay Period and Effect on Pre-Movement Activity

2000 ◽  
Vol 84 (2) ◽  
pp. 986-1005 ◽  
Author(s):  
Donald J. Crammond ◽  
John F. Kalaska
Keyword(s):  
Reaction Time ◽  
Prior Information ◽  
Primary Motor Cortex ◽  
Response Selection ◽  
Premotor Cortex ◽  
Motor Planning ◽  
Large Change ◽  
Delay Period ◽  
Short Latency ◽  
Planning Stage

In instructed-delay (ID) tasks, instructional cues provide prior information about the nature of a movement to execute after a delay. Neuronal responses in dorsal premotor cortex (PMd) during the instructed-delay period (IDP) between the CUE and subsequent GO signals are presumed to reflect early planning stages initiated by the prior information. In contrast, in multiple-choice reaction-time (RT) tasks, all motor planning and execution processes must occur after the GO signal. These assumptions predict that neuronal planning correlates recorded during the IDP of ID trials should share common features with early post-GO activity in RT trials, and that those response components need not be recapitulated after the GO signal of ID trials. These two predictions were tested by comparing activity recorded in RT and ID tasks from 503 neurons in PMd and caudal (MIc) and rostral (MIr) primary motor cortex. The incidence and strength of directionally tuned IDP activity declined progressively from PMd to MIc. The directional tuning of activity during the IDP of ID trials was more similar to that in the reaction-time epoch (RTE) of RT trials than after movement onset, especially in PMd. A modulation of post-GO activity was often observed between RT and ID trials and was confined mainly to the RTE. This effect was also most prominent in PMd. The most common change was a reduction in intensity of short-latency phasic responses to the GO signal between RT and ID trials, especially in PMd cells with a short-latency phasic response to CUE signals. However, the largest group of cells in each area showed no large change in peak RTE activity between RT and ID trials, whether they were active in the IDP or not. Since early phasic CUE-related responses are least likely to be recapitulated after the GO signal in ID trials, they may be a neuronal correlate of an early planning stage such as response selection. Tonic IDP responses, which are not as strongly associated with a post-GO reduction in activity, may be related to other aspects of motor planning and preparation. Finally, a major component of the movement-related activity in both MI and PMd is not susceptible to modification by prior information and is indivisibly coupled temporally to movement execution.

Relationship of Reaction Time and Movement Time in a Gross Motor Skill

1973 ◽  
Vol 36 (2) ◽  
pp. 453-454 ◽  
Author(s):  
Richard Groves
Keyword(s):  
Reaction Time ◽  
Motor Skill ◽  
Movement Time ◽  
Gross Motor ◽  
Moment Coefficient ◽  
Relationship Of ◽  
Gross Motor Skill

The purpose of the study was to investigate the independence of reaction time (RT) and movement time (MT) in a gross motor skill, the racing start in swimming. RT and MT were quantified for each S by counting frames of film for five trials. The Pearson product-moment coefficient of –.231 ( p > .05) between means indicated that RT and MT were independent factors.

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