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J Tanji

Publications and source records attributed to J Tanji.

At least 55 records · Page 3Linked to original sources
PubMed1994

Projections from the globus pallidus to the thalamic areas projecting to the dorsal area 6 of the macaque monkey: a multiple tracing study.

In the brains of 3 Japanese monkeys (Macaca fuscata), a combined injection of the tract-tracers Fast Blue (FB), Diamidino Yellow (DY), and horseradish peroxidase-conjugated with wheat germ agglutinin (WGA-HRP) was performed: the retrograde tracers, FB and DY, were injected into a rostral and a caudal sectors of the dorsal part in area 6, and the anterograde tracer, WGA-HRP, was injected into the internal segment of the globus pallidus (GPi). In the thalamus, FB- and DY-labeled neurons were distributed in a segregated manner. A substantial number of the FB-labeled and DY-labeled thalamic neurons were located within the thalamic areas containing fine axons labeled with WGA-HRP. The results suggest that the GPi may project to both the rostral and caudal sectors of the dorsal part of area 6 through the thalamus.

Amidines↗
PubMed1994

Role for supplementary motor area cells in planning several movements ahead.

To achieve a volitional goal, we need to execute multiple movements in a specific temporal order. After repetitive performance of a particular sequence of movements, we are able to memorize and execute the whole sequence without external guidance. Where and how in the brain do we store information necessary for the orderly performance of multiple movements? We have found a group of cells in the cerebral cortex of monkeys whose activity is exclusively related to a sequence of multiple movements performed in a particular order. Such cellular activity exists in the supplementary motor area, but not in the primary motor cortex. We propose that these cells contribute a signal about the order of forthcoming multiple movements, and are useful for planning and coding of several movements ahead.

Animals↗
PubMed1994

Neuronal activity in the primate supplementary, pre-supplementary and premotor cortex during externally and internally instructed sequential movements.

This study recorded the activity of neurons in the (i) supplementary motor area (SMA), (ii) pre-SMA (the motor area immediately rostral to the SMA), (iii) premotor cortex (PMC) and (iv) primary motor cortex (MI), while the monkey performed a conditional sequential motor task that ensures sequencing of multiple movements to the same manipulandum. This paradigm was chosen in order to prevent the participation of spatial cues in prompting the correct motor sequence. Three different movements (turn-push-pull) were performed under two task conditions: (i) internally determined (I): the monkey had to generate a pre-determined sequence from memory and without visual guidance; (ii) externally triggered (E): the correct sequence of movements was performed by following lights illuminated one after the other. Neuronal activity during the following periods were analyzed: instruction (300 ms following the onset of the auditory instruction signal); delay (interval between the end of the instruction period or the termination of the previous movement and the movement trigger); premovement (interval between the trigger signal and the movement onset); movement (interval between the mechanically-sensed movement onset and the completion of the movement) and reward (500 ms period centered at the time of reward delivery). Pre-SMA neurons were generally more active during the delay and premovement as compared to the movement, instruction and reward periods. Activity in the pre-SMA was more related to E during the pre-movement period, but exhibited a preferential relationship to I in the movement period. SMA neurons were more active when the sequential motor task was internally generated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The supplementary motor area in the cerebral cortex.

The supplementary motor area (SMA) occupies an expanse of frontal agranular cortex rostral to the primary motor cortex (MI), largely in the mesial surface of the hemisphere. It is basically organized topographically, although the topography is not as apparent as in the MI. The traditionally defined SMA is now regarded as including two separate areas. The caudal part (SMA proper or F3) projects directly to the MI and to the spinal cord. The rostral part (pre-SMA or F6) is more remote from MI and receive projections from the prefrontal cortex and the cingulate motor areas. The supplementary eye field (SEF) is a small area separate from either the SMA or pre-SMA. The SEF is connected to cortical and subcortical areas related to oculomotor control. The SMA is active when subjects perform distal as well as proximal limb movement. Although the SMA is active in relation to relatively simple motor tasks, the functional significance of this relation to 'simple' movement is debatable. The SMA activity is subject to functional plasticity. The SMA is more active than the primary motor cortex if motor tasks are demanding in certain respects. Similarities of lesion effects of the SMA and basal ganglia suggests their intimate relation linked anatomically by the cortico-basal ganglia loops. Studies in both human subjects and in subhuman primates indicate the importance of the SMA in motor tasks that demand retrieval of motor memory. The SMA appears also crucial in temporal organization of movements, especially in sequential performance of multiple movements.

Animals↗
PubMed1994

Corticocortical and thalamocortical responses of neurons in the monkey primary motor cortex and their relation to a trained motor task.

1. We studied the responsiveness of neurons in the primary motor cortex (MI) of monkeys (Macacafuscata) to electrical stimulation of the supplementary motor area (SMA), primary sensory cortex (SI), and the ventral subnucleus of the thalamus (VPLo) with chronically implanted electrodes. 2. All neurons examined in this study were characterized by their relation to a motor task performed by the animals. They responded to stimulation of the cortical or thalamic area with excitation from one area alone (n = 128) or from multiple areas (n = 84) of all combinations. In a majority of neurons, response latencies to both cortical and thalamic stimulation were within 5 ms. 3. A vast majority of neurons (80%) that were active during a preparatory period for forthcoming reaching movements were activated by SMA stimulation. They were activated only infrequently by SI or thalamic stimulation. 4. Movement-related neurons (active immediately before and during reaching movements) were activated by thalamic, SI, or SMA stimulation or by any combination of those stimuli. More than half of the movement-related neurons activated exclusively by either thalamic or SMA stimulation exhibited activity onset times earlier than those observed in the earliest muscles. By contrast, most movement-related neurons that responded only to SI stimulation were late in their activity onset. 5. These findings suggest that the SMA input to MI is important in developing a preparatory type of activity in MI, whereas the thalamus (VPLo) provides substantial inputs in movement execution. The roles played by inputs from SI and SMA in relation to motor execution are debatable and are discussed here with reference to previous reports.

Animals↗
PubMed1993

Input organization of distal and proximal forelimb areas in the monkey primary motor cortex: a retrograde double labeling study.

The present double-labeling study was designed to demonstrate the morphological framework for motor control in coordinated distal and proximal forelimb movements, which may partly, at least, depend on corticocortical and thalamocortical inputs to the forelimb area in the primary motor cortex. After intracortical microstimulation mapping of the forelimb area in the primary motor cortex of four macaque monkeys, a retrograde tracing study with fluorescent dyes was attempted to label simultaneously neurons in cortical and subcortical sites projecting to the distal forelimb representation area and those projecting to the proximal representation area of the primary motor cortex. Neurons projecting to distal and proximal forelimb parts of the primary motor cortex were largely separate in the following areas: the premotor area, primary somatosensory area, secondary somatosensory area, area 5, and thalamus. In contrast, there was no precise topographic organization of labeled projection neurons in the following areas: the supplementary motor area, cingulate motor area, primary motor cortex adjacent to the injection sites, claustrum, and basal nucleus of Meynert. The present study revealed that the forelimb area of the primary motor cortex receives both segregated and intermixed inputs from cortical and subcortical sources. In particular, the fact that the forelimb area of the primary motor cortex receives topographically organized inputs from the premotor area and nontopographically organized inputs from the supplementary motor area and cingulate motor area indicates possible different functional roles of frontal premotor areas in control of coordinated distal and proximal forelimb movements.

Animals↗
PubMed1993

The role of premotor cortex and the supplementary motor area in the temporal control of movement in man.

In the present study temporal control of movement was systematically analysed in patients with unilateral lesions of the lateral or medial premotor cortex (PMC) or supplementary motor area (SMA) and in age-matched controls. The ability to learn new temporal adjustments was evaluated by examining rhythm reproduction using either the left or right hand or both hands in an alternating manner. A severe impairment in rhythm reproduction was found after lateral or medial PMC lesions; the deficit was most pronounced when our patients were required to use both hands in an alternating manner. The impairment occurred in the absence of difficulties in manual dexterity or impairments in discriminating the rhythm patterns. In a second series of experiments the contribution of the SMA in organizing movements in the time domain was examined. In this series, two patients with left-sided lesions, including the SMA but sparing tissue from the lateral hemispheric surface, and seven age-matched controls were requested to reproduce rhythm constellations in the presence of a sound signal and from memory. Results reveal that patients with left medial lesions involving the SMA had most severe difficulties to produce any rhythms from memory, though they were able to produce the rhythms under auditory pacing. This deficit in programming sequential patterns from memory in the time domain should be interpreted in the context of a decline in the ability to benefit from previous stimulus presentation, which prevents an effective later programming of these sequences when they have to be rehearsed from memory. It was found that patients with left SMA lesions had an increase in reaction time on a sequential digit task when sequences had to be produced under delayed conditions; by contrast, the controls showed a decrease of reaction time after previous stimulus presentation. The present findings extend previous knowledge on sequential motor tasks and argue for a critical role for both the SMA and the premotor cortex in the generation of sequences from memory that fit into a precise timing plan.

Adult↗
PubMed1992

Pallidal inputs to thalamocortical neurons projecting to the supplementary motor area: an anterograde and retrograde double labeling study in the macaque monkey.

The relationship between thalamocortical neurons projecting to the supplementary motor area (SMA) and pallidothalamic projection fibers was examined with an anterograde and retrograde double labeling technique in macaque monkeys (Macaca fuscata). In each monkey, Fast Blue (FB) was injected into the hand-arm area of the SMA after mapping the somatotopy using intracortical microstimulation, and horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP) was injected into the ipsilateral internal segment of the globus pallidus (GPi). As a result, numerous projection neurons labeled with FB were distributed in pallidal terminal areas labeled with WGA-HRP in the ventral nuclear group of the thalamus. The present findings indicate that the SMA receives strong indirect projections from the GPi via the thalamus.

Afferent Pathways↗
PubMed1992

A motor area rostral to the supplementary motor area (presupplementary motor area) in the monkey: neuronal activity during a learned motor task.

1. The rostromesial agranular frontal cortex of macaque monkey (Macaca fuscata), traditionally defined as the supplementary motor area (SMA), was studied using various physiological techniques to delineate two different areas rostrocaudally. 2. Field and unitary responses to electrical stimulation of the primary motor cortex were distinct in the caudal part, but minimal or absent in the rostral part. Intracortical microstimulation readily evoked limb or orofacial movements in the caudal part, but only infrequently in the rostral part. Neuronal responses to visual stimuli prevailed in the rostral part, but somatosensory responses were rare. The opposite was true in the caudal part. 3. The rostral part, roughly corresponding to area 6a beta, was operationally defined as the presupplementary motor area (pre-SMA). The caudal part was redefined as the SMA proper. 4. Single-cell activity in the pre-SMA was quantitatively compared with that in the SMA proper in relation to a trained motor task. 5. Phasic responses to visual cue signals indicating the direction of forthcoming arm-reaching movement were more abundant in the pre-SMA. 6. Activity changes during the preparatory period, which lasted until the occurrence of the trigger signal for the reaching movement, were more frequent in the pre-SMA. 7. Phasic, movement-related activity was more frequent in the SMA, and its onset was often time locked to the movement onset. In the pre-SMA, the occurrences of response time locked to the movement-trigger signal were more frequent than in the SMA. 8. Among neurons in both areas, directional selectivity was found in all the cue, preparatory, and movement-related responses.

Animals↗
PubMed1991

Reorganization of activity in the supplementary motor area associated with motor learning and functional recovery.

The supplementary motor area (SMA) of primates has been implicated in the initiation and execution of limb movements. However, when a motor task was extensively overlearned, few SMA neurons, if any, were active before the movement onset. Subsequent lesions of the primary motor cortex gave rise to the appearance of premovement activity changes, indicating usedependent reorganization of the neuronal activity in SMA.

Animals↗
PubMed1991

Two movement-related foci in the primate cingulate cortex observed in signal-triggered and self-paced forelimb movements.

1. Single-unit activity in the cingulate cortex of the monkey was recorded during the performance of sensorially (visual, auditory, or tactile) triggered or self-paced forelimb key press movements. 2. Microelectrodes were inserted into the broad rostrocaudal expanse of the cingulate cortex, including the upper and lower banks of the cingulate sulcus and the hemispheric medial wall of the cingulate gyrus. 3. A total of 1,042 task-related neurons were examined, the majority of which were related to the execution of the key press movements. In greater than 60% of them, the movement-related activity preceded the activity in the distal flexor muscles. 4. The movement-related neurons were distributed, in two foci, in the posterior and anterior parts of the cingulate cortex, both including the upper and lower banks of the cingulate sulcus. The posterior focus was found to largely overlap the area projecting to the forelimb area of the primary motor cortex by the use of the horseradish peroxidase (HRP) method. 5. About 40% of the cingulate cortical neurons showed equimagnitude responses during the signal-triggered and self-paced movements. The neurons exhibiting a selective or differential response to the self-paced motor task were more frequently observed in the anterior than in the posterior cingulate cortex. 6. The long-lead type of changes in activity, ranging from 500 ms to 2 s, were observed mainly before the self-paced and, much less frequently, before the triggered movements. They were particularly abundant in the anterior cingulate cortex. 7. Only a few of the neurons showed activity time-locked to the onset of the sensory signals. 8. These observations indicate that the anterior and posterior parts of the cingulate cortex are distinct entities participating in the performance of limb movements, even if the movements are simple, such as those in this study.

Animals↗
PubMed1991

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

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.

Animals↗
PubMed1990

Selective coding of motor sequence in the supplementary motor area of the monkey cerebral cortex.

We describe a property of neurons in the supplementary motor area (SMA) of the cerebral cortex of monkey that is different from those in the primary motor area (M1) in relation to execution of a sequential motor task. A group of SMA neurons was active when the animal remembered and pressed three touch-pads in a predetermined sequence but inactive when the same movement was guided by sequentially presented visual signals. This finding indicates that the SMA is involved in the performance of sequential movements on the basis of the information stored inside the brain.

Animals↗
PubMed1990

An output zone of the monkey primary motor cortex specialized for bilateral hand movement.

We have identified a subregion in the monkey primary precentral motor cortex (MI) that is characterized by its relationship to bilateral or ipsilateral hand movements. The subregion is located between the digit and face representation areas. The majority of single cells in this portion of MI exhibit distinct activity before and during visually triggered key-press movements performed by means of ipsilateral or contralateral digit flexion. Intracortical microstimulation evoked responses of ipsilateral, in addition to contralateral, digit muscles.

Animals↗
PubMed1989

Activity of digital area neurons of the primary somatosensory cortex in relation to sensorially triggered and self-initiated digital movements of monkeys.

Single-cell activity was examined in digital areas of the primary somatosensory cortex (SI) of monkeys performing sensorially triggered and self-initiated digital movements with the aim of rigorously determining the relative timing of onset of the neuronal activity with respect to movement onset. The activity of prime mover muscles for execution of a key-press movement was recorded simultaneously with the neuronal activity; movement onset was defined as the onset of muscle activity. Neuronal receptive fields were also identified. The following findings emerged from this study: (1) Few neurons, if any, in the SI(areas 3b, 1, 2), including pyramidal tract neurons, were active prior to movement onset. (2) The movement-related activity of SI neurons was basically similar in cases of signal-triggered and self-initiated movement. (3) No neuron in the SI showed activity associated with ipsilateral digital movement. (4) A majority of movement-related neurons in the precentral motor cortex, in contrast, started their activity before movement onset. These findings suggest that SI neuronal activity participates little in providing information necessary for developing motor responses in the initial phase of simple digital movements.

Afferent Pathways↗
PubMed1989

Changing concepts of motor areas of the cerebral cortex.

Recent development of studies on cerebral cortex of primates provides evidence that there exist multiple motor representation areas in the frontal lobe. By analyzing the activity of single cells in association with performance of a variety of motor behavior, new concepts on the functional role of each area are developing.

Humans↗
PubMed1989

Digit-muscle responses evoked from multiple intracortical foci in monkey precentral motor cortex.

1. The precentral motor cortex, including the anterior bank of the central sulcus of monkey (Macaca fuscata), was systemically penetrated with microelectrodes to determine the spatial organization of the microexcitable cortical elements that can produce responses in digit muscles. 2. At 200-microns intervals on each electrode track, low-current intracortical microstimuli were delivered and the muscle responses evoked from four digit muscles were recorded. The responses, obtained with 5, 8, 15, and 25 microA, were quantified and plotted on a map displaying an unfolded view of the precentral gyrus. 3. For all four muscles studied [first interosseus, thenar, extensor digitorum communis (EDC) and flexor digitorum profundus (FDP)], the effective stimulus points evoking muscle responses at a current of 5 microA were scattered over wide areas. The low-threshold foci, largely buried in the anterior bank of the central sulcus but partly extending to a region rostral to the sulcus, were found in multiple spots separated by a few millimeters. 4. Stimulation of individual sites at a current of 5 microA often evoked responses in several different muscles. Antagonist muscles were frequently coactivated. 5. A three-dimensional display of the distribution of response magnitude evoked from the precentral cortex indicates several peaks for each digit muscle. The peaks were either sharply demarcated from surrounding areas of minimal responses or gradually shifted into regions of low-grade responses. 6. Taken together, the data suggest that the digit area of motor cortex does not have a simple organization in which each muscle is represented by a single focus. Rather, each muscle has multiple foci that have varying degrees of efficacy in producing responses and with variable overlap onto foci of other muscles.

Animals↗