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101.
102.
Rapid eye movements (REMs), EEG alpha, and tonic heart rate (HR) were measured during 6 types of cognitive tasks—imagining a liked person, suppressing thoughts of the person, searching one's mind for alternative solutions, arithmetic involving little concentration, problems involving high concentration, and choosing a preferred activity. The latter 3 required verbalization, the former 3 did not. Only suppression and search did not differ significantly from each other on at least one physiological variable. Imagining, suppression, and search yielded few REMs, high alpha, and low HR. High concentration yielded many REMs, low alpha, and high HR. Choice yielded many REMs, low alpha, and intermediate HR. Low concentration yielded few REMs, low alpha, and high HR. Suppression produced somewhat less alpha than imagining but did not differ significantly in REMs. 相似文献
103.
K. Sasaki H. Gemba 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1986,64(3):603-606
Summary Monkeys were trained to perform hand movements in a reaction time task with discrimination between positive (go) and negative
(no-go) light signals, and field potentials in various cortical areas were recorded and analysed with chronically implanted
cortical electrodes. As previously reported, areas such as the prefrontal, premotor and motor cortices were active in association
with simple visually-initiated, reaction-time hand movements. The caudal part of the dorsal bank of the principal sulcus was
found to be activated specifically on no-go trials during discrimination, and revealed a relatively sharp surface-negative,
depth-positive potential. The potential appeared at a latency of 110–150 ms, which was 150–210 ms earlier than the movement
onset on go trials. With reversal of the go and no-go signals, this potential was found to be recorded only on no-go trials,
irrespective of the colour used for the stimulus. It is suggested that the activity in the dorsal bank of the principal sulcus
is related to the judgement not to execute the movement and/or the suppression of motor execution. 相似文献
104.
Dr. H. Gemba K. Sasaki 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1984,55(1):26-32
Summary A monkey was trained to lift a lever by wrist extension in response to a light stimulus. During the learning process of the task over several months, field potentials related not only to the task performance but also to substitution and stimulation experiments were recorded with chronically implanted electrodes on the surface and at a depth of 2.5–3.0 mm in the prefrontal, premotor, motor and prestriate cortices. In the substitution experiment, an examiner lifted a lever for the monkey so that it was watching the light and rewarded without the hand movement. In the stimulation experiment, the same light stimulus was simply delivered to the monkey. In a naive monkey which lifted the lever independently of the stimulus, stimulus-locked potentials were evoked by the task experiment in those cortices except the motor cortex, but none was elicited by the substitution or stimulation experiment. In a welltrained monkey, the substitution and stimulation experiments induced almost the same potentials as those prior to the task movement in respective cortices except the motor cortex, in which the component of cerebellar-induced premovement potential was not observed during the substitution and stimulation experiments. At an intermediate stage of learning, the situation was intermediate between the naive and well-trained stages and most premovement potentials except those in the motor cortex were elicited by the substitution experiment in reduced sizes, but nothing by the stimulation experiment.The present study suggests that the neuronal circuits for the operantly conditioned movement are functionally organized and gradually consolidated in the learning process, and that the consolidation is made earlier for the circuit involving association and premotor cortices than the circuit including the motor cortex in the process. The circuit to the motor cortex via the cerebro-cerebellar interconnection is recruited only on the execution of movement. 相似文献
105.
Kazutoshi Kudo T. Ohtsuki 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,122(1):23-30
Subjects made a fast elbow extension movement to designated target in response to a go signal. In 45% of trials a stop signal
was presented after the go signal, to which subjects were asked to stop the movement as rapidly as possible. The interstimulus
interval (ISI), or time interval between the go and stop signals, was randomly varied between 0 and 200 ms. Electromyographic
(EMG) activity was recorded from biceps brachii and triceps brachii. Subjects could sometimes completely inhibit initiation
of the movements when the ISI was 0 ms, but could rarely do so when the ISI exceeded 100 ms. For responses that were initiated
but stopped on the way, the amplitude of the movement decreased linearly as the time interval (=modification time) from the
stop signal to EMG onset increased. The peak velocity increased linearly as the movement amplitude increased. This tendency
was similar to those previously reported in step-tracking movements with various amplitudes. In spite of the similarity in
the kinematics of the movement, the EMG pattern was different from that of step-tracking movement. While the initial agonist
burst (AG1) decreased linearly after the modification time exceeded 100 ms, the antagonist burst (ANT) increased compared
with the go trial for the modification time from 0 to 200 ms and decreased after the modification time exceeded 300 ms. This
change of activation is analogous to functional modification of middle-latency reflex EMG response to load, or cutaneous perturbation.
In conclusion, it is suggested that adaptive mechanisms, which would functionally modify the reflex responses, are also continuously
working during voluntary movements in response to sudden changes in environmental information.
Received: 3 November 1997 / Accepted: 3 February 1998 相似文献
106.
The behavioral and neurochemical effects of striatal DA depletions were investigated in rats lesioned as weanlings (Day 27) or as adults (250-300 g). Administration of 6-OHDA into the medial forebrain bundle resulted in comparably large (> or = 95%) depletions of tissue levels of DA in both age groups. As expected, rats depleted of DA as adults exhibited marked deficits in motoric behavior and body weight regulation that persisted for the 8 days of postsurgical observation. In contrast, rats depleted of DA as weanlings were spared from such deficits, and their behavior closely resembled that of age-matched controls. Microdialysis studies revealed dialysate levels of striatal DA that paralleled these age-dependent behavioral differences. At a time when age-related behavioral differences were still quite pronounced (5-6 days postsurgery), basal DA levels were reduced by 80% of control values in rats lesioned as adults whereas basal DA levels in rats lesioned as weanlings were unchanged relative to their controls. Finally, adults depleted of striatal DA as weanlings were no more sensitive to the movement-impairing effects of intrastriatal sulpiride (3.0 or 10.0 micrograms/hemisphere) infusions than were control rats. These data suggest that weanlings compensate for large, but incomplete, denervation of striatal DA with markedly enhanced release and turnover from residual terminals. This developmental plasticity may prevent the occurrence of behavioral deficits soon after the lesion and also the supersensitivity to the challenging effects of DA antagonists as animals grow into adulthood. 相似文献
107.
Kobayashi M Masuda Y Fujimoto Y Matsuya T Yamamura K Yamada Y Maeda N Morimoto T 《Physiology & behavior》2002,75(3):377-385
Although rhythmic jaw movement in feeding has been studied in mammals, such as rats, rabbits and monkeys, the cellular and molecular mechanisms underlying it are not well understood. Transgenic and gene-targeting technologies enable direct control of the genetic makeup of the mouse, and have led to the development of a new category of reagents that have the potential to elucidate the cellular and molecular mechanisms of neural networks. The present study attempts to characterize rhythmic jaw movements in the mouse and to demonstrate its relevance to rhythmic jaw movements found in higher mammals using newly developed jaw-tracking systems and electromyograms of the masticatory muscles. The masticatory sequence of the mouse during feeding was classified into two stages, incision and chewing. Small and rapid (8 Hz) open-close jaw movements were observed during incision, while large and slow (5 Hz) open-close jaw movements were observed during chewing. Integrated electromyograms of the masseteric and digastric muscles were larger during chewing than those observed during incision. Licking behavior was associated with regular (8 Hz), small open-close jaw movements with smaller masseteric activity than those observed during mastication. Grooming showed variable patterns of jaw movement and electromyograms depending on the grooming site. These results suggest that there are neuronal mechanisms producing different frequencies of rhythmic jaw movements in the mouse, and we conclude that the mouse is useful for understanding rhythmic jaw movements in higher mammals. 相似文献
108.
MacDougall HG Brizuela AE Curthoys IS 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2003,148(2):166-175
Recent studies have shown that, although responses to long-duration, constant-current surface galvanic vestibular stimulation
(GVS) show substantial interindividual variability, individual subjects show a reliable, repeatable, idiosyncratic oculomotor
response pattern to GVS. It follows that GVS may be a more reliable stimulus than may have been anticipated from the literature.
The aim of the present study was to examine the metrics of 3D eye-movement responses to maintained (120 s), unilateral and
bilateral surface GVS. Eye movements were measured using computerised video-oculography. Two experiments were conducted: Experiment
1 examined whether the normal response is linear over increasing levels of current; and Experiment 2 examined (1) whether
the normal response to surface GVS is symmetrical when comparing stimulated sides, (2) whether the normal response to surface
GVS is symmetrical when the polarity of the stimulating current was reversed, and (3) whether there is additivity in the normal
response to combinations of unilateral/bilateral surface GVS. Five subjects participated in Experiment 1 and eight subjects
participated in Experiment 2. In both experiments, the onset of stimulation produced characteristic eye-movement responses:
changes in torsional position with the upper pole of both eyes rolling towards the anode and away from the cathode; together
with horizontal and torsional nystagmus with slow phases towards the anode and away from the cathode; and negligible vertical
nystagmus. These responses reversed direction at stimulus offset. In the fixation condition of Experiment 1, the magnitude
of ocular torsional position (OTP) and torsional nystagmus responses showed a linear relationship over conditions of increasing
current strength, as did OTP, torsional and horizontal nystagmus responses in darkness. The results of Experiment 2 showed
that responses to unilateral stimulation are symmetrical between stimulated sides, symmetrical between stimulating polarities,
and additive (with respect to responses to bilateral stimulation). The principles derived from these findings, as well as
those of recent studies, provide a foundation for future work investigating eye-movement responses to surface GVS in patients
with known types of vestibular dysfunction.
Electronic Publication 相似文献
109.
Hisashi Aoki Reiko Tsukahara Kyonosuke Yabe 《European journal of applied physiology》1989,58(4):426-432
Summary The effects of pre-motion silent period (PSP) on dynamic force exertion were studied in ten healthy subjects performing ballistic elbow extensions. The experiments were designed to evaluate the significance of mean differences between the averaged dynamic force curves of two groups: PSP-presence groups and PSP-absence groups. The presence of PSP was judged quantitatively and automatically by means of a newly developed method using statistical analysis. The results indicated that there were two effects of PSP on dynamic force exertion: one was a reducing effect, observed prior to the movement; the other was a reinforcing effect, observed in the first part of the ballistic movement. The duration of the reinforcement was significantly correlated with the duration of the reducing effect of PSP. The findings suggested that the reinforcement of dynamic force may be produced by the pre-stretch of agonistic muscles caused by prior force reduction due to PSP occurrence. The fact that PSP plays an important role in dynamic force exertion suggests that PSP may be incorporated in the central motor control system designed to interrupt the background activity, to stretch the agonist and to reinforce the dynamic force. 相似文献
110.
Knox PC Davidson JH Anderson D 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2005,165(1):1-7
Quantitative analysis of eye movements is a useful tool for examining the behavioural effects of ageing. Although the effect of ageing on saccadic eye movement has been examined in some detail, the effect of ageing on a second class of eye movement, smooth pursuit (SP), has received less attention. We examined the initiation of SP in a group of fifteen healthy older people (mean age 72 years) and compared their performance with that of ten young controls (mean age 21 years). Although their performance was qualitatively similar, pursuit latency was increased in the older group. Investigation of the gap effect on pursuit revealed that, while the gap effect was present in the older group, it seemed to be directionally asymmetrical. When the longer absolute latencies were taken into account, although the gap effect in the two groups was identical for leftward tasks, for rightward tasks it was reduced in the older group, although this did not reach statistical significance. The difference between the old and young groups was driven by some of the older subjects. At the longest gap duration employed (400 ms), while there was a clear gap effect for leftward tasks in these subjects, there was no reduction in latency, or increases in latency, for rightward tasks. This asymmetry was not related to chronological age within the older group. These results suggest an age-related alteration in SP initiation that is more complex than general slowing of information processing in ageing. They may be indicative of additional ageing effects specific to the oculomotor or closely related systems. 相似文献