1,720,963 research outputs found
Hypnotizability-dependent accuracy in the reproduction of haptically explored paths.
No full textThe study assessed differences between highly (Highs) and low hypnotizable (Lows) subjects in the blindfolded reproduction of paths connected at acute or obtuse angles. Reproduction attempts were made after path exploration performed by one finger, with or without concomitant cognitive activities (mental computation or imagery of exploring an angle larger than the explored one). The variables analyzed were: subjective experience (scores of the exploring effort, reproduction difficulty, perceived accuracy of reproduction, attention to mental computation and efficacy of imagery), exploration time, relative error in reproduction (under or overestimation) and the percentage of "successful" trials (absolute error <10°). The results showed that the subjective experience of exploration/reproduction and the exploration times are similar in Highs and Lows and that all subjects underestimate the explored angles and reproduce the acute angle more accurately than the obtuse one. Exploration of the acute angle concomitant with imagery of a larger one reduced its underestimation in both groups. Highs exhibited a larger number of successful trials after exploration of the obtuse angle, while Lows (males) decreased their relative error in the reproduction of the acute angle. In conclusion, in the more demanding condition of reproducing an obtuse angle, the Highs' reproduction was more accurate and more independent of cognitive load than that of the Lows
Postural effects of imagined leg pain as a function of hypnotizability.
No full textIt has been shown that, in subjects with high hypnotizability (Highs), imagined somatosensory stimulation can involuntarily activate the neural circuits involved in the modulation of reflex action. In this vein, aim of the study was to investigate whether the imagery of nociceptive stimulation in one leg may produce both subjective experience of pain and congruent postural adjustments during normal upright stance. The displacement of the centre of pressure (CoP) was studied during imagery of leg pain (LP) and during the control conditions of imagery of tactile stimulation of the same leg and of throat pain (TP) in 12 Highs and 12 low hypnotizable subjects (Lows). The results showed that the vividness of imagery was higher in Highs than in Lows for all tasks and that only Highs reported actually feeling pain during LP and TP. Congruently, during LP only Highs displaced their CoP towards the leg opposite to the one that was the object of painful imagery and increased their CoP mean velocity and area of excursion. Since the Highs' postural changes were not accounted for only by vividness of imagery and perceived pain intensity, high hypnotizability is apparently responsible for part of the postural effects of pain imagery
Offline consolidation of spatial memory: Do the cerebellar output circuits play a role? A study utilizing a Morris water maze protocol in male Wistar rats
Full text linkTo address whether the cerebellum takes part to spatial memory consolidation related to navigation, male Wistar rats were trained daily (4 days), in a Morris water maze to found a submerged escape platform by use of distal cues (place training test). Retention of the allocentric map was evaluated in the probe test (without platform), before the place test. Bilateral shutdown of deep cerebellar nuclei was carried by infusion of the GABA-A agonist muscimol (0.25 μl at 1 μg/μl) immediately after each place test. Histology revealed a dorsal dentate nucleus (DDN) group, with muscimol diffusion confined to dentate nuclei, and a ventromedial/dentate nuclei (VMDN) group, with muscimol additionally involving fastigial, interpositus and vestibular nuclei. In the place test, Vehicle, DDN and VMDN groups reduced latency and distance to the platform over the 4 days and within the single day, indicative of efficient acquisition and working memory; navigational trajectories however differed in that, while Vehicle and DDN groups evolved to use direct paths, VMDN group indulged to navigate in proximity to the platform, suggesting an impairment in refining the spatial map. In the probe test VMDN, unlike Vehicle and DDN animals, failed to develop a preference for the quadrant where the platform was previously located, indicating a consolidation deficit. In conclusion, ventromedial cerebellar related structures may contribute to the process of consolidation of an allocentric spatial memory: their inactivation may have impaired the offline integration of idiothetic information with allothetic signals within the navigational network, leading to a coarse resolution map. © 2019 Elsevier B.V
Hypnotizability- related effects of vestibular impairment on posture and locomotion
No full textBody sway and locomotion are differentially modulated in high (highs) and low (lows) hypnotizable subjects undergoing alteration of visual and neck/leg proprioceptive inputs. The study's aim was to investigate whether partial impairment of vestibular information due to backward head extension affects postural (Study 1) and locomotor behavior (Study 2) differentially in highs and lows. Results showed that, at variance with the visual and proprioceptive modalities, vestibular inactivation did not induce major differences between the 2 groups, with the exception of improvement in walking straight across consecutive trials, which was observed only in highs. The article presents an overview of the structures and mechanisms possibly involved in the observed hypnotizability-related differences in motor control and suggests that hypnotic susceptibility might be a relevant factor in neuro-rehabilitative treatments because it accounts for part of the variability in the sensorimotor self
Body sway modulation by hypnotisability and gender during low and high demanding postural conditions.
No full textThe cognitive trait of hypnotisability, associated with the proneness to accept suggestions, exhibits several physiological correlates including the modulation of sensorimotor integration and, in particular, of postural control. In this respect, we have shown that, at eyes closure, healthy subjects with high hypnotisability scores (highs) having their feet 2 cm apart show larger and faster body sway with respect to low hypnotizable individuals (lows). The aim of the present study was to investigate whether hypnotisability modulates body sway during slightly more demanding and very difficult postural conditions such as feet together bipedal posture and one legged stance, respectively. Stabilometric variables were studied: the body Centre of Pressure (CoP) Area and mean Velocity, the CoP mean position (Xmean, Ymean) and its variability (SDx, SDy) in the frontal and sagittal planes were acquired in 18 highs (9 females) and 18 lows (9 females). Results showed that the previously observed lows’ smaller and slower body sway was not present any longer. Nonetheless, hypnotisability interacted with gender in the modulation of the variability of the CoP movement in the frontal plane during both the bipedal, feet together posture and one legged stance, as significant gender differences were observed only among lows. In conclusion, results confirm a role of hypnotisability in sensorimotor integration and support the relevance of hypnotic assessment in clinical settings, as hypnotisability may be responsible for part of the postural variability
Is high hypnotizability a trouble in balance control?
No full textHypnotizability is a cognitive trait measured by
standard scales and associated with peculiar physiological
responses to cognitive and physical stimulations. Hypnotizability-
related diVerences can also be observed in nonhypnotic
state and in the absence of speciWc suggestions. In the
normal bipedal stance subjects with high hypnotizability
(Highs) exhibit a higher tolerance of alteration of the visual
and leg/neck proprioceptive input with respect to low hypnotizable
individuals (Lows). Aim of the study was to investigate
whether this characteristic represents a disadvantage
during highly demanding postural tasks. Sixteen Highs and 16
Lows of both genders participated in an experimental session
consisting of maintaining balance while standing with
open or closed eyes on a seesaw platform allowing roll
movements. The results did not show signiWcant diVerences
between Highs and Lows in inclination area and time, with
the exception of a greater ability of Highs with respect to
Lows when they began the task displacing the body weight
from the left to the right leg. Thus, high hypnotizability
does not represent a disadvantage for balance control during
highly demanding postural tasks. Together with previous
studies, the present Wndings suggest that the Highs’ postural
control might shift from a very “economic”, preeminently
centrally driven functioning mode, characteristic of easy
postural tasks, to an eYcaciously periphery-controlled
mode, required by diYcult postural tasks
Hypnotizability and sensorimotorintegration: An Italian Space Agency Project
No full textIn highly hypnotizable individuals (highs), postural control is more independent of sensory information than in low hypnotizable subjects (lows). The aim of the study was to find out whether locomotion is also less affected in highs than in lows by visual suppression and changes in the neck proprioceptive input. Eighteen highs and 20 lows were asked to walk straight ahead, blindfolded, in basal conditions (face forward), during real and imagined right/left head rotation and mental computation. Highs detected deviations from the straight trajectory better than lows. Their walking direction was more straight during basal conditions and less influenced than the lows' one by mental computation and real/imagined rotation of the head. The results confirm highs' lower dependence on sensory inputs, although this cannot be definitely attributed to a better internal representation of space or to higher behavioral automaticity
Preliminary evidence on the role of vestibolo- and neo-cerebellar circuits in the consolidation of spatial memory related to navigation.
No full textTo evaluate if the cerebellum takes part in the process of consolidation of the memory traces related to navigation, we tested in a Morris water maze two groups of male rats, chronically implanted for injection into the cerebellar nuclei of saline or muscimol (MU), a GABAA agonist with a transient inhibitory action. During the acquisition phase (Place test) animals were trained to find a submerged escape
platform by the use of distal cues in a protocol of 8 trials/day (2 blocks of 4 trials) for 5 days, and injected immediately after. A Probe test was applied before Place test; the time spent in the area where the platform was previously located is an index of consolidation.Based on histology, MU-treated animals were sorted in: (a) dorsal dentate group (DDN) and (b) ventromedial dentate group (VMDN), in which the injected drug reached also the vestibular nuclei. In the place test, the VMDN showed versus controls (C), longer latencies in reaching the platform in the first block of each day, indicating a less efficient retention. In the probe test, C and DDN showed a gradual increase of time spent in reference quadrant up to values around 40% at day 4 while the VMDN remained around the value of 25 %, regarded as casual distribution. Results seem to exclude a role of the cerebellum trough the dentate nucleus in the process of spatial memory consolidation, at least at the time span of our protocol, and suggest that such a role could be exerted trough the vestibular system
Hypnotizability and sensorimotor integration: veering in locomotion
No full textIn highly hypnotizable individuals (highs), postural control is more independent of sensory information than in low hypnotizable subjects (lows). The aim of the study was to find out whether locomotion is also less affected in highs than in lows by visual suppression and changes in the neck proprioceptive input. Eighteen highs and 20 lows were asked to walk straight ahead, blindfolded, in basal conditions (face forward), during real and imagined right/left head rotation and mental computation. Highs detected deviations from the straight trajectory better than lows. Their walking direction was more straight during basal conditions and less influenced than the lows' one by mental computation and real/imagined rotation of the head. The results confirm highs' lower dependence on sensory inputs, although this cannot be definitely attributed to a better internal representation of space or to higher behavioral automaticity. Copyright © International Journal of Clinical and Experimental Hypnosis. Copyright © International Journal of Clinical and Experimental Hypnosis
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