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Aging and qualitative characteristics of memories for perceived and imagined complex events.

Older and younger adults' memory for perceived and imagined events was examined with a procedure in which everyday situations are simulated in the laboratory. Subjects perceived some situations and imagined others. Later, they were asked to rate their memory for various aspects of these situations (e.g., amount of perceptual detail, thoughts and feelings). A recall test followed the ratings. On the rating scale, for both perceived and imagined events, older subjects reported better memory for their thoughts and feelings than did younger subjects. In addition, on the recall test, older subjects produced more thoughts and feelings than did younger subjects, whereas younger subjects produced more perceptual and spatial information. These results suggest that older subjects may not inhibit personal information (e.g., thoughts and feelings), and this information may interfere with memory for other aspects of information, such as perceptual and contextual details (Hasher & Zacks, 1988).

Adolescent↗

Explanation, imagination, and confidence in judgment.

This article concerns a class of experimental manipulations that require people to generate explanations or imagine scenarios. A review of studies using such manipulations indicates that people who explain or imagine a possibility then express greater confidence in the truth of that possibility. It is argued that this effect results from the approach people take in the explanation or imagination task: They temporarily assume that the hypothesis is true and assess how plausibly it can account for the relevant evidence. From this view, any task that requires that a hypothesis be treated as if it were true is sufficient to increase confidence in the truth of that hypothesis. Such tasks cause increased confidence in the hypothesis at the expense of viable alternatives because of changes in problem representation, evidence evaluation, and information search that take place when the hypothesis is temporarily treated as if it were true.

Decision Making↗

Pushing the limits of imagination: mental practice for learning sequences.

In 2 experiments, the efficacy of motor imagery for learning to type number sequences was examined. Adults practiced typing 4-digit numbers. Then, during subsequent training, they either typed in the same or a different location, imagined typing, merely looked at each number, or performed an irrelevant task. Repetition priming (faster responses for old relative to new numbers) was observed on an immediate test and after a 3-month delay for participants who imagined typing. Improvement across the delay in typing old and new numbers was found for the imagined and actual typing conditions but not for the other conditions. The findings suggest that imagery can be used to acquire and retain representations of sequences and to improve general typing skill.

Humans↗

The activation pattern in normal humans during suppression, imagination and performance of saccadic eye movements.

The distribution of activated cerebral regions was examined in nine normal subjects during four different eye movement-related conditions: (1) fixation-fixation on a central light emitting diode; (2) saccadic suppression-fixation on a diode in the presence of flashing lateral targets; (3) reflexive/volitional saccades-performance of overt eye movements to two laterally lit targets and back to the centre; and (4) imagined saccades-imagining, but not performing, the same eye movements. The regional neural activity was measured indirectly using repetitive bolus injections of oxygen-15-labelled water and positron emission tomography (PET) to yield time-integrated images of the normalized count distribution. These were aligned and anatomically normalized to a standard stereotactic space and the averages of each condition were analysed categorically using statistical parametric mapping. Compared to central fixation, reflexive/volitional saccades significantly activated regions in the classically known cortical oculomotor regions. The most notable activation during the saccade suppression task, compared to central fixation alone, was a bilateral activation of the parietal cortex with a right-sided preponderance, activation of the supplementary eye field/caudal cingulate regions, and activation of frontal regions close to the frontal eye fields. Imagined performance of eye movements without overt eye movements activated the supplementary eye field and frontal eye fields identically to regions involved in overt eye movements, thus demonstrating that over eye movements are not a prerequisite of the activation of these regions in normal humans.

Adult↗

Indexing the experience of sex change in hypnosis and imagination.

The authors suggested a change of sex to high hypnotizable participants in hypnosis and imagination conditions and indexed the subjects' experiences with a continuous, concurrent behavioral measure that involved them turning a dial to indicate changes in the strength of the suggested effect. In addition, the researchers indexed the participants' experiences through retrospective ratings of realness, involuntariness, and active thinking. The dial rating showed that the onset of the experience was more rapid for hypnotic than for imagination participants. Moreover, there were differences in the relationship between dial ratings and retrospective ratings across the conditions as well as across the suggestion, test, and cancellation phases of the item. The findings are discussed in terms of how the dial method provides a better understanding of suggested sex change as well as a better understanding of the private experience of hypnosis and imagination.

Adult↗

A study of the impact of a simple stimulus on a receiver's imagination in mediated communication.

Mediated communication involves a form of intimate partnership where, as in the case of face-to-face intimate relationships, parties have a strong desire to exchange emotion and ensure a connection by way of receiving and responding to personal messages. So, in mediated communication, although partners have an effective means of conveying a connection, they still are in need of an equally effective means of conveying emotional state; they need a so-called "emotion-related channel." A desire to develop an efficient means of conveying emotion in mediated communication has driven this study. A study was carried out to determine the effects of a simple stimulus on one's imagination when subjects considered the simple stimulus to be a message from an intimate partner. Twenty-one subjects were first subjected to a simple pattern stimulus. They then experienced the same stimulus as a message received from an intimate partner in mediated communication. They subsequently answered questionnaires on their impressions of the stimulus, the emotional states of their imagined partners, and their own emotional states. A statistical analysis was then carried out. From a close examination of the findings, some interesting points were discovered. One important finding is that from the simple stimulus, subjects were able to imagine not only an intimate partner but also the emotional state of that partner. This and other findings lend support to the notion that a simple stimulus could serve as an emotion-related channel, in mediated communication.

Adult↗

Partially overlapping neural networks for real and imagined hand movements.

Neuroimagery findings have shown similar cerebral networks associated with imagination and execution of a movement. On the other hand, neuropsychological studies of parietal-lesioned patients suggest that these networks may be at least partly distinct. In the present study, normal subjects were asked to either imagine or execute auditory-cued hand movements. Compared with rest, imagination and execution showed overlapping networks, including bilateral premotor and parietal areas, basal ganglia and cerebellum. However, direct comparison between the two experimental conditions showed that specific cortico-subcortical areas were more engaged in mental simulation, including bilateral premotor, prefrontal, supplementary motor and left posterior parietal areas, and the caudate nuclei. These results suggest that a specific neuronal substrate is involved in the processing of hand motor representations.

Adult↗

Effects of perceived and imagined odors on taste detection.

We assessed the influence of different odors on detection of a sweet tastant, and the ability of imagined odors to elicit the same effects as perceived odors on taste perception. The tastant used was sucrose, and the two odorants were strawberry and ham. In the first experiment, participants either smelled or imagined one of two odors during taste detection tasks (between-subject design), whereas in the second one, subjects completed both the odor imagery and perception conditions with taste detection tasks (within-subject design). The effect was odorant-specific: detection of sucrose was significantly better when subjects smelled strawberry than when they smelled ham. Furthermore, imagined odors influenced taste perception in the same way as did perceived odors. We concluded that the odor-specific effect on taste perception is an authentic perceptual phenomenon. Our results also support the notion that odor-induced changes in taste perception are mediated centrally. Finally, our findings are in agreement with reports supporting the existence of odor imagery.

Adolescent↗

Adult age differences in memory for imagined and performed actions.

Young and older adults were presented a list of 24 descriptions of simple actions. For each list item, subjects were either instructed to perform the action or else were instructed to imagine themselves performing the action. On a surprise recall test, age differences were found for both performed and imagined actions as well as for source judgments (remembering which actions had been performed and which imagined). The latter effect, however, resulted from the near chance level of performance of a minority of the older adults; the performance of the majority of the older adults overlapped with that of the young adults on the source judgment task.

Adolescent↗

Imagining rotation by endogenous versus exogenous forces: distinct neural mechanisms.

Previous neuroimaging studies of mental image transformations have sometimes implicated motor processes and sometimes not. In this study, prior to neuroimaging the subjects either viewed an electric motor rotating an angular object, or they rotated the object manually. Following this, they performed the identical mental rotation task in which they compared members of pairs of such figures, but were asked to imagine the figures rotating as they had just seen the model rotate. When results from the two rotation conditions were directly compared, motor cortex (including area M1) was found to be activated only when subjects imagined the rotations as a consequence of manual activity. Thus, there are at least two, qualitatively distinct, ways to imagine objects rotating in images, and these different strategies can be adopted voluntarily.

Adolescent↗

Exploring imagined movements in patients with schizophrenia.

Patients with schizophrenia demonstrate impairments indicative of an inability to accurately monitor internally generated images. Motor imagery measures the ability to generate internal images of intended but not executed motor movements. Ten patients with schizophrenia completed actual and imagined versions of a pointing task with a well defined speed-accuracy trade-off function. For controls, movement time increases as target size decreases for both actual and imagined movements. Despite showing the expected speed-accuracy trade-off for actual movements, the imagined movements of schizophrenics showed no reliable relationship to target size. This was true for each patient and appeared to be independent of symptom profile. These results suggest that patients with schizophrenia are unable to generate accurate internal images of their own motor movements.

Adult↗

Both actual and imagined locomotion suppress spontaneous vestibular nystagmus.

Acute unilateral vestibulopathy is characterized by a combination of signs and symptoms including spontaneous nystagmus, postural imbalance and gait disturbance. A functional link between these vestibulo-ocular and vestibulo-spinal motor responses has been demonstrated. These responses use common vestibular input and partially overlapping neuronal networks, but it is not known if and to what extent they are linked or operate separately. We found that slow phase velocity of spontaneous vestibular nystagmus in patients with acute vestibulopathy was suppressed by 26% during actual walking (ANOVA p< 0.02, = 6). It was also suppressed by imagined locomotion: by 26% during the imagination of walking and by 42% during the imagination of running ( p< 0.003, = 10). The suppression of vestibular nystagmus might be beneficial for patients, for it alleviates the disturbing impression of movement of the visual scene (oscillopsia) caused by involuntary eye movements.

Adult↗

Linear classification of low-resolution EEG patterns produced by imagined hand movements.

Electroencephalograph (EEG)-based brain-computer interfaces (BCI's) require on-line detection of mental states from spontaneous EEG signals. In this framework, surface Laplacian (SL) transformation of EEG signals has proved to improve the recognition scores of imagined motor activity. The results we obtained in the first year of an European project named adaptive brain interfaces (ABI) suggest that: 1) the detection of mental imagined activity can be obtained by using the signal space projection (SSP) method as a classifier and 2) a particular type of electrodes can be used in such a BCI device, reconciling the benefits of SL waveforms and the need for the use of few electrodes. Recognition of mental activity was attempted on both raw and SL-transformed EEG data from five healthy people performing two mental tasks, namely imagined right and left hand movements.

Adult↗

Interviewing children with the cognitive interview: assessing the reliability of statements based on observed and imagined events.

This paper investigated whether criteria stemming from the Reality Monitoring (RM) framework could be trusted to assess the reliability of statements obtained by the use of a cognitive interview (CI). Fifty-eight children, aged 10-11, participated. One-third watched a film about a fakir and were then interviewed according to a CI (n= 19). The remaining two-thirds made up a story about a fakir and were then interviewed according to either a CI (n= 21), or a structured interview (SI) (n= 18). The CI statements based on observed events contained more visual, affective, spatial and temporal information compared to CI statements based on imagined events. The CI statements based on imagined events did not differ from the SI statements based on imagined events. Considerable developmental work is recommended to turn the RM technique to a reliable test that could be used by practitioners.

Adult↗

Imagination in practice.

Current focus in the health care ethics literature on the character of the practitioner has a reputable pedigree. Rather than offer a staple diet of Aristotelian ethics in the undergraduate curricula, perhaps instead one should follow Murdoch's suggestion and help the practitioner to develop vision and moral imagination, because this has a practical rather than a theoretical aim. The imaginative capacity of the practitioner plays an important part in both the quality of the nurse's role enactment and the moral strategies which the nurse uses. It also plays a central part in the practitioner's ability to communicate with a patient and in the type of person which the practitioner becomes. Can the moral imagination be stimulated and nurtured? Some philosophers and literary critics argue that not only is this possible, but that literature is the means of doing so. If this is the case then a place should be made for literature in already crowded health care curricula.

Dehumanization↗

Brain activation by central command during actual and imagined handgrip under hypnosis.

The purpose was to compare patterns of brain activation during imagined handgrip exercise and identify cerebral cortical structures participating in "central" cardiovascular regulation. Subjects screened for hypnotizability, five with higher (HH) and four with lower hypnotizability (LH) scores, were tested under two conditions involving 3 min of 1) static handgrip exercise (HG) at 30% of maximal voluntary contraction (MVC) and 2) imagined HG (I-HG) at 30% MVC. Force (kg), forearm integrated electromyography, rating of perceived exertion, heart rate (HR), mean blood pressure (MBP), and differences in regional cerebral blood flow distributions were compared using an ANOVA. During HG, both groups showed similar increases in HR (+13 +/- 5 beats/min) and MBP (+17 +/- 3 mmHg) after 3 min. However, during I-HG, only the HH group showed increases in HR (+10 +/- 2 beats/min; P < 0.05) and MBP (+12 +/- 2 mmHg; P < 0.05). There were no significant increases or differences in force or integrated electromyographic activity between groups during I-HG. The rating of perceived exertion was significantly increased for the HH group during I-HG, but not for the LH group. In comparison of regional cerebral blood flow, the LH showed significantly lower activity in the anterior cingulate (-6 +/- 2%) and insular cortexes (-9 +/- 4%) during I-HG. These findings suggest that cardiovascular responses elicited during imagined exercise involve central activation of insular and anterior cingulate cortexes, independent of muscle afferent feedback; these structures appear to have key roles in the central modulation of cardiovascular responses.

Blood Pressure↗

Strength increases from the motor program: comparison of training with maximal voluntary and imagined muscle contractions.

1. This study addressed potential neural mechanisms of the strength increase that occur before muscle hypertrophy. In particular we examined whether such strength increases may result from training-induced changes in voluntary motor programs. We compared the maximal voluntary force production after a training program of repetitive maximal isometric muscle contractions with force output after a training program that did not involve repetitive activation of muscle; that is, after mental training. 2. Subjects trained their left hypothenar muscles for 4 wk, five sessions per week. One group produced repeated maximal isometric contractions of the abductor muscles of the fifth digit's metacarpophalangeal joint. A second group imagined producing these same, effortful isometric contractions. A third group did not train their fifth digit. Maximal abduction force, flexion/extension force and electrically evoked twitch force (abduction) of the fifth digit were measured along with maximal integrated electromyograms (EMG) of the hypothenar muscles from both hands before and after training. 3. Average abduction force of the left fifth digit increased 22% for the Imagining group and 30% for the Contraction group. The mean increase for the Control group was 3.7%. 4. The maximal abduction force of the right (untrained) fifth digit increased significantly in both the Imagining and Contraction groups after training (10 and 14%, respectively), but not in the Control group (2.3%). These results are consistent with previous studies of training effects on contralateral limbs. 5. The abduction twitch force evoked by supramaximal electrical stimulations of the ulnar nerve was unchanged in all three groups after training, consistent with an absence of muscle hypertrophy. The maximal force of the left great toe extensors for individual subjects remained unchanged after training, which argues against strength increases due to general increases in effort level. 6. Increases in abduction and flexion forces of the fifth digit were poorly correlated in subjects of both training groups. The fifth finger abduction force and the hypothenar integrated EMG increases were not well correlated in these subjects either. Together these results indicate that training-induced changes of synergist and antagonist muscle activation patterns may have contributed to force increases in some of the subjects. 7. Strength increases can be achieved without repeated muscle activation. These force gains appear to result from practice effects on central motor programming/planning. The results of these experiments add to existing evidence for the neural origin of strength increases that occur before muscle hypertrophy.

Adult↗

Personality, imaginative involvement, and self-reported somatic complaints: relevance to the concept of alexithymia.

Forty-five undergraduate students were investigated to determine the relationship between personality dispositions, capacity for imaginative involvement, and self-reported physical symptoms. The results showed that somatic complaints were associated with variables reflecting psychological vulnerability and dysphoric affect (e.g. anxiety and worry/depression). Imaginative involvement, and especially the Absorption Scale, correlated positively with self-reported somatic symptoms. Factor analyses revealed that Absorption Scale and the Creative Imagination Scale loaded on a general psychological distress factor. Moreover, self-reported somatic symptoms correlated negatively with 'inner directedness' and 'sociable' coping style, and positively with the coping styles 'sensitive' and 'inhibited', thus suggesting a link between emotional expressiveness and somatic complaints. The relevance of these results to the concept of alexithymia is discussed.

Adult↗