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J Glicksohn

Publications and source records attributed to J Glicksohn.

13 recordsLinked to original sources
PubMed2001

Temporal cognition and the phenomenology of time: a multiplicative function for apparent duration.

The literature on time perception is discussed. This is done with reference both to the "cognitive-timer" model for time estimation and to the subjective experience of apparent duration. Three assumptions underlying the model are scrutinized. I stress the strong interplay among attention, arousal, and time perception, which is at the base of the cognitive-timer model. It is suggested that a multiplicative function of two key components (the number of subjective time units and their size) should predict apparent duration. Implications for other cognitive domains are drawn, and in particular an analogy is suggested between apparent duration and apparent movement.

Arousal↗
PubMed1999

Cognitive dedifferentiation in eidetics and synaesthesia: hunting for the ghost once more.

Both synaesthesia and eidetics have a common characteristic of cognitive dedifferentiation. Synaesthesia (e.g. colour-hearing) entails the dedifferentiation of the sensory modalities, while eidetic imagery entails the dedifferentiation of imagery and perception. One can profitably gain by investigating both within the same study. Moreover, some of the same issues have arisen in these, hitherto, separate research literatures. This behoves a common framework for analysis and investigation. We applied a technique previously used for identifying child eidetikers, for screening the adult population, looking at both phenomena in the same sample. After screening, we selected a total of twenty-nine individuals for controlled testing of both phenomena and their variants (structural eidetic imagery, typographic eidetic imagery, colour-hearing synaesthesia, colour-mood synaesthesia). Our participants also completed a number of questionnaires of relevance (absorption, dissociation, and hallucination). We found that the personality trait of absorption underlies the commonality of experience tapped by both typographic and structural eidetic imagery. Furthermore, the latter phenomena were found to have a common pseudohallucinatory experiential base. For subjects scoring relatively high on the absorption scale, there is a negative correlation between structural eidetic imagery and colour-mood synaesthetic differentiation, replicating to a degree results reported earlier.

Adult↗
PubMed1997

Auditory inattention in right-hemisphere-damaged patients with and without visual neglect.

Fifteen right-hemisphere-damaged patients, eight with- and seven without visual neglect (N+ and N-, respectively), were assessed for the presence of auditory neglect using free-field bilateral simultaneous stimulation (BSS) and pseudorandom unilateral stimulation. Eight healthy subjects served as controls. Both N+ and N- groups extinguished left-sided sound stimuli in the BSS condition. N+ (but not N-) patients showed a right-side advantage in sound localization and were inferior, compared to normal individuals, in their ability to localize unilaterally administered sounds on the left side. Blindfolding significantly improved the localization performance. In a task demanding stimulus identification, both N+ and N- groups performed abnormally when auditory stimuli came from the left. Free-field stimulation is thus an adequate technique for the detection of auditory neglect. The results are consistent with the notion that left-sided neglect reflects a pathologically exaggerated attentional bias towards the right in normal individuals.

Adult↗
PubMed1995

Changes of brain anatomy in patients with posttraumatic stress disorder: a pilot magnetic resonance imaging study.

No abnormalities in magnetic resonance images were recorded in patients with posttraumatic stress disorder other than an increased incidence (50%) of a small cleft in the callosal-septal interface, a cavum of the septum pellucidum. A similar grade of cavum was obtained in 14% of normal volunteers matched for age, socioeconomic background, and military experience. The cavum is believed to have antedated the disorder and is conceived to be a neurodevelopmental aberration. The possibility that the cavum is a marker of vulnerability to stress in psychopathology is discussed.

Adult↗
PubMed1995

First month of neuroleptic treatment in schizophrenia: only partial normalization of the late positive components of visual ERP.

In a previous study we recorded visual event-related potentials (ERP) in drug-naive schizophrenics during passive-attention and active-attention tasks. Patients, compared to normal controls, had much lower late positive components (LPC) in both sessions, but nearly normal LPC increase from passive to active task. The present sample consisted of drug-naive and drug-free patients who were tested before and during the first month of neuroleptic treatment. Neuroleptics initiated gradual amelioration of psychiatric symptoms expressed by reduced Brief Psychiatric Rating Scale (BPRS) scores. Schizophrenics compared to controls showed a session-related increase in LPC amplitude, but this process of LPC recovery was too minor to fully normalize the low LPC amplitudes in patients. Furthermore, the treatment either did not improve or even reduce the LPC reaction to the active-attention task. These findings indicate that normalization of low LPC in schizophrenia might require a long period of treatment, and that patients' reduced LPC reactivity to the task might be contributed, rather than treated, by neuroleptics.

Adult↗
PubMed1993

The representation of patterns of structural brain asymmetry in normal individuals.

Hemispheric asymmetries were examined in 20 normal individuals who underwent MR scanning. The asymmetry indices were represented for a series of contiguous, consecutive coronal images through the occipital and frontal lobes, along the dorso-ventral [DV] axis. A monotonic decrease in size of the parieto-occipital hemispheric areal asymmetry was observed, from a marked left predominance to a greater degree of symmetry. When frontal and occipital lobe asymmetries were compared, the familiar frontal-right vs occipital-left counterclockwise torque was observed, but was found to be more prominent in the dorsal aspect of the frontal cuts and the ventral aspect of the occipital cuts. At the individual level, a within-subject linear model for predicting cerebral area as a function of cut, hemisphere and DV, revealed this marked DV effect. The use of the within-subject linear model further enabled the individual assessment of structural asymmetries, and provided criteria by which subjects could be grouped. We further show how a deviation of the occipital falx will engender different hemispheric asymmetries, depending on the orientation of the coronal imaging plane. Given the latter, we recommend planning the coronal cuts based on a low-ventricular transaxial scout, wherein the deviated falx, if present, can be taken into account.

Adolescent↗
PubMed1992

An exploratory study of syncretic experience: eidetics, synaesthesia and absorption.

Synaesthesia and eidetic imagery are both syncretic experiences entailing a dedifferentiation of perceptual qualities. In this paper the correlation between synaesthesia and eidetic imagery is explored. Ten subjects selected for possible eidetic and/or synaesthetic ability were tested in a battery of tasks that tap structural and typographic eidetic imagery, and colour-hearing and colour-mood synaesthesia. It was found that both structural and typographic eidetic imagery were correlated with measures of synaesthesia, indicating a relationship between the two phenomena.

Adult↗
PubMed1991

Occipital lobe morphology in normal individuals assessed by magnetic resonance imaging (MRI).

The topography of visual evoked potentials (VEP) is dependent on occipital lobe morphology. Using magnetic resonance imaging we examine the sulcal pattern (the calcarine and parieto-occipital sulci), and assess the size of the cuneus and the asymmetry of the occipital lobes, computed separately for its ventral and dorsal segments. No differences were found for either the cuneus or the sulci pattern. In contrast, hemispheric asymmetry values appeared to be substantial. The predominance of the left occipital area was seen distinctly in the ventro-caudal portion of the occipital lobe. It was frequently reversed in the dorsal aspect of the lobe, notably in more rostral cuts. Such complexities may lead to ambiguities in interpreting VEP asymmetries.

Adolescent↗
PubMed1989

Bilateral alpha distribution and anatomic brain asymmetries.

The parieto-occipital (PO) index of the VEP alpha-afterdischarge (AD) was assessed bilaterally in normal subjects in three successive sessions separated by one-three weeks with two within-session retests. Correlations between PO values and asymmetries of occipital and parietal width, mastoid area, basal angle, cephalic, and plagiocephaly indices were established in simple correlation and stepwise multiple regression analysis. Occipital width, notably in the right hemisphere correlated reliably with the PO index in relaxed wakefulness and the vigilance task. The population having normal and reversed occipital brain width is predicted to have different parieto-occipital AD distribution. Some errors of lateral EEG measurements introduced by slant cranial deformity are discussed in order to call attention to the fact that anatomy-related lateral EEG changes may masquerade as cognition-related asymmetries.

Adolescent↗
PubMedDate not supplied

Can music alleviate cognitive dysfunction in schizophrenia?

It has recently been reported that students performed relatively better on cognitive tasks after listening to music. Conceivably, music might reduce the level of arousal in subjects who are tense, thereby improving their performance. A test case would be schizophrenic subjects, noted for poor performance on tasks demanding attention, who have been characterized as suffering from hyperarousal, which mediates these attentional deficits. We investigated whether cognitive task performance could be facilitated by music in schizophrenics and report a beneficial effect.

Adult↗
PubMedDate not supplied

A new look at sleep position via head slant.

We investigated whether the degree of plagiocephaly (P) (head slant) would predict the particular "position of comfort" adopted prior to sleep. A marked flattening of the right occipital bone (left-dominant occipital plagiocephaly) was noted for the majority of our subjects, coupled with a tendency to prefer a right-sided "position of comfort". Two subjects exhibiting right-dominant occipital P adopted an extreme left-sided sleep position, providing further support for this relationship. We call attention to the possibility that the "position of comfort" adopted prior to sleep, may be a variable of relevance for the entire sleep cycle.

Female↗