Hypnosis,memory and amnesia.

Hypnotized subjects respond to suggestions from the hypnotist for imaginative experiences involving alterations in perception and memory. Individual differences in hypnotizability are only weakly related to other forms of suggestibility. Neuropsychological speculations about hypnosis focus on the right hemisphere and/or the frontal lobes. Posthypnotic amnesia refers to subjects'' difficulty in remembering, after hypnosis, the events and experiences that transpired while they were hypnotized. Posthypnotic amnesia is not an instance of state-dependent memory, but it does seem to involve a disruption of retrieval processes similar to the functional amnesias observed in clinical dissociative disorders. Implicit memory, however, is largely spared, and may underlie subjects'' ability to recognize events that they cannot recall. Hypnotic hypermnesia refers to improved memory for past events. However, such improvements are illusory: hypermnesia suggestions increase false recollection, as well as subjects'' confidence in both true and false memories. Hypnotic age regression can be subjectively compelling, but does not involve the ablation of adult memory, or the reinstatement of childlike modes of mental functioning, or the revivification of memory. The clinical and forensic use of hypermnesia and age regression to enhance memory in patients, victims and witnesses (e.g. recovered memory therapy for child sexual abuse) should be discouraged.     

Mesmerizing memories: brain substrates of episodic memory suppression in posthypnotic amnesia

Two groups of participants, one susceptible to posthypnotic amnesia (PHA) and the other not, viewed a movie. A week later, they underwent hypnosis in the fMRI scanner and received a suggestion to forget the movie details after hypnosis until receiving a reversal cue. The participants were tested twice for memory for the movie and for the context in which it was shown, under the posthypnotic suggestion and after its reversal, while their brain was scanned. The PHA group showed reduced memory for movie but not for context while under suggestion. Activity in occipital, temporal, and prefrontal areas differed among the groups, and, in the PHA group, between suggestion and reversal conditions. We propose that whereas some of these regions subserve retrieval of long-term episodic memory, others are involved in inhibiting retrieval, possibly already in a preretrieval monitoring stage. Similar mechanisms may also underlie other forms of functional amnesia.     

Pain Modulation in Waking and Hypnosis in Women: Event-Related Potentials and Sources of Cortical Activity

Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N140 wave, showed reduced activity within medial and superior frontal gyri (BA9,8), paraippocampal gyrus (BA34), and postcentral gyrus (BA1), while for the P200, activity was reduced within middle and superior frontal gyri (BA9 and BA10), anterior cingulate (BA33), cuneus (BA19) and sub-lobar insula (BA13). These findings demonstrate that hypnotic suggestions can exert a top-down modulatory effect on attention/preconscious brain processes involved in pain perception.     

ESTIMATION OF GLYCOLIPIDS IN FOUR SELECTED LOBES OF HUMAN BRAIN IN NEUROLOGICAL DISEASES1

Glycolipid (ganglioside, cerebroside and cerebroside sulphate) and cholesterol concentrations for cerebral grey matter from frontal, occipital, temporal and hippocampal lobes of patients with neurological diseases (Alzheimer's disease, senile dementia, cerebrocortical atrophy, schizophrenia and chronic alcoholism) and controls are reported. The results indicate that the concentrations of these lipids are not uniform in the different lobes of both diseased and control brains. The concentrations of the cerebrosides and cerebroside sulphates were generally highest in the occipital lobe and lowest in the frontal lobe; ganglioside N-acetymeuraminic acid (NANA) concentrations on the other hand were lowest in the occipital lobe and highest in the frontal lobe. About one-half of the total NANA was found in the lipid-free residues. There was a general decrease in the concentrations of the glycolipids in the grey matter from the frontal, temporal and hippocampal lobes of brain obtained from patients with neurological diseases (the chronic alcoholic being excluded) below the control values from patients with no known neurological diseases. The cholesterol concentrations in the schizophrenic and alcoholic brains were reduced slightly in all the lobes studied. The general decrease in the glycolipid concentration in the diseased brain may indicate the extent of cortical degeneration.     

Endocranial cast of Hexian Homo erectus from South China

In this paper, we present data on the morphological features and linear measurements for the Hexian Homo erectus and other comparative endocasts, in order to highlight variation during human brain evolution. The endocast of Hexian was reconstructed in 1982, and an endocranial volume of 1,025 ml was estimated. The geological age is about 412 ka, or roughly contemporaneous with the Zhoukoudian (ZKD) specimens. There are some differences between Hexian and the modern Chinese male endocasts in our sample, including low position of the greatest breadth, low maximum height, a well-marked and prominent frontal keel, the flat surface of the frontal lobes, prominent sagittal keel along the center frontal and parietal lobes, depressed Sylvian areas and parietal lobes superiorly, strong posterior projection of the occipital lobes, anterior position of the cerebellar lobes relative to the occipital lobes, and the relative simplicity of the meningeal vessels. Compared with the ZKD, Indonesian, and African Homo erectus specimens, Hexian has more morphological features in common with ZKD. Principal component analyses indicate that Hexian is closest to the ZKD Homo erectus compared with the modern Chinese and other Homo erectus, but its great breadth distinguishes it. Metric analyses show that the brain height, frontal breadth, cerebral height, frontal height, and parietal chord from Homo erectus to modern humans increased, while the length, breadth, frontal chord, and occipital breadth did not change substantially.     

Magnetic resonance imaging and magnetic resonance spectroscopy in a patient with amyotrophic lateral sclerosis and frontotemporal dementia

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) have been investigated in a single neurodegenerative disease manifesting as either amyotrophic lateral sclerosis (ALS) or frontotemporal dementia (FTD) alone, but have not been examined in combined disorders such as ALS with FTD (ALS-FTD). To our knowledge, this study is the first attempt to demonstrate relationship between MRI abnormalities and MR spectroscopic metabolite changes of the motor cortex, frontal white matter and corticospinal tract in a patient with the diagnosis of ALS with probable upper motor neuron signs (ALS-PUMNS) and FTD. Patient presented underwent MRI of the brain and MRS. The ratio of N-acetylaspartate (NAA) to creatine (Cr), choline to Cr, myo-inositol (ml) to Cr and glutamate-glutamine (Glx) to Cr were derived from peak area measurement. Spectra from the right motor cortex, frontal white matter and corticospinal tract were obtained. MR images were evaluated for sulcus centralis enlargement, corticospinal tract hyperintensity and frontal lobes atrophy. Spectra showed reduced NAA/Cr and Glx/Cr ratio, yet the ratio of Cho/Cr exhibited significant elevation. MR images revealed sulcus centralis enlargement, high signal intensity of corticospinal tract and atrophy of both frontal lobes. Proton spectroscopic metabolic changes in a current patient fully correlate with previously reported MRS metabolic changes in ALS alone. Surprisingly, normal ml (glial marker) values have been found in almost all measured voxels of interest except in the frontal white matter. These findings differ from the previous findings in ALS or FTD alone. In conclusion, these findings support the concept that ALS, FTD and ALS-FTD may represent different manifestations of a single pathological continuum.     

Ethanol Induces Sedation and Hypnosis via Inhibiting Histamine Release in Mice

Ethanol is one of the most highly abused psychoactive compounds worldwide and induces sedation and hypnosis. The histaminergic system is involved in the regulation of sleep/wake function and is a crucial player in promoting wakefulness. To explore the role and mechanism of the histaminergic system in ethanol-induced sedation and hypnosis, we recorded locomotor activity (LMA) and electroencephalography (EEG)/electromyography (EMG) in mice using an infrared ray passive sensor recording system and an EEG/EMG recording system, respectively, after administration of ethanol. In vivo microdialysis coupled with high performance liquid chromatography and fluorometry technology were used to detect histamine release in the mouse frontal cortex (FrCx). The results revealed that ethanol significantly suppressed LMA of histamine receptor 1 (H₁R)-knockout (KO) and wild-type (WT) mice in the range of 1.5–2.5 g/kg, but suppression was remarkably stronger in WT mice than in H₁R-KO mice. At 2.0 and 2.5 g/kg, ethanol remarkably increased non-rapid eye movement sleep and decreased wakefulness, respectively. Neurochemistry experimental data indicated that ethanol inhibited histamine release in the FrCx in a dose-dependent manner. These findings suggest that ethanol induces sedation and hypnosis via inhibiting histamine release in mice.

     

Regional distribution of adenosine deaminase in the human neuraxis

Adenosine deaminase was determined in 28 different areas of the human neuraxis in 5 adult male cadavers, with no known disease of the nervous system, using a very sensitive colorimetric method. The enzyme was highest in the frontal lobe white matter, and lowest in the medulla and all levels of the spinal cord. Enzyme content was about twice as great in the white matter of the frontal and temporal lobes and cerebellum as it was in the cortical gray matter of these areas, but only slightly higher in the white matter of the parietal and occipital lobes as compared to gray. Average values of the enzyme were found in the remaining areas of the brain, with the exception of the pons and cerebellar white matter, where a higher than average value was noted.     

Quantitative differences among the brains of cephalopods

The relative sizes of 30 lobes of the brains of 63 species of cephalopods have been compared. Some of the observed differences could be related to the way of life of the animal and others to the taxonomic relationships. The octopods are separated from the decapods by their larger brachial and other suboesophageal lobes, larger inferior frontal systems and smaller optic lobes. Vampyroteulhis lies somewhat between these two main groups. The vertical lobe system is large in sepioids and loliginids, smaller in decapods from deeper water, but large in Vampyroteuthis. In octopods, it is large in the typical epibenthic forms but smaller in those from deeper water and very small in cirrates. The inferior frontal system is very large in epibenthic octopods and Benthoctopus and in cirrates, but smaller in epipelagic and bathypelagic forms. The optic lobes are larger in decapods than in octopods from comparable depths and are especially large in deep-sea decapods. They are larger in epipelagic octopods than in the typical benthic forms. The photosensitive vesicles vary by nearly two orders of magnitude. They are very small in squids living in surface waters, larger in mesopelagic forms and enormous in some cranchiids and in Balhyteuthis. In Histioteulhis , the side with the larger eye had an optic lobe twice as big as that on the side of the smaller eye, but with only slight differences in other parts of the brain. In the octopods, the inferior frontal system was generally large, being concerned with the tactile memory system, and tends to be inversely related to the size of the optic lobe.     

Distribution of oxytocin-like and vasopressin-like immunoreactivities within the central nervous system of the cuttlefish, <Emphasis Type="Italic">Sepia officinalis</Emphasis>

We have investigated the distribution of oxytocin/vasopressin (OT/VP) superfamily peptides in the central nervous system (CNS) of the cuttlefish, Sepia officinalis, by using antibodies raised against mammalian OT and VP. Several populations of OT-like and VP-like immunoreactive cell bodies and fibers were widely distributed in cerebral structures involved in learning processes (vertical lobe complex, optic lobes), behavioral communication (peduncle, lateral basal and chromatophore lobes), feeding behavior (inferior frontal, brachial and buccal lobes), sexual activity (dorsal basal, subpedunculate, olfactory lobes), and metabolism (visceral lobes). The two most remarkable findings of this study were the occurrence of OT-like immunoreactivity in many amacrine cells of the vertical lobe and the dense accumulation of VP-like immunoreactive cell bodies in the subpedunculate 1 lobe. No double-immunolabeled cell bodies or fibers were found in any lobes of the CNS, indicating, for the first time in a decapod cephalopod mollusc, the existence of distinct oxytocinergic-like and vasopressinergic-like systems. The widespread distribution of the immunoreactive neurons suggests that these OT-like and VP-like peptides act as neurotransmitters or neuromodulators. This research was supported by grants from the “Région Basse-Normandie” (FRANCE) and the LARC-Neurosciences network (FRANCE).     

Some cognitive effects of frontal-lobe lesions in man

The study of patients undergoing unilateral frontal-lobe excisions for the relief of focal epilepsy has revealed specific cognitive disorders that appear against a background of normal functioning on many intellectual, perceptual and memory tasks. Lesions that invade the frontal eye field cause subtle impairments of voluntary oculomotor control, which reveal themselves as an inability to suppress an initial glance at a potentially distracting stimulus. After frontal lobectomy in either hemisphere, deficits are found quite consistently on motor-differentiation tasks (Konorski 1972) in which the subject must learn to produce different responses to different, randomly presented, environmental signals. More directly related to the concept of planning are those sequential tasks in which the subject is free to choose his own order of responding, but must not make the same response twice. Here the left frontal lobe plays the major role, a finding consistent with the notion of left-hemisphere dominance for the programming of voluntary actions. In contrast, the right frontal lobe appears to be more critically involved in monitoring the temporal sequence of externally ordered events, although the verbal or non-verbal nature of the stimuli remains a relevant factor.     

Executive function is less sensitive to estradiol than spatial memory: performance on an analog of the card sorting test in ovariectomized aged rhesus monkeys

Functions supported by the frontal lobes are particularly sensitive to the detrimental effects of aging. Recent studies on postmenopausal women find that estrogen replacement therapy benefits performance on tasks dependent on the frontal lobes. To determine whether estrogen has a similar influence in a rhesus monkey model of menopause, we tested five aged, long-term ovariectomized rhesus monkeys in a modified version of the Wisconsin Card Sort test which had been adapted to the nonhuman primate. In this test, monkeys had to select 3-D objects based either on color (blue, red, yellow) or shape (block, tube, cup) and had to be able to switch their response as a function of reinforcement contingencies. The monkeys were treated with placebo and ethinyl estradiol (EE2, 450 ng/kg/day) in alternation with each successive test. Contrary to our hypothesis, estradiol treatment did not affect performance. Because previous studies in the same monkeys [Neurobiol. Aging 23 (2002) 589] had shown that EE2 improves performance on a spatial memory task dependent on the hippocampus, but not on another task dependent upon the frontal lobes (the delayed response), we conclude that executive processes may be less sensitive to the effects of estradiol than hippocampal-dependent tasks.     

A frontal lobe surface analysis in three archaic African human fossils: OH 9, Buia,and Bodo

The evolution of the frontal lobes represents a major issue in paleoneurology. In this survey, we used a surface analysis to describe the frontal morphology of three relevant East African specimens from early and middle Pleistocene: OH 9, UA 31, and Bodo. When compared with a modern human endocast, UA 31 and Bodo display a flatter dorso-lateral surface, while OH 9 shows a general flattening of the whole dorsal morphology. OH 9 is the specimen with older chronology and with orbits more separated from the prefrontal cortex than in UA 31 and Bodo. The morphology of these three specimens is in agreement with the hypothesis that increase of the frontal curvature is due to the shifting of the facial block under the anterior cranial fossa. Apart from variations in size and general proportions, surface analysis can be useful in analyzing morphological changes localized in specific cortical areas. The three fossils are used as case study to discuss and review some relevant issues concerning frontal lobe evolution and paleoneurology.     

Frontal White Matter Volume Is Associated with Brain Enlargement and Higher Structural Connectivity in Anthropoid Primates

Previous research has indicated the importance of the frontal lobe and its ‘executive’ connections to other brain structures as crucial in explaining primate neocortical adaptations. However, a representative sample of volumetric measurements of frontal connective tissue (white matter) has not been available. In this study, we present new volumetric measurements of white and grey matter in the frontal and non-frontal neocortical lobes from 18 anthropoid species. We analyze this data in the context of existing theories of neocortex, frontal lobe and white versus grey matter hyperscaling. Results indicate that the ‘universal scaling law’ of neocortical white to grey matter applies separately for frontal and non-frontal lobes; that hyperscaling of both neocortex and frontal lobe to rest of brain is mainly due to frontal white matter; and that changes in frontal (but not non-frontal) white matter volume are associated with changes in rest of brain and basal ganglia, a group of subcortical nuclei functionally linked to ‘executive control’. Results suggest a central role for frontal white matter in explaining neocortex and frontal lobe hyperscaling, brain size variation and higher neural structural connectivity in anthropoids.     

La spécificité de l’auto-analyse freudienne: un expérimentalisme sans laboratoire

WithThe Interpretation of Dreams, Freud introduced his readers into the psychoanalytic technique. Freud’s strategy was a reaction to the difficulties produced by the establishment of laboratories of hypnosis, difficulties due to the resistance of patients and to the large diffusion of suggestion in everyday life. The possibility of resistance enables subjects to take an active role. This led to a change of the former configuration of experimental hypnotism where the subjects had to be deceived. In contrast to the doctors of the hypnosis movement, Freud abandoned the project of constructing a laboratory of hypnosis and elaborated reading and writing practices instead. Early psychoanalysis thus develops in the form of an “experimentalism without a laboratory”, a specific articulation of dreaming, reading and writing.     

Variations and asymmetries in regional brain surface in the genus Homo

Paleoneurology is an important field of research within human evolution studies. Variations in size and shape of an endocast help to differentiate among fossil hominin species whereas endocranial asymmetries are related to behavior and cognitive function. Here we analyse variations of the surface of the frontal, parieto-temporal and occipital lobes among different species of Homo, including 39 fossil hominins, ten fossil anatomically modern Homo sapiens and 100 endocasts of extant modern humans. We also test for the possible asymmetries of these features in a large sample of modern humans and observe individual particularities in the fossil specimens.This study contributes important new information about the brain evolution in the genus Homo. Our results show that the general pattern of surface asymmetry for the different regional brain surfaces in fossil species of Homo does not seem to be different from the pattern described in a large sample of anatomically modern H. sapiens, i.e., the right hemisphere has a larger surface than the left, as do the right frontal, the right parieto-temporal and the left occipital lobes compared with the contra-lateral side. It also appears that Asian Homo erectus specimens are discriminated from all other samples of Homo, including African and Georgian specimens that are also sometimes included in that taxon. The Asian fossils show a significantly smaller relative size of the parietal and temporal lobes. Neandertals and anatomically modern H. sapiens, who share the largest endocranial volume of all hominins, show differences when considering the relative contribution of the frontal, parieto-temporal and occipital lobes. These results illustrate an original variation in the pattern of brain organization in hominins independent of variations in total size. The globularization of the brain and the enlargement of the parietal lobes could be considered derived features observed uniquely in anatomically modern H. sapiens.     

Characteristics of the spatio-temporal organization of the P300 component of AEP during the "active" and "passive" stimulus perception in healthy subjects

The concern of the work was in detection and analysis of P300 component of the acoustic evoked potential in healthy subjects in different experimental situations. During counting the rare sounds, P300 was most pronounced in the frontocentral and parietooccipital areas mainly of the left-hemisphere. The response shape was correlated with characteristics of the basic rhythm of the background EEG. Responses of simple and complex shapes were distinguished. The simplest responses were recorded in subjects with hypersynchronous alpha-rhythm. Analysis of three-dimensional dipole source localization showed that structures of the brainstem, limbic system, and frontal lobes participate in generation of the wave. In all the subjects, the decisive role in response generation was played by the brainstem structures. In persons with hypersynchronous alpha-rhythm, the contribution of the frontal lobes was less pronounced. During "passive" listening of sounds, P300 parameters significantly differed from those observed during counting only in 46% of cases (in persons having no hypersynchronous alpha-rhythm). A simplification of the response shape during "passive" listening was observed in these cases, the area of the maximal response expression was shifted to symmetrical areas of the right-hemisphere, the number of dipole sources reduced due to a decrease in the contribution of the frontal and limbic structures into the response generation.     

Glutathione peroxidase activity in surgical and autopsied human brains

Glutathione peroxidase (GSHPx) activity was assayed in normal cerebral gray and white matter samples obtained from frontal, temporal, occipital and parietal lobes during surgical approach to an underlying lesion, and also in normal autopsied human frontal gray and white matter. GSHPx was assayed by a 2 step enzyme reaction which was monitored by following the oxidation of NADPH at 340 nm. It was found that all the brain samples studied contained GSHPx activity. Parietal lobe appeared to have the lowest GSHPx activity compared to temporal, occipital or frontal lobes. Mean enzyme activity in autopsied samples was comparable to that in surgical material. However, considerable loss of activity was observed after 10 years of tissue storage at –80°C.This investigation was supported by the Verterans Administration.