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PubMed2006

Postictal mania versus postictal psychosis: differences in clinical features, epileptogenic zone, and brain functional changes during postictal period.

PURPOSE: To clarify the differences between postictal mania (PIM) and postictal psychosis (PIP). METHODS: Five patients with PIM were compared to 17 patients with PIP, with respect to clinical, epileptological, electrophysiological, and neuroimaging features. PIM was distinguished from PIP by the symptoms observed in the postictal period based on the ICD-10 criteria. RESULTS: Postictal manic episodes lasted for a longer period than postictal psychotic episodes. Patients with PIM had more recurrent postictal episodes than patients with PIP. The age at onset of epilepsy in patients with PIM was older than that in patients with PIP. PIM was associated with frontal lobe and temporal lobe epilepsies, whereas PIP was associated with temporal lobe epilepsy. The estimated epileptogenic zone was on the language dominant side in PIM, whereas there was no predominant hemispheric laterality in PIP. Electroencephalography (EEG) performed during the early period of postictal manic and psychotic episodes showed decreased frequency of interictal epileptiform discharges in both PIM and PIP. Single-photon emission computed tomography (SPECT) during postictal manic and psychotic episodes showed increased perfusion in the temporal and/or frontal lobes in both PIM and PIP. Three patients with PIM showed increased perfusion during postictal episodes on bilateral or the language nondominant side, which were contralateral to the estimated epileptogenic zone, whereas three patients with PIP showed increased perfusion on the areas, which were ipsilateral to the estimated epileptogenic zone. CONCLUSIONS: PIM has a distinct position among the mental disorders observed in the postictal period.

Age of Onset↗

PubMed2002

Brain function in Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is the second most commonly occurring genetically inherited disease in humans. It is an X-linked condition that affects approximately one in 3300 live male births. It is caused by the absence or disruption of the protein dystrophin, which is found in a variety of tissues, most notably skeletal muscle and neurones in particular regions of the CNS. Clinically DMD is characterized by a severe pathology of the skeletal musculature that results in the premature death of the individual. An important aspect of DMD that has received less attention is the role played by the absence or disruption of dystrophin on CNS function. In this review we concentrate on insights into this role gained from investigation of boys with DMD and the genetically most relevant animal model of DMD, the dystrophin-deficient mdx mouse. Behavioural studies have shown that DMD boys have a cognitive impairment and a lower IQ (average 85), whilst the mdx mice display an impairment in passive avoidance reflex and in short-term memory. In DMD boys, there is evidence of disordered CNS architecture, abnormalities in dendrites and loss of neurones, all associated with neurones that normally express dystrophin. In the mdx mouse, there have been reports of a 50% decrease in neurone number and neural shrinkage in regions of the cerebral cortex and brainstem. Histological evidence shows that the density of GABA(A) channel clusters is reduced in mdx Purkinje cells and hippocampal CA1 neurones. At the biochemical level, in DMD boys the bioenergetics of the CNS is abnormal and there is an increase in the levels of choline-containing compounds, indicative of CNS pathology. The mdx mice also display abnormal bioenergetics, with an increased level of inorganic phosphate and increased levels of choline-containing compounds. Functionally, DMD boys have EEG abnormalities and there is some preliminary evidence that synaptic function is affected adversely by the absence of dystrophin. Electrophysiological studies of mdx mice have shown that hippocampal neurones have an increased susceptibility to hypoxia. These recent findings on the role of dystrophin in the CNS have implications for the clinical management of boys with DMD.

Adult↗

PubMed2000

How study of respiratory physiology aided our understanding of abnormal brain function in panic disorder.

There is a substantial body of literature demonstrating that stimulation of respiration (hyperventilation) is a common event in panic disorder patients during panic attack episodes. Further, a number of abnormalities in respiration, such as enhanced CO2 sensitivity, have been detected in panic patients. This led some to posit that there is a fundamental abnormality in the physiological mechanisms that control breathing in panic disorder and that this abnormality is central to illness etiology. More recently, however, evidence has accumulated suggesting that respiratory physiology is normal in panic patients and that their tendency to hyperventilate and to react with panic to respiratory stimulants like CO2 represents the triggering of a hypersensitive fear network. The fear network anatomy is taken from preclinical studies that have identified the brain pathways that subserve the acquisition and maintenance of conditioned fear. Included are the amygdala and its brain stem projections, the hippocampus, and the medial prefrontal cortex. Although attempts to image this system in patients during panic attacks have been difficult, the theory that the fear network is operative and hyperactive in panic patients explains why both medication and psychosocial therapies are clearly effective. Studies of respiration in panic disorder are an excellent example of the way in which peripheral markers have guided researchers in developing a more complete picture of the neural events that occur in psychopathological states.

Arousal↗

PubMedDate not supplied

[The interrelation of interhemispheric functional brain asymmetry and the morphofunctional asymmetries of the female reproductive system in in its comparative evolutionary aspect].

In experiments carried out in female rats it has been established that there is a connection between morphological asymmetry of uterine horns and adnexa and orientation of encephalic interhemispheric asymmetry (EIHA). Unilateral adnexectomy and ablation of one of the uterine horns resulted in modifications of EIHA, which increased during pregnancy in the remaining horn. Comparative analysis of experimental results and the data obtained during examination of pregnant women (such as interconnections of the placentation side with gestational dominant and initial orientation of the lateral phenotype) suggests an important role of asymmetry of the visceral part of female reproductive system in the formation of EIHA in onto- and phylogenesis. Possible mechanisms of self-organization of the polar functional systems are discussed under evolutionary aspect.

Adnexa Uteri↗

PubMed1999

Regional brain function, emotion and disorders of emotion.

Significant progress has been made in our understanding of the neural substrates of emotion and its disorders. Neuroimaging methods have been used to characterize the circuitry underlying disorders of emotion. Particular emphasis has been placed on the prefrontal cortex, anterior cingulate, parietal cortex, and the amygdala as critical components of the circuitry that may be dysfunctional in both depression and anxiety.

Affective Symptoms↗

PubMed2005

[Time perception in functional brain imaging].

BACKGROUND: Knowledge of physiological mechanisms underlying time perception is still rather limited. The aim of our study was to search for a 'time accumulator', i.e. the part of the brain where information on the duration of time is stored. METHODS AND RESULTS: Nine healthy volunteers were given a time reproduction task during event-related fMRI. Subjects were instructed to retain the duration of the stimulus presented (presentation phase) and then to reproduce it by pressing a button (reproduction phase). Two different analyses were made: event-related (P < 0.05, FWR corrected) and parametric (BOLD signal increase/decrease during the presentation/reproduction phases correlated with the time intervals; P < 0.01, FDR corrected). When the event-related approach was employed, activation was noted bilaterally in the inferior prefrontal cortex (IPFC), supplementary motor area (SMA), precuneus and secondary visual cortex. On the right, there was activation in the dorsolateral prefrontal cortex (DLPFC), gyrus cinguli and inferior parietal lobule. On the left, the primary sensory-motor cortex was activated. While during the presentation phase the left DLPFC activity inversely correlated with the presented duration, a nearly identical area showed positive correlation in the reproduction phase. CONCLUSIONS: The event-related analysis did not allow distinguishing the process of time perception from many cognitive processes running simultaneously. In turn, the parametric analysis was based on visualizing regions, in which the signal correlated with the varying duration of the time interval provided the level of attention, decision-making and the processes of behavioral response planning and execution were constant. Moreover, the right and left DLPFC seem to play different roles in time perception. While the left one is functioning as a "time accumulator", the right one is rather involved in the recognition of previously perceived intervals.

Adult↗

PubMed1991

Brain function, learning styles, and cancer patient education.

As cancer care moves into the outpatient setting and hospital stays are shortened, patients and their family members are expected to take on tremendous responsibilities in providing their own self-care. At the same time, stress and anxiety about the diagnosis of cancer, the disease itself, and cancer therapy can effect learning. Information processing, learning styles, and learning barriers need to be considered when developing and implementing cancer education programs.

Aged↗

PubMed2000

Effects of nutrients on brain function.

While many of the above examples support a role of these dietary components in modifying the synthesis, storage, release and actions of various neurotransmitter molecules in the central nervous system, most of the responses to eating everyday foods are expected to produce subtle changes in physiological and/or behavioral parameters. However, the observed subtle changes may have significant consequences when present in individuals with altered homeostasis as might be present in various disease states or certain environmental situations (e.g. depression, PMS, stress). Studies in the future should investigate the effects of various diets, e.g., vegetarian, macrobiotic, traditional Eastern, etc. on physiological and psychological functioning. Care should be taken to differentiate between the responses of subgroups of subjects, e.g. male vs. female, old vs. young, and lean vs. obese, as some differences in the rate of neurotransmitter synthesis and receptor dynamics have been reported in some studies. Chronic consumption of these diets may lead to long-term alterations in the neurotransmitter systems' dynamics, or as is often the situation with long-term pharmacological treatments, may result in adaptive changes to minimize the acute effects of such treatments. To date, no such studies have been performed that have systematically addressed many of these issues. Future studies will require careful design so as to enhance the chances of detecting such alterations in function. However, the most significant alterations in function occur when a dietary component is administered in a purified form, separate from the normal diet. In this case the compound should be treated more like a pharmacological agent than a nutrient since adverse (i.e. antinutritive) effects may result. The most difficult studies however will use everyday foods with the aim of detecting changes based on the underlying biochemical changes.

Amino Acids↗

PubMed1997

Oldest-old healthy brain function. The genomic potential.

There will be a remarkable increase in the number of people older than 85 years--the oldest-old--in the next 50 years. This age group is especially vulnerable to increasing disabilities, many of which are the result of the aging nervous system. Among these aging changes, the most devastating and likely to have the greatest impact on our society is the development of dementia. Since dementia is present in the majority of those who live to the current maximum of the human life span, this suggests that dementia is a normal aging event. Although the exact causes of this common cognitive failure in the oldest-old are not known, there is recent evidence from genetic studies of aging and Alzheimer disease to suggest that there are a number of susceptibility genes that may modify or delay the onset of late-life brain failure. These gene families form a natural target for devising strategies for significantly delaying the onset of late-life dementia.

Aged↗

PubMed1985

Positron emission tomography: human brain function and biochemistry.

Positron emission tomography (PET) is an analytical imaging technique that provides a way of making in vivo measurements of the anatomical distribution and rates of specific biochemical reactions. This ability of PET to measure and image dynamic biochemistry builds a bridge between the basic and clinical neurosciences founded on the commonality of the types of measurements made. Clinical findings with PET in humans are suggesting hypotheses that can be tested rigorously in the basic science laboratory.

Acoustic Stimulation↗

PubMedDate not supplied

[Changes in individual resistance of cardiovascular and respiratory systems of rats to posthemorrhagic hypoxia after pharmacological impact on brain function].

In experiments on rats it was shown that injection to rats before hemorrhage of analeptic corasol or prior injections during three days of the inhibitory mediator sodium oxybutyrate decrease individual resistance of the respiratory and circulatory systems (arterial blood pressure, cardiac output, organ portal blood flow) to posthemorrhagic hypoxia. Injection to animals before the hemorrhage of GABA-A antagonist picrotoxin significantly raises individual resistance to massive bleeding. Individual resistance to acute hemorrhage correlates with individual sensitivity of cardiovascular and respiratory systems to corasol.

Animals↗

PubMed1989

Pharmacological effects of indeloxazine, a new cerebral activator, on brain functions distinct from other cerebral metabolic enhancers.

The effects of indeloxazine hydrochloride [(+/-)-2-[(inden-7-yloxy)methyl]morpholine hydrochloride, YM-08054], a new cerebral metabolic enhancer, on learned behavior and central monoaminergic function were compared to those of other cerebral metabolic enhancers in animals. Indeloxazine enhanced passive learned behaviour in rats and ameliorated cerebral ischemia-induced learned disturbances in gerbils. Reserpine-induced hypothermia in mice, ponto-genicullo-occipital (PGO) waves in reserpinized cats and caudate spindle activity in cats were reduced by the administration of indeloxazine, suggesting that the drug possesses facilitatory effects on central monoaminergic systems. In contrast, piracetam, calcium-hopantenate, idebenone and bifemelane had no significant effect on learned behavior or central monoaminergic function, with the exception of bifemelane which antagonized reserpine-induced hypothermia. These results are in contrast to the findings that all tested cerebral metabolic enhancers, including indeloxazine, prolonged the survival time of mice subjected to anoxia. The greater effect of indeloxazine to other cerebral metabolic enhancers, in facilitating learned behavior, may be attributable to its broader effects on central monoaminergic systems.

Animals↗

PubMed1997

Magnetic resonance imaging of human brain function. Principles, practicalities, and possibilities.

This article presents a review of functional magnetic resonance (fMR) imaging. Included are four sections that address the principles, practicalities, and potentials of fMR imaging. The current types of hemodynamic contrast available with fMR imaging, including blood volume, perfusion, and oxygenation, are discussed. Technical issues of fMR imaging, including interpretability and sensitivity, are described, and several currently unresolved issues are addressed. Also reviewed are commonly used fMR imaging platforms and clinical and research applications.

Brain↗

PubMed2003

Nicotinic acetylcholine receptors: from structure to brain function.

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels and can be divided into two groups: muscle receptors, which are found at the skeletal neuromuscular junction where they mediate neuromuscular transmission, and neuronal receptors, which are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. nAChRs are pentameric structures that are made up of combinations of individual subunits. Twelve neuronal nAChR subunits have been described, alpha2-alpha10 and beta2-beta4; these are differentially expressed throughout the nervous system and combine to form nAChRs with a wide range of physiological and pharmacological profiles. The nAChR has been proposed as a model of an allosteric protein in which effects arising from the binding of a ligand to a site on the protein can lead to changes in another part of the molecule. A great deal is known about the structure of the pentameric receptor. The extracellular domain contains binding sites for numerous ligands, which alter receptor behavior through allosteric mechanisms. Functional studies have revealed that nAChRs contribute to the control of resting membrane potential, modulation of synaptic transmission and mediation of fast excitatory transmission. To date, ten genes have been identified in the human genome coding for the nAChRs. nAChRs have been demonstrated to be involved in cognitive processes such as learning and memory and control of movement in normal subjects. Recent data from knockout animals has extended the understanding of nAChR function. Dysfunction of nAChR has been linked to a number of human diseases such as schizophrenia, Alzheimer's and Parkinson's diseases. nAChRs also play a significant role in nicotine addiction, which is a major public health concern. A genetically transmissible epilepsy, ADNFLE, has been associated with specific mutations in the gene coding for the alpha4 or beta2 subunits, which leads to altered receptor properties.

Animals↗

PubMed2002

Social stress in tree shrews: effects on physiology, brain function, and behavior of subordinate individuals.

Social stress is known to be involved in the etiology of central nervous disorders such as depression. In recent years, animal models have been developed that use chronic stress to induce neuroendocrine and central nervous changes that might be similar to those occurring in the course of the development of depressive disorders. The present review gives a summary of observations made in the tree shrew chronic social stress model. During periods of daily social stress, male tree shrews develop symptoms that are known from many depressed patients such as persistent hyperactivities of both the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system, disturbances in sleeping patterns, and reduced motor activity. Moreover, various physiological parameters indicate an acceleration of the over all metabolic rate in socially stressed tree shrews. Some of these parameters can be renormalized by antidepressants thus supporting the view of the tree shrew social stress paradigm as model for major depression. In the brains of socially stressed animals, monoamine receptors show dynamic changes that reflect adaptation to the persistent monoaminergic hyperactivity during periods of chronic stress. In addition to the changes in neurotransmitter systems, there are structural changes in neurons, e.g., retraction of the dendrites of hippocampal pyramidal neurons. Together, these processes are suggested as a cause of behavioral alterations that can be counteracted by antidepressants in this naturalistic social stress model.

Animals↗

PubMed2004

Volumetric estimation of functional brain regions in small children using spatially filtered magnetoencephalography: differentiating thumb from middle finger.

It is difficult to localize the somatosensory cortex in children under 6 years using magnetoencephalography (MEG) with conventional median nerve stimulation. One main reason is that MEG data recorded from small children have poor signal-to-noise ratio due to their small heads and short hands. To find a better approach, this study investigated neuromagnetic activities following finger stimulation using spatially filtered MEG. Four healthy children have been studied with a whole cortex MEG system. Electric stimulation was applied to the thumb and the middle fingers with two Digital Rings. Two trials were recorded for each hand. Focal increases of spectral power were localized using spectrogram and synthetic aperture magnetometry (SAM). A clear response at a latency of 21 ms was identified in 3 children (3/4). Dipole modeling localized the somatosensory cortex in 2 children (2/4). SAM successfully localized the somatosensory cortex in 4 children (4/4). Interestingly, the functional region estimated for the thumb was significantly larger than that of the middle finger (p < 0.01). However, it is possible that this effect is due to a larger source amplitude rather than larger source volume. Our results demonstrated that the developed approach could map the somatosensory cortex in children ranging in age from 3 to 6. To our knowledge, this is the first report using non-invasive methods to provide quantitative data indicating that the functional area of the thumb is larger than that of the middle finger in small children.

Child↗

PubMed1994

Single photon emission computed tomography (SPECT) measures of brain function in schizophrenia.

This study explores SPECT measured in schizophrenic patients at rest. Left temporal lobe activity was found to be decreased with increasing positive symptoms' scores scores. Medicated patients showed a reversal of this pattern underlying this positive symptom effect. Patients with a recent history of auditory hallucinations showed an atypical right temporal lobe dominance, which occurred independently of medication status. These preliminary data are suggestive of the potential utility of SPECT to elucidate symptom/medication/brain activity interrelationships in schizophrenia.

Antipsychotic Agents↗

PubMed2003

Chipping away at brain function: mining for insights with microarrays.

The impact of microarray studies on neurobiology has been limited because, with the exception of a few outstanding papers, most reports provide little more than lists of genes, often leaving the reader at a loss to understand which and how many of the identified transcripts will be true positives with significant biological impact. However, some recent papers have offered considerable biological insight by providing independent in vivo confirmation of the roles of candidate genes, offering a glimpse of the potential power of microarrays in neurobiological research.

Animals↗