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PubMed1983

Neurohypophysial hormones and brain function: the neurophysiological effects of oxytocin and vasopressin.

An increasing body of evidence suggests that the neurohypophysial hormones, in addition to their classical actions, may also act as neurotransmitters. They have a widespread but discontinuous distribution in the CNS; apart from their presence in the magnocellular nuclei they may be found in the hippocampus, amygdala, septum, substantia nigra, brainstem and spinal cord. They exert profound effects on behavior, particularly on memory, a function frequently ascribed to the hippocampus, amygdala and septum; on memory consolidation, internal reward and self stimulation functions frequently ascribed to brainstem and diencephalic aminergic systems including the substantia nigra and on sensory and autonomic responses which involve the medulla and spinal cord. When applied to the CNS they alter multiple unit activity in certain regions, particularly the hippocampus and cells which contain neural lobe hormones appear to be able to drive other cells synaptically. Finally application of the hormones can profoundly affect the activity of single nerve cells in just those parts of the CNS where, on the basis of their behavioral actions, they might be expected to act.

Animals↗

PubMed1984

The study of brain function impairment in fetal alcohol syndrome: some fruitful directions for research.

Fetal alcohol syndrome (FAS) is the most prevalent known preventable health hazard to the human fetus by a noxious agent. It is associated with impairments of the central nervous system that are expressed in the forms of mental retardation of varying severity, learning disabilities, attentional deficits and an increased vulnerability to stress. Results of psychophysiological studies of the effects of ethanol on the central nervous system are reviewed, with the aim of exploring how conclusions derived from them can serve as testable hypotheses in FAS research. The experimental methods used in such studies are examined for their applicability to FAS research. It is concluded that FAS research effort will benefit from the inclusion of psychophysiological studies.

Brain↗

PubMedDate not supplied

Assessing brain function in post-traumatic coma by means of bit-mapped SEPs, BAEPs, CT, SPET and clinical scores. Prognostic implications.

Sixty-eight severely head injured comatose patients were studied. Bit-colour-mapped SEPs to median nerve stimulation, BAEPs, CT and SPET regional values and ICP were assessed in relation to clinical information in evaluating cerebral function. All these variables were related to a 1-year outcome. Statistical tests confirmed the higher predictive reliability of both neurophysiological and perfusive (SPET) functional parameters compared to CT structural findings. Generally, SEPs appeared to be more reliable in predicting outcome than BAEPs. Modifications of frontal components could occur independently of post-central ones, being closely related to underlying cerebral lesions. The parameter showing the greatest correlation with outcome in the first recording session was the P25 latency, whereas this prognostic role was mainly assumed by the amplitude value of the frontal N30-P45 complex in a second recording session carried out during the third week following head trauma.

Adolescent↗

PubMed2003

Induced gamma-band activity and human brain function.

Oscillatory activity in the gamma-band range has been related both to gestalt perception and to cognitive functions such as attention, learning, and memory. After giving a brief account of recent findings from electroencephalography and intracortical recordings, the present review will focus on spectral activity in the magnetoencephalogram. Here, gamma-band effects are topographically more local and involve higher frequencies than in the electroencephalogram. Bottom-up-driven auditory spatial mismatch detection elicits gamma-band activity over posterior parietal cortex, whereas auditory pattern mismatch processing leads to gamma-band enhancements over anterior temporal and inferior frontal regions. These topographies support representations of auditory spatial and pattern information in the putative dual auditory "where" and "what" pathways, respectively. During top-down-guided auditory spatial and pattern-working memory tasks, prefrontal gamma-band increases are observed in addition to activations over putative auditory stream areas. Moreover, stimulus maintenance in working memory is accompanied by coherence increases between sensory and prefrontal regions. Gamma-band topographies in magnetoencephalogram are highly comparable with hemodynamic brain imaging studies but yield additional information on the temporal dynamics of activations and connectivity patterns. In summary, magnetoencephalographic gamma-band activity revealed both local synchronization patterns and cortico-cortical interactions accompanying cognitive processes at a good spatial and high temporal resolution.

Animals↗

PubMed1997

[Brain functional MRI using 3D-SPGR pulse sequence].

We reported the effects of motor cortex stimulation of normal volunteers using conventional MR imaging techniques on standard 1.5 T clinical scanner. The imaging technique was an optimized conventional 2D and 3D spoiled GRASS. In the 3D-SPGR measurement, a slab of 96 mm with 32 partition was evaluated in sagital direction. The motor cortex stimulation was achieved by touching each finger to thumb in a sequential, self-paced, and repetitive manner. During stimulation, areas of increased signal intensity were identified in the sensorimotor cortex with both 2D and 3D SPGR method. The 3D-SPGR method in sagital direction is rather insensitive to inflow effects, thus signal increases with 3D-SPGR method is mainly due to the blood oxygenation level dependent effects.

Brain↗

PubMed1998

Developmental regulation of pituitary adenylate cyclase activating polypeptide (PACAP) and its receptor 1 in rat brain: function of PACAP as a neurotrophic factor.

To function as a trophic factor PACAP and PACAP-R must be expressed in the nervous system during early development. We report here on the distribution of PACAP mRNA in the developing nervous system of the rat and compare its expression with that of PACAP-R. We discuss primary neuron culture experiments that study the neurotrophic activity of PACAP. Experimental results that indicate the presence of PACAP and its receptor in the developing nervous system, together with the observed neuropeptide activity on various populations of neurons, support the view that PACAP exhibits important neurotrophic activities comparable to those of the classical neurotrophic factors.

Animals↗

PubMed1987

[Experimental study of evoked potentials in predicting the reversibility of brain function following tentorial herniation].

Brainstem auditory evoked potentials (BAEP), somatosensory evoked potentials (SEP) and EEG were recorded sequentially in cat with mass-induced intracranial hypertension in correlation with mass volume, intracranial pressure (ICP), systemic blood pressure (BP) and size of the pupils. 1) As the intracranial pressure was raised by expansion of a supratentorial epidural balloon, suppression of cortical SEP (CSEP) and pupillary abnormality appeared first, EEG, waves IV and III of BAEP and wave III of short latency SEP (SSEP) were suppressed in this order. 2) As far as wave IV of BAEP remained and decompression was started within 30 minutes after peaks of CSEP completely suppressed, changes in P1 and N1 of CSEP were reversible. 3) Further raising of ICP was followed by loss of waves IV and III of BAEP and wave III of SSEP in this order. Simultaneously with loss of wave III in SSEP, systemic blood pressure dropped rapidly. By immediate balloon deflation after disappearance of wave III of SSEP, animals recovered from hypotension, but hardly from suppression in EEG, CSEP and BAEP. 4) Preservation of wave IV of BAEP indicated good improvement of pupillary abnormality even after removal of compression. These results suggest that for the patient with disturbed consciousness caused by supratentorial mass lesion, decompressive procedure should be started before wave V of BAEP and brainstem components of SEP disappear. EP monitor seems to be useful clinical method for preventing irreversible change of the brain in patients with coma caused by supratentorial mass lesions.

Animals↗

PubMed1989

Does kallikrein improve the brain function in dementia?

Forty biological units of Kallikrein were administered intramuscularly to nine persons suffering from multi-infarct dementia. With automatic analysis equipment, the wave-form recognition method was used to analyze EEG before injection, immediately after injection, and 30, 60, 90, and 120 minutes after injection. The results of analysis done the five times after injection were then compared with the analysis results before injection. With the passage of time after injection, delta and theta waves showed a gradually decreasing tendency, while alpha and beta waves showed a gradual increase. It was inferred that these changes in the EEG were caused by an increase in the flow of cerebral blood, which in turn was the effect of the dilatation of cerebral blood vessels resulting from the action of the Kallikrein.

Aged↗

PubMed2005

Constitutive neuronal expression of CCR2 chemokine receptor and its colocalization with neurotransmitters in normal rat brain: functional effect of MCP-1/CCL2 on calcium mobilization in primary cultured neurons.

Chemokines and their receptors are well described in the immune system, where they promote cell migration and activation. In the central nervous system, chemokine has been implicated in neuroinflammatory processes. However, an increasing number of evidence suggests that they have regulatory functions in the normal nervous system, where they could participate in cell communication. In this work, using a semiquantitative immunohistochemistry approach, we provide the first neuroanatomical mapping of constitutive neuronal CCR2 localization. Neuronal expression of CCR2 was observed in the anterior olfactory nucleus, cerebral cortex, hippocampal formation, caudate putamen, globus pallidus, supraoptic and paraventricular hypothalamic nuclei, amygdala, substantia nigra, ventral tegmental area, and in the brainstem and cerebellum. These data are largely in accordance with results obtained using quantitative autoradiography with [(125)I]MCP-1/CCL2 and RT-PCR CCR2 mRNA analysis. Furthermore, using dual fluorescent immunohistochemistry we studied the chemical phenotype of labeled neurons and demonstrated the coexistence of CCR2 with classical neurotransmitters. Indeed, localization of CCR2 immunostaining is observed in dopaminergic neurons in the substantia nigra pars compacta and in the ventral tegmental area as well as in cholinergic neurons in the substantia innominata and caudate putamen. Finally, we show that the preferential CCR2 ligand, MCP-1/CCL2, elicits Ca(2+) transients in primary cultured neurons from various rat brain regions including the cortex, hippocampus, hypothalamus, and mesencephalon. In conclusion, the constitutive neuronal CCR2 expression in selective brain structures suggests that this receptor could be involved in neuronal communication and possibly associated with cholinergic and dopaminergic neurotransmission and related disorders.

Animals↗

PubMedDate not supplied

Effects of the novel neuroprotective agent, riluzole, on human brain function and behavior: II. Double-blind, placebo-controlled EEG mapping and psychometric studies under hypoxia.

In a double-blind, placebo-controlled study, the antihypoxidotic properties of the novel neuroprotective agent, riluzole, were investigated utilizing blood gas analysis, EEG mapping and psychometry under a transient, reversible, hypoxic hypoxidosis. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2) (found at 6000 m altitude), which was inhaled for 23 min under normobaric conditions by 20 healthy, young volunteers. They randomly received, after an adaptation session, single oral doses of placebo, and 50, 100 and 200 mg riluzole. Evaluation of blood gases, EEG mapping and psychometry were carried out 0, 2, 4, 6 and 8 h postdrug, each time under the 23-min hypoxia. Blood gas analysis demonstrated a drop in PO2 from 106 to 37 and 36 mmHg, in PCO2 from 35 to 31 and 31 mmHg at 14 and 23 min of inhalation, respectively, while pH increased from 7.43 to 7.48 and 7.48. Base excess and standard bicarbonate remained stable. EEG mapping exhibited under hypoxia a marked increase of delta/theta, decrease of alpha and an increase of superimposed beta activity, as well as a slowing of the centroid of the total activity, which reflects deterioration of vigilance. Riluzole in lower doses and at early hours after higher doses did not attenuate this hypoxia-induced vigilance decrement, while with higher doses (100-200 mg) in later recording periods (6-8 h) brain protection occurred. As compared with placebo, delta/theta power increased at 2-8 h after 50 mg riluzole and up to 4 h after 100 mg riluzole, while a decrease occurred at 4 and 8 h after 100 mg and at 6-8 h after 200 mg. Alpha power showed no changes after 50 mg, an increase at 2 and 8 h after 100 mg and a decrease at 4 h after 200 mg, with no changes thereafter. Beta power decreased at various times after all three doses. At the behavioral level, hypoxic hypoxidosis induced a deterioration of the noopsyche, which was not mitigated by riluzole. In regard to the thymopsyche, there was even a slight deterioration after all three doses, as compared with placebo.

Adult↗

PubMed1999

Are brain functions really additive?

Although Positron Emission Tomography (PET) and functional magnetic resonance imaging (fMRI) studies commonly subtract data obtained during two or more experimental conditions to decompose a complex task, there have been few opportunities to evaluate this approach directly. In the present study, PET was used to study three motor speech tasks selected such that two were constituent components of the third, making possible a direct examination of decomposition by subtraction. In Experiment 1, a group of 13 right-handed normal volunteers participated in three activation studies: syllable repetition; phonation; and repetitive lip closure. A scanning session was devoted to a single task, repeated four times. In Experiment 2, six of the original subjects performed the same three activation studies during a single scanning session. Whether tasks were studied in separate scanning sessions or combined within a single session, the results of decomposition by compound subtraction differed significantly from the results obtained when individual tasks were compared to a simple baseline condition. These data failed to demonstrate task additivity, a necessary property if decomposition by subtraction is to provide an accurate characterization of the brain activity accompanying complex behavior.

Adult↗

PubMed1994

Quantum optical coherence in cytoskeletal microtubules: implications for brain function.

'Laser-like,' long-range coherent quantum phenomena may occur biologically within cytoskeletal microtubules. This paper presents a theoretical prediction of the occurrence in biological media of the phenomena which we term 'superradiance' and 'self-induced transparency'. Interactions between the electric dipole field of water molecules confined within the hollow core of microtubules and the quantized electromagnetic radiation field are considered, and microtubules are theorized to play the roles of non-linear coherent optical devices. Superradiance is a specific quantum mechanical ordering phenomenon with characteristic times much shorter than those of thermal interaction. Consequently, optical signalling (and computation) in microtubules would be free from both thermal noise and loss. Superradiant optical computing in networks of microtubules and other cytoskeletal structures may provide a basis for biomolecular cognition and a substrate for consciousness.

Animals↗

PubMed1996

Brain functional imaging SPECT in agyria-pachygyria.

Agyria-pachygyria or lissencephaly type I, a diffuse cortical malformation, provides infantile spasms (IS) which are refractory and persisting after the first decade, an age at which IS have disappeared in the other causes. In order to study the functional postnatal development of the lissencephalic cortex, we measured regional cerebral blood flow (rCBF) using SPECT (Single photon emission computed tomography) and 133Xe in 14 children with lissencephaly, aged from 4 months to 12 years (mean = 40 months) compared to normal children of the same age range and to children with cryptogenic IS aged from 3 months to 3 years (mean = 13 months). rCBF was calculated in frontal (FR) and parieto-temporo-occipital (PTO) cortex as well as the ratio FR/PTO. FR/PTO was higher in lissencephalic patients than in controls (P < 0.001) due to higher FR rCBF (P < 0.001), particularly in patients aged less than 3 years. FR/PTO was also higher in lissencephalic patients than in patients with cryptogenic IS (P < 0.001) also due to higher FR rCBF (P < 0.001). The values of FR/PTO and FR rCBF remained stable during the first years of life and did not exhibit any age- or topography-related changes as they do in controls or in patients with cryptogenic IS. There results suggest that the normal process of postnatal development in the brain is lacking in agyria-pachygyria. That could play a role in determining the persistence of epileptic spasms, the specific seizure type of this malformation.

Aging↗

PubMed2004

Language-related brain function during word repetition in post-stroke aphasics.

We compared fMRI findings (using SPM99) obtained with repetition task in normal subjects with those of two patients with Broca's and Wernicke's aphasia who received speech therapy and showed complete recovery. Both aphasic patients with left hemisphere damage who showed complete recovery exhibited activation of only the compensatory area in the right hemisphere during the repetition task. Recovery from Broca's aphasia involves reorganization and neuromodulation between the external temporopolar area and the anterior superior temporal area of the superior temporal gyrus, putamen and the inferior frontal gyrus, while that from Wernicke's aphasia involves reorganization and neuromodulation between the superior temporal gyrus of the temporal region, the posterior supramarginal gyrus and inferior parietal lobule of the parietal region.

Adult↗

PubMed1987

Positron emission tomography study of human brain functional development.

From over 100 children studied with 2-deoxy-2[18F]fluoro-D-glucose and positron emission tomography we selected 29 children (aged 5 days to 15.1 years) who had suffered transient neurological events not significantly affecting normal neurodevelopment. These 29 children were reasonably representative of normal children and provided an otherwise unobtainable population in which to study developmental changes in local cerebral metabolic rates for glucose (lCMRGlc). In infants less than 5 weeks old lCMRGlc was highest in sensorimotor cortex, thalamus, brainstem, and cerebellar vermis. By 3 months, lCMRGlc had increased in parietal, temporal, and occipital cortices; basal ganglia; and cerebellar cortex. Frontal and dorsolateral occipital cortical regions displayed a maturational rise in lCMRGlc by approximately 6 to 8 months. Absolute values of lCMRGlc for various grey matter regions were low at birth (13 to 25 mumol/min/100 gm), and rapidly rose to reach adult values (19 to 33 mumol/min/100 gm) by 2 years. lCMRGlc continued to rise until, by 3 to 4 years, it reached values of 49 to 65 mumol/min/100 gm in most regions. These high rates were maintained until approximately 9 years, when they began to decline, and reached adult rates again by the latter part of the second decade. The highest increases of lCMRGlc over adult values occurred in cerebral cortical structures; lesser increases were seen in subcortical structures and in the cerebellum. This time course of lCMRGlc changes matches that describing the process of initial overproduction and subsequent elimination of excessive neurons, synapses, and dendritic spines known to occur in the developing brain. The determination of changing metabolic patterns accompanying normal brain development is a necessary prelude to the study of abnormal brain development with positron emission tomography.

Adolescent↗

PubMed2000

A cultural effect on brain function.

We present behavioral and anatomical evidence for a multi-component reading system in which different components are differentially weighted depending on culture-specific demands of orthography. Italian orthography is consistent, enabling reliable conversion of graphemes to phonemes to yield correct pronunciation of the word. English orthography is inconsistent, complicating mapping of letters to word sounds. In behavioral studies, Italian students showed faster word and non-word reading than English students. In two PET studies, Italians showed greater activation in left superior temporal regions associated with phoneme processing. In contrast, English readers showed greater activations, particularly for non-words, in left posterior inferior temporal gyrus and anterior inferior frontal gyrus, areas associated with word retrieval during both reading and naming tasks.

Adult↗

PubMed1996

Brain functional profiles in formal and semantic fluency tasks: a SPECT study in normals.

SPECT method is used to analyze changes in regional cerebral blood flow in a group of 19 normal subjects during a baseline task (repetition of two words) and two verbal fluency tasks, a semantic fluency and a formal fluency. The semantic fluency task was associated with a relative CBF increase in the right dorso-lateral and medial frontal region when compared with that seen in the baseline condition. No specific activation was found for the formal fluency task compared to that seen in the baseline task. We suggest that the activation of the right frontal region reflects semantic categorization strategies in semantic fluency. The lack of activation of the left frontal region may be due to an activation induced by the nature of the baseline task (i.e., a self-paced repetition task).

Adult↗

PubMed2001

Anterior brain functions and hypnosis: a test of the frontal hypothesis.

Neuropsychological frontal lobe tests were used to compare individuals with high (n = 8) and low (n = 9) hypnotizability during both baseline and hypnosis conditions. Subjects were assessed on two hypnotic susceptibility scales and a test battery that included the Stroop test, word fluency to letter- and semantic-designated categories, tests of simple reaction time and choice reaction time, a vigilance task, and a questionnaire of 40 self-descriptive statements of focused attention. Effects for hypnotic susceptibility and hypnosis/control conditions were scant across the dependent variables. High hypnotizables scored higher on the questionnaire at baseline, and their performance on the word-fluency task during hypnosis was reduced to a greater extent than lows. Findings indicate that although the frontal area may play an important role regarding hypnotic response, the mechanisms seem to be much more complex than mere general inhibition.

Adult↗