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Al- cerebral dysfunction has also been related to increased hos- though no other families with this specific MAO A point tility purchase cheap vardenafil online diabetic with erectile dysfunction icd 9 code. Verbal signal decoding and P300 amplitudes in an mutation have been reported vardenafil 10 mg mastercard erectile dysfunction over the counter medications, this report highlighted the evoked potential paradigm predicted impulsiveness and potential of the candidate gene approach to the molecular anger in prison inmates (147) cheap vardenafil 20mg on line erectile dysfunction yoga exercises. In terms of regional localiza- genetics of aggression. At about the same time, Nielson et tion, neuropsychological tasks sensitive to frontal and tem- al. Thus, neuropsychological and associated with a reduction of CSF 5-HIAA concentration cognitive studies do suggest that abnormalities of higher in impulsive violent offenders (nearly all with DSM-III integrative functions, consistent with reduced cortical in- IED) (134). In the same study, the presence of the L allele hibitory influences on aggression, result in more disinhibi- was also associated with history of suicide attempts in all tion of aggressive behaviors. Although this finding was not replicated laboratory paradigms may discriminate aggressive individu- by Abbar et al. The PSAP has been externally validated in violent offenders and more specifically for severe suicide attempts. However, sional measures of impulsive aggression (137). In this brief the heritability of these laboratory measures has not been report of only 21 personality-disordered subjects, those with systematically assessed in studies of families or sibs of impul- the LL genotype had significantly higher aggression scores sive or aggressive probands, a logical prerequisite to an endo- than subjects with the UU genotype. However, an associa- phenotypic approach to borderline personality disorder. It Neuroanatomy of Aggression may be that the TPH polymorphism is in linkage disequilib- rium with different genes in different populations. Lappa- Prefrontal cortex, particularly prefrontal orbital cortex and lainen et al. Astudy of a 5- roles in the generation of aggression as well. The critical HT6 receptor allelic variant in patients with schizophrenia role of prefrontal orbital cortex is exemplified by the case and in controls was negative for an association with aggres- of Phineas Gage, a solid, upstanding railroad worker, who, sive behavior (141). NEUROPSYCHOLOGY OF AGGRESSION Other clinical cases support the central role of orbital pre- frontal cortex in regulation of aggression (153–157). Irrita- The relationship between aggression and neuropsychology bility and angry outbursts have also been associated with is in part dependent on the syndrome in which aggression damaged orbital frontal cortex in neurologic patients (158), is observed. For example, the cognitive impairment of de- and frontal and temporal hypoperfusion has been noted mentia may be associated with aggressive behavior. Lesions of prefrontal lescents with conduct disorder, verbal processing deficits are cortex, particularly orbital frontal cortex, early in childhood associated with greater aggressiveness and antisocial behav- can result in antisocial disinhibited, aggressive behavior later ior (144). Low executive cognitive function is also related in life (160). Chapter 119: Pathophysiology and Treatment of Aggression 1715 Temporal lobe lesions have also been associated with a in orbital frontal cortex (176). These deficits were more susceptibility to violent behavior, as suggested by multiple pronounced in persons without psychosocial deprivation case reports of patients with temporal lobe tumors. In a study of patients with personality disorders, an study of violent patients, many anterior inferior temporal inverse relationship was found between life history of aggres- lobe tumors were reported (161,162), and aggressive behav- sive impulsive behavior and regional glucose metabolism ior has been associated with temporal lesions (163). Al- in orbital frontal cortex and right temporal lobe. Patients though temporal disease may express itself in a variety of meeting criteria for borderline personality disorder had de- ways, there does appear to be a clear association between creased metabolism in frontal regions corresponding to temporal pathology and aggressive behavior. Single photon emission computed tomography with rage attacks, and studies of patients who have under- studies have also suggested reduced perfusion in prefrontal gone amygdalectomy (164), although destructive behaviors cortex, as well as focal abnormalities in left temporal lobe have also been observed in the context of coagulation of the and increased activity in anteromedial frontal cortex in lim- amygdala (165). Patients with bilateral amygdala damage bic system in aggressive persons with reduced prefrontal judged unfamiliar persons to be more trustworthy than con- perfusion in antisocial personality-disordered alcoholism trols, a finding consonant with the role of the amygdala in (179), and hypoperfusion in the left frontoparietal region social judgments of potential threat (166). The association of violent behavior with aggressive be- Cingulate cortex has also been implicated especially in pos- havior with localized seizure activity provides a further guide terior regions in aggressive borderline patients (178), a find- to brain regions implicated in the modulation of aggression. However, only a few patients with temporal Extensive connections between amygdala and prefrontal lobe epilepsy engage in aggressive behaviors in the interictal cortex have been described, suggesting an inhibitory influ- or periictal periods (170–172). These clinical correlations, ence of frontal cortex on the amygdala (181). Amygdalo- although pointing to regions of interest for imaging studies, tomy has been associated with reduced aggressive outbursts cannot directly address the circuitry involved in impulsive in patients with intractable aggression (182), but there have aggression in the absence of specific neurologic disease. Imaging Neurotransmitter Systems in Structural Imaging and Aggression Aggression Reduced prefrontal gray matter has been associated with Serotonin autonomic deficits in patients with antisocial personality disorders characterized by aggressive behaviors (173). Al- Ascending serotonergic neurons from the raphe nuclei though these deficits are not visually perceptible, they reach project widely throughout the brain, including projections statistical significance and are consistent with the neurologic to dorsolateral prefrontal cortex and medial temporal lobe. Diffuse tracts extend from dorsal and medial raphe project Functional Imaging and Aggression to frontal lobe. Both 5-HT2A and 5-HT1A receptors are One technique used to identify brain activity in individuals found in high concentrations in human prefrontal cortex, as displaying aggressive behavior is the assessment of in vivo are 5-HT transporter sites (183), and patients with localized cerebral glucose metabolism through positron emission to- frontotemporal contusions show significantly lower 5-HT mography. Studies of this type tend to implicate brain hypo- metabolites in CSF than patients with diffuse cerebral con- metabolism in a variety of regions but particularly frontal tusions (184). Greater -CIT binding to 5-HT transporters and temporal cortex. In psychiatric patients with a history has also been reported in nonhuman primates with a higher of repetitive violent behavior, decreased blood flow consis- -CIT binding associated with greater aggressiveness (185). In a study of homicide gressive behavior in posterior orbital frontal cortex and me- offenders, bilateral diminution of glucose metabolism was dial frontal cortex in the amygdala, whereas increased 5- observed in both medial frontal cortex and at a trend level HT2A number in orbital frontal cortex, posterior temporal 1716 Neuropsychopharmacology: The Fifth Generation of Progress cortex, and amygdala have been correlated with prosocial may have a disinhibiting effect on the generation of aggres- behavior in primates (186). Thus, serotonergic modulation sion by amygdala and related structures. The administration of FEN has been shown to increase In animal studies, 1-methyl-4-phenyl-1,2,3,6-tetrahydro- cortical metabolism in frontal, temporal, and parietal cortex pyridine–induced unilateral striatal dopamine deficiency in (187–189). In a study of depressed patients that included vervet monkeys was associated with increased frequency of patients with a comorbid diagnosis of borderline personality aggressive behaviors toward other members of the group in disorder and a history of suicide attempts, activation of cor- the monkey colony (193). Greater heterogeneity was also tex including orbital and cingulate cortex was significantly found in striatal dopamine transporter density, as assessed by 123I( -CIT distribution) of impulsive violent offenders blunted in the depressed patients, particularly in those who attempted suicide, compared with the control subjects. The than controls (88), a finding possibly consistent with hy- depressed patients showed no significant changes in their potheses that aggressive behavior is associated with increased glucose metabolic response to FEN compared with placebo, dopaminergic transmission in contrast to the controls (189). In another study, intrave- nous administration of m-CPP in patients with alcoholism resulted in blunted glucose metabolic responses in right or- PHARMACOLOGIC TREATMENT OF bital frontal cortex, left anterolateral prefrontal cortex, pos- AGGRESSION terior cingulate cortex, and thalamus compared with con- trols (190). In the first study directly comparing glucose The rational clinical psychopharmacology of aggressive be- havior began in the mid-1970s with the first placebo-con- metabolism after FEN and placebo in personality-disor- trolled, double-blind, study of lithium carbonate in prison dered patients with impulsive aggression, neurologically inmates (9). In this study, impulsive, but not premeditated normal subjects showed increased metabolism in orbital (or other antisocial behavior), aggression was reduced to frontal and adjacent ventral medial frontal cortex as well as extremely low levels during a 3-month course of treatment cingulate and inferior parietal cortex after FEN compared with lithium carbonate; levels of aggression remained un- with placebo, whereas impulsive-aggressive patients ap- changed in inmates treated with placebo. Notably, all gains peared to show significant increases only in the inferior pari- were lost within a month after a switch to placebo. Between-group comparisons demonstrated antiaggressive effect of lithium was replicated in subsequent blunted responses of glucose metabolism in orbital frontal, studies including a blinded placebo-controlled trial in hospi- ventral medial frontal, and cingulate cortex in the impulsive talized aggressive children with conduct disorder (194) and personality-disordered patients compared with the neuro- a blinded, placebo-controlled trial of 42 mentally disabled logically normal subjects.
Further- a 5-HT receptor-mediated increase in Ca2 influx has more generic 20mg vardenafil free shipping erectile dysfunction urethral medication, the effect of 5-HT on the membrane properties of 3 been described in a subpopulation of striatal nerve terminals these cells has not been examined trusted vardenafil 20 mg erectile dysfunction age statistics. Another electrophysiologic effect that may be mediated The first known protein G -coupleds 5-HT receptor cheap vardenafil uk erectile dysfunction treatment michigan, the 5- through 5-HT receptors that are positively coupled to ade- HT4 receptor, was identified on the basis of pharmacologic nylate cyclase is the enhancement of the hyperpolarizing- and biochemical criteria (e. The Ih channels, responses to adenylyl cyclase) (9). Subsequently, a receptor which are homologous to cyclic nucleotide-gated channels with matching pharmacologic and other properties was in specialized sensory neurons, are positively modulated by cloned and found to be expressed in various regions of the cAMP (153,154). An increase in Ih tends to prevent exces- brain (143). Two other 5-HT receptors positively coupled sive hyperpolarization and increase neuronal excitability. Because their pharma- a number of regions of the brain, including the thalamus cology differed from that of the previously described 5-HT4 (155), prepositus hypoglossi (156), substantia nigra zona site, they were designated as 5-HT6 and 5-HT7 receptors compacta (157), and hippocampus (158), 5-HT has been (144–146). At this time, electrophysiologic studies are avail- shown to enhance Ih through a cAMP-dependent mecha- able only for the 5-HT4 and 5-HT7 receptors and are de- nism. Results of a pharmacologic analysis with multiple scribed below. Recently, the first drug with selectivity Binding studies using a selective 5-HT4 ligand indicate that toward the 5-HT7 receptor was shown to block activation 5-HT4 receptors are present in several discrete regions of of adenylyl cyclase by 5-HT agonists in guinea pig hippo- the mammalian brain, including the striatum, substantia campus (33). The increasing availability of such selective nigra, olfactory tubercle, and hippocampus (147). Because drugs should greatly enhance the electrophysiologic evalua- these regions also express 5-HT4-receptor mRNA, it appears tion of G -coupleds 5-HT receptors. The best studied of these regions is the hippocampus, in which both biochemical and electro- INTRACELLULAR SIGNAL TRANSDUCTION physiologic studies have provided a detailed picture of the PATHWAYS actions of 5-HT at 5-HT4 receptors. Electrophysiologic Multiple Signaling Pathways: G Proteins studies show that 5-HT4 receptors mediate an inhibition and Second Messengers of a calcium-activated potassium current that is responsible for the generation of a slow after-hyperpolarization in hip- Multiple intracellular signaling pathways constitute a com- pocampal pyramidal cells of the CA1 region (74,148,149). Inhibition of adenylate cyclase 24 Neuropsychopharmacology: The Fifth Generation of Progress was the first intracellular pathway to be described for campal homogenates suggests that both the 5-HT4 and 5- Gi/o protein-coupled receptors, such as the 5-HT1A recep- HT7 receptors are involved in cAMP formation (adenylate tor. However, it is now clear that these receptors regulate cyclase isoform unknown) in the hippocampus (164). Inter- multiple signaling pathways and effector molecules (Fig. Although all these signals are sensitive to pertussis G11,G14, and G15/16) activate phospholipase C in a pertussis toxin, so that Gi/o proteins are implicated, they may be toxin-insensitive manner. Activation of phospholipase C mediated by distinct G protein complexes. For example, was the first signal transduction mechanism identified for coupling to GIRK channels is mediated by subunits the 5-HT2-receptor family and is essentially universal. This released from Gi (and possibly Go) proteins, whereas inhibi- probably reflects the wide distribution of G and the 2 q/11 tion of Ca channels is mediated by subunits released functional redundancy of these two G proteins. The profile of signaling molecules varies HT receptor has been shown to couple in a pertussis 2C from cell to cell, offering diverse signaling possibilities and toxin-sensitive manner to G in Xenopus oocytes (e. In con- receptor activation of phospholipase C is cell-type depen- trast, recent evidence suggests that phospholipase C activa- dent; this signal is mediated by G protein subunits and tion in a native setting (choroid plexus) is mediated entirely thus requires the presence of a -regulated phospholipase by G coupling (167). The subunits, generated by dissociation of to G with subsequent cytoskeletal rearrangement has been 13 the heterotrimeric Gi protein, also activate the type 2 iso- recently described in a transfected cell line (168). This activation is conditional, evidence suggests that 5-HT2A and 5-HT2C receptors cou- dependent on the coactivation by G s (i. Phospholipase A2 is a well-characterized inde- ing actions of G i and G do not offset each other. The pendent signal transduction pathway that leads to arachi- answer may lie in the details. In addition to the large family donic acid, with subsequent prostaglandin and leukotriene of G proteins (21 subunits, 5 subunits, and 11 sub- formation (169). Most of these in vascular smooth muscle and is also thought to be inde- molecules are found in the central nervous system. The G pendent of phospholipase C activation (170,171). The 5- protein that contributes activation of type 2 adenylate HT2Areceptor increases phospholipase D activity via a small cyclase is G i1 or G i2 heterotrimer (160), whereas all three G-protein ARF (adenosine diphosphate ribosylation factor) G i subunits ( i3 i2 i1) have the ability to inhibit pathway, with protein kinase C activation being the princi- adenylate cyclase types 5 and 6 (161). This type brain-derived neurotrophic factor expression in hippocam- of interaction has been shown to occur in brain, in which pus (173,174). In addition, a 5-HT2A receptor-mediated G -linkedi receptors enhance -adrenergic responses (162); increase in transforming growth factor- 1, secondary to a similar interaction may take place in cells that coexpress a 5-HT receptor family member with one of the 5-HT protein kinase C activation, has been described (175). The 1A receptors (5-HT , 5-HT , or 5-HT ) linked to activation 5-HT2A and 5-HT2C receptors elicit region-specific in- 4 6 7 of adenylate cyclase. Extensive, complex cross-talk between the 5-HT2A ond messenger pathways defined in brain, the 5-HT recep- and 5-HT2B receptor and the 5-HT1B/D receptor has been 4 tor was one of the last 5-HT receptors to be cloned (143). In transfected cells, the 5-HT6 receptor couples tion (177). Coactivation of the 5-HT2A receptor blocks this to adenylate cyclase type 5, the typical G s-sensitive isoform interaction by an unknown mechanism. In contrast, the 5-HT7receptor increases intracellular parallel, interacting, and converging intracellular signaling calcium, which activates calmodulin-stimulated adenylate pathways illustrate the complexity of receptor signaling, cyclase type 1 or 8. A recent characterization of rat hippo- even within a single receptor subclass. Examples of potential converging and interacting signaling pathways for 5-hydroxy- tryptamine-receptorsubtypes. Thisfigureillustrates onlyafew ofthenearly unlimitedpossibilities, depending on the cell phenotype. Also listed are additional effectors activated by one or another of these receptors with pathways of activation that have not yet been determined. Physiologic Correlates below for 5-HT1, 5-HT2, and 5-HT4 receptors, for which intracellular transduction pathways have been studied most In general, the electrophysiologic effects of 5-HT corre- intensively. The G /Gi o-coupled 5-HT1 5-HT1 Receptors receptors generally mediate inhibitory effects on neuronal firing through an opening of inwardly rectifying K chan- The opening of K channels via 5-HT1A receptors in dorsal nels or a closing of voltage-gated Ca2 channels. Inhibitions raphe neurons is mediated by pertussis toxin-sensitive G mediated by 5-HT1 receptors have been observed in neu- proteins (178,179). The molecular mechanisms underlying rons located in diverse regions of the central nervous system, the opening of K channels are most likely common to all ranging from pyramidal cells of the cerebral cortex and hip- neurotransmitter receptors that couple through the G /Gi o pocampus to serotoninergic neurons of the brainstem raphe family of G proteins. The Gq/11-coupled 5-HT2 family of receptors gener- activate a pertussis toxin-sensitive G protein that couples to ally mediates slow excitatory effects through a decrease in the opening of inwardly rectifying K channels through a K conductance or an increase in nonselective cation con- membrane-delimited pathway (74,180). Slow excitatory effects mediated by 5-HT2 recep- cepted that the rather than subunits regulate the chan- tors have been observed in a number of regions, including nels (181–183). The effector mechanism that ultimately the spinal cord and brainstem (e. Interestingly, at least where these receptors are most concentrated. The 5-HT one of the potassium K subunits identified in heart, 3 receptors, which are ligand-gated channels with structural GIRK-1, is expressed at high levels in hippocampus (184), homology to nicotinic cholinergic receptors, mediate fast which suggests that it might be involved in mediating the excitatory effects of 5-HT. Specific examples are given 5-HT1A receptor-induced hyperpolarization in this region.
More importantly purchase vardenafil visa impotence prostate, from of TMS over visual cortex can produce a subjective flash of the perspective of cognitive neuroscience 10mg vardenafil erectile dysfunction treatment by yoga, combining TMS light (or phosphene) buy vardenafil 10mg lowest price erectile dysfunction history. Precisely timed pulses can also inter- with functional imaging will open up new avenues for the fere with, or augment, other complex tasks (see ref. Thus, TMS alone without imaging has been used chain in brain–behavior relationships and is thus a powerful as a relatively spatially crude mapping technique, largely new research tool. In general, SPMs The first step in functional imaging is to find out which characterize experimentally elicited changes in terms of areas of the brain show activity (based on increased blood (multiple) activation foci. Regions of the SPM with high flow) when a subject performs some mental or physical task, or low values are interpreted as regional activations. The assumption is that the differences in the two sets of images represent the differences in brain activity during the test stimulus and during the control task. Functional and Effective Brain However, these are fairly subtle effects. A small change in Connectivity the signal can confound the data in unknown ways. The Intuitively, it is common to think of brain functional connec- fMRI signal is inherently noisy and often changes because tivity as two or more separate anatomic areas of the brain of instability of the instrumentation and environmental in- that influence each other in the performance of some mental fluences on the subject. For this reason, the problem of or physical task (e. Both in electrophysiology and functional neuroimaging, connectivity of different areas of the brain Determination of Regional Activation has been based on the correlation between regions. In the The concept of constructing an interpolated spatial map of case of electrophysiology, this means the EEG signal (24, a statistical parameter, significance probability mapping, was 27–32), and in functional neuroimaging, this means the developed in the analysis of multichannel electrophysiologic time course of regional blood flow or glucose use (18,21, (EEG) data (23,24). Fox and Mintun (16) introduced what they called change Friston et al. Present fMRI-processing meth- remote neurophysiologic events, and effective connectivity, odology draws on both these ideas. In its simplest form, a the influence of one neural system on another (i. Viewed in this tion of activation values for two different conditions during way, functional connectivity is simply the observed covari- the course of an experiment. To characterize distributed brain ence condition at that location). By using the associated p systems, the functional connectivity (covariance) matrix, values and the number of degrees of freedom, the t values obtained from a time series of neurophysiologic measure- can be converted to z values (gaussian distribution: mean ments, is subjected to principal component analysis (PCA) 0, variance 1) to obtain z maps. This is the basis for statistical (20,35) (Appendix II). The resulting eigenimages (principal parametric mapping (25), formally described as the con- components or spatial modes) each identify a spatially dis- struction of spatially extended statistical processes, or maps, tributed system, comprising regions of the brain that are to test a hypothesis (usually about neurophysiology) di- jointly implicated by virtue of their functional interactions rectly. Generally based on a linear and parametric model, (connectivity). This analysis of neuroimaging time series is statistical parametric maps (SPMs) are image processes with predicated on established techniques in electrophysiology voxel values that are, under the null hypothesis, distributed (both EEG and multiunit recordings). For example, in the according to a known probability density function, usually analysis of multichannel EEG data, the underlying spatial gaussian. In the same way that a t value is interpreted by modes that best characterize the observed spatiotemporal 396 Neuropsychopharmacology: The Fifth Generation of Progress dynamics are identified with a Karhunen–Loeve expansion. Transcranial Magnetic Stimulation as a Commonly, this expansion is in terms of the eigenvectors Probe to Alter Connectivity Networks of the covariance matrix associated with the time series. The Although the PCA and structural equation modeling tech- spatial modes are then identical to the principal components niques are well grounded statistically and quite powerful, identified with a PCA. The activity of two theoretically linked regions may Structural Equation Modeling be modulated, either directly or via changes in neurotrans- Principal component analysis and factor analysis approaches mitter release, by neurologic activity in a third region that attempt to integrate the spatially distributed activations is outside of the field of view of the imaging experiment, found in SPMs into functional systems characterized by the or has not been included in the structural equation anatomic eigenimages or spatial modes. The two regions may also be responding to different go further and explore the influence of one area on another aspects of the test stimulus, either inherently because of the (effective connectivity), not just the correlation (functional nature of the task, or because of engagement of the subject connectivity). Many anatomic connections are reciprocal, in performing the task. Structural equation modeling is an attempt to nerve connections, nerve excitability, and nerve conduction address this problem. One might think of this as two anatomic areas with In describing their neural structural equation models, a single connection. The anatomic model simply Medical University of South Carolina (42,43) demonstrated represents the discrete anatomic brain regions and the neu- that TMS might be combined with neuroimaging to explore roanatomic connections between them used in the struc- the connectivity of more complex three-dimensional net- tural equation models. These anatomic models have been works in the brain to allow the direct assessment of neural derived from the observation of patients with brain lesions connectivity without requiring the subject to engage in any and from animal studies, or inferred from neuroimaging specific behavior. The interregional correla- Because TMS seems to have a disruptive effect in most tions of activity are used to assign numeric weights to the areas of the brain, its most likely use will be to suppress the connections in the anatomic model, which leads to the func- activity of a region of the brain or disrupt communication tional model. A functional model, therefore, represents the between areas. This may be done by simply applying the influences of regions within the model on each other TMS pulse at the moment the task is performed or the through the anatomic connections, and both the magnitude stimulus is applied, and noting the changed response pat- and the sign of the path coefficients can be estimated. It may also turn out that it will be possible to apply some respects, the functional model is close to the notion TMS after a precisely timed delay to modulate responses of effective connectivity (20,37) because it depicts the influ- (44) and so investigate brain communications at time reso- ence of one region on another. The difference is that the lutions far greater than that of the hemodynamic response, influences in the functional model, unlike effective connec- approaching that of EEG. Thus, TMS provides a noninva- tions, are explicitly depicted as direct and indirect effects sive means of perturbing brain circuits both spatially and through the anatomic model. Effective connectivity, as de- at high temporal resolution. Because it is a noncognitive fined by Aertsen et al. In structural equation modeling, effective con- to basic neurophysiologic parameters such as nerve excitabil- nections, or total effects, are further decomposed into direct ity and conduction times. A similar distinction can be made in covariance analysis, which is often characterized as exploratory (objective) or confirma- tory (theoretical) analysis. PCA and factor analysis are essen- INTEGRATING TRANSCRANIAL MAGNETIC tially exploratory techniques because no constraints are STIMULATION WITH FUNCTIONAL placed on how the variance in the system is expressed. Struc- IMAGING: PROBLEMS AND CHALLENGES tural equation modeling is typically thought of as a confirm- atory approach (confirmatory factor analysis) because a Stimulating the brain with TMS while simultaneously im- causal model is usually being confirmed or disconfirmed aging brain activity presents a host of unique technical prob- (39). We discuss several of these issues and recent attempts at dealing with them. Placement of the Coil—Structural or Functional Guidance One of the most obvious problems in combining imaging and stimulation revolves around how to position the TMS coil over the skull. Most researchers have used either a struc- tural or functional guidance system. Structural Guidance The shape of the coil determines the magnetic field in the brain, and thus the pattern of induced electric current (7, 45). For circular coils, the magnetic field is most intense near the windings. When a circular coil is placed flat against the scalp, it induces a toroidal ring of electric current in the underlying cortex that is of the same size as the coil itself but more diffuse.
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In ischemic of new protein to exacerbate necrotic cell death. New evi- stroke, the blood supply to the brain is disrupted by cerebro- dence suggests that ischemic injury may also be exacerbated vascular disease. For decades, extensive research and clinical by the inducible proteins that mediate programmed cell approaches to combat stroke have focused on the vascular death. These mechanisms are appealing targets for therapeu- aspects of cerebral ischemia.
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