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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transcranial magnetic stimulation has been suggested as a possible therapeutic tool in depression. In behavioral models of depression, magnetic stimulation induced similar effects to those of electroconvulsive shock. This study demonstrates the effect of a single session of rapid TMS on tissue monoamines in rat brain. Alterations in monoamines were selective and specific in relation to brain areas and type of monoamine. The results imply on a biochemical basis to the suggested ECT-like treatment potential of TMS.
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PMID:Transcranial magnetic stimulation induces alterations in brain monoamines. 920 81

Repetitive magnetic stimulation (rTMS) is a non-invasive, painless method to induce transient activation in circumscript regions of the human cortex. In contrast to TMS with single pulses rTMS allows a more effective stimulation of association cortex and temporary interference with the proper functioning of stimulated areas. Possible applications for examination of the functional anatomy of language lateralisation, memory functions and visual perception are discussed. Possible therapeutic for movement disorders and depression are discussed. On the basis of theoretical considerations and current experience rTMS induced epileptogenic effects are discussed and safety recommendations are given.
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PMID:[Repetitive transcranial magnetic stimulation. Possibilities, limits and safety aspects]. 978 79

Repetitive transcranial magnetic stimulation (rTMS) has been shown to affect mood in health and disease. Evidence to date has demonstrated an antidepressant potential for low- and high-frequency rTMS treatment. In animal behavioral models of depression magnetic stimulation of the brain induced similar effects to those of electroconvulsive shock (ECS). In this study the effects of repeated rTMS on rat brain noradrenaline, dopamine, serotonin and their metabolites levels, as well as on beta-adrenergic and 5-HT2 receptor characteristics were studied. After 10 days of treatment, beta-adrenergic receptors were significantly up regulated in the frontal cortex, down regulated in the striatum and were unchanged in the hippocampus. 5-HT2 receptors were down regulated in the frontal cortex and were not changed in the other brain areas. No change in benzodiazepine receptors in the frontal cortex and cerebellum were demonstrated. These findings demonstrate specific and selective alterations induced by repeated rTMS, which are distinct from those induced by other antidepressant treatments. TMS therapeutic effects in humans and behavioral and biochemical effects in animal, suggest that TMS has a unique mechanism of action which requires further investigation.
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PMID:Chronic repetitive transcranial magnetic stimulation alters beta-adrenergic and 5-HT2 receptor characteristics in rat brain. 987 93

Major depression may result from decreased left frontal lobe function with respect to the right. Fast frequency repetitive transcranial magnetic stimulation (FF r-TMS) excites the underlying cortex whereas slow frequency repetitive transcranial magnetic stimulation (SF r-TMS) causes cortical inhibition. Left frontal FF r-TMS attenuates major depression whereas the inhibitory effects of right frontal SF r-TMS are unknown. This study tested the hypothesis that right frontal SF r-TMS would treat depressed patients with minimal effect on controls. A psychiatrist administered the Beck depression inventory and Hamilton D depression rating scales to eight depressed patients and six controls before and after the treatment protocol. Eight sessions of 100 right frontal lobe SF r-TMS were given at motor threshold and 0.5 Hz over a 6 week period. No adverse outcomes were noted in either group. A significant antidepressant effect was noted in depressed patients on the Beck and Hamilton D depression rating scales (p<0.05). No change on either scale was noted in the controls. In conclusion right frontal lobe SF r-TMS is a safe, non-invasive treatment for major depression that deserves further investigation.
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PMID:Right frontal lobe slow frequency repetitive transcranial magnetic stimulation (SF r-TMS) is an effective treatment for depression: a case-control pilot study of safety and efficacy. 1036 35

TMS is a powerful new tool with extremely interesting research and therapeutic potentials. Further understanding of the ways by which TMS changes neuronal function, especially as a function of its use parameters, will improve its ability to answer neuroscience questions as well as to treat diseases. Because of its noninvasiveness, it does not readily fit under the umbrella of neurosurgery. Nevertheless, it is important for neurosurgeons to be aware of TMS, because findings from TMS studies will have implications for neurosurgical approaches like DBS and VNS. Indeed, it is possible to think of using TMS as a potential noninvasive initial screening tool to identify whether perturbation of a circuit has short-term clinical effects. In the example of chronic refractory depression or OCD, which is generally a chronic illness, it might then follow that rather than having daily or weekly TMS for the rest of their lives, patients would have DBS electrodes implanted in the same circuit. Whatever road the future takes, TMS is an important new tool that will likely be of interest to neurosurgeons over the next 20 years and perhaps even longer.
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PMID:Transcranial magnetic stimulation. 1285 95

Low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) can depress the excitability of the cortex locally and has been proposed for the treatment of disorders such as schizophrenia and epilepsy. Some have speculated that the depressant effect is related to long-term depression (LTD) of cortical synapses. Because in vitro LTD can be enhanced by pretreatment of synapses with higher-frequency stimulation, we hypothesized that if rTMS depression had mechanisms in common with LTD, higher-frequency priming would increase it also. In 25 healthy volunteers in two experiments, we measured motor-evoked potentials (MEPs) from TMS of the motor cortex to define the baseline response. Subthreshold rTMS (6 Hz, fixed rate or frequency modulated) was used to prime the motor cortex, followed by suprathreshold 1 Hz stimulation for 10 min at just above the MEP threshold. Over the next 60 min, we recorded MEPs every 10 sec and found significant increases in the amount of cortical depression with both types of 6 Hz priming rTMS relative to sham. The MEP depression from 6 Hz-primed 1 Hz rTMS showed no evidence of decay after 60 min. Pretreatment with 6 Hz primes both 1 Hz rTMS depression and LTD. Although not conclusive evidence, this strengthens the case for overlapping mechanisms and suggests a potent new technique for enhancing low-frequency rTMS depression that may have experimental and clinical applications.
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PMID:Priming stimulation enhances the depressant effect of low-frequency repetitive transcranial magnetic stimulation. 1464 80

The effect of mechanical ventilation on the diaphragm motor cortex remains unknown. We assessed the effect of mechanical ventilation on diaphragm motor cortex excitability by measuring the costal and crural diaphragm motor-evoked potential (MEP) elicited by single and paired transcranial magnetic stimulation. In six healthy subjects, MEP recruitment curves of the costal and crural diaphragms were assessed at relaxed end expiration during spontaneous breathing [baseline tidal volume (Vt(baseline))] and isocapnic volume cycled ventilation delivered noninvasively (NIV) at three different levels of tidal volume (Vt(baseline), Vt(baseline) + 5 ml/kg liters, and Vt(baseline) + 10 ml/kg liters). The costal and crural diaphragm response to peripheral stimulation of the right phrenic nerve was not reduced by NIV. NIV reduced the costal and crural MEP amplitude during NIV (P < 0.0001) with the maximal reduction at Vt(baseline) + 5 ml/kg. Response to paired TMS showed that NIV (Vt(baseline) + 5 ml/kg) significantly increased the sensitivity of the cortical motoneurons to facilitatory (>9 ms) interstimulus intervals (P = 0.002), suggesting that the diaphragm MEP amplitude depression during NIV is related to neuromechanical inhibition at the level of motor cortex. Our results demonstrate that mechanical ventilation directly inhibits central projections to the diaphragm.
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PMID:Depression of diaphragm motor cortex excitability during mechanical ventilation. 1502 May 75

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive tool used to manipulate activity in specific neural circuits of the human brain. Clinical studies suggest that, in some patients with major depression, rTMS has the potential to alleviate symptoms that may be related to functional abnormalities in a frontocingulate circuit. This paper reviews the rationale for the use of rTMS in this context. The following topics are discussed: symptoms and cognition in major depression, with special emphasis on the initiation of speech; neuroimaging studies of depression; rTMS as treatment for depression; structure and function of the mid-dorsolateral frontal and anterior cingulate cortices; and combined TMS/positron emission tomography studies of frontocortical connectivity.
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PMID:Transcranial magnetic stimulation (TMS) of the human frontal cortex: implications for repetitive TMS treatment of depression. 1530 43

This study examined whether muscle fatigue alters the facilitatory effect of motor imagery on corticospinal excitability. We aimed to determine if post-exercise depression of potentials evoked magnetically from the motor cortex is associated with alterations in internally generated movement plans. In experiment 1, motor-evoked potentials (MEPs) were recorded from two right hand and two right forearm muscles, at rest and during motor imagery of a maximal handgrip contraction, in eight neurologically normal subjects, before and after a 2-min maximal voluntary handgrip contraction. Resting MEP amplitude was facilitated by motor imagery in three of the four muscles, but consistently only in two. Motor imagery also reduced the trial-to-trial variability of resting MEPs. Following the exercise, resting MEP amplitude was depressed reliably in only one muscle engaged in the task, although two other muscles exhibited some depression. Motor imagery MEPs were smaller after exercise, but the degree of facilitation compared to the rest MEP was unchanged. In experiment 2, TMS intensity was increased after exercise-induced MEP depression so that the MEP amplitude matched the pre-exercise baseline. The amplitude of the MEP facilitated with motor imagery was not altered by MEP depression, nor was it increased when the TMS intensity was increased. These results suggest, at least with a simple motor task, that while post-exercise depression reduces corticospinal excitability, it does not appear to significantly affect the strength of the input to the motor cortex from those areas of the brain responsible for the storage and generation of internal representations of movement.
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PMID:Facilitation of cortically evoked potentials with motor imagery during post-exercise depression of corticospinal excitability. 1550 93

Vagal nerve stimulation (VNS) is used as a treatment for Epilepsy and is currently under investigation as a treatment for depression (see [M.S. George, Z. Nahas, X. Li, F.A. Kozel, B. Anderson, K. Yamanaka, J.H. Chae, M.J. Foust, Novel treatments of mood disorders based on brain circuitry (ECT, MST, TMS, VNS, DBS), Semin. Clin. Neuropsychiatry 7 (2002) 293-304; M.S. George, A.J. Rush, H.A. Sackeim, L.B. Marangell, Vagus nerve stimulation (VNS): utility in neuropsychiatric disorders, Int. J. Neuropsychopharmacol. 6 (2003) 73-83] for reviews). The mechanism of action of VNS is not fully understood [E. Ben-Menachem, Vagus-nerve stimulation for the treatment of epilepsy, Lancet Neurol. 1 (2002) 477-482] despite numerous imaging investigations (see [E. Ben-Menachem, Vagus-nerve stimulation for the treatment of epilepsy, Lancet Neurol. 1 (2002) 477-482; M.S. George, Z. Nahas, X. Li, F.A. Kozel, B. Anderson, K. Yamanaka, J.H. Chae, M.J. Foust, Novel treatments of mood disorders based on brain circuitry (ECT, MST, TMS, VNS, DBS), Semin. Clin. Neuropsychiatry 7 (2002) 293-304; M.S. George, A.J. Rush, H.A. Sackeim, L.B. Marangell, Vagus nerve stimulation (VNS): utility in neuropsychiatric disorders, Int J Neuropsychopharmacol 6 (2003) 73-83; M.S. George, H.A. Sackeim, L.B. Marangell, M.M. Husain, Z. Nahas, S.H. Lisanby, J.C. Ballenger, A.J. Rush, Vagus nerve stimulation. A potential therapy for resistant depression? Psychiatr. Clin. North Am. 23 (2000) 757-783] for reviews). However, there is some evidence to suggest that the locus coeruleus may play a role modulating the effects of VNS. This study investigated the effects of VNS (0.3mA), of sufficient intensity to recruit the A and B fibre components of the vagus [D.M. Woodbury, J.W. Woodbury, Effects of vagal stimulation on experimentally induced seizures in rats, Epilepsia 31 (Suppl. 2) (1990) S7-S19], on the discharge rate of single neurons from the locus coeruleus. This study is the first to demonstrate a direct neuronal response from the locus coeruleus following acute challenge of VNS in the anaesthetised rat. The results of this study indicate that neuronal activity of the locus coeruleus is modulated by VNS. This pathway through the locus coeruleus may be significant for mediating the clinical effects of VNS.
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PMID:Recordings from the rat locus coeruleus during acute vagal nerve stimulation in the anaesthetised rat. 1584 58


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