Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
2.
Public Underst Sci ; 33(1): 121-138, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37542420

RESUMEN

Political actors pay attention to newspapers because they stimulate them to address a topic, reflect public opinion, provide feedback to their decisions, and help them to generate effective messages. Previous surveys showed that this is true for scientific issues. It follows that the newspaper coverage of scientific issues should appear as politically oriented, as observed regarding climate change. Here, we tested this prediction regarding educational neuroscience. This scientific issue is interesting because it implies no major economic interest and because the relevance of neuroscience regarding teaching in the classroom is still highly controversial. As hypothesized, we observed that the French press appeared strongly polarized: the right-leaning press was mostly favorable to educational neuroscience, whereas critical opinions were mainly found in the social-democrat press. Although the relevance of neuroscience toward teaching was rarely discussed in scientific arguments, political actors often invoked educational neuroscience in the press to legitimate their decision.


Asunto(s)
Disentimientos y Disputas , Opinión Pública , Cambio Climático , Instituciones Académicas
3.
Med Sci (Paris) ; 37(11): 1035-1041, 2021 Nov.
Artículo en Francés | MEDLINE | ID: mdl-34851282

RESUMEN

In order to effectively contribute to scientific knowledge, biomedical observations have to be validated and debated by scientists in the relevant field. Along this debate that mainly takes place in the scientific literature, citation of previous studies plays a major role. However, only a few academic studies have quantitatively evaluated the suitability and accuracy of scientific citations. Here we review these academic studies. Two types of misuse have been pointed out: Citation bias and citation distortion. First, scientific citations favor positive results and those supporting authors' conclusion. Second, many statements linked to a reference actually misrepresent the referenced findings. About 10% of all citations in biomedicine are strongly inaccurate and misleading for the reader. Finally, we give two examples illustrating how some citation misuses do affect public health: The opioid crisis in the USA and the unjustified fostering of hydroxychloroquine for Covid-19 treatment in France.


TITLE: Le mésusage des citations et ses conséquences en médecine. ABSTRACT: Les observations biomédicales ne deviennent une source de connaissance qu'après un débat entre chercheurs. Au cours de ce débat, la citation des études antérieures tient un rôle majeur, mais les travaux académiques qui en évaluent l'usage sont rares. Ils ont cependant pu révéler deux types de problèmes : les biais de citation et les écarts de sens entre l'étude antérieure citée et ce qu'en dit l'article citant. Dans cette revue, nous synthétisons ces travaux et en dégageons les principales caractéristiques : les études favorables à la conclusion des auteurs citants sont plus souvent citées que celles qui les questionnent ; des écarts de sens majeurs affectent environ 10 % des citations. Nous illustrons par deux exemples les conséquences de ce mésusage des citations.


Asunto(s)
Salud Pública , Sesgo de Publicación , Publicaciones , Desinformación , Humanos , Epidemia de Opioides , Tratamiento Farmacológico de COVID-19
4.
Harv Rev Psychiatry ; 28(6): 395-403, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33156157

RESUMEN

Most experts in the field of psychiatry recognize that neuroscience advances have yet to be translated into clinical practice. The main message delivered to laypeople, however, is that mental disorders are brain diseases cured by scientifically designed medications. Here we describe how this misleading message is generated. We summarize the academic studies describing how biomedical observations are often misrepresented in the scientific literature through various forms of data embellishment, publication biases favoring initial and positive studies, improper interpretations, and exaggerated conclusions. These misrepresentations also affect biological psychiatry and are spread through mass media documents. Exacerbated competition, hyperspecialization, and the need to obtain funding for research projects might drive scientists to misrepresent their findings. Moreover, journalists are unaware that initial studies, even when positive and promising, are inherently uncertain. Journalists preferentially cover them and almost never inform the public when those studies are disconfirmed by subsequent research. This explains why reductionist theories about mental health often persist in mass media even though the scientific claims that have been put forward to support them have long been contradicted. These misrepresentations affect the care of patients. Indeed, studies show that a neuro-essentialist conceptualization of mental disorders negatively affects several aspects of stigmatization, reduces the chances of patients' healing, and overshadows psychotherapeutic and social approaches that have been found effective in alleviating mental suffering. Public information about mental health should avoid these reporting biases and give equal consideration to the biological, psychological, and social aspects of mental health.


Asunto(s)
Psiquiatría Biológica/normas , Medios de Comunicación , Salud Mental/normas , Publicaciones/normas , Psiquiatría Biológica/tendencias , Humanos , Salud Mental/tendencias , Estigma Social , Estereotipo
5.
Health (London) ; 24(6): 684-700, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-30854900

RESUMEN

Attention-deficit/hyperactivity disorder is the most frequent mental disorder among school-age children. This condition has given rise to a large mediatic coverage, which contributed to the shaping of the lay public's perceptions. We therefore conducted two studies on the way attention-deficit/hyperactivity disorder was portrayed in the TV programs and the lay-public press in France between 1995 and 2015, but the growing part played by the Internet required an additional study to analyze and compare the scientific material which is available to the French lay public depending on the source of information used. We studied the 50 first French websites dedicated to attention-deficit/hyperactivity as indexed by Google® search engine using a structured quantitative content analysis for the web. We illustrate our results with excerpts derived from the websites. The conceptions of attention-deficit/hyperactivity disorder available on the Internet are essentially biomedical and comprise an important level of scientific distortion. Findings concerning other mass media such as television programs and the press also demonstrate massive and systematic distortions caused by the role of experts and the pharmaceutical industry. Furthermore, the most consulted media present the highest level of scientific distortions.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Comunicación , Decepción , Conducta en la Búsqueda de Información , Internet , Televisión , Niño , Francia , Humanos
6.
Public Underst Sci ; 28(2): 191-200, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30370822

RESUMEN

News value theory rates geographical proximity as an important factor in the process of issue selection by journalists. But does this apply to science journalism? Previous observational studies investigating whether newspapers preferentially cover scientific studies involving national scientists have generated conflicting answers. Here we used a database of 123 biomedical studies, 113 of them involving at least one research team working in eight countries (Australia, Canada, France, Ireland, Japan, New Zealand, the United Kingdom, and the United States). We compiled all the newspaper articles covering these 123 studies and published in English, French, and Japanese languages. In all eight countries, we found that newspapers preferentially covered studies involving a national team. Moreover, these "national" studies on average gave rise to a larger number of newspaper articles than "foreign" studies. Finally, our study resolves the conflict with previous conclusions by providing an alternative interpretation of published observations.

7.
Int J Qual Stud Health Well-being ; 12(sup1): 1298244, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28532330

RESUMEN

Two models of attention deficit hyperactivity disorder (ADHD) coexist: the biomedical and the psychosocial. We identified in nine French newspapers 159 articles giving facts and opinions about ADHD from 1995 to 2015. We classified them according to the model they mainly supported and on the basis of what argument. Two thirds (104/159) mainly supported the biomedical model. The others either defended the psychodynamic understanding of ADHD or voiced both models. Neurological dysfunctions and genetic risk factors were mentioned in support of the biomedical model in only 26 and eight articles, respectively. These biological arguments were less frequent in the most recent years. There were fewer articles mentioning medication other than asserting that medication must be combined with psychosocial interventions (14 versus 57 articles). Only 11/159 articles claimed that medication protects from school failure. These results were compared to those of our two previous studies. Thus, both French newspapers and the specialized press read by social workers mainly defended either the psychodynamic understanding of ADHD or a nuanced version of the biomedical model. In contrast, most French TV programmes described ADHD as an inherited neurological disease whose consequences on school failure can be counteracted by a very effective medication.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/psicología , Actitud Frente a la Salud , Periódicos como Asunto , Opinión Pública , Trabajadores Sociales/psicología , Francia , Humanos
8.
R Soc Open Sci ; 4(2): 160254, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28386409

RESUMEN

Studies with low statistical power increase the likelihood that a statistically significant finding represents a false positive result. We conducted a review of meta-analyses of studies investigating the association of biological, environmental or cognitive parameters with neurological, psychiatric and somatic diseases, excluding treatment studies, in order to estimate the average statistical power across these domains. Taking the effect size indicated by a meta-analysis as the best estimate of the likely true effect size, and assuming a threshold for declaring statistical significance of 5%, we found that approximately 50% of studies have statistical power in the 0-10% or 11-20% range, well below the minimum of 80% that is often considered conventional. Studies with low statistical power appear to be common in the biomedical sciences, at least in the specific subject areas captured by our search strategy. However, we also observe evidence that this depends in part on research methodology, with candidate gene studies showing very low average power and studies using cognitive/behavioural measures showing high average power. This warrants further investigation.

9.
PLoS One ; 12(2): e0172650, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28222122

RESUMEN

OBJECTIVE: To investigate the replication validity of biomedical association studies covered by newspapers. METHODS: We used a database of 4723 primary studies included in 306 meta-analysis articles. These studies associated a risk factor with a disease in three biomedical domains, psychiatry, neurology and four somatic diseases. They were classified into a lifestyle category (e.g. smoking) and a non-lifestyle category (e.g. genetic risk). Using the database Dow Jones Factiva, we investigated the newspaper coverage of each study. Their replication validity was assessed using a comparison with their corresponding meta-analyses. RESULTS: Among the 5029 articles of our database, 156 primary studies (of which 63 were lifestyle studies) and 5 meta-analysis articles were reported in 1561 newspaper articles. The percentage of covered studies and the number of newspaper articles per study strongly increased with the impact factor of the journal that published each scientific study. Newspapers almost equally covered initial (5/39 12.8%) and subsequent (58/600 9.7%) lifestyle studies. In contrast, initial non-lifestyle studies were covered more often (48/366 13.1%) than subsequent ones (45/3718 1.2%). Newspapers never covered initial studies reporting null findings and rarely reported subsequent null observations. Only 48.7% of the 156 studies reported by newspapers were confirmed by the corresponding meta-analyses. Initial non-lifestyle studies were less often confirmed (16/48) than subsequent ones (29/45) and than lifestyle studies (31/63). Psychiatric studies covered by newspapers were less often confirmed (10/38) than the neurological (26/41) or somatic (40/77) ones. This is correlated to an even larger coverage of initial studies in psychiatry. Whereas 234 newspaper articles covered the 35 initial studies that were later disconfirmed, only four press articles covered a subsequent null finding and mentioned the refutation of an initial claim. CONCLUSION: Journalists preferentially cover initial findings although they are often contradicted by meta-analyses and rarely inform the public when they are disconfirmed.


Asunto(s)
Investigación Biomédica , Causalidad , Periodismo/normas , Periódicos como Asunto , Reproducibilidad de los Resultados , Bases de Datos Factuales , Conductas Relacionadas con la Salud , Humanos , Difusión de la Información , Medicina Interna , Factor de Impacto de la Revista , Estilo de Vida , Metaanálisis como Asunto , Neurología , Publicaciones Periódicas como Asunto , Psiquiatría , Factores de Riesgo
10.
PLoS One ; 11(6): e0158064, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27336301

RESUMEN

CONTEXT: There are growing concerns about effect size inflation and replication validity of association studies, but few observational investigations have explored the extent of these problems. OBJECTIVE: Using meta-analyses to measure the reliability of initial studies and explore whether this varies across biomedical domains and study types (cognitive/behavioral, brain imaging, genetic and "others"). METHODS: We analyzed 663 meta-analyses describing associations between markers or risk factors and 12 pathologies within three biomedical domains (psychiatry, neurology and four somatic diseases). We collected the effect size, sample size, publication year and Impact Factor of initial studies, largest studies (i.e., with the largest sample size) and the corresponding meta-analyses. Initial studies were considered as replicated if they were in nominal agreement with meta-analyses and if their effect size inflation was below 100%. RESULTS: Nominal agreement between initial studies and meta-analyses regarding the presence of a significant effect was not better than chance in psychiatry, whereas it was somewhat better in neurology and somatic diseases. Whereas effect sizes reported by largest studies and meta-analyses were similar, most of those reported by initial studies were inflated. Among the 256 initial studies reporting a significant effect (p<0.05) and paired with significant meta-analyses, 97 effect sizes were inflated by more than 100%. Nominal agreement and effect size inflation varied with the biomedical domain and study type. Indeed, the replication rate of initial studies reporting a significant effect ranged from 6.3% for genetic studies in psychiatry to 86.4% for cognitive/behavioral studies. Comparison between eight subgroups shows that replication rate decreases with sample size and "true" effect size. We observed no evidence of association between replication rate and publication year or Impact Factor. CONCLUSION: The differences in reliability between biological psychiatry, neurology and somatic diseases suggest that there is room for improvement, at least in some subdomains.


Asunto(s)
Susceptibilidad a Enfermedades/epidemiología , Susceptibilidad a Enfermedades/etiología , Vigilancia de la Población , Biomarcadores , Humanos , Trastornos Mentales/epidemiología , Trastornos Mentales/etiología , Enfermedades del Sistema Nervioso/epidemiología , Enfermedades del Sistema Nervioso/etiología , Publicaciones , Curva ROC , Reproducibilidad de los Resultados , Factores de Riesgo , Tamaño de la Muestra
11.
PLoS One ; 11(5): e0155940, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27195806

RESUMEN

CONTEXT: Previous studies suggested that many patients, who have given their informed consent to participate in randomized controlled trials (RCT), have somewhat limited understanding of what a placebo treatment is. We hypothesized that the relationship between patients and their health professionals plays a central role in this understanding. METHODS: We interviewed 12 patients included in RCTs (nine suffering from Parkinson's disease and three from Huntington's disease) and 18 health professionals involved with RCTs (eight principal investigators, four associated physicians and six clinical research associates). Semi-structured interviews were conducted after the RCTs had ended but before the treatment allocation was revealed. RESULTS: Only two patients clearly understood the aim of placebo-controlled RCTs. Only one principal investigator said she asks all her patients whether they agree to participate in RCTs. The seven others said they only ask patients who seem more likely to be compliant. Their selection criteria included docility and personality traits associated in other studies with enhanced placebo responses. According to 13 of the 18 health professionals, their relationship with patients may influence the amplitude of the placebo response. All but one clinical research associates added that the placebo response could result from a "maternal" type of care. All principal investigators said they have a strong influence on their patient's decision to participate. Finally, when interviewees were asked to narrate a memory of a medically unexplained healing, in eight of 11 physicians' narratives the beneficiary was a child while in 10 of 12 patients' narratives it was an adult. CONCLUSION: Our observations suggest that the interrelationship between health professionals and patients involved in RCTs could be compared to that between parents and children. Therefore, adherence to formal rules regarding informed consent does not ensure a balanced relationship between patients and health professionals.


Asunto(s)
Consentimiento Informado/normas , Relaciones Médico-Paciente , Placebos , Ensayos Clínicos Controlados Aleatorios como Asunto/normas , Conocimientos, Actitudes y Práctica en Salud , Personal de Salud/psicología , Personal de Salud/normas , Humanos , Enfermedad de Huntington/tratamiento farmacológico , Consentimiento Informado/psicología , Enfermedad de Parkinson/tratamiento farmacológico , Pacientes/psicología , Ensayos Clínicos Controlados Aleatorios como Asunto/psicología
12.
Public Underst Sci ; 24(2): 200-9, 2015 02.
Artículo en Inglés | MEDLINE | ID: mdl-23825292

RESUMEN

Biomedical findings mature from uncertain observations to validated facts. Although subsequent studies often refute initial appealing findings, newspapers privilege the latter and often fail to cover refutations. Thus, biomedical knowledge and media reporting may diverge with time. Here we investigated how French television reported on three scientific questions relative to attention deficit hyperactivity disorder (ADHD) from 1995 to 2010: i) is ADHD mainly genetic in origin, ii) does methylphenidate treatment decrease the risk of academic underachievement, and iii) are brain imaging techniques able to reveal ADHD in individual patients? Although scientific evidence regarding these questions has evolved during these 16 years, we observed that nine out of ten TV programs broadcast between 2007 and 2010 still expressed only opinions against the current scientific consensuses. The failure of TV programs to reflect the evolution of the scientific knowledge might be related to a biased selection of medical experts.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/psicología , Conocimiento , Ciencia , Televisión , Francia , Humanos
13.
PLoS One ; 7(9): e44275, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22984483

RESUMEN

CONTEXT: Because positive biomedical observations are more often published than those reporting no effect, initial observations are often refuted or attenuated by subsequent studies. OBJECTIVE: To determine whether newspapers preferentially report on initial findings and whether they also report on subsequent studies. METHODS: We focused on attention deficit hyperactivity disorder (ADHD). Using Factiva and PubMed databases, we identified 47 scientific publications on ADHD published in the 1990s and soon echoed by 347 newspapers articles. We selected the ten most echoed publications and collected all their relevant subsequent studies until 2011. We checked whether findings reported in each "top 10" publication were consistent with previous and subsequent observations. We also compared the newspaper coverage of the "top 10" publications to that of their related scientific studies. RESULTS: Seven of the "top 10" publications were initial studies and the conclusions in six of them were either refuted or strongly attenuated subsequently. The seventh was not confirmed or refuted, but its main conclusion appears unlikely. Among the three "top 10" that were not initial studies, two were confirmed subsequently and the third was attenuated. The newspaper coverage of the "top 10" publications (223 articles) was much larger than that of the 67 related studies (57 articles). Moreover, only one of the latter newspaper articles reported that the corresponding "top 10" finding had been attenuated. The average impact factor of the scientific journals publishing studies echoed by newspapers (17.1 n = 56) was higher (p<0.0001) than that corresponding to related publications that were not echoed (6.4 n = 56). CONCLUSION: Because newspapers preferentially echo initial ADHD findings appearing in prominent journals, they report on uncertain findings that are often refuted or attenuated by subsequent studies. If this media reporting bias generalizes to health sciences, it represents a major cause of distortion in health science communication.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/patología , Investigación Biomédica , Periódicos como Asunto , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Trastorno por Déficit de Atención con Hiperactividad/genética , Medios de Comunicación , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/genética , Predisposición Genética a la Enfermedad , Humanos , Factor de Impacto de la Revista , Metaanálisis como Asunto , Receptores de Dopamina D4/genética , Trastornos Relacionados con Sustancias/patología , Universidades
16.
PLoS One ; 6(1): e14618, 2011 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-21297951

RESUMEN

BACKGROUND: There is often a huge gap between neurobiological facts and firm conclusions stated by the media. Data misrepresentation in the conclusions and summaries of neuroscience articles might contribute to this gap. METHODOLOGY/PRINCIPAL FINDINGS: Using the case of attention deficit hyperactivity disorder (ADHD), we identified three types of misrepresentation. The first relies on prominent inconsistencies between results and claimed conclusions and was observed in two scientific reports dealing with ADHD. Only one out of the 61 media articles echoing both scientific reports adequately described the results and, thus questioned the claimed conclusion. The second type of misrepresentation consists in putting a firm conclusion in the summary while raw data that strongly limit the claim are only given in the results section. To quantify this misrepresentation we analyzed the summaries of all articles asserting that polymorphisms of the gene coding for the D4 dopaminergic receptor are associated with ADHD. Only 25 summaries out of 159 also mentioned that this association confers a small risk. This misrepresentation is also observed in most media articles reporting on ADHD and the D4 gene. The third misrepresentation consists in extrapolating basic and pre-clinical findings to new therapeutic prospects in inappropriate ways. Indeed, analysis of all ADHD-related studies in mice showed that 23% of the conclusions were overstated. The frequency of this overstatement was positively related with the impact factor of the journal. CONCLUSION/SIGNIFICANCE: Data misrepresentations are frequent in the scientific literature dealing with ADHD and may contribute to the appearance of misleading conclusions in the media. In synergy with citation distortions and publication biases they influence social representations and bias the scientific evidence in favor of the view that ADHD is primarily caused by biological factors. We discuss the social consequences and the causes of data misrepresentations and suggest a few corrective actions.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Medios de Comunicación/normas , Neurociencias/normas , Humanos , Informática Médica
17.
J Neurochem ; 116(3): 449-58, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21128941

RESUMEN

D(2)-like antagonists potentiate dopamine release. They also inhibit dopamine uptake by a mechanism yet to be clarified. Here, we monitored dopamine uptake in the striatum of anesthetized mice. The dopamine overflow was evoked by brief electrical stimulation of the medial forebrain bundle (four pulses at 100 Hz) and was monitored with carbon fiber electrodes combined with continuous amperometry. The decay phase of evoked overflows reflects dopamine half-life, which entirely depends on uptake. The D(2)-like antagonists haloperidol and eticlopride enhanced the half-life by 45% and 48%, respectively, a moderate effect as compared to the uptake blocker nomifensine (528%). Both D(2)-like antagonists did not affect dopamine uptake in mice lacking D(2) receptors. Inhibition of tonic dopamine release by gamma-butyrolactone did not mimic the enhancing effect of D(2) antagonists on dopamine half-life. However, prolonged stimulation boosted dopamine uptake and this effect was not observed after haloperidol treatment or in mice lacking D(2) receptors. Therefore, dopamine uptake is accelerated in conditions of excessive D(2) stimulation but not finely tuned in resting conditions. Inhibition of dopamine uptake by D(2) antagonists synergizes with the potentiation of dopamine release to strongly alter the phasic dopamine signaling.


Asunto(s)
Cuerpo Estriado/metabolismo , Antagonistas de Dopamina/administración & dosificación , Antagonistas de los Receptores de Dopamina D2 , Dopamina/metabolismo , Receptores de Dopamina D2/metabolismo , Animales , Cuerpo Estriado/efectos de los fármacos , Antagonistas de Dopamina/farmacología , Estimulación Eléctrica/métodos , Haloperidol/farmacología , Haz Prosencefálico Medial/fisiología , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Noqueados , Vías Nerviosas/fisiología , Nomifensina/farmacología , Terminales Presinápticos/efectos de los fármacos , Terminales Presinápticos/metabolismo , Receptores de Dopamina D2/deficiencia , Salicilamidas/farmacología , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/genética , Área Tegmental Ventral/metabolismo
18.
Neurobiol Dis ; 35(3): 376-84, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19501163

RESUMEN

In Parkinson's disease dopamine depletion imbalances the two major output pathways of the striatum. L-DOPA replacement therapy is believed to correct this imbalance by providing effective D1 and D2 receptor stimulation to striatonigral and striatopallidal neurons, respectively. Here we tested this assumption in the rat model of Parkinsonism by monitoring the spike response of identified striatal neurons to cortical stimulation. As predicted, in 6-hydroxydopamine lesioned rats we observed that L-DOPA (6 mg/kg+benserazide), apomorphine and the D2 agonist quinpirole (0.5 mg/kg i.p.) counteract the enhanced responsiveness of striatopallidal neurons. Unexpectedly, the depressed responsiveness of striatonigral neurons was corrected by quinpirole whereas D1 stimulation exerted no (apomorphine, cPB) or worsening effects (L-DOPA, SKF38393 10 mg/kg). Therefore, quinpirole, but not D1 stimulation, restores functional equilibrium between the two striatal output pathways. Our results might explain the therapeutic effect of D2-based medications in Parkinson's disease.


Asunto(s)
Cuerpo Estriado/fisiopatología , Trastornos Parkinsonianos/fisiopatología , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , 2,3,4,5-Tetrahidro-7,8-dihidroxi-1-fenil-1H-3-benzazepina/farmacología , Potenciales de Acción/efectos de los fármacos , Animales , Antiparkinsonianos/farmacología , Apomorfina/farmacología , Benserazida/farmacología , Cuerpo Estriado/efectos de los fármacos , Modelos Animales de Enfermedad , Dopaminérgicos/farmacología , Agonistas de Dopamina/farmacología , Levodopa/farmacología , Masculino , Neuronas/efectos de los fármacos , Oxidopamina , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/tratamiento farmacológico , Quinpirol/farmacología , Ratas , Ratas Sprague-Dawley , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D2/agonistas
19.
Trends Neurosci ; 32(1): 2-8, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18986716

RESUMEN

Although psychostimulants alleviate the core symptoms of attention-deficit/hyperactivity disorder (ADHD), recent studies confirm that their impact on the long-term outcomes of ADHD children is null. Psychostimulants enhance extracellular dopamine. Numerous review articles assert that they correct an underlying dopaminergic deficit of genetic origin. This dopamine-deficit theory of ADHD is often based upon an overly simplistic dopaminergic theory of reward. Here, I question the relevance of this theory regarding ADHD. I underline the weaknesses of the neurochemical, genetic, neuropharmacological and imaging data put forward to support the dopamine-deficit hypothesis of ADHD. Therefore, this hypothesis should not be put forward to bias ADHD management towards psychostimulants.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/etiología , Trastorno por Déficit de Atención con Hiperactividad/metabolismo , Dopamina/deficiencia , Animales , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Trastorno por Déficit de Atención con Hiperactividad/genética , Estimulantes del Sistema Nervioso Central/uso terapéutico , Dopamina/genética , Humanos , Teoría Psicológica
20.
Eur J Neurosci ; 27(9): 2313-21, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18445222

RESUMEN

Striatonigral and striatopallidal neurons form distinct populations of striatal projection neurons. Their discharge activity is imbalanced after dopaminergic degeneration in Parkinson's disease. Striatal projection neurons receive massive cortical excitatory inputs from bilateral intratelencephalic (IT) neurons projecting to both the ipsilateral and contralateral striatum and from collateral axons of ipsilateral neurons that send their main axon through the pyramidal tract (PT). Previous anatomical studies in rats suggested that IT and PT inputs preferentially excite striatonigral and striatopallidal neurons, respectively. Here we used electrophysiological criteria to identify them with antidromic stimulations. We show that the spontaneous discharge activity of IT neurons is depressed, whereas that of PT neurons is not affected in the rat cortex ipsilateral to 6-hydroxydopamine injection. However, our functional experiments do not support the hypothesis of a differential cortical input to striatal pathways. Firstly, although the conduction velocity of PT neurons is 4.6 times faster than that of IT neurons, identified striatopallidal and striatonigral neurons exhibit identical latencies of their spike responses to electrical stimulation of the ipsilateral cortex. Secondly, although PT neurons are ipsilateral, both striatal populations exhibit similar sensitivity to the stimulation of the ipsilateral and contralateral cortex. We suggest that IT neurons provide the main excitatory input to both striatal populations and that the corticostriatal PT input is weaker. Therefore, our functional data do not support our previous hypothesis that the deficit of IT neurons associated with the dopaminergic depletion might contribute to the striatal imbalance. This imbalance might rather result from intrinsic striatal mechanisms.


Asunto(s)
Cuerpo Estriado/citología , Cuerpo Estriado/fisiología , Vías Nerviosas/citología , Vías Nerviosas/fisiología , Neuronas/citología , Trastornos Parkinsonianos/fisiopatología , Animales , Electrodos Implantados , Electroencefalografía , Lateralidad Funcional/fisiología , Masculino , Ratas , Ratas Sprague-Dawley
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...