Electroencephalographic findings in patients with major depressive disorder during cognitive or emotional tasks: a systematic review

Objective: Major depressive disorder (MDD) is a prevalent psychiatric condition characterized by multiple symptoms that cause great distress. Uncovering the brain areas involved in MDD is essential for improving therapeutic strategies and predicting response to interventions. This systematic review discusses recent findings regarding cortical alterations in depressed patients during emotional or cognitive tasks, as measured by electroencephalography (EEG). Methods: A search of the MEDLINE/PubMed and Cochrane databases was carried out using the keywords EEG and depression, confined to article title. Results: The studies identified reveal the frontal cortex as an important brain structure involved in the complex neural processes associated with MDD. Findings point to disorganization of right-hemisphere activity and deficient cognitive processing in MDD. Depressed individuals tend to ruminate on negative information and respond with a pattern of relatively higher right frontal activity to emotional stimuli associated with withdrawal and isolation. Conclusion: Patients with MDD may have altered dynamic patterns of activity in several neuroanatomical structures, especially in prefrontal and limbic areas involved in affective regulation. Identification of these alterations might help predict the response of patients to different interventions more effectively and thus maximize the effects both of pharmacotherapeutic and of psychotherapeutic strategies.

Plasticidade sináptica: natureza e cultura moldando o Self / Synaptic plasticity: nature and nurture shaping the self

O cérebro em desenvolvimento segue inicialmente um plano genético, estabelecido pela história evolutiva da espécie humana, porém é muito sensível ao ambiente. Estímulos ambientais modificam a estrutura dos circuitos neurais, refinando e tornando as sinapses, alvo de ação dos neurotransmissores, mais eficientes por meio de atividade elétrica e mensageiros químicos. O objetivo desse estudo é discutir teoricamente como a plasticidade e a especificação prévia de sistemas cerebrais coexistem no cérebro. Conclui-se destacando a importância de integrar aspectos de aprendizagem social e da biologia na construção e refinamento das variadas habilidades humanas.

The developing brain requires a genetic plan, established by the evolutionary history of human species, but it is also very sensitive to the surrounding environment. Environmental stimuli can modify the structure of neural circuits, refining and making synapses, which are the target of neurotransmitters, more efficient by electrical activity and chemical messengers. The aim of the present study is to discuss theoretically how both plasticity and previous specification of brain systems coexist in the brain. The conclusion shows the importance to integrate aspects of social learning and biology in building and refining the various humane skills.