The Effects of Tobacco Smoke and Nicotine on Cognition and the Brain

Tobacco smoke consists of thousands of compounds including nicotine. Many constituents have known toxicity to the brain, cardiovascular, and pulmonary systems. Nicotine, on the other hand, by virtue of its short-term actions on the cholinergic system, has positive effects on certain cognitive domains including working memory and executive function and may be, under certain conditions, neuroprotective. In this paper, we review recent literature, laboratory and epidemiologic, that describes the components of mainstream and sidestream tobacco smoke, including heavy metals and their toxicity, the effect of medicinal nicotine on the brain, and studies of the relationship between smoking and (1) preclinical brain changes including silent brain infarcts; white matter hyperintensities, and atrophy; (2) single measures of cognition; (3) cognitive decline over repeated measures; and (4) dementia. In most studies, exposure to smoke is associated with increased risk for negative preclinical and cognitive outcomes in younger people as well as in older adults. Potential mechanisms for smoke’s harmful effects include oxidative stress, inflammation, and atherosclerotic processes. Recent evidence implicates medicinal nicotine as potentially harmful to both neurodevelopment in children and to catalyzing processes underlying neuropathology in Alzheimer’s Disease. The reviewed evidence suggests caution with the use of medicinal nicotine in pregnant mothers and older adults at risk for certain neurological disease. Directions for future research in this area include the assessment of comorbidities (alcohol consumption, depression) that could confound the association between smoking and neurocognitive outcomes, the use of more specific measures of smoking behavior and cognition, the use of biomarkers to index exposure to smoke, and the assessment of cognition-related genotypes to better understand the role of interactions between smoking/nicotine and variation in genotype in determining susceptibility to the neurotoxic effects of smoking and the putative beneficial effects of medicinal nicotine.     

Differences in feedback- and inhibition-related neural activity in adult ADHD

The objective of this study was to examine response inhibition- and feedback-related neural activity in adults with attention deficit hyperactivity disorder (ADHD) using event-related functional MRI. Sixteen male adults with ADHD and 13 healthy/normal controls participated in this study and performed a modified Go/NoGo task. Behaviourally, attention and inhibition problems in the ADHD group were observed; no feedback-related differences between the groups were detected. The neuroimaging data showed that the ADHD group displayed more activation in the inferior frontal gyrus and putamen during response inhibition. During feedback-related processes, the ADHD group displayed less activation in the inferior frontal/orbitofrontal cortex, hippocampus/nucleus accumbens, and caudate nucleus, but more activity in the inferior frontal gyrus. These results indicate that at least two distinguishable underlying brain networks related to response inhibition and feedback are altered in adults with ADHD.     

Neural functional organization of hallucinations in schizophrenia: Multisensory dissolution of pathological emergence in consciousness

Although complex hallucinations are extremely vivid, painful symptoms in schizophrenia, little is known about the underlying mechanisms of multisensory integration in such a phenomenon. We investigated the neural basis of these altered states of consciousness in a patient with schizophrenia, by combining state of the art neuroscientific exploratory methods like functional MRI, diffusion tensor imaging, cortical thickness analysis, electrical source reconstruction and trans-cranial magnetic stimulation. The results shed light on the functional architecture of the hallucinatory processes, in which unimodal information from different modalities is strongly functionally connected to higher-order integrative areas.     

“Hearing voices”: Auditory hallucinations as failure of top‐down control of bottom‐up perceptual processes

Auditory hallucination is a key characteristic of schizophrenia that seriously debilitates the patient, with consequences for social engagement with others. Hallucinatory experiences are also observed in healthy individuals in the general population who report “hearing voices” in the absence of an external acoustic input. A view on auditory hallucinations and “hearing voices” is presented that regards such phenomena as perceptual processes, originating from speech perception areas in the left temporal lobe. Healthy individuals “hearing voices” are, however, often aware that the experience comes from inner thought processes, which is not reported by hallucinating patients. A perceptual model can therefore, not alone explain the difference in the phenomenology of how the “voices heard” are attributed to either an inner or outer cause. An expanded model is thus presented which takes into account top‐down cognitive control, localized to prefrontal cortical areas, to inhibit and re‐attribute the perceptual mis‐representations. The expanded model is suggested to be empirically validated using a dichotic listening speech perception paradigm with instructions for top‐down control of attention focus to either the right or left side in auditory space. It is furthermore suggested to use fMRI to validate the temporal and frontal lobe neuronal correlates of the cognitive processes involved in auditory hallucinations.     

Neuroscience and multiple realization: a reply to Bechtel and Mundale

One trend in recent work on topic of the multiple realization of psychological properties has been an emphasis on greater sensitivity to actual science and greater clarity regarding the metaphysics of realization and multiple realization. One contribution to this trend is Bechtel and Mundale’s examination of the implications of brain mapping for multiple realization. Where Bechtel and Mundale argue that studies of brain mapping undermine claims about the multiple realization, this paper challenges that argument.     

Review for Cognitive Systems Research of the book The Brain and AI,by authors Karl Schlagenhauf and Fanji Gu

The human brain is often considered the most complex system known. It has a fantastic capacity to learn and remember, to recognize patterns in space and time, solve problems of all kinds, innovate tools and machines, create beautiful art and science. Is it reasonable to believe that we, in a foreseeable future, will be able to understand all the wonders of our own brain, enough to be able to mimic it and build artificial brains and minds that correspond to or even surpass the capacity of the human origin? Can we seriously believe that we (soon, or ever) will be able to build robots that know of and can reflect upon their own existence?This review of the book, The Brain and AI, deals with such issues, but in a very special way. It is written as a fascinating dialogue between the two authors, Chinese scientist Fanji Gu and German engineer Karl Schlagenhauf, where they discuss the development of neuroscience and artificial intelligence (AI) with a critical examination of given “truths” in these fields. The Brain and AI is indeed worth reading for many reasons, regardless if you are a student or researcher in any of the many fields of science discussed here (e.g. physics, computer science, neuroscience, cognitive science psychology, social science), or if you are just interested in the current and future development of brain research and artificial intelligence. The book is both educating and entertaining and can be strongly recommended.     

Similar improvements in inhibitory control following low-volume high-intensity interval exercise and moderate-intensity continuous exercise

ObjectivesWe previously demonstrated that a traditional high-volume (HV) high-intensity interval exercise (HIIE) was more effective in improving post-exercise inhibitory control (IC) than moderate-intensity continuous exercise (MCE). Nevertheless, because HV-HIIE is performed with a higher volume and longer duration, it may result in decreased adherence to this exercise for some individuals. In this study, we compared the effect of a practical low-volume (LV) HIIE to that of MCE on post-exercise IC improvements.DesignTwenty healthy males performed both LV-HIIE and MCE on a cycle ergometer in a crossover design.MethodLV-HIIE was consisted of ten 1-min bouts at 90% of the peak oxygen consumption (VO_{2 peak}) with 1-min active recovery at 30% of VO_{2 peak}, which had a total duration of 20 min. MCE was performed for 40 min at 60% of VO_{2 peak}. To evaluate IC, the Stroop test was administered before exercise, immediately after exercise, and every 10 min during the 30-min post-exercise recovery period.ResultsIC significantly improved immediately after LV-HIIE and MCE compared with that before each exercise (both Ps < 0.05). The improved IC remained significant until the 20-min post-exercise recovery period for both protocols (all Ps < 0.05). The degrees of post-exercise IC improvements throughout the 30-min post-exercise recovery period did not differ significantly between protocols.ConclusionsThese findings demonstrated that despite lower exercise volume and shorter exercise duration, LV-HIIE could improve post-exercise IC similar to MCE.     

我听故我在？自我声音识别机制的探索

自我声音是自我相关信息之一,同时也是个体识别身份时最重要的标志之一。声音具有骨传导和空气传导的传导方式和个体动机水平的差异都影响个体自我声音识别。在进行自我声音识别认知加工的过程中,会激活右半球额叶大部分脑区,并且在P3和N2成分上与在非我身份声音识别中同样存在显著差异。从声音刺激和个体动机两种角度来开展自我声音识别研究,并结合进化心理学与脑成像技术探索其神经机制,宜成为未来研究的一个方向。     

正念的心理和脑机制

正念是源于东方禅修的一种有意识、非评判的对当前状态进行注意的方法, 也是一种意识状态或心理过程。其早期研究侧重于各种身心疾病的治疗和康复等临床功效, 近年来其研究重点逐渐转向各种作用机制。在心理机制上, 正念与感知觉敏感性的变化, 注意、记忆和情绪的改善有关。在脑机制上, 它不仅与额区θ波和枕区γ波以及事件相关电位P300成分的变化有关还与前额叶、扣带回、脑岛等脑区功能激活和结构改变有关。最后, 文章指出了目前正念研究在内容和方法学上的不足以及未来研究的方向。