We whole-heartedly agree with Mecacci and Haselager(2014) on the need to investigate the psychosocial effects of deep brain stimulation (DBS), and particularly to find out how to prevent adverse psychosocial effects. We also agree with the authors on the value of an embodied, embedded, enactive approach (EEC) to the self and the mind–brain problem. However, we do not think this value primarily lies in dissolving a so-called “maladaptation” of patients to their DBS device. In this comment, we challenge three (...) central claims of the authors on the basis of our direct experience with psychosocial effects of DBS in 45 obsessive- compulsive disorder (OCD) patients treated at the AMC in Amsterdam, The Netherlands, and our indepth qualitative interviews with 18 of them (de Haan et al. 2013). We end our comment by sketching out our perspective on the practical merits of an EEC approach to DBS. (shrink)

IntroductionParkinson’s disease patients have a significantly higher risk of developing dementia in later disease stages, leading to severe impairments in quality of life and self-functioning. Questions remain on how deep brain stimulation affects cognition, and whether we can individualize therapy and reduce the risk for adverse cognitive effects. Our aim in this systematic review is to assess the current knowledge in the field and determine if the findings could influence clinical practice.MethodsWe have conducted a systematic review according to (...) PRISMA guidelines through MEDLINE and Embase databases, with studies being selected for inclusion via a set inclusion and exclusion criteria.ResultsSixty-seven studies were included in this systematic review according to the selected criteria. This includes 6 meta-analyses, 18 randomized controlled trials, 17 controlled clinical trials, and 26 observational studies with no control arms. The total number of PD patients encompassed in the studies cited in this review is 3677, not including the meta-analyses.ConclusionCognitive function in PD patients can deteriorate, in most cases mildly, but still impactful to the quality of life. The strongest evidence is present for deterioration in verbal fluency, while inconclusive evidence is still present for executive function, memory, attention and processing speed. Global cognition does not appear to be significantly impacted by DBS, especially if cognitive screening is performed prior to the procedure, as lower baseline cognitive function is connected to poor outcomes. Further randomized controlled studies are required to increase the level of evidence, especially in the case of globus pallidus internus DBS, pedunculopontine nucleus DBS, and the ventral intermediate nucleus of thalamus DBS, and more long-term studies are required for all respective targets. (shrink)

Direct electrical stimulation has been widely applied in both guidance of lesion resection and scientific research; however, the design and selection of intraoperative cognitive mapping tasks have not been updated in a very long time. We introduce updated mapping tasks for language and non-language functions and provide recommendations for optimal design and selection of intraoperative mapping tasks. In addition, with DES becoming more critical in current neuroscientific research, a task design that has not been widely used in DES (...) yet was introduced for more delicate mapping of brain functions especially for research purposes. We also illustrate the importance of designing a common task series for DES and other non-invasive mapping techniques. This review gives practical updated guidelines for advanced application of DES in clinical and neuroscientific research. (shrink)

Modern cognitive and clinical psychology offer insight into how people deal with natural disasters. In my methodological paper, I make a strong case for incorporating experimental findings and theoretical concepts of modern psychology into environmental historical disaster research. I show how psychological factors may influence the production and interpretation of historical sources with respect to perceptions of and responses to disasters. While previous psychological approaches to history mostly involve psychoanalysis, I focus on empirical psychology. Specifically, I review a number (...) of well documented heuristics, biases, and memory modulations as described by cognitive psychology. Moreover, I argue that including investigations on disaster related mental disorders would complement the environmental historical research of natural disasters. My approach highlights a strong potential for interdisciplinary collaborations among environmental historians and psychologists. (shrink)

Objective: Deep brain stimulation targeted to the ventral intermediate nucleus of the thalamus is effective for motor symptoms in essential tremor, but there is limited data on cognitive outcomes. We examined cognitive outcomes in a large cohort of ET DBS patients.Methods: In a retrospective analysis, we used repeated-measures ANOVA testing to examine whether the age of tremor onset, age at DBS surgery, hemisphere side implanted with lead, unilateral vs. bilateral implantations, and presence of surgical complications influenced the (...) cognitive outcomes. Neuropsychological outcomes of interest were verbal memory, executive functioning, working memory, language functioning, visuospatial functioning, and general cognitive function.Results: We identified 50 ET DBS patients; 29 males; the mean age of tremor onset was 35.84 years with a median age of 38 years. The mean age at DBS was 68.18 years. There were 37 unilateral 30 left, seven right, and 13 bilateral brain implantations. In the subgroup analysis, there was a significant interaction between assessment and age of tremor onset ; F = 4.47; p = 0.043 for working memory. The post hoc testing found improvements for younger onset ET. Similarly, there was a significant interaction between assessment and complications vs. no complications subgroups; F = 4.34; p = 0.043 for verbal memory with worsening scores seen for ET patients with complications. The remaining tests were not significant.Conclusion: In this large cohort of ET patients with, DBS was not accompanied by a significant decline in many cognitive domains. These outcomes were possibly related to the selection of patients with normal cognitive functioning before surgery, unilateral DBS implantations for the majority, and selection of patients with optimal response to DBS. (shrink)

International Studies in the Philosophy of Science, Volume 26, Issue 3, Page 335-343, September 2012.

Deception scholars have argued that increasing the liar’s cognitive system artificially can produce deception cues. However, if too much load is imposed the truth tellers’ performance can also be impaired. To address this issue, we designed a veracity task that incorporated a secondary task to increase cognitive load gradually. Also, because deception has been associated with activity in the inferior frontal cortex (IFC), we examined the influence of transcranial direct current stimulation of the IFC on performance. During (...) stimulation, participants truthfully or deceptively indicated whether each of a number of statements shown on screen was true or not. Higher load decreased recall but not general compliance or response times (RTs). Truthful trials yielded higher compliance rates and faster RTs than deceptive trials except for the highest load level. Anodal right stimulation decreased compliance in truthful trials when participants were not overloaded. Truth telling was more vulnerable to cognitive load and tDCS than lying. (shrink)

Objective: Caloric vestibular stimulation has traditionally been used as a tool for neurological diagnosis. More recently, however, it has been applied to a range of phenomena within the cognitive neurosciences. Here, we provide an overview of such studies and review our work using CVS to investigate the neural mechanisms of a visual phenomenon - binocular rivalry. We outline the interhemispheric switch model of rivalry supported by this work and its extension to a metarivalry model of interocular-grouping phenomena. In (...) addition, studies showing a slow rate of binocular rivalry in bipolar disorder are discussed, and the relationship between this finding and the interhemispheric switch model is described. We also review the effects of CVS in various clinical contexts, explain how the technique is performed and discuss methodological issues in its application. (shrink)

In a study in Brain, Dr. Susan Harkema and her fellow researchers demonstrated that the input of an electronic epidural stimulator in the lower spinal cord of four completely paralyzed patients allowed them to regain voluntary movement in their toes, defying the longstanding scientific position regarding sensory and motor complete paralysis. Harkema herself admits that she thought this achievement was impossible at the outset, as she believed that the body is incapable of movement without receiving complex signals from the brain. (...) Many cognitive neuroscientists continue to maintain this standpoint of Cartesian dualism. In response, I argue that the insights of Maurice Merleau-Ponty provide a possible explanation of the results of this new research. Merleau-Ponty insisted that I am my body and that the body has its own kind of knowledge about the world. This framework serves as the backdrop for recent phenomenological studies in cognitive neuroscience. In this vein, this essay will consider how Merleau-Ponty’s account of embodiment provides an ample model for explaining the findings of Susan Harkema’s current spinal cord research. (shrink)

Transcranial direct current stimulation has been widely utilized in research settings and modulates brain activity. The application of anodal tDCS on the prefrontal cortex has indicated improvement in cognitive functioning. The cingulate cortex, situated in the medial aspect of the prefrontal cortex, has been identified as a core region performing cognitive functions. Most of the previous studies investigating the impact of stimulation on the prefrontal cortex stimulated the dorsolateral prefrontal cortex, however, the impact of stimulation (...) on cingulate has not been explored. The current study investigates the effect of stimulation on the resting-state functional connectivity of the anterior cingulate cortex with other regions of the brain and changes in behavioral results in a color-word Stroop task, which has repeatedly elicited activation in different regions of the cingulate. Twenty subjects were randomly assigned to the experimental and sham group, and their medial prefrontal area was stimulated using MRI compatible tDCS. Resting-state functional magnetic resonance imaging and cognitive Stroop task were monitored before, during, and after the stimulation. Neuroimaging results indicated a significant decrease in resting-state functional connectivity in the experimental group during and after stimulation as compared to before stimulation in two clusters including right insular cortex, right central operculum cortex, right frontal operculum cortex and right planum polare with the left anterior cingulate cortex selected as the seed. The behavioral results indicated a significant decrease in reaction time following stimulation in the experimental group compared to the sham group. Moreover, the change in functional connectivity in subcortical regions with L-ACC as the seed and change in RT was positively correlated. The results demonstrated that ACC has a close functional relationship with the subcortical regions, and stimulation of ACC can modulate these connections, which subsequently improves behavioral performance, thus, providing another potential target of stimulation for cognitive enhancement.Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT04318522. (shrink)

Pain has not only sensory, but also emotional and cognitive, components. Some studies have explored the effect of pain on time perception, but the results remain controversial. Whether individual pain-related emotional and cognitive factors play roles in this process should also be explored. In this study, we investigated the effect of electrical stimulation–induced pain on interval timing using a temporal bisection task. During each task session, subjects received one of five types of stimulation randomly: no stimulus (...) and 100 and 300 ms of non-painful and painful stimulation. Pain-related emotional and cognitive factors were measured using a series of questionnaires. The proportion of “long” judgments of a 1,200-ms visual stimulus duration was significantly smaller with 300 ms painful stimulation than with no stimulus and 100 ms and 300 ms non-painful stimulation. The point of subjective equality did not differ among sessions, but the average Weber fraction was higher for painful sessions than for no-stimulus session. The pain fear score correlated positively with the PSE under 100 ms non-painful and painful and 300 ms painful stimulation. Pain catastrophizing and pain anxiety scores correlated significantly with the WF under no stimulus and 100 ms non-painful stimulation, respectively. These results suggest that electrical stimulation–induced pain affects temporal sensitivity, and that pain-related emotional and cognitive factors are associated with the processing of time perception. (shrink)

We recently demonstrated, by means of short latency afferent inhibition (SAI), that before an imagined movement, during the reaction time (RT), SAI decreases only in the movement-related muscle (sensorimotor modulation) and that a correlation exists between sensorimotor modulation and motor imagery (MI) ability. Excitatory anodal transcranial direct current stimulation (a-tDCS) on M1 could enhance the MI outcome; however, mechanisms of action are not completely known. Here, we assessed if a-tDCS on M1 prior to an MI task could affect sensorimotor (...) modulation. Participants imagined abducting the index or little finger in response to an acoustic signal. SAI was evaluated from the first dorsal interosseus after the “go” signal, before the expected electromyographic (EMG) activity. Participants received 20-min 1.5 mA a-tDCS or sham-tDCS on M1 on two different days, in random order. Results showed that a-tDCS on M1 increases the sensorimotor modulation consisting of a weakening of SAI after the Go signal with respect to sham-tDCS, in the movement-related muscle right before the beginning of MI. These results suggest that a-tDCS on M1 further potentiate those circuits responsible for sensorimotor modulation in the RT phase of MI. Increased sensorimotor modulation during MI may be one of the mechanisms involved in MI improvement after a-tDCS over M1. (shrink)

BackgroundThe cognitive outcomes induced by subthalamic nucleus deep brain stimulation (STN-DBS) remain unclear, especially in PD patients with mild cognitive impairment (MCI). This study explored the cognitive effects of STN-DBS in PD patients with MCI.MethodsThis was a retrospective cohort study that included 126 PD patients who underwent STN-DBS; all patients completed cognitive and motor assessments before and at least 6 months after surgery. Cognitive changes were mainly evaluated by the Montreal cognitive assessment (MoCA) (...) scale and the seven specific MoCA domains, including visuospatial/executive function, naming, attention, language, abstract, delayed recall, and orientation. Motor improvement was evaluated by the UPDRS-III. Cognitive changes and motor improvements were compared between PD-MCI and normal cognitive (NC) patients. Logistic regression analyses were performed to explore predictors of post-operative cognitive change.ResultsAt the time of surgery, 61.90% of the included PD patients had MCI. Compared with the PD-MCI group, the PD-NC group had a significantly higher proportion of cases with post-operative cognitive decline during follow-up of up to 36 months (mean 17.34 ± 10.61 months), mainly including in global cognitive function, visuospatial/executive function and attention. Covariate-adjusted binary logistic regression analyses showed that pre-operative global cognitive status was an independent variable for post-operative cognitive decline. We also found that pre-operative cognitive specific function could predict its own decline after STN-DBS, except for the naming and orientation domains.ConclusionPD-MCI patients are at a lower risk of cognitive decline after STN-DBS compared with PD-NC patients. (shrink)

The Role of Dorsal Premotor Cortex in Resolving Abstract Motor Rules provides alternative hypotheses about the cognitive functions affected by the application of repetitive transcranial magnetic stimulation. Their model simulated the effect of stimulation of the left dorsal premotor cortex right as participants provide a Models were used to demonstrate that the increased variability in observed response times can result from interference in replanning during the process of responding to the uninstructed stimulus.

ObjectiveProcessing Speed, the ability to perceive and react fast to stimuli in the environment, has been shown to be impaired in children with attention deficit hyperactivity disorder. However, it is unclear whether PS can be improved following targeted treatments for ADHD. Here we examined potential changes in PS following application of transcranial electric stimulation combined with cognitive training in children with ADHD. Specifically, we examined changes in PS in the presence of different conditions of mental fatigue.MethodsWe used a (...) randomized double-blind active-controlled crossover study of 19 unmedicated children with ADHD. Participants received either anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex or transcranial random noise stimulation, while completing CT, and the administration order was counterbalanced. PS was assessed before and after treatment using the MOXO-CPT, which measures PS in the presence of various conditions of mental fatigue and cognitive load.ResultstRNS combined with CT yielded larger improvements in PS compared to tDCS combined with CT, mainly under condition of increased mental fatigue. Further improvements in PS were also seen in a 1-week follow up testing.ConclusionThis study provides initial support for the efficacy of tRNS combined with CT in improving PS in the presence of mental fatigue in pediatric ADHD. (shrink)

According to a prominent suggestion in the ethics of transcranial neurostimulation the effects of such devices can be treated as ethically on par with established, pre-neurotechnological alterations of the mind. This parity allegedly is supported by situated cognition theories showing how external devices can be part of a cognitive system. This article will evaluate this suggestion. It will reject the claim, that situated cognition theories support ethical parity. It will however point out another reason, why external carriers or modifications (...) of the mental might come to be considered ethically on par with internal carriers. Section “Why Could There Be Ethical Parity between Neural Tissue and External Tools?” presents the ethical parity theses between external and internal carriers of the mind as well as neurotechnological alterations and established alterations. Section “Extended, Embodied, Embedded: Situated Cognition as a Relational Thesis” will elaborate the different situated cognition approaches and their relevance for ethics. It will evaluate, whether transcranial stimulation technologies are plausible candidates for situated cognition theses. Section “On the Ethical Relevance of Situated Cognition Theses” will discuss criteria for evaluating whether a cognitive tool is deeply embedded with a cognitive system and apply these criteria to transcranial brain stimulation technologies. Finally it will discuss the role diverse versions of situated cognition theory can play in the ethics of altering mental states, especially the ethics of transcranial brain stimulation technologies. (shrink)

Background: There is increasing evidence to support the efficacy of transcranial direct current stimulation applications in cognitive augmentation and rehabilitation. Neuromodulation achieved with tDCS may further regulate regional cerebral perfusion affiliated through the neurovascular unit; however, components of cerebral perfusion decrease across aging. A novel neuroimaging approach, functional near-infrared spectroscopy, can aid in quantifying these regional perfusional changes. To date, the interaction of the effects of tDCS on cognitive performance across the lifespan and obtained fNIRS hemodynamic responses (...) remain unknown.Objective: This review aims to examine the effects of tDCS on cognitive performance and fNIRS hemodynamic responses within the context of cognitive aging.Methods: Six databases were searched for studies. Quality appraisal and data extraction were conducted by two independent reviewers. Meta-analysis was carried out to determine overall and subgroup effect sizes.Results: Eight studies met inclusion criteria. The overall effect size demonstrates that tDCS can alter cognitive performance and fNIRS signals, with aging being a potential intermediary in tDCS efficacy.Conclusion: From the studies included, the effects of tDCS on cognitive performance and fNIRS metrics are most prominent in young healthy adults and appear to become less robust with increasing age. Given the small number of studies included in this review further investigation is recommended. (shrink)

The ventrolateral prefrontal cortex plays a pivotal role in cognitive reappraisal. Previous studies suggested a functional asymmetry of the bilateral VLPFC, but the evidence is still insufficient during cognitive reappraisal. In this study, we conducted an online single-pulse transcranial magnetic stimulation to investigate the causal and distinct roles of the left and right VLPFC in reappraisal. Participants were instructed to reappraise or attend to pictures depicting social exclusion scenarios while the spTMS was applied over the left or (...) right VLPFC of the participants’ brains. The results showed that spTMS of either the left or the right VLPFC would increase reappraisal difficulty. Meanwhile, the outcome of reappraisal significantly deteriorated when the right VLPFC was temporally interrupted by spTMS, while the verbal fluency during oral reporting of the reappraisal strategy was significantly reduced when the left VLPFC was interrupted by spTMS. Taken together, these findings provide causal evidence for the involvement of left and right VLPFC with distinct roles: while the left VLPFC is responsible for the linguistic especially semantic process of generating and selecting appraisals according to the goal of emotion regulation, the right VLPFC plays a critical role in inhibiting inappropriate negative emotions and thoughts generated by the effective scenarios. These findings deepen our understanding of the neurocognitive mechanism of emotion regulation. (shrink)

Auditory stimulation training (AST) has been proposed as a potential treatment for chil-dren with specific language impairments (SLI). The current study was designed to test this as-sumption by using an AST with technically modulated musical material (ASTM) in a random-ized control group design. A total of 101 preschool children (62 male, 39 females; mean age = 4.52 years, SD = 0.62) with deficits in speech comprehension and poor working memory ca-pacity were randomly allocated into one of two treatment groups (...) or a control group. Children in the ASTM group (n = 40) received three 30-minute sessions per week over 12 weeks, whereas children in the comparison group received pedagogical activities during these intervals (n = 24). Children in the control group (n = 37) received no treatment. Working memory, phoneme dis-crimination and speech perception skills were tested prior to (baseline) and after treatment. Chil-dren in the ASTM group showed significantly greater working memory capacity, speech per-ception, and phoneme discrimination skills after treatment, whereas children in the other groups did not show such improvement. Taken together, these results suggest that ASTM can enhance auditory cognitive performance in children with SLI. (shrink)

Libet discovered that a substantial duration (> 0.5-1.0 s) of direct electrical stimulation of the surface of the somatosensory cortex at threshold currents is required before human subjects can report that a conscious somatosensory experience had occurred. Using a reaction time method we confirm that a similarly long stimulation duration at threshold currents is required for activation of elementary visual experiences (phosphenes) in human subjects following stimulation of the surface of the striate cortex. However, the reaction times (...) for the subject to respond to the cessation of the visual experience after the end of electrical stimulation could be as brief as 225-242 ms. We also carried out extensive studies in cats under a variety of anesthetic conditions using the same electrodes and parameters of stimulation employed in the human studies to study the patterns of neuronal activity beneath the stimulating surface electrode. Whereas sufficiently strong currents can activate neurons within milliseconds, stimulating currents close to threshold activate sustained neural activity only after at least 350-500 ms. When currents are close to threshold, some neurons are inhibited for several hundreds of millisecond before the balance between inhibition and excitation shifts towards excitation. These results suggest that the prolonged latencies, i.e., latencies beyond 200-250 ms, for the emergence of conscious experience following direct cortical stimulation result from a delay in the sustained activation of underlying cortical neurons at threshold currents rather than being due to any unusually long duration in central processing time. Intracellular records from cortical neurological cells during repetitive electrical stimulation of the surface of the feline striate cortex demonstrate that such stimulation induces a profound depolarizing shift in membrane potential that may persist after each stimulus train. Such a depolarization is evidence that extracellular K+ concentrations have increased during electrical stimulation. Such an increase in extracellular K+ progressively increases cortical excitability until the threshold for sustained activation of cortical neurons is reached and then exceeded. Consequently, the long latency for threshold activation of cortical neurons depends upon a dynamically increasing cortical facilatory process that begins hundreds of milliseconds before there is sustained activation of such neurons. In some cases, this facilatory process must overcome an initial stimulus-induced inhibition before neuronal firing commences. (shrink)

A central debate in philosophy and neuroscience pertains to whether PFC activity plays an essential role in the neural basis of consciousness. Neuroimaging and electrophysiology studies have revealed that the contents of conscious perceptual experience can be successfully decoded from PFC activity, but these findings might be confounded by post- perceptual cognitive processes, such as thinking, reasoning, and decision-making, that are not necessary for con- sciousness. To clarify the involvement of the PFC in consciousness, we present a synthesis of (...) research that has used intracranial electrical stimulation (iES) for the causal modulation of neural activity in the human PFC. This research provides compelling evidence that iES of only certain prefrontal regions (i.e., orbitofrontal cortex and anterior cingu- late cortex) reliably perturbs conscious experience. Conversely, stimulation of anterolateral prefrontal sites, often con- sidered crucial in higher-order and global workspace theories of consciousness, seldom elicits any reportable alterations in consciousness. Furthermore, the wide variety of iES-elicited effects in the PFC (e.g., emotions, thoughts, and olfactory and visual hallucinations) exhibits no clear relation to the immediate environment. Therefore, there is no evidence for the kinds of alterations in ongoing perceptual experience that would be predicted by higher-order or global workspace theories. Nevertheless, effects in the orbitofrontal and anterior cingulate cortices suggest a specific role for these PFC subregions in supporting emotional aspects of conscious experience. Overall, this evidence presents a challenge for higher-order and global workspace theories, which commonly point to the PFC as the basis for con- scious perception based on correlative and possibly confounded information. (shrink)

Deep Brain Stimulation (DBS) is a relatively new, experimental treatment for patients suffering from treatment-refractory Obsessive Compulsive Disorder (OCD). The effects of treatment are typically assessed with psychopathological scales that measure the amount of symptoms. However, clinical experience indicates that the effects of DBS are not limited to symptoms only: patients for instance report changes in perception, feeling stronger and more confident, and doing things unreflectively. Our aim is to get a better overview of the whole variety of changes (...) that OCD patients experience during DBS treatment. For that purpose we conducted in-depth, semi-structured interviews with 18 OCD patients. In this paper, we present the results from this qualitative study.We list the changes grouped in four domains: with regard to (a) person, (b) (social) world, (c)characteristics of person-world interactions, and (d) existential stance. We subsequently provide an interpretation of these results. In particular, we suggest that many of these changes can be seen as different expressions of the same process; namely that the experience of anxiety and tension gives way to an increased basic trust and increased reliance on one’s abilities. We then discuss the clinical implications of our findings, especially with regard to properly informing patients of what they can expect from treatment, the usefulness of including CBT in treatment, and the limitations of current measures of treatment success. We end by making several concrete suggestions for further research. (shrink)

Many studies have discussed the neural basis of asset bubbles. They found that the dorsolateral prefrontal cortex (DLPFC) played an important role in bubble formation, but whether a causal relationship exists and the mechanism of the effect of the DLPFC on bubbles remains unsettled. Using transcranial direct current stimulation (tDCS), we modulated the activity of the DLPFC and investigated the causal relationship between the DLPFC and the asset bubble in the classical learning-to-forecast experiment. 126 subjects were randomly divided into (...) three groups and received different stimulations (left anodal/right cathodal, right anodal/left cathodal or sham stimulation) respectively. We also conducted a 2-back task before and after stimulation to measure changes in subjects’ cognitive abilities and explore in detail the cognitive mechanism of the effect of DLPFC stimulation on asset bubbles. Based on our results, we found that the bubble of the left anodal/right cathodal stimulation group was significantly smaller than that of the sham stimulation group. In the meantime, subjects performed significantly better in the 2-back task after left anodal/right cathodal stimulation but not right anodal/left cathodal or sham stimulation, which is consistent with their performance in the learning-to-forecast experiment, supporting the cognitive mechanism to some extent. Furthermore, we examined different forecasting rules across individuals and discovered that the left anodal/right cathodal stimulation group preferred the adaptive learning rule, while the sham and right anodal/left cathodal stimulation groups adopted a pure trend-following rule that tended to intensify market volatility aggressively. (shrink)

Libet demonstrated that a substantial duration (>0.5-1.0 s) of direct electrical stimulation of the surface of a sensory cortex at a threshold or liminal current is required before a subject can experience a percept. Libet and his co-workers originally proposed that the result could be due either to spatial and temporal facilitation of the underlying neurons or additionally to a prolonged central processing time. However, over the next four decades, Libet chose to attribute the prolonged latency for evoking conscious (...) experience to a prolonged central processing time. In my view, Libet has not provided any convincing evidence, either on the basis of his own past work or in his critique of my paper, for his hypothesis of a central processing time exceeding 0.5s before conscious experience emerges following direct electrical threshold stimulation of the cortical surface. I stand by my original results and conclusion that such prolonged latencies are largely the consequence of a dynamically increasing cortical facilitatory process that begins hundreds of milliseconds before there is a sustained neuronal activation. In some cases, the facilitatory process must overcome an initial stimulus-induced inhibition before neuronal firing commences. (shrink)

As cognitive neuroscience has advanced, the list of prospective internal, biological enhancements has steadily expanded. Education and training, as well as the use of external information‐processing devices, may be labeled as “conventional” means of cognition enhancement (CE). They are often well established and culturally accepted. By contrast, methods of enhancing cognition through “unconventional” means, such as ones involving deliberately created nootropic drugs, gene therapy, or neural implants, are nearly all to be regarded as experimental at the present time. Transcranial (...) magnetic stimulation (TMS), genetic interventions, brain‐computer interfaces and new senses are highly experimental and unlikely to be important over the next 15 years. Many of the concerns about enhancement are nonspecific to the tools used to achieve it, which means that enhancement–ethic scrutiny should also apply to nonbiological external enhancements. (shrink)