Working Memory: Imaging the Magic Number Four

AbstractMany brain regions have been implicated in memory performance, but the relationship between memory capacity and neural activity has not been clear. Recent studies show that activity in the posterior parietal cortex increases with working memory load, implicating this region in the storage of representations in visual memory

Turning the other lobe: : Directional biases in brain diagrams

© 2017 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 3.0 License (http://www.creativecommons.org/licenses/by/3.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).Past research shows that in drawn or photographic portraits, people are significantly more likely to be posed facing to their right than their left. We examined whether the same type of bias exists among sagittal images of the human brain. An exhaustive search of Google images using the term 'brain sagittal view' yielded 425 images of a left or right facing brain. The direction of each image was coded and revealed that 80% of the brains were right-facing. This bias was present in images that did not contain any representation of a human head. It is argued that the effect might be aesthetic in nature, the result of the Western tradition of reading left to right or due to the facial factors that underlie the bias previously found in portraits.Peer reviewe

Temperamental variation in learned irrelevance in humans

BACKGROUND Learned irrelevance (LIRR) represents one of the mechanisms of attentional set-shifting and refers to the inability to attend to, or to learn about, any aspect of a stimulus previously experienced as irrelevant. Although it has been extensively studied in the context of clinical populations, not much is known about LIRR effects in relation to normal variation in individual differences. The present study was designed to assess how temperamental factors may modulate LIRR. PARTICIPANTS AND PROCEDURES Sixty-eight healthy volunteers performed a visual discrimination learning task modelled after Wisconsin Card Sorting Test. To test the susceptibility to learned irrelevance, participants were expected to shift their attention either to a dimension that prior to the extra-dimensional shift was completely irrelevant, or to a dimension that was previously partly correlated with reinforcement. Temperamental traits were assessed using the Formal Characteristics of Behaviour-Temperament Inventory (Zawadzki & Strelau, 1997). Intelligence level was stratified according to Raven\u27s Advanced Progressive Matrices (Raven, Raven, & Court, 2003). RESULTS Low level of Briskness and high level of Perseverance were related to enhanced susceptibility to LIRR. High levels of Activity and Emotional Reactivity were related to the poorer performance on the extra-dimensional set-shifting. No effects of other temperament characteristics or intelligence on LIRR were observed. CONCLUSIONS The results confirm a strong variation in LIRR related to individual differences in temperament, which appears to be unrelated to DA function. Our results highlight the importance of considering individual differences in studies on cognitive control

Using facial electromyography to detect preserved emotional processing in disorders of consciousness: A proof-of-principle study

Objective To examine whether emotional functioning can be observed in patients who are behaviourally non-responsive using peripheral markers of emotional functioning. Method We tested two patients, both diagnosed as being in a vegetative state (VS) following hypoxia secondary to cardiac arrest. Thirty-seven healthy participants with no history of neurological illness served as a control group. The activity of two facial muscles (zygomaticus major, corrugator supercilii) was measured using facial electromyography (EMG) to probe for patterned responses that differentiate between auditorily presented joke and non-joke stimuli in VS patients. Results One of the two VS patients we tested demonstrated greater zygomatic and reduced corrugator activity in response to jokes compared with non-jokes. Critically, these responses followed the pattern and temporal profile of muscle activity observed in our healthy control sample. Conclusions Despite their behaviorally non-responsive profile, some patients diagnosed as VS appear to retain some aspects of emotional experience. Significance Our findings represent, to our knowledge, the first demonstration that a patient diagnosed as VS can exhibit intact emotional responses to humor as assessed by facial EMG. Therefore, our approach may constitute a feasible bedside tool capable of providing novel insight into the mental and emotional lives of patients who are behaviourally non-responsive

Detecting and interpreting conscious experiences in behaviorally non-responsive patients

Decoding the contents of consciousness from brain activity is one of the most challenging frontiers of cognitive neuroscience. The ability to interpret mental content without recourse to behavior is most relevant for understanding patients who may be demonstrably conscious, but entirely unable to speak or move willfully in any way, precluding any systematic investigation of their conscious experience. The lack of consistent behavioral responsivity engenders unique challenges to decoding any conscious experiences these patients may have solely based on their brain activity. For this reason, paradigms that have been successful in healthy individuals cannot serve to interpret conscious mental states in this patient group. Until recently, patient studies have used structured instructions to elicit willful modulation of brain activity according to command, in order to decode the presence of willful brain-based responses in this patient group. In recent work, we have used naturalistic paradigms, such as watching a movie or listening to an audio-story, to demonstrate that a common neural code supports conscious experiences in different individuals. Moreover, we have demonstrated that this code can be used to interpret the conscious experiences of a patient who had remained non-responsive for several years. This approach is easy to administer, brief, and does not require compliance with task instructions. Rather, it engages attention naturally through meaningful stimuli that are similar to the real-world sensory information in a patient\u27s environment. Therefore, it may be particularly suited to probing consciousness and revealing residual brain function in highly impaired, acute, patients in a comatose state, thus helping to improve diagnostication and prognostication for this vulnerable patient group from the critical early stages of severe brain-injury

Thirty-five years of computerized cognitive assessment of aging — Where are we now?

Over the past 35 years, the proliferation of technology and the advent of the internet have resulted in many reliable and easy to administer batteries for assessing cognitive function. These approaches have great potential for affecting how the health care system monitors and screens for cognitive changes in the aging population. Here, we review these new technologies with a specific emphasis on what they offer over and above traditional ‘paper-and-pencil’ approaches to assessing cognitive function. Key advantages include fully automated administration and scoring, the interpretation of individual scores within the context of thousands of normative data points, the inclusion of ‘meaningful change’ and ‘validity’ indices based on these large norms, more efficient testing, increased sensitivity, and the possibility of characterising cognition in samples drawn from the general population that may contain hundreds of thousands of test scores. The relationship between these new computerized platforms and existing (and commonly used) paper-and-pencil tests is explored, with a particular emphasis on why computerized tests are particularly advantageous for assessing the cognitive changes associated with aging

Alive inside

This article provides an ethical analysis of the U.S. practice guideline update on disorders of consciousness. Our analysis focuses on the guideline’s recommendations regarding the use of investigational neuroimaging methods to assess brain-injured patients. Complex and multifaceted ethical issues have emerged because these methods alter the clinical understanding of consciousness. We address issues of false hope, patient suffering, and cost. We argue that, in spite of these concerns, there is significant benefit to using neuroimaging to assess brain-injured patients in most cases