Background: How the prefrontal cortex (PFC) recovers its functionality following lesions remains a conundrum. Recent work has uncovered the importance of transient low-frequency oscillatory activity (LFO; < 4 Hz) for the recovery of an injured brain. We aimed to determine whether persistent cortical oscillatory dynamics contribute to brain capability to support 'normal life' following injury.
View Article and Find Full Text PDFThe two main large-scale distributed networks, Central Executive (CEN) and Default Mode (DMN) have been extensively studied, but their relationship to hemispheric specialization has not been comprehensively addressed. We present evidence that they are neuroanatomically asymmetric: the CEN components are volumetrically larger in the right hemisphere, and DMN components are volumetrically larger in the left hemisphere. Based on this, the possibility that CEN and DMN are also functionally asymmetric is introduced and implications of the putative functional asymmetry of large-scale distributed networks for refining our understanding of hemispheric specialization are examined.
View Article and Find Full Text PDFBackground: To date, public health policies implemented during the COVID-19 pandemic have been evaluated on the basis of their ability to reduce transmission and minimise economic harm. We aimed to assess the association between COVID-19 policy restrictions and mental health during the COVID-19 pandemic.
Methods: In this longitudinal analysis, we combined daily policy stringency data from the Oxford COVID-19 Government Response Tracker with psychological distress scores and life evaluations captured in the Imperial College London-YouGov COVID-19 Behaviour Tracker Global Survey in fortnightly cross-sections from samples of 15 countries between April 27, 2020, and June 28, 2021.
COVID-19 has infected millions of people and upended the lives of most humans on the planet. Researchers from across the psychological sciences have sought to document and investigate the impact of COVID-19 in myriad ways, causing an explosion of research that is broad in scope, varied in methods, and challenging to consolidate. Because policy and practice aimed at helping people live healthier and happier lives requires insight from robust patterns of evidence, this article provides a rapid and thorough summary of high-quality studies available through early 2021 examining the mental-health consequences of living through the COVID-19 pandemic.
View Article and Find Full Text PDFCOVID-19 is a highly infectious viral disease caused by the novel coronavirus SARS-CoV-2. While it was initially regarded as a strictly respiratory illness, the impact of COVID-19 on multiple organs is increasingly recognized. The brain is among the targets of COVID-19, and it can be impacted in multiple ways, both directly and indirectly.
View Article and Find Full Text PDFMaking decisions when an objectively correct option is not obvious, involves different neurobiological mechanisms than "veridical" decision making. The dorsolateral prefrontal cortex (DLPFC) exhibits a distinct pattern of prefrontal activation in non-veridical cognition, but little is known about the role of underlying neurobiological endophenotypes. A functional polymorphism in the brain-derived neurotrophic factor (BDNF) gene, causing a valine (Val) to methionine (Met) amino acid substitution at codon 66, has been shown to be associated with structural and functional changes in DLPFC and affect veridical decision making.
View Article and Find Full Text PDFActa Neurobiol Exp (Wars)
February 2017
We test the emerging hypothesis that prefrontal cortical mechanisms involved in non-veridical decision making do not overlap with those of veridical decision making. Healthy female subjects performed an experimental task assessing free choice, agent-centered decision making (The Cognitive Bias Task) and a veridical control task related to visuospatial working memory (the Moving Spot Task). Transcranial magnetic stimulation (TMS) was applied to the left and right dorsolateral prefrontal cortex (DLPFC) using 1 Hz and 10 Hz (intermittent) rTMS and sham protocols.
View Article and Find Full Text PDFThe relationship between specific genes and particular diseases in neuropsychiatry is unclear, and newer studies focus on shared domains of neurobiological and cognitive pathology across different disorders. This paper reviews the evidence for an association between schizophrenia and frontotemporal dementia, including symptom similarity, familial co-morbidity, and neuroanatomical changes. Genetic as well as epigenetic findings from both schizophrenia and frontotemporal dementia are also discussed.
View Article and Find Full Text PDFHemispheric asymmetry represents a cardinal feature of cerebral organization, but the nature of structural and functional differences between the hemispheres is far from fully understood. Using Magnetic Resonance Imaging morphometry, we identified several volumetric differences between the two hemispheres of the human brain. Heteromodal inferoparietal and lateral prefrontal cortices are more extensive in the right than left hemisphere, as is visual cortex.
View Article and Find Full Text PDFTraumatic brain injury (TBI) is a neurological injury that can affect the cognitive, emotional, psychological, and physical functioning of an individual. The clinical neuropsychologist working with TBI patients must take a holistic approach when assessing and treating the patient and consider the patient in total, including premorbid and post-incident factors, to formulate a comprehensive and accurate picture of the patient. This approach will guide the clinician regarding multiple types of treatment the patient may require.
View Article and Find Full Text PDFObjective: Novelty and routinization-related information processing disturbances were examined in adolescent males with ADHD using an oddball paradigm and electrophysiological measurement of theta (4-7Hz) activity.
Methods: Fifty-four unmedicated adolescent males (12-18years) with Attention Deficit Hyperactivity Disorder (ADHD) and matched controls performed an auditory oddball task. Theta activity was sub-averaged, and Fourier Integrals with simultaneous measurement of electrodermal activity (EDA) was used to index response to stimulus novelty and routinization.
Drug addiction is associated with impaired judgment in unstructured situations in which success depends on self-regulation of behavior according to internal goals (adaptive decision-making). However most executive measures are aimed at assessing decision-making in structured scenarios, in which success is determined by external criteria inherent to the situation (veridical decision-making). The aim of this study was to examine the performance of Substance Abusers (SA, n = 97) and Healthy Comparison participants (HC, n = 81) in two behavioral tasks that mimic the uncertainty inherent in real-life decision-making: the Cognitive Bias Task (CB) and the Iowa Gambling Task (IGT) (administered only to SA).
View Article and Find Full Text PDFCognitive neuroscience researchers have hypothesized that context-dependent and context-independent response selection is associated with the left and right frontal lobe, respectively, in right-handed adult males. Patients with left frontal lobe lesions show context-independent reasoning in a cognitive bias task (CBT), while those with right frontal lesions show context-dependent reasoning. Young children show more context-independent responses in a modified CBT (mCBT), while adolescents and adults show more context-dependent responses.
View Article and Find Full Text PDFGiven the pervasive nature of executive deficit, assessment of executive functions is of crucial importance in neuropsychiatry, child and adolescent psychiatry, geriatric psychiatry, and other related areas. A number of neuropsychologic tests of executive function commonly are used in assessing several clinical disorders, including but not limited to traumatic brain injury, schizophrenia, depression, attention deficit disorder/attention deficit hyperactivity disorder, and dementia. Because the concept of executive control in its current form constitutes an over arching construct, a construct that is based on the cognitive symptoms of the frontal lobe disorder caused by many disparate underlying conditions, no single measure of executive function can adequately tap the construct in its entirety.
View Article and Find Full Text PDFCoherent cognition requires activity to be brought together across diverse brain networks. Synchronous, in-phase oscillations in the high-frequency (40 Hz) Gamma range are thought to be one mechanism underlying the functional integration of brain networks. While sex differences have been observed across a range of cognitive functions, their role in normal cortical synchronization has not been elucidated.
View Article and Find Full Text PDFDecline in cognitive function is well recognized, yet few neurophysiological correlates of age-related cognitive decline have been identified. In this study we examined the impact of age on neurocognitive function and Gamma phase synchrony among 550 normal subjects (aged 11-70). Gamma phase synchrony was acquired to targets in the auditory oddball paradigm.
View Article and Find Full Text PDFA cognitive bias task (CBT) delineates two different cognitive selection mechanisms in the prefrontal cortex. To identify functional anatomy of context-dependent reasoning, we used technetium-99mhexamethyl- propyleneamine oxime (99mTc HM-PAO) single photon emission computed tomography (SPECT) and statistical parametric mapping. Twelve right-handed men 20-24 years old were instructed to look at a target card and then select the choice card (among two) that they preferred (modified CBT; mCBT).
View Article and Find Full Text PDFTwo functionally and neurally distinct cognitive selection mechanisms involve the prefrontal lobes: those based on internal representations (context dependent) and those involving exploratory processing of novel situations (context independent). We used a cognitive bias task (CBT) representing contextual reasoning to correlate lateralization with age in the frontal lobes. Subjects included 37 healthy right-handed male children and adolescents (age range, 5-18 years).
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