Page 46-51 Flashcards
What happens in the prefrontal cortex that is compatible with PASA and successful memory in older adults?
The prefrontal cortex shows increased activation, which is compatible with PASA and successful memory in older adults.
What may mediate successful memory in older adults according to the text?
Successful memory in older adults may be mediated by a posterior-anterior shift in memory networks functional connectivity.
What happens to the default mode network (DMN) in aging, and what consequences does it have?
In aging, the DMN shows lower functional connectivity within its regions, leading to reduced task-related deactivation. This can result in the DMN becoming active during tasks, explaining difficulty in allocating cognitive resources and age-related differences in cognitive performance.
What is the Brain Maintenance Hypothesis, and what does it propose as the best predictor of cognitive conservation?
The Brain Maintenance Hypothesis suggests that the best predictor of cognitive conservation is brain maintenance, which involves the absence of damage or pathology. Older adults with well-preserved memory and cognition have few brain changes, supporting the idea of brain conservation.
According to a meta-analysis of fMRI in normal aging (Li et al., 2015), what changes in brain activation are observed in older adults?
Older adults hypo-activate visual networks and hyper-activate fronto-parietal control and default networks, with fronto-parietal network activation often associated with behavioral performance as a form of compensation.
Why is the literature inconsistent regarding the activation of the rPFC and its relation to cognitive performance?
The inconsistency in the literature about the activation of the rPFC and its relation to cognitive performance may be due to factors such as more studies, differences in task demand levels, and variations in the success or failure of compensation.
What does the Resting-State fMRI (rs-fMRI) measure, and how is it performed?
Resting-State fMRI measures intrinsic brain activity during rest. It is performed by having individuals lie in the scanner without performing a task while collecting BOLD fMRI data for the whole brain.
What is the default mode network (DMN) and its significance in resting-state fMRI?
The DMN is a network that shows lower functional connectivity within its regions during aging. It is significant in resting-state fMRI as its activation is associated with the deactivation of task-positive networks, providing insights into brain organization.
According to Raichle (2011), what is the concept of intrinsic brain activity, and how is it studied with resting-state fMRI?
The concept of intrinsic brain activity refers to activity in the resting state. Resting-state fMRI involves individuals lying in the scanner without performing a task, and functional connectivity analysis allows the identification of distinct patterns of brain connections.
How is spontaneous/intrinsic/endogenous brain activity observed, and what is its function according to current knowledge?
Spontaneous/intrinsic/endogenous brain activity is observed through resting-state fMRI and single-cell recording. Its function is not fully understood, but various proposals include random noise fluctuations, emergent properties of anatomical circuitries, and homeostatic mechanisms linked to the history of task activation.
What evidence suggests functional relevance in spontaneous brain activity despite the traditional view of the brain as a sensory-motor analyzer?
Evidence includes the great energy consumption by the brain, advantageous activity in the infra-slow frequency range, and the observation that resting-state activity predicts individual cognitive performance differences and can distinguish clinical conditions.
How does Baldassarre et al. (2016) demonstrate the relevance of spontaneous brain activity in stroke patients?
Baldassarre et al. (2016) found a double dissociation in stroke patients, linking spatial attentional deficits to disruption of inter-hemispheric functional connectivity in the dorsal attention network and motor deficits to disruption in the motor network, highlighting the role of spontaneous brain activity.
What are some proposed explanations for the observed resting-state brain activity, according to different models?
Proposed explanations include random noise fluctuations, emergent properties of anatomical circuitries driven by noise, homeostatic mechanisms linked to the history of task activation, and prior expectations for the execution of behaviorally relevant tasks and personal traits.
According to the text, are prefrontal asymmetries only task-driven, or are they also present at rest?
Prefrontal asymmetries are not only task-driven; they are also present at rest, as investigated using rs-EEG in different cognitive tasks.
What is the Stroop Test, and what rs-EEG findings are associated with better performance in the verbal Stroop task?
The Stroop Test involves measuring the Stroop effect in verbal and spatial tasks. In the verbal Stroop task, a left-lateralization of rs-EEG, especially in the MFG and lPFC, is associated with better performance (less cost for incongruent trials).
In the study on monitoring tasks, what rs-EEG findings are associated with better performance?
In the monitoring tasks study, right-lateralization of rs-EEG in the PFC, especially in the MFG, is associated with better performance.
According to the study on task-switching, what does right-lateralized rest activity correlate with in terms of switching and mixing costs?
Right-lateralized rest activity in the MFG correlates with lower mixing costs in the task-switching paradigm.
What do generative models propose about the meaning of spontaneous brain activity in a Bayesian framework?
Generative models propose that spontaneous brain activity constantly produces top-down dynamics, optimizing generative models for future interactions. Spontaneous activity reflects transitions between generic priors, exploring the brain’s dynamic repertoire and reducing the complexity of generative models.
How do generative models reconcile different types of spontaneous activity often studied separately?
Generative models suggest that low-frequency brain fluctuations during spontaneous activity optimize generative models for future interactions, reconciling resting state activity and replays often studied separately.
What clinical significance does resting-state activity have, especially in neurological and psychiatric diseases?
Disruptions in functional connectivity reported in various neurological and psychiatric diseases indicate changes in resting state coherence, serving as an early biomarker of brain disease.
What alterations in functional connectivity are observed in ADHD according to the text?
In ADHD, alterations include increased short-range connectivity, decreased long-range connectivity, decreased global efficiency, and increased local efficiency, affecting the small-world properties of the brain.
How is the DMN connectivity disrupted in Alzheimer’s disease, and what is the clinical significance?
Alzheimer’s disease is characterized by DMN connectivity disruption, both in normal aging and even more so in AD. Changes in resting state coherence between nodes of a network serve as an early biomarker of Alzheimer’s disease.
Who introduced the idea of the localization of function, and what was the method used in cranioscopy?
Gall and phrenology introduced the idea of the localization of function. Cranioscopy involved suggesting features of an individual based on the shape of the skull, created by pressure from the underlying brain.
What was the aim of Damadian’s machine in the early 1970s regarding NMR and medical applications?
Damadian aimed to distinguish healthy and malignant tissues using NMR, proposing to use differences in relaxation times. However, there was no image formation method at that time.
What is the significance of Lauterbur’s contribution to NMR imaging in 1973?
Lauterbur introduced a projection method for creating NMR images, using one-dimensional projections combined into a 2D image. This involved magnetic field gradients, changing the spin frequency of atomic nuclei and allowing recovery of spatial information.
What discovery by Ogawa et al. (1990) added a fourth dimension to MRI images, and what does it measure?
Ogawa et al. (1990) discovered the Blood Oxygenation Level Dependent (BOLD) signal, adding a fourth dimension (time) to MRI images. It measures changes in blood oxygenation over time as a function of neuronal activity, providing a link between anatomy and function.
