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Neurophysiological changes associated with dementia in Down syndrome
Published in Vee P. Prasher, Down Syndrome and Alzheimer’s Disease, 2018
Frank E. Visser, Satnam Kunar, Vee P. Prasher
The auditory evoked potential (AEP) (P3 or P300) response is recorded around 300 milliseconds after a stimulus of an infrequent but relevant tone has been presented in a series of frequent ‘ignored’ tones. The P300 or ‘P3b’ component is a scalp positivity that is typically maximal at centroparietal midline sites around 300 milliseconds after the stimulus.43 Although there is no consensus about the precise cognitive processes underlying the P3 component,44–46 it is clearly sensitive to attentional resource allocation and working memory load. Factors that influence the P300 size include subjective probability, stimulus saliency, attention and inter-stimulus interval, whereas the P300 is relatively independent of the sensory input characteristics.47,48 One view is that the P300 reflects the updating of working memory.45 Although the P300 latency is closely related to the complexity of the stimulus evaluation phase, the P300 amplitude is most sensitive to the subjective probability of the target’s occurrence, where decreased probability results in larger amplitudes.49
Meditation, Neurobiological Changes, Genes, and Health
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
Our own lab has also shown that both meditation and tai chi, a moving form of meditation, have greater ability to improve executive attention and the underlying neural networks, than aerobic activity, when compared to a sedentary control group (Hawkes et al. 2014). EEG activity was measured while participants performed a complex computer game (a spatial switch task, in which rules changed every two trials). The long term meditation and tai chi groups not only had better performance on the task than the other groups, but also showed significantly larger P3b event related potentials (ERPs), as you see in Figure 17.2. P3b ERPs are attentionally associated EEG activity occurring 300 ms after the onset of the stimulus on the computer screen, which triggered a given switch trial. Larger ERPs are associated with greater attention given to the task, so this demonstrates the greater attentional network activity in the tai chi and meditation groups (Hawkes et al. 2014). What areas of the brain are associated with this improvement in executive attentional networks? We determined this using independent component analysis, which separates the ERP into its sources from different regions of the cortex. The ACC showed one of the greatest contributions to the differences in ERP size between groups.
The role of glucose in supporting cognition and mood regulation
Published in Philip N. Murphy, The Routledge International Handbook of Psychobiology, 2018
Andrew Scholey, Riccarda Peters, Carlee Cleeland, David White
Another study highlighting the modularity of the hippocampus through glucose ingestion was conducted in a different modality, measuring event-related potentials (ERPs) measured in EEG (Riby et al., 2008). After the ingestion of oral glucose or placebo, ERPs were recorded during the performance of an oddball task. The consumption of glucose has been found to be associated with the reduction in P3b amplitude in comparison to placebo, whereas other ERP components important for attentional processes were not modulated. The P3b component reflects memory updating processes and has been shown to be dependent on the hippocampus.
Consciousness in a Rotor? Science and Ethics of Potentially Conscious Human Cerebral Organoids
Published in AJOB Neuroscience, 2023
Federico Zilio, Andrea Lavazza
GNWT considers consciousness to be less distributed (it specifically speaks of brain-wide information sharing (Dehaene 2014), but it still implies a high degree of liberalism regarding experience and the brain. In fact, it would be sufficient for an HCO to develop a sufficiently complex network that broadcasts information in its entire structure for it to obtain awareness. Thus, if an HCO grows in such a way as to resemble long-distant patterns of cortico-cortical interactions and sufficient functional and anatomical differentiation, it may be able to distribute information in a global, i.e., unified and selected way, enabling an initial form of consciousness. The neural activity in P3b is mainly related to post-stimulus activity, observed during subjective reports and mediated by the simultaneous involvement of multiple areas of the brain. Therefore, it would be necessary to identify the presence of component P3b as a result of some external stimuli, such as, for example, light-based sensory stimulation (Quadrato et al. 2017) or pharmacological manipulation (Colombi et al. 2021), although at the moment there is no evidence that this stimulation can cause such a sufficient event-related potential, since HCOs, so far, lack most of the functional and anatomical characteristics found in normal brains.3 In this sense, it is misleading to refer to HCOs as “mini brains”.
The Effects of Total Sleep Deprivation on Attention Capture Processes in Young and Older Adults: An ERP Study
Published in Experimental Aging Research, 2023
Paniz Tavakoli, Anthony Murkar, Meggan Porteous, Julie Carrier, Rebecca Robillard
In young adults, the P3b was larger following deviant compared to standard trials. In older adults, however, the amplitude of the P3b was attenuated and did not vary significantly between standard and deviant trials. The P3b reflects processes related to sustained active attention in tasks requiring stimulus evaluation and categorization (for reviews, see Johnson, 1988; Polich, 2007; Polich & Criado, 2006). A variety of factors have been found to affect the P3b, such as stimulus information content and probability (Donchin & Coles, 1988; Johnson, 1988; Kok, 2001; Oken, 1997; Polich, 1987; Sommer, Leuthold, & Matt, 1998; Verleger, 1988). The differences in P3b amplitude between groups suggest that the influence of factors that may normally affect the P3b amplitude is altered in older adults.
Changes of attention-related brain activity over 6 months after acute organophosphate pesticide poisoning: a prospective follow-up study
Published in Clinical Toxicology, 2022
Tharaka L. Dassanayake, Vajira S. Weerasinghe, Indika B. Gawarammana, Nicholas A. Buckley
The present paper reports the neurophysiological findings of that study. Specifically, we investigated sub-acute and long-term changes of neuroelectrophysiological markers of attention, namely cognitive event-related potentials (ERPs) recorded in a behavioral task that taps into attentional processes of the brain. ERPs are electroencephalographic responses generated by sensory, cognitive, or motor processes of the brain. In this research we focused on a pre-attentive (N1) and an attentive (P3b) processing component of ERPs elicited by a classic auditory oddball task. In this paradigm, the subject is presented with rare target stimuli and frequent non-target or standard stimuli randomly intermixed within a task block [18,19]. The subject attends to the targets (by mentally counting them or by pressing a response button) while ignoring the standards. Both types of stimuli evoke the negative, N1 ERP component–an index of pre-attentive cortical processing. The targets, in addition, elicit the positive, P300 component [20] – now more specifically referred to as the P3b component [19] – that peaks around a latency of 300 ms post-stimulus in the centroparietal scalp sites. P3b is thus considered an electrophysiological signature of working memory and context updating [see 19,21,22 for reviews]. Accordingly, P3b latency is considered an index of the speed of stimulus classification, whereas P3b amplitude is sensitive to the neural resource allocation for attentional processing.