Lateral prefrontal and posterior parietal cortical areas exhibit task-dependent activation during working memory tasks in humans and monkeys. Neurons in these regions become synchronized during ...attention-demanding tasks, but the contribution of these interactions to working memory is largely unknown. Using simultaneous recordings of neural activity from multiple areas in both regions, we find widespread, task-dependent, and content-specific synchronization of activity across the fronto-parietal network during visual working memory. The patterns of synchronization are prevalent among stimulus-selective neurons and are governed by influences arising in parietal cortex. These results indicate that short-term memories are represented by large-scale patterns of synchronized activity across the fronto-parietal network.
Abstract Paradigms requiring either a GO or a NO-GO response are often used to study the neural mechanisms of response inhibition. Here this issue is examined from the perspective of event-related ...beta (14–30 Hz) oscillatory activity. Two macaque monkeys performed a task that began with a self-initiated lever depression and maintenance (sustained motor output) and required a visual pattern discrimination followed by either a lever release (GO) or continued lever-holding (NO-GO) response. Analyzing simultaneous local field potentials (LFPs) from primary somatosensory, frontal motor, and posterior parietal cortices, we report two results. First, beta oscillation desynchronized shortly after stimulus presentation, the onset of which was approximately the same for both the GO and NO-GO conditions (∼110 ms). Since it is well known that beta desynchronization is a reliable indicator of movement preparation, this result suggests that early motor preparation took place in both conditions. Second, following the GO/NO-GO decision (∼190 ms), beta activity rebounded significantly (∼300 ms) only in the NO-GO condition. Coherence and Granger causality measures revealed that the dynamical organization of the rebounded beta network was similar to that existing during the sustained motor output prior to stimulus onset. This finding suggests that response inhibition led to the restoration of the sensorimotor network to its prestimulus state.
Cortical coordination dynamics and cognition Bressler, Steven L.; Kelso, J.A.Scott
Trends in Cognitive Sciences,
2001, 2001-Jan-01, 2001-1-00, 20010101, Letnik:
5, Številka:
1
Book Review, Journal Article
Recenzirano
New imaging techniques in cognitive neuroscience have produced a deluge of information correlating cognitive and neural phenomena. Yet our understanding of the inter-relationship between brain and ...mind remains hampered by the lack of a theoretical language for expressing cognitive functions in neural terms. We propose an approach to understanding operational laws in cognition based on principles of coordination dynamics that are derived from a simple and experimentally verified theoretical model. When applied to the dynamical properties of cortical areas and their coordination, these principles support a mechanism of adaptive inter-area pattern constraint that we postulate underlies cognitive operations generally.
The operation of a cryogenic Resistive WELL (RWELL) in liquid argon vapor is reported for the first time. It comprises a Thick Gas Electron Multiplier (THGEM) structure coupled to a resistive ...Diamond-Like Carbon (DLC) anode deposited on an insulating substrate. The multiplier was operated at cryogenic temperature (90 K, 1.2 bar) in saturated argon vapor and characterized in terms of charge gain and electrical stability. A comparative study with standard, non-resistive THGEM (a.k.a LEM) and WELL multipliers confirmed the RWELL advantages in terms of discharge quenching – i.e. superior gain and stability.
•Lower respiratory tract infection (LRTI) rates increased 26% among Alaska American Indian/Alaska Native adults, compared to a 38% decrease in non-Alaska American Indian/Alaska Native adults.•LRTI ...rates were higher in Alaska compared to non-Alaska.•The most common diagnosis associated with LRTI was pneumonia, followed by essential hypertension.•The median length of hospital stay was longer in Alaska compared to non-Alaska sites.•A lack of piped water and household crowding likely contributed to the high rates of LRTI.
Objectives: This study describes the changes in lower respiratory tract infection (LRTI) rates from 1998 to 2014 among hospitalized American Indian/Alaska Native (AI/AN) adults residing in Alaska and other Indian Health Service (IHS) regions.
Methods: Age-adjusted hospital discharge rates and rate ratios were calculated from the IHS Direct and Contract Health Services Inpatient Dataset, IHS National Patient Information Reporting System for AI/AN adults ≥18 years, hospitalized at an IHS-operated, tribally operated, or contract hospital with an LRTI-associated diagnosis during 1998–2014.
Results: Overall, there were 13 733 LRTI-associated hospitalizations in Alaska (1998–2014), with an age-adjusted rate of 13.7/1000 adults. Among non-Alaska (non-AK) AI/AN, there were a total of 79 170 hospitalizations, with a rate of 8.6/1000 adults. In the pre-PCV7 and pre-PCV13 periods, LRTI rates were higher in Alaska (AK) AI/AN (12.4 and 14.1, respectively) when compared to non-AK AI/AN (10.1 and 9.1, respectively) (P < 0.0001). In the post-PCV7 and post-PCV13 periods, LRTI rates were also higher in AK (13.5 and 15.0, respectively) compared to non-AK (9.2 and 7.3, respectively) (P < 0.0001).
Conclusions: Over the study period, a 26% increase in rates of LRTI among adult AI/AN residing in AK compared with a 38% decrease in rates among AI/AN residing in non-AK were observed. This disparity is likely due to a variety of factors such as tobacco use, crowding, etc. Strategies to reduce LRTI in AI/AN adults are needed.
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