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Organic Chemicals
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Working memory task: They applied the N-Back task during the fMRI acquisition for activation of the working memory circuitry. The N-Back task173,174 is a continuous performance task that is commonly used in functional imaging for the study of cognition where memory loads can be adjusted using the parameter N.
A review of laboratory studies on the acute effects of movement and exercise on cognition in children
Published in Romain Meeusen, Sabine Schaefer, Phillip Tomporowski, Richard Bailey, Physical Activity and Educational Achievement, 2017
A study by Schaefer, Lövdén, Wieckhorst, and Lindenberger (2010) asked 9-year-old children and young adults to walk on a treadmill in two conditions: either at their preferred speed, or at a fixed speed of 2.5 km/h, which was slower than preferred. Participants were also asked to perform a working-memory task, n-back, under different difficulty conditions. For the n-back task, participants are presented with a series of numbers over loudspeakers. They had to indicate whether the current number is identical to the number presented n positions earlier in the sequence. The easiest condition was n-back 1 (comparing the number to the previous number), and the most difficult condition was n-back 4 (comparing the number to the number that was presented four positions earlier). Since the task requires a constant updating of memory, it is rather demanding. When performing the task while walking at their preferred speed as opposed to sitting, participants were more successful in the cognitive task, and this effect was more pronounced in the children (Figure 10.1). However, when the treadmill speed was fixed, performances in n-back did not differ between walking and sitting. The authors argue that preferred-speed walking might have optimized arousal levels, whereas walking at a slower than preferred speed requires some attention, such that the cognitive task does not profit from this task condition.
Application of Functional Near-Infrared Spectroscopy in Brain Mapping
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Afrouz Azari-Anderson, Fatima A. Chowdhry, Yasaman Ardeshirpour, Nader Shahni Karamzadeh, Elizabeth G. Smith, Viktor Chernomordik, Amir H. Gandjbakhche
fNIRS has been a valuable tool in monitoring the brain activation at cortical regions during the execution of functional tasks. Several studies have compared the accuracy of fNIRS with that of fMRI, signifying the ability of fNIRS to probe the cognitive function of the brain (Maggio, 2014; Müller and Osterreich, 2014; Panerai et al., 2005; Wong et al., 2008). fNIRS measurements, performed during several widely used function tasks, such as N-Back and Go/No-Go, are used to investigate the neural basis of working memory processes and response inhibition in prefrontal cortex (PFC) region, respectively. In short, in a classical N-Back paradigm, 0-back, 1-back, and 2-back conditions can be investigated. For a 0-back task, subjects will press the button when the target signal (e.g., “X”) appears. For 1-back and 2-back tasks, the subject is instructed to press the button if the presented cue matches one and two letters/images back, respectively. In Go/No-Go task, the Go and No-Go cues are displayed on the screen and subjects are asked to respond when they observe the Go signal and vice versa when No-Go cue is shown. Visual, auditory, and motor tasks are other examples of functional tasks that are often used in fNIRS studies investigating brain function and activation at the occipital lobe, Broca’s area, and motor cortex regions. Table 3.1 provides examples of studies applying fNIRS at different cortical domains and using various functional tasks.
Nutrient effects on working memory across the adult lifespan
Published in Nutritional Neuroscience, 2023
Selene Cansino, Frine Torres-Trejo, Cinthya Estrada-Manilla, Adriana Flores-Mendoza, Gerardo Ramírez-Pérez, Silvia Ruiz-Velasco
Participants performed the verbal and spatial n-back tasks in counterbalanced order, and within each domain, they performed two levels of difficulty (1-back and 2-back) in counterbalanced order. Data from the 1-back task were not included in the analyses because this task demands few processing resources, and some participants’ performance showed ceiling effects. Prior to performing each of the four n-back tasks, the participants performed brief versions of each task as training. Each trial from both the verbal and spatial n-back tasks started with the presentation of the stimulus (letter or circle) for 300 ms, followed by a period of 2700 ms. After this time, the next stimulus was displayed. The participants were allowed to provide their response during the 3000-ms period following the onset of the stimulus. In the verbal 2-back task, the participants were requested to indicate whether the current letter was equal to or not equal to that presented two trials earlier. In the spatial version, the participants were required to indicate whether the current circle was presented in the same position as that displayed two trials earlier (2-back). The participants performed 72 trials from each task, and 33% of the trials were targeted (the letter or position of the current trial was equal to that presented two trials earlier).
Effects of operational assessment of the 4:4 and 4:4/6:6 watch systems on sleepiness, fatigue, and stress responses during patrolling on a navy missile patrol boat
Published in Chronobiology International, 2022
Mikko Myllylä, Heikki Kyröläinen, Tommi Ojanen, Juha-Petri Ruohola, Olli J. Heinonen, Tero Vahlberg, Kai I. Parkkola
Cognitive tests (SART, N-Back) were conducted to assess the participants’ cognitive performance. The Sustained Attention to Response Task (SART) is a measure developed to evaluate sustained attention and inhibitory control (Robertson et al. 1997). The n-back task (N-Back) is a continuous performance task that is considered useful for experimental research in working memory and is also considered to predict inter-individual differences in fluid intelligence (Jaeggi et al. 2010). During the study weeks, the participants performed the cognitive tests with laptop computers using the index finger of the dominant hand. To obtain reliable results, laptop computers were situated on tables, an unused new keyboard was attached to every computer and the participants performed the tests using the same keyboard and computer in both data collection periods. Completing the SART required approximately 5 min and the test consisted of numbers 1–9 appearing 225 times in random order. The participants attempted to respond to the appearance of each number by pressing a button on the keyboard, except when the number 3 appeared, which happened 25 times during the test. Completing the N-Back test required approximately 10 min and the test consisted of appearing letters. The participants attempted to respond to each letter that appeared instructed N items ago by pressing a button on the keyboard. In this study, the N-Back test was modified so that it consisted only of trials N = 0, N = 1 and N = 2. Trial N = 3 was left out of the N-Back in this study to shorten the duration of the test.
Ankle-foot orthoses improve walking but do not reduce dual-task costs after stroke
Published in Topics in Stroke Rehabilitation, 2021
Richard Drake, Kim Parker, Kerry-Lee Clifton, Stefan Allen, James Adderson, Anita Mountain, Gail A. Eskes
The secondary task was an auditory n-back task programmed in Empirisoft’s DirectRT (http://www.empirisoft.com/directrt.aspx). N-back tasks involve listening to a series of stimuli in order to judge whether the currently presented stimulus is the same as the one presented n-times ago. In this study, participants heard a sequence of letters through a wireless headset and responded ‘yes’ to matches and ‘no’ to non-matches via voice-operated relay. Response times and accuracy were recorded. Blocks consisted of 18 stimuli, six of which were matches. The task was first performed while seated and at an n-level of 1 in order to measure participants’ ability to perform the task. Individuals who scored less than 13 out of 18 were excluded from the study. For those who achieved at least 13 on the 1-back, one block of the 2-back test was then performed while seated (single-task condition). Individuals with scores greater than 13 on the 2-back were given the 2-back during the dual-task gait testing, while individuals with scores lower than 13 on the 2-back were given the 1-back. Participants completed four blocks of the n-back task per each of the two dual-task walking conditions. Accuracy (percent correct) and response times (RT, ms) were collected. The validity of the letter n-back task as a measure of working memory has been supported through behavioral and neuroimaging data.34