12. The Role of the Human Prefrontal Cortex in the Response Suppression of Eye Movements

2017 ◽  
Author(s):  
Jason Lloyd Chan
Keyword(s):  
Prefrontal Cortex ◽  
Eye Movement ◽  
Intersection Point ◽  
Response Suppression ◽  
Task Selection ◽  
Ratio Increase ◽  
Time Courses ◽  
Anti Saccades ◽  
Increased Activity

Increased activity in a population of prefrontal cortex neurons has been shown, in previous studies, to precede correct anti‐saccades in primates. In addition, the time courses of two competing processes in these neurons, task selection (which prepares for an eye movement) and saccade suppression (which prepares for the suppression of an eye movement), intersect at a specific time after the presentation of a coloured instruction cue. The purpose of this study is to use eye tracking behaviour to investigate this intersection point and its role in response suppression in regard to the generation of anti‐saccades in humans. Subjects were instructed before a stimulus appears, using a colour cue, to either look towards the stimulus (pro‐saccade) or away from the stimulus (anti‐saccade). Instruction period times varied from 100ms to 1400ms, in 50ms steps. Based on previous primate electrophysiological data, the ratio of direction errors (pro‐saccades on anti‐saccade trials) to correct anti‐saccades was expected to increase around 400ms to 500ms, when the processes of task selection and saccade suppression diverge. A slight ratio increase was found and full results are forthcoming.

Dorsolateral Prefrontal Cortex Enables Updating of Established Memories

2018 ◽  
Vol 29 (10) ◽  
pp. 4154-4168 ◽  
Author(s):  
Lisa Marieke Kluen ◽  
Lisa Catherine Dandolo ◽  
Gerhard Jocham ◽  
Lars Schwabe
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Neural Mechanisms ◽  
Related Activity ◽  
Future Behavior ◽  
New Information ◽  
Dorsolateral Prefrontal ◽  
Increased Activity ◽  
The Brain

Abstract Updating established memories in light of new information is fundamental for memory to guide future behavior. However, little is known about the brain mechanisms by which existing memories can be updated. Here, we combined functional magnetic resonance imaging and multivariate representational similarity analysis to elucidate the neural mechanisms underlying the updating of consolidated memories. To this end, participants first learned face–city name pairs. Twenty-four hours later, while lying in the MRI scanner, participants were required to update some of these associations, but not others, and to encode entirely new pairs. Updating success was tested again 24 h later. Our results showed increased activity of the dorsolateral prefrontal cortex (dlPFC) specifically during the updating of existing associations that was significantly stronger than when simple retrieval or new encoding was required. The updating-related activity of the dlPFC and its functional connectivity with the hippocampus were directly linked to updating success. Furthermore, neural similarity for updated items was markedly higher in the dlPFC and this increase in dlPFC neural similarity distinguished individuals with high updating performance from those with low updating performance. Together, these findings suggest a key role of the dlPFC, presumably in interaction with the hippocampus, in the updating of established memories.

scholarly journals Role of Prefrontal Cortex during Sudoku task: fNIRS study

2020 ◽  
Author(s):  
Patil Ashlesh ◽  
K K Deepak ◽  
Kochhar Kanwal Preet
Keyword(s):  
Prefrontal Cortex ◽  
Near Infrared ◽  
Brain Activity ◽  
Neural Substrates ◽  
List Type ◽  
Heuristic Rules ◽  
Functional Near Infrared Spectroscopy ◽  
Time Activity ◽  
Increased Activity

AbstractSudoku is a popular leisure time activity that involves no math, but is based on logic based combinatorial number placement in a matrix. Many studies have been dedicated towards finding an algorithm to solve Sudoku but investigation of the neural substrates involved in Sudoku has been challenging. It is difficult to measure the brain activity during 9×9 Sudoku using traditional fMRI technique due to the procedural constraints. 16 optodes fNIRS (functional near infrared spectroscopy) forms an excellent alternative to study the activity of prefrontal cortex (PFC) during Sudoku task. Sudoku task was divided into two steps to understand the differential function of the PFC while applying heuristic rules. Classical two-way ANOVA as well as General Linear Model based approach was used to analyze the data. 28-noise free recording from right-handed participants revealed increased activity in all 16 optode locations during step 1 (3 × 3 subgrids) and step 2 (easy level 9×9 Sudoku) as compared to rest. Contrasting the step2-step1 revealed that medial regions of PFC were preferentially activated. These findings suggest the role of these regions, while applying multiple heuristic rules to solve 9×9 Sudoku puzzle.Graphical abstractHighlightsThis is first fNIRS study that tried to unravel the role of PFC during Sudoku task.Uniquely divided the Sudoku task into two steps to understand the differential role of PFC while applying multiple heuristic rules.Both the medial and lateral regions of PFC are activated during Sudoku task.However, the medial regions of PFC play a differential role, especially when we consider the row and the column rule of Sudoku.

scholarly journals Fixation target representation in prefrontal cortex during the antisaccade task

2017 ◽  
Vol 117 (6) ◽  
pp. 2152-2162 ◽  
Author(s):  
Xin Zhou ◽  
Christos Constantinidis
Keyword(s):  
Prefrontal Cortex ◽  
Eye Movements ◽  
Eye Movement ◽  
Visual Stimulus ◽  
Dorsolateral Prefrontal Cortex ◽  
Neuron Activity ◽  
Antisaccade Task ◽  
Subcortical Structures ◽  
Dorsolateral Prefrontal

Neurons that discharge strongly during the time period of fixation of a visual target and cease to discharge before saccade initiation have been described in the brain stem, superior colliculus, and cortical areas. In subcortical structures, fixation neurons play a reciprocal role with saccadic neurons during the generation of eye movements. Their role in the dorsolateral prefrontal cortex is less obvious, and it is not known if they are activated by fixation, inhibit saccade generation, or play a role in more complex functions such as the inhibition of inappropriate responses. We examined the properties of prefrontal fixation neurons in the context of an antisaccade task, which requires an eye movement directed away from a prepotent visual stimulus. We tested monkeys with variants of the task, allowing us to dissociate activity synchronized on the fixation offset, presentation of the visual stimulus, and saccadic onset. Fixation neuron activity latency was most strongly tied to the offset of the fixation point across task variants. It was not well predicted by the appearance of the visual stimulus, which is essential for planning of the correct eye movement and inhibiting inappropriate ones. Activity of fixation neurons was generally negatively correlated with that of saccade neurons; however, critical differences in timing make it unlikely that they provide precisely timed signals for the generation of eye movements. These results demonstrate the role of fixation neurons in the prefrontal cortex during tasks requiring timing of appropriate eye movement and inhibition of inappropriate actions. NEW & NOTEWORTHY Properties of neurons that discharge during eye fixation and go silent before saccade initiation have been described in subcortical structures involved in eye movement generation, but their role in the dorsolateral prefrontal cortex presents a puzzle. Our results demonstrate the role of fixation neurons in the prefrontal cortex during tasks requiring precise timing of appropriate eye movement and inhibition of inappropriate actions.

Alcohol Dependence Conceptualized as a Stress Disorder

2019 ◽  
pp. 198-220
Author(s):  
Leandro F. Vendruscolo ◽  
George F. Koob
Keyword(s):  
Prefrontal Cortex ◽  
Alcohol Use ◽  
Alcohol Dependence ◽  
Glucocorticoid Receptors ◽  
Critical Role ◽  
Emotional States ◽  
Brain Circuits ◽  
Negative Emotional State ◽  
Alcohol Alcohol

Alcohol use disorder is a chronically relapsing disorder that involves (1) compulsivity to seek and take alcohol, (2) difficulty in limiting alcohol intake, and (3) emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability) in the absence of alcohol. Alcohol addiction encompasses a three-stage cycle that becomes more intense as alcohol use progresses: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. These stages engage neuroadaptations in brain circuits that involve the basal ganglia (reward hypofunction), extended amygdala (stress sensitization), and prefrontal cortex (executive function disorder). This chapter discusses key neuroadaptations in the hypothalamic and extrahypothalamic stress systems and the critical role of glucocorticoid receptors. These neuroadaptations contribute to negative emotional states that powerfully drive compulsive alcohol drinking and seeking. These changes in association with a disruption of prefrontal cortex function that lead to cognitive deficits and poor decision making contribute to the chronic relapsing nature of alcohol dependence.

scholarly journals Role of Primate Cerebellar Hemisphere in Voluntary Eye Movement Control Revealed by Lesion Effects

2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Movement Control ◽  
Cerebellar Hemisphere ◽  
Target Velocity ◽  
Eye Movement Control ◽  
Pursuit Eye Movements ◽  
Catch Up

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.

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