Neural Mechanisms: Contributions and Control

2021 ◽  
pp. 103-137
Author(s):  
Cheryl A. Coker
Keyword(s):  
Neural Mechanisms ◽  
And Control

scholarly journals Deficits in monitoring self-produced speech in Parkinson’s disease

2019 ◽  
Author(s):  
Henry Railo ◽  
Niklas Nokelainen ◽  
Saara Savolainen ◽  
Valtteri Kaasinen
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neural Mechanisms ◽  
Speech Impairment ◽  
Self Monitoring ◽  
Evoked Activity ◽  
And Control ◽  
N1 Wave ◽  
Electrophysiological Correlate

AbstractObjectiveSpeech deficits are common in Parkinson’s disease, and behavioural findings suggest that the deficits may be due to impaired monitoring of self-produced speech. The neural mechanisms of speech deficits are not well understood. We examined a well-documented electrophysiological correlate of speech self-monitoring in patients with Parkinson’s disease and control participants.MethodsWe measured evoked electroencephalographic responses to self-produced and passively heard sounds (/a/ phonemes) in age-matched controls (N=18), and Parkinson’s disease patients who had minor speech impairment, but reported subjectively experiencing no speech deficits (N=17).ResultsDuring speaking, auditory evoked activity 100 ms after phonation (N1 wave) was less suppressed in Parkinson’s disease than controls when compared to the activity evoked by passively heard phonemes. This difference between the groups was driven by increased amplitudes to self-produced phonemes, and reduced amplitudes passively heard phonemes in Parkinson’s disease.ConclusionsThe finding indicates that auditory evoked activity is abnormally modulated during speech in Parkinson’s patients who do not subjectively notice speech impairment. This mechanism could play a role in producing speech deficits in as the disease progresses.

scholarly journals Brain activity links performance in science reasoning with conceptual approach

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Jessica E. Bartley ◽  
Michael C. Riedel ◽  
Taylor Salo ◽  
Emily R. Boeving ◽  
Katherine L. Bottenhorn ◽  
...  
Keyword(s):  
Problem Solving ◽  
Undergraduate Students ◽  
Brain Function ◽  
Visual Motion ◽  
Brain Activity ◽  
Neural Mechanisms ◽  
Conceptual Approach ◽  
Conceptual Coherence ◽  
Science Reasoning ◽  
And Control

AbstractUnderstanding how students learn is crucial for helping them succeed. We examined brain function in 107 undergraduate students during a task known to be challenging for many students—physics problem solving—to characterize the underlying neural mechanisms and determine how these support comprehension and proficiency. Further, we applied module analysis to response distributions, defining groups of students who answered by using similar physics conceptions, and probed for brain differences linked with different conceptual approaches. We found that integrated executive, attentional, visual motion, and default mode brain systems cooperate to achieve sequential and sustained physics-related cognition. While accuracy alone did not predict brain function, dissociable brain patterns were observed when students solved problems by using different physics conceptions, and increased success was linked to conceptual coherence. Our analyses demonstrate that episodic associations and control processes operate in tandem to support physics reasoning, offering potential insight to support student learning.

Memory Repression: Brain Mechanisms underlying Dissociative Amnesia

2010 ◽  
Vol 22 (3) ◽  
pp. 602-613 ◽  
Author(s):  
Hirokazu Kikuchi ◽  
Toshikatsu Fujii ◽  
Nobuhito Abe ◽  
Maki Suzuki ◽  
Masahito Takagi ◽  
...  
Keyword(s):  
Neural Activity ◽  
Memory Retrieval ◽  
Direct Evidence ◽  
Neural Mechanisms ◽  
Stressful Event ◽  
Memory Impairments ◽  
Dissociative Amnesia ◽  
And Control ◽  
Increased Activity ◽  
With Memory

Dissociative amnesia usually follows a stressful event and cannot be attributable to explicit brain damage. It is thought to reflect a reversible deficit in memory retrieval probably due to memory repression. However, the neural mechanisms underlying this condition are not clear. We used fMRI to investigate neural activity associated with memory retrieval in two patients with dissociative amnesia. For each patient, three categories of face photographs and three categories of people's names corresponding to the photographs were prepared: those of “recognizable” high school friends who were acquainted with and recognizable to the patients, those of “unrecognizable” colleagues who were actually acquainted with but unrecognizable to the patients due to their memory impairments, and “control” distracters who were unacquainted with the patients. During fMRI, the patients were visually presented with these stimuli and asked to indicate whether they were personally acquainted with them. In the comparison of the unrecognizable condition with the recognizable condition, we found increased activity in the pFC and decreased activity in the hippocampus in both patients. After treatment for retrograde amnesia, the altered pattern of brain activation disappeared in one patient whose retrograde memories were recovered, whereas it remained unchanged in the other patient whose retrograde memories were not recovered. Our findings provide direct evidence that memory repression in dissociative amnesia is associated with an altered pattern of neural activity, and they suggest the possibility that the pFC has an important role in inhibiting the activity of the hippocampus in memory repression.

scholarly journals Brain activity links performance in science reasoning with conceptual approach

2019 ◽  
Author(s):  
Jessica E. Bartley ◽  
Michael C. Riedel ◽  
Taylor Salo ◽  
Emily R. Boeving ◽  
Katherine L. Bottenhorn ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Brain Function ◽  
Visual Motion ◽  
Classroom Practices ◽  
Brain Activity ◽  
Neural Mechanisms ◽  
Conceptual Approach ◽  
Science Reasoning ◽  
And Control ◽  
Insight Into

ABSTRACTUnderstanding how students learn is crucial for helping them succeed. We examined brain function in 107 undergraduate students during a task known to be challenging for many students – physics problem solving – to characterize underlying neural mechanisms and determine how these support comprehension and proficiency. Further, we applied module analysis to response distributions, defining groups of students who answered using similar physics conceptions, and probed for brain differences linked with different conceptual approaches. We found integrated executive, attentional, visual motion, and default mode brain systems cooperate to achieve sequential and sustained physics-related cognition. While accuracy alone did not predict brain function, dissociable brain patterns were observed when students solved problems using different physics conceptions, and increased success was linked to conceptual coherence. Our analyses demonstrate that episodic associations and control processes operate in tandem to support physics reasoning, offering insight into effective classroom practices to promote student success.

Evidence for hypoxic depression of CO2-ventilation response in carotid body-resected humans

1991 ◽  
Vol 70 (2) ◽  
pp. 590-593 ◽  
Author(s):  
Y. Honda ◽  
I. Hashizume
Keyword(s):  
Carotid Body ◽  
Response Curve ◽  
Minute Ventilation ◽  
Neural Mechanisms ◽  
Control Groups ◽  
Response Curves ◽  
End Tidal ◽  
And Control ◽  
The Brain ◽  
Ventilation Response

Steady-state CO2-ventilation response curves with hyperoxia (end-tidal PO2 greater than 200 Torr) and mild hypoxia (end-tidal PO2 approximately equal to 60 Torr) were compared in five carotid body-resected (BR) patients and five control patients. The data were analyzed by fitting a linear equation, V = S(PETCO2-B), where V is minute ventilation S is the response curve slope. PETCO2 is end-tidal PCO2, and B is the response curve threshold. S slightly increased from hyperoxia to hypoxia in both BR and control groups. On the other hand, B moderately increased with hypoxia in BR patients, whereas it slightly decreased in controls. These changes were all not significant. However, in accordance with the change in B, the response curve to hypoxia at V of 10 1/min was significantly shifted in opposite directions in the two groups, i.e., rightward and leftward shift in BR and control groups, respectively. Thus the average magnitude of V calculated at PETCO2 of 40 Torr in hypoxia was significantly lower in BR patients than in controls (P less than 0.01). We conclude that this hypoxic depression of the CO2-ventilation response found in BR patients may have resulted, at least in part, from modulation of the brain stem neural mechanisms that were elicited by loss of afferent discharges from the carotid body.

scholarly journals Acute stress blunts prediction error signals in the dorsal striatum during reinforcement learning

2021 ◽  
Author(s):  
Joana Carvalheiro ◽  
Vasco A. Conceição ◽  
Ana Mesquita ◽  
Ana Seara-Cardoso
Keyword(s):  
Reinforcement Learning ◽  
Acute Stress ◽  
Dorsal Striatum ◽  
Learning Task ◽  
Neural Mechanisms ◽  
Prediction Errors ◽  
Functional Magnetic Resonance ◽  
Behavioural Performance ◽  
And Control ◽  
Gains And Losses

AbstractReinforcement learning, which implicates learning from the rewarding and punishing outcomes of our choices, is critical for adjusted behaviour. Acute stress seems to affect this ability but the neural mechanisms by which it disrupts this type of learning are still poorly understood. Here, we investigate whether and how acute stress blunts neural signalling of prediction errors during reinforcement learning using model-based functional magnetic resonance imaging. Male participants completed a well-established reinforcement learning task involving monetary gains and losses whilst under stress and control conditions. Acute stress impaired participants’ behavioural performance towards obtaining monetary gains, but not towards avoiding losses. Importantly, acute stress blunted signalling of prediction errors during gain and loss trials in the dorsal striatum — with subsidiary analyses suggesting that acute stress preferentially blunted signalling of positive prediction errors. Our results thus reveal a neurocomputational mechanism by which acute stress may impair reward learning.

scholarly journals Neural mechanisms of perceptive and affective processing of body stimuli in Anorexia nervosa – are there developmental effects?

2018 ◽  
Author(s):  
Stefanie Horndasch ◽  
Julie Roesch ◽  
Oliver Kratz ◽  
Anne Vogel ◽  
Hartmut Heinrich ◽  
...  
Keyword(s):  
Body Image ◽  
Anorexia Nervosa ◽  
Brain Regions ◽  
Neural Mechanisms ◽  
Affective Processing ◽  
Adult Women ◽  
Neural Processing ◽  
Size Estimation ◽  
Emotional Reasoning ◽  
And Control

AbstractObjectiveDifferent components of body image processing seem to be reflected by different neural mechanisms. A core symptom of Anorexia nervosa (AN) is a disturbance of body image with correlates found on a neural level. The present study focusses at the neural processing of visual body stimuli of different weight categories in adolescent and adult AN patients.Method33 adolescents aged 12–18 years (15 AN patients, 18 control participants) and 36 adult women (19 AN patients, 17 control participants) underwent functional magnetic resonance imaging (fMRI) while performing a perceptive and an affective body image task involving photographic stimuli of women belonging to different BMI categories.ResultsDifferential effects on activation depending on the BMI of the women shown in the pictures were found in frontal brain regions, the thalamus, caudate and the fusiform gyrus. Group effects differentiating between AN patients and control participants were seen mainly in the caudate and insula.DiscussionDuring a perceptive task, diminished activation of regions involved in perceptive and evaluative functions as well as emotional reasoning was seen in AN. During evaluation of the neural processing in an affective task there was a tendency towards activation differences reflecting reduced ability of size estimation and impaired integration of visual and body perception with emotions.

Genesis and Control of the Respiratory Rhythm in Adult Mammals

Physiology ◽  
2003 ◽  
Vol 18 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Gérard Hilaire ◽  
Rosario Pásaro
Keyword(s):  
Respiratory Rhythm ◽  
Neural Mechanisms ◽  
Pacemaker Neurons ◽  
Respiratory Rhythmogenesis ◽  
Respiratory Network ◽  
And Control ◽  
Vitro Data ◽  
In Vitro Data

The neural mechanisms responsible for respiratory rhythmogenesis in mammals were studied first in vivo in adults and subsequently in vitro in neonates. In vitro data have suggested that the pacemaker neurons are the kernel of the respiratory network. These data are reviewed, and their relevance to adults is discussed.

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