scholarly journals Dorsolateral prefrontal cortex supports speech perception in listeners with cochlear implants

2021 ◽  
Author(s):  
Arefeh Sherafati ◽  
Noel Dwyer ◽  
Aahana Bajracharya ◽  
Mahlega S Hassanpour ◽  
Adam T Eggebrecht ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Cochlear Implants ◽  
Dorsolateral Prefrontal Cortex ◽  
Functional Neuroimaging ◽  
Optical Tomography ◽  
Memory Task ◽  
Normal Hearing ◽  
Speech Understanding ◽  
Dorsolateral Prefrontal ◽  
The Brain

Cochlear implants are neuroprosthetic devices that can restore hearing in individuals with severe to profound hearing loss by electrically stimulating the auditory nerve. Because of physical limitations on the precision of this stimulation, the acoustic information delivered by a cochlear implant does not convey the same level of spectral detail as that conveyed by normal hearing. As a result, speech understanding in listeners with cochlear implants is typically poorer and more effortful than in listeners with normal hearing. The brain networks supporting speech understanding in listeners with cochlear implants are not well understood, partly due to difficulties obtaining functional neuroimaging data in this population. In the current study, we assessed the brain regions supporting spoken word understanding in adult listeners with right unilateral cochlear implants (n=20) and matched controls (n=18) using high-density diffuse optical tomography (HD-DOT), a quiet and non-invasive imaging modality with spatial resolution comparable to that of functional MRI. We found that while listening to spoken words in quiet, listeners with cochlear implants showed greater activity in the left dorsolateral prefrontal cortex, overlapping with functionally-defined domain-general processing seen in a spatial working memory task. These results suggest that listeners with cochlear implants require greater cognitive processing during speech understanding than listeners with normal hearing, supported by compensatory recruitment in the left dorsolateral prefrontal cortex.

scholarly journals Prefrontal and Parietal Attractor Networks Mediate Working Memory Judgments

2020 ◽  
Author(s):  
Sihai Li ◽  
Christos Constantinidis ◽  
Xue-Lian Qi
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Critical Role ◽  
Memory Task ◽  
Delayed Response ◽  
Persistent Activity ◽  
Neural Basis ◽  
Brain Areas ◽  
Dorsolateral Prefrontal

ABSTRACTThe dorsolateral prefrontal cortex plays a critical role in spatial working memory and its activity predicts behavioral responses in delayed response tasks. Here we addressed whether this predictive ability extends to categorical judgments based on information retained in working memory, and is present in other brain areas. We trained monkeys in a novel, Match-Stay, Nonmatch-Go task, which required them to observe two stimuli presented in sequence with an intervening delay period between them. If the two stimuli were different, the monkeys had to saccade to the location of the second stimulus; if they were the same, they held fixation. Neurophysiological recordings were performed in areas 8a and 46 of the dlPFC and 7a and lateral intraparietal cortex (LIP) of the PPC. We hypothesized that random drifts causing the peak activity of the network to move away from the first stimulus location and towards the location of the second stimulus would result in categorical errors. Indeed, for both areas, when the first stimulus appeared in a neuron’s preferred location, the neuron showed significantly higher firing rates in correct than in error trials. When the first stimulus appeared at a nonpreferred location and the second stimulus at a preferred, activity in error trials was higher than in correct. The results indicate that the activity of both dlPFC and PPC neurons is predictive of categorical judgments of information maintained in working memory, and the magnitude of neuronal firing rate deviations is revealing of the contents of working memory as it determines performance.SIGNIFICANCE STATEMENTThe neural basis of working memory and the areas mediating this function is a topic of controversy. Persistent activity in the prefrontal cortex has traditionally been thought to be the neural correlate of working memory, however recent studies have proposed alternative mechanisms and brain areas. Here we show that persistent activity in both the dorsolateral prefrontal cortex and posterior parietal cortex predicts behavior in a working memory task that requires a categorical judgement. Our results offer support to the idea that a network of neurons in both areas act as an attractor network that maintains information in working memory, which informs behavior.

scholarly journals Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

2016 ◽  
Vol 113 (52) ◽  
pp. E8492-E8501 ◽  
Author(s):  
Roland G. Benoit ◽  
Daniel J. Davies ◽  
Michael C. Anderson
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Episodic Simulation ◽  
Dorsolateral Prefrontal ◽  
Future Events ◽  
The Right ◽  
Development Of Anxiety ◽  
The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

Altruism from the Perspective of the Social Neurosciences

e-Neuroforum ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. A11-A18
Author(s):  
Sabine Windmann ◽  
Grit Hein
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Anterior Insula ◽  
Future Research ◽  
Levels Of Explanation ◽  
Temporoparietal Junction ◽  
The Social ◽  
Dorsolateral Prefrontal ◽  
The Brain ◽  
Research Studies

Abstract Altruism is a puzzling phenomenon, especially for Biology and Economics. Why do individuals reduce their chances to provide some of the resources they own to others? The answer to this question can be sought at ultimate or proximate levels of explanation. The Social Neurosciences attempt to specify the brain mechanisms that drive humans to act altruistically, in assuming that overtly identical behaviours can be driven by different motives. The research has shown that activations and functional connectivities of the Anterior Insula and the Temporoparietal Junction play specific roles in empathetic versus strategic forms of altruism, whereas the dorsolateral prefrontal cortex, among other regions, is involved in norm-oriented punitive forms of altruism. Future research studies could focus on the processing of ambiguity and conflict in pursuit of altruistic intentions.

The Effects of Frontal Lobe Lesions on Goal Achievement in the Water Jug Task

2001 ◽  
Vol 13 (8) ◽  
pp. 1129-1147 ◽  
Author(s):  
Mary Kathryn Colvin ◽  
Kevin Dunbar ◽  
Jordan Grafman
Keyword(s):  
Prefrontal Cortex ◽  
Problem Solving ◽  
Frontal Lobe ◽  
Dorsolateral Prefrontal Cortex ◽  
Functional Neuroimaging ◽  
Hill Climbing ◽  
Sorting Task ◽  
Card Sorting ◽  
Dorsolateral Prefrontal ◽  
Frontal Lobe Lesion

Patients with prefrontal cortex lesions are impaired on a variety of planning and problem-solving tasks. We examined the problem-solving performance of 27 patients with focal frontal lobe damage on the Water Jug task. The Water Jug task has never been used to assess problem-solving ability in neurologically impaired patients nor in functional neuroimaging studies, despite sharing structural similarities with other tasks sensitive to prefrontal cortex function, including the Tower of Hanoi, Tower of London, and Wisconsin Card Sorting Task (WCST). Our results demonstrate that the Water Jug task invokes a unique combination of problem-solving and planning strategies, allowing a more precise identification of frontal lobe lesion patients' cognitive deficits. All participants (patients and matched controls) appear to be utilizing a hill-climbing strategy that does not require sophisticated planning; however, frontal lobe lesion patients (FLLs) struggled to make required “counterintuitive moves” not predicted by this strategy and found within both solution paths. Left and bilateral FLLs were more impaired than right FLLs. Analysis of the left hemisphere brain regions encompassed by the lesions of these patients found that poor performance was linked to left dorsolateral prefrontal cortex damage. We propose that patients with left dorsolateral prefrontal cortex lesions have difficulty making a decision requiring the conceptual comparison of nonverbal stimuli, manipulation of select representations of potential solutions, and are unable to appropriately inhibit a response in keeping with the final goal.

Dissociation of Spatial-, Object-, and Sound-Coding Neurons in the Mediodorsal Nucleus of the Primate Thalamus

2003 ◽  
Vol 89 (2) ◽  
pp. 1067-1077 ◽  
Author(s):  
Ikuo Tanibuchi ◽  
Patricia S. Goldman-Rakic
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Single Neuron ◽  
Neuronal Responses ◽  
Mediodorsal Nucleus ◽  
Sound Coding ◽  
Spatial Tasks ◽  
Dorsolateral Prefrontal ◽  
Information Segregation ◽  
The Brain

The mediodorsal nucleus (MD) is the thalamic gateway to the prefrontal cortex, an area of the brain associated with spatial and object working memory functions. We have recorded single-neuron activities from the MD nucleus in monkeys trained to perform spatial tasks with peripheral visual stimuli and a nonspatial task with foveally presented pictures of objects and faces—tasks identical to those we have previously used to map regional specializations in the dorso- and ventro-lateral prefrontal cortex, respectively. We found that MD neurons exhibited categorical specificity—either responding selectively to locations in the spatial tasks or preferentially to specific representations of faces and objects in the nonspatial task. Spatially tuned neurons were located in parts of the MD connected with the dorsolateral prefrontal cortex while neurons responding to the identity of stimuli mainly occupied more ventral positions in the nucleus that has its connections with the inferior prefrontal convexity. Neuronal responses to auditory stimuli were also examined, and vocalization sensitive neurons were found in more posterior portions of the MD. We conclude that MD neurons are dissociable by their spatial and nonspatial coding properties in line with their cortical connections and that the principle of information segregation in cortico-cortical pathways extends to the “association” nuclei of the thalamus.

Neuropsychological correlates of syndromes in schizophrenia

1997 ◽  
Vol 170 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Ross M. G. Norman ◽  
A. K. Malla ◽  
S. L. Morrison-Stewart ◽  
E. Helmes ◽  
P. C. Williamson ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Temporal Lobe ◽  
Neuropsychological Tests ◽  
Dorsolateral Prefrontal Cortex ◽  
Neuropsychological Performance ◽  
Left Temporal Lobe ◽  
Impaired Performance ◽  
Dorsolateral Prefrontal ◽  
Reality Distortion ◽  
The Brain

BackgroundOn the basis of Liddle's three-syndrome model of schizophrenia, it was predicted that: (1) symptoms of psychomotor poverty would be particularly correlated with impaired performance on neuropsychological tests likely to reflect functioning of the dorsolateral prefrontal cortex; (2) disorganisation would be particularly correlated with impaired performance on tests sensitive to medio-basal prefrontal functioning; and (3) reality distortion would be particularly correlated with measures sensitive to temporal lobe functioning.MethodThe above hypotheses were tested on 87 subjects with a confirmed diagnosis of schizophrenia. Patients' symptoms were scored for each of the three syndromes. Patients completed six neuropsychological tests designed to measure impairment in specific areas of the brain.ResultsThere was no support for the first two hypotheses. There was, however, evidence of a specific relationship between reality distortion and neuropsychological performance usually considered to be related to left temporal lobe functioning.ConclusionsAlthough not directly supporting the first two hypotheses; the results are, in general, consistent with there being different cortical-subcortical circuits associated with each of psychomotor poverty and disorganisation. Temporal lobe functioning appears to have particular significance for the reality distortion syndrome.

scholarly journals Brain functional changes across the different phases of bipolar disorder

2015 ◽  
Vol 206 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Edith Pomarol-Clotet ◽  
Silvia Alonso-Lana ◽  
Noemi Moro ◽  
Salvador Sarró ◽  
Mar C. Bonnin ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Prefrontal Cortex ◽  
Frontal Cortex ◽  
Parietal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Cognitive Task ◽  
Memory Task ◽  
Mixed Effects ◽  
Linear Mixed Effects ◽  
Dorsolateral Prefrontal

BackgroundLittle is known about how functional imaging changes in bipolar disorder relate to different phases of the illness.AimsTo compare cognitive task activation in participants with bipolar disorder examined in different phases of illness.MethodParticipants with bipolar disorder in mania (n = 38), depression (n = 38) and euthymia (n = 38), as well as healthy controls (n = 38), underwent functional magnetic resonance imaging during performance of the n-back working memory task. Activations and de-activations were compared between the bipolar subgroups and the controls, and among the bipolar subgroups. All participants were also entered into a linear mixed-effects model.ResultsCompared with the controls, the mania and depression subgroups, but not the euthymia subgroup, showed reduced activation in the dorsolateral prefrontal cortex, the parietal cortex and other areas. Compared with the euthymia subgroup, the mania and depression subgroups showed hypoactivation in the parietal cortex. All three bipolar subgroups showed failure of de-activation in the ventromedial frontal cortex. Linear mixed-effects modelling revealed a further cluster of reduced activation in the left dorsolateral prefrontal cortex in the patients; this was significantly more marked in the mania than in the euthymia subgroup.ConclusionsBipolar disorder is characterised by mood state-dependent hypoactivation in the parietal cortex. Reduced dorsolateral prefrontal activation is a further feature of mania and depression, which may improve partially in euthymia. Failure of de-activation in the medial frontal cortex shows trait-like characteristics.

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