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The Journal of Neuroscience : the... Mar 2022The shift in control from dorsomedial to dorsolateral striatum during skill and habit formation has been well established, but whether striatal subregions orchestrate...
The shift in control from dorsomedial to dorsolateral striatum during skill and habit formation has been well established, but whether striatal subregions orchestrate this shift cooperatively or competitively remains unclear. Cortical inputs have also been implicated in the shift toward automaticity, but it is unknown whether they mirror their downstream striatal targets across this transition. We addressed these questions using a five step heterogeneous action sequencing task in male rats that is optimally performed by automated chains of actions. By optimizing automatic habitual responding, we discovered that loss of function in the dorsomedial striatum accelerated sequence acquisition. In contrast, loss of function in the dorsolateral striatum impeded acquisition of sequencing, demonstrating functional opposition within the striatum. Unexpectedly, the mPFC was not involved; however, the lateral orbitofrontal cortex was critical. These results shift current theories about striatal control of behavior to a model of competitive opposition, where the dorsomedial striatum interferes with the development of dorsolateral-striatum dependent behavior. We provide the most direct evidence to date that the dorsomedial and dorsolateral striatum compete for control in the acquisition of habitual action sequences. The dorsolateral striatum was critical for sequencing behavior, but loss of dorsomedial striatum function enhanced acquisition. In addition, we found that the mPFC was not required for the formation of automated actions. Using a task that optimizes habitual responding, we demonstrate that the arbitration of dorsomedial and dorsolateral control is not modulated by medial prefrontal cortical activity. However, we find evidence for the role of the lateral orbitofrontal cortex in action sequencing. These results have implications for our understanding of how habits and skills form.
Topics: Animals; Corpus Striatum; Gray Matter; Habits; Male; Neostriatum; Rats
PubMed: 35086903
DOI: 10.1523/JNEUROSCI.1907-21.2022 -
The Journal of Emergency Medicine May 2023Posterior circulation stroke can present with dizziness/vertigo without other general neurological symptoms or signs, making it difficult to detect, and missed stroke... (Review)
Review
BACKGROUND
Posterior circulation stroke can present with dizziness/vertigo without other general neurological symptoms or signs, making it difficult to detect, and missed stroke can deteriorate. Therefore, a sign that can be easily identified during an examination would be helpful to improve the detection of this type of stroke.
OBJECTIVE
The objective of this review is to highlight an ocular sign that is seen in posterior circulation strokes called ocular lateral deviation (OLD). OLD is mostly seen in dorsolateral medullary strokes, and it is also seen in pontine and cerebellar strokes. OLD is detected by asking a patient to look straight ahead and then briefly close their eyes. Upon re-opening their eyes, the examiner will see that the eyes have deviated to one side; the patient's eyes will then make corrective saccade(s) to return to looking straight ahead. Complete eye deviation is a central sign of posterior circulation stroke.
DISCUSSION
OLD is an under-recognized vestibular ocular sign of central vestibulopathies including posterior circulation stroke. The most common location is in the dorsolateral medulla, where one-third of such strokes have complete OLD. Eye deviation can also be appreciated on computed tomography or magnetic resonance imaging. OLD can be detected up to 6 months after a posterior circulation stroke.
CONCLUSIONS
Checking for the sign of complete eye deviation in patients with dizziness/vertigo could be a simple, quick method for detecting posterior circulation stroke, and a means to improving the patients' outcome.
Topics: Humans; Vertigo; Dizziness; Stroke; Eye; Magnetic Resonance Imaging
PubMed: 37037761
DOI: 10.1016/j.jemermed.2023.02.010 -
Frontiers in Human Neuroscience 2017Cognitive deficits are a core and disabling feature of psychotic disorders, specifically schizophrenia. Current treatments for impaired cognition in schizophrenia remain... (Review)
Review
Cognitive deficits are a core and disabling feature of psychotic disorders, specifically schizophrenia. Current treatments for impaired cognition in schizophrenia remain insufficient. Recent research suggests transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex can potentiate cognitive improvements in healthy individuals and those with psychiatric conditions, such as schizophrenia. However, this burgeoning literature has not been quantitatively evaluated. Through a literature search and quantitative review, we identified 194 papers on tDCS, psychosis, and cognition. Selection criteria included pre/post design and sham control to achieve specific sham-adjusted effect sizes. The 6 retained studies all address schizophrenia populations and include single and repeated stimulation, as well as within and between subject designs. Small positive effects were found for anodal stimulation on behavioral measures of attention and working memory, with tentative findings for cognitive ability and memory. Cathodal stimulation yielded a small positive effect on behaviorally measured cognitive ability. Neurophysiological measures of attention showed a small to medium down-modulation effect for anodal stimulation. Implications of these findings and guidelines for future research are discussed. As revealed by this report, due to the paucity of data available, much remains unknown regarding the clinical efficacy of tDCS in schizophrenia.
PubMed: 28210217
DOI: 10.3389/fnhum.2017.00044 -
Sex differences in bipolar disorder: The dorsolateral prefrontal cortex as an etiopathogenic region.Frontiers in Neuroendocrinology Jan 2024Bipolar disorder (BD) is worldwide a prevalent mental illness and a leading risk factor for suicide. Over the past three decades, it has been discovered that sex... (Review)
Review
Bipolar disorder (BD) is worldwide a prevalent mental illness and a leading risk factor for suicide. Over the past three decades, it has been discovered that sex differences exist throughout the entire panorama of BD, but the etiologic regions and mechanisms that generate such differences remain poorly characterized. Available evidence indicates that the dorsolateral prefrontal cortex (DLPFC), a critical region that controls higher-order cognitive processing and mood, exhibits biological disparities between male and female patients with psychiatric disorders, which are highly correlated with the co-occurrence of psychotic symptoms. This review addresses the sex differences in BD concerning epidemiology, cognitive impairments, clinical manifestations, neuroimaging, and laboratory abnormalities. It also provides strong evidence linking DLPFC to the etiopathogenesis of these sex differences. We emphasize the importance of identifying gene signatures using human brain transcriptomics, which can depict sexually different variations, explain sex-biased symptomatic features, and provide novel targets for sex-specific therapeutics.
Topics: Humans; Male; Female; Bipolar Disorder; Dorsolateral Prefrontal Cortex; Prefrontal Cortex; Sex Characteristics; Brain
PubMed: 37993020
DOI: 10.1016/j.yfrne.2023.101115 -
Neural Plasticity 2021Numerous neuroimaging studies have demonstrated that the brain plasticity is associated with chronic low back pain (cLBP). However, there is a lack of knowledge...
Numerous neuroimaging studies have demonstrated that the brain plasticity is associated with chronic low back pain (cLBP). However, there is a lack of knowledge regarding the underlying mechanisms of thalamic pathways for chronic pain and psychological effects in cLBP caused by lumbar disc herniation (LDH). Combining psychophysics and magnetic resonance imaging (MRI), we investigated the structural and functional brain plasticity in 36 patients with LDH compared with 38 age- and gender-matched healthy controls. We found that (1) LDH patients had increased psychophysical disturbs (i.e., depression and anxiety), and depression (Beck-Depression Inventory, BDI) was found to be an outstanding significant factor to predict chronic pain (short form of the McGill Pain Questionnaire, SF-MPQ); (2) the LDH group showed significantly smaller fractional anisotropy values in the region of posterior corona radiate while gray matter volumes were comparable in both groups; (3) resting state functional connectivity analysis revealed that LDH patients exhibited increased temporal coupling between the thalamus and dorsolateral prefrontal cortex (DLPFC), which further mediate the relationship from chronic pain to depression. Our results emphasized that thalamic pathways underlying prefrontal cortex might play a key role in regulating chronic pain and depression of the pathophysiology of LDH.
Topics: Adult; Chronic Pain; Depression; Dorsolateral Prefrontal Cortex; Female; Humans; Low Back Pain; Male; Middle Aged; Nerve Net; Pain Measurement; Thalamus; Time Factors
PubMed: 34659398
DOI: 10.1155/2021/7498714 -
Journal of the Neurological Sciences Oct 2018The rapid methodological development and growing availability of neuromodulation techniques have spurred myriad studies investigating their clinical effectiveness.... (Review)
Review
Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex to alleviate depression and cognitive impairment associated with Parkinson's disease: A review and clinical implications.
The rapid methodological development and growing availability of neuromodulation techniques have spurred myriad studies investigating their clinical effectiveness. Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) has in many instances been proven to exert antidepressant-like effects superior to placebo and equivalent to standard psychopharmacological treatment. Due to the similar neuroanatomy and neurophysiology of executive and affective control processes, rTMS to the DLPFC may be able to address multiple issues simultaneously. This review pools available literature on the therapeutic usage of rTMS on non-motor symptoms of Parkinson's disease associated with the DLPFC (i.e. mood disturbance and cognitive impairment). To the best of the author's knowledge, it is one of the few available of its' kind, up to this date. Most studies included in the review found beneficial effects of high frequency prefrontal rTMS on PD-related depression. In regard to the usability of rTMS to alleviate cognitive impairment associated with PD, definitive claims are yet to be established.
Topics: Cognitive Dysfunction; Depression; Humans; Parkinson Disease; Prefrontal Cortex; Transcranial Magnetic Stimulation
PubMed: 30149227
DOI: 10.1016/j.jns.2018.08.014 -
Urology Apr 2016To investigate the safety, efficacy, and versatility of dorsolateral graft urethroplasty using penile skin.
OBJECTIVES
To investigate the safety, efficacy, and versatility of dorsolateral graft urethroplasty using penile skin.
MATERIALS AND METHODS
Between 2010 and 2013, 37 men with anterior urethral strictures underwent dorsolateral graft urethroplasty using penile skin by a single surgeon (EP). Inclusion criterion was patients with anterior urethral strictures. Exclusion criteria were lichen sclerosus-related strictures, absence of available penile skin because of previous surgery, and obliterative urethral strictures. Clinical outcome was considered a failure when any postoperative instrumentation was needed, including dilatation.
RESULTS
Mean (± standard deviation) patients age was 51 (±15.4) years. Stricture etiology was iatrogenic in 25 cases (67%), unknown in 10 (27%), trauma in 2 (6%). Stricture site was penile in 21 (57%) and peno-bulbar in 16 (43%). Median (range) stricture length was 5 cm (1-15). Of 37 patients, 30 (81%) had received previous treatments. Median (range) follow-up was 21 months (12-47). Of 37 patients, 34 (92%) had successful treatment and 3 (8%) had failed treatment. The 3 patients with failed treatment were treated with urethrostomy and are awaiting further reconstruction. Study limitations include the small sample size and the limited follow-up.
CONCLUSION
With a mid-term follow-up time, the dorsolateral graft urethroplasty using penile skin is shown to be a safe, efficient, and versatile technique for the repair of short-mid-long anterior urethral strictures.
Topics: Foreskin; Humans; Male; Middle Aged; Retrospective Studies; Treatment Outcome; Urethra; Urethral Stricture; Urologic Surgical Procedures, Male
PubMed: 26743395
DOI: 10.1016/j.urology.2015.12.014 -
Cerebral Cortex (New York, N.Y. : 1991) Jan 2024The aim of this paper is to investigate dynamical functional disturbance in central executive network in minimal hepatic encephalopathy and determine its association...
The aim of this paper is to investigate dynamical functional disturbance in central executive network in minimal hepatic encephalopathy and determine its association with metabolic disorder and cognitive impairment. Data of magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging were obtained from 27 cirrhotic patients without minimal hepatic encephalopathy, 20 minimal hepatic encephalopathy patients, and 24 healthy controls. Central executive network was identified utilizing seed-based correlation approach. Dynamic functional connectivity across central executive network was calculated using sliding-window approach. Functional states were estimated by K-means clustering. Right dorsolateral prefrontal cortex metabolite ratios (i.e. glutamate and glutamine complex/total creatine, myo-inositol / total creatine, and choline / total creatine) were determined. Neurocognitive performance was determined by psychometric hepatic encephalopathy scores. Minimal hepatic encephalopathy patients had decreased myo-inositol / total creatine and choline / total creatine and increased glutamate and glutamine complex / total creatine in right dorsolateral prefrontal cortex (all P ≤ 0.020); decreased static functional connectivity between bilateral dorsolateral prefrontal cortex and between right dorsolateral prefrontal cortex and lateral-inferior temporal cortex (P ≤ 0.001); increased frequency and mean dwell time in state-1 (P ≤ 0.001), which exhibited weakest functional connectivity. Central executive network dynamic functional indices were significantly correlated with right dorsolateral prefrontal cortex metabolic indices and psychometric hepatic encephalopathy scores. Right dorsolateral prefrontal cortex myo-inositol / total creatine and mean dwell time in state-1 yielded best potential for diagnosing minimal hepatic encephalopathy. Dynamic functional disturbance in central executive network may contribute to neurocognitive impairment and could be correlated with metabolic disorder.
Topics: Humans; Hepatic Encephalopathy; Magnetic Resonance Imaging; Glutamine; Creatine; Liver Cirrhosis; Glutamic Acid; Inositol; Choline; Brain
PubMed: 38365269
DOI: 10.1093/cercor/bhae036 -
Brain : a Journal of Neurology Feb 2015Abnormal gamma-aminobutyric acid inhibitory neurotransmission is a key pathophysiological mechanism underlying schizophrenia. Transcranial magnetic stimulation can be...
Abnormal gamma-aminobutyric acid inhibitory neurotransmission is a key pathophysiological mechanism underlying schizophrenia. Transcranial magnetic stimulation can be combined with electroencephalography to index long-interval cortical inhibition, a measure of GABAergic receptor-mediated inhibitory neurotransmission from the frontal and motor cortex. In previous studies we have reported that schizophrenia is associated with inhibitory deficits in the dorsolateral prefrontal cortex compared to healthy subjects and patients with bipolar disorder. The main objective of the current study was to replicate and extend these initial findings by evaluating long-interval cortical inhibition from the dorsolateral prefrontal cortex in patients with schizophrenia compared to patients with obsessive-compulsive disorder. A total of 111 participants were assessed: 38 patients with schizophrenia (average age: 35.71 years, 25 males, 13 females), 27 patients with obsessive-compulsive disorder (average age: 36.15 years, 11 males, 16 females) and 46 healthy subjects (average age: 33.63 years, 23 females, 23 males). Long-interval cortical inhibition was measured from the dorsolateral prefrontal cortex and motor cortex through combined transcranial magnetic stimulation and electroencephalography. In the dorsolateral prefrontal cortex, long-interval cortical inhibition was significantly reduced in patients with schizophrenia compared to healthy subjects (P = 0.004) and not significantly different between patients with obsessive-compulsive disorder and healthy subjects (P = 0.5445). Long-interval cortical inhibition deficits in the dorsolateral prefrontal cortex were also significantly greater in patients with schizophrenia compared to patients with obsessive-compulsive disorder (P = 0.0465). There were no significant differences in long-interval cortical inhibition across all three groups in the motor cortex. These results demonstrate that long-interval cortical inhibition deficits in the dorsolateral prefrontal cortex are specific to patients with schizophrenia and are not a generalized deficit that is shared by disorders of severe psychopathology.
Topics: Adult; Anatomy, Cross-Sectional; Antipsychotic Agents; Electroencephalography; Electromyography; Female; Humans; Inhibition, Psychological; Male; Motor Cortex; Obsessive-Compulsive Disorder; Prefrontal Cortex; Psychiatric Status Rating Scales; Schizophrenia; Schizophrenic Psychology; Transcranial Magnetic Stimulation
PubMed: 25524710
DOI: 10.1093/brain/awu360 -
Psychoneuroendocrinology Jan 2021While high levels of glucocorticoids are generally neuro-damaging, a related adrenal steroid, dehydroepiandrosterone (DHEA), has anti-glucocorticoid and neuroprotective...
While high levels of glucocorticoids are generally neuro-damaging, a related adrenal steroid, dehydroepiandrosterone (DHEA), has anti-glucocorticoid and neuroprotective properties. Previous work has shown increased circulating levels of DHEA and abnormal cortisol/DHEA ratios in people with schizophrenia, however reports are limited and their relationship to neuropathology is unclear. We performed the largest study to date to compare levels of serum DHEA and cortisol/DHEA ratios in people with schizophrenia and healthy controls, and investigated the extent to which cortisol/DHEA ratios predict brain volume. Serum cortisol and DHEA were assayed in 94 people with schizophrenia and 81 healthy controls. T1-weighted high-resolution anatomical scans were obtained using a 3 T Achieva scanner on a subset of 59 people with schizophrenia and 60 healthy controls. Imaging data were preprocessed and analyzed using SPM12. People with schizophrenia had significantly increased serum DHEA levels (p = 0.002), decreased cortisol/DHEA ratios (p = 0.02) and no difference in cortisol levels compared to healthy controls. Cortisol/DHEA ratios were inversely correlated with hippocampal (r = -0.33 p = 0.01) and dorsolateral prefrontal cortex (r = -0.30, p = 0.02) volumes in patients. Our findings suggest that the cortisol/DHEA ratio may be a molecular blood signature of hippocampal and cortical damage. These results further implicate the role of DHEA and hypothalamic-pituitary-adrenal axis dysfunction in the pathophysiology of schizophrenia.
Topics: Case-Control Studies; Dehydroepiandrosterone; Dorsolateral Prefrontal Cortex; Hippocampus; Humans; Hydrocortisone; Organ Size; Schizophrenia
PubMed: 33169678
DOI: 10.1016/j.psyneuen.2020.104916