scholarly journals The Neural Correlates of Similarity- and Rule-based Generalization

2017 ◽  
Vol 29 (1) ◽  
pp. 150-166 ◽  
Author(s):  
Fraser Milton ◽  
Pippa Bealing ◽  
Kathryn L. Carpenter ◽  
Abdelmalek Bennattayallah ◽  
Andy J. Wills
Keyword(s):  
Imaging Study ◽  
Learning Systems ◽  
Rule Based ◽  
Parietal Lobes ◽  
Rule Group ◽  
Similarity Group ◽  
Feature Based ◽  
Associative Account ◽  
The Right ◽  
Occipital Lobes

The idea that there are multiple learning systems has become increasingly influential in recent years, with many studies providing evidence that there is both a quick, similarity-based or feature-based system and a more effortful rule-based system. A smaller number of imaging studies have also examined whether neurally dissociable learning systems are detectable. We further investigate this by employing for the first time in an imaging study a combined positive and negative patterning procedure originally developed by Shanks and Darby [Shanks, D. R., & Darby, R. J. Feature- and rule-based generalization in human associative learning. Journal of Experimental Psychology: Animal Behavior Processes, 24, 405–415, 1998]. Unlike previous related studies employing other procedures, rule generalization in the Shanks–Darby task is beyond any simple non-rule-based (e.g., associative) account. We found that rule- and similarity-based generalization evoked common activation in diverse regions including the pFC and the bilateral parietal and occipital lobes indicating that both strategies likely share a range of common processes. No differences between strategies were identified in whole-brain comparisons, but exploratory analyses indicated that rule-based generalization led to greater activation in the right middle frontal cortex than similarity-based generalization. Conversely, the similarity group activated the anterior medial frontal lobe and right inferior parietal lobes more than the rule group did. The implications of these results are discussed.

scholarly journals Visual Hypo and Hypergnosia as Exemplars of Poles of Psychic Tonus in the Occipital Lobes: Multiple Case Analyses

2008 ◽  
Vol 19 (4) ◽  
pp. 153-168
Author(s):  
Claude M. J. Braun ◽  
Anik Guimond
Keyword(s):  
Visual Imagery ◽  
Visual Hallucination ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Unilateral Lesion ◽  
Temporal Lobes ◽  
Parietal Lobes ◽  
Multiple Case ◽  
The Right ◽  
Occipital Lobes

The “psychic tonus” model or PTM [1] of hemispheric specialization states that the left hemisphere is a psychic and behavioral activator and that the right hemisphere is an inhibitor. The PTM predicts that the tonus of visual representation ought to manifest hemispheric specialization in the occipital lobes. Specifically PTM predicts that pathological positive visual tonus (visual hallucination) ought to be associated more frequently with right occipital lesions. PTM also predicts that pathological negative visual tonus (loss of visual imagery) ought to result more often from left occipital lesions. We reviewed 78 cases of post lesion hallucination and 12 cases of post lesion loss of evocation of images, all following a unilateral lesion. Analyses of these relevant previously published cases support the predictions. In accordance with previously published demonstrations of hemispheric specialization for auditory tonus in the temporal lobes and for somesthetic tonus in the parietal lobes, the present findings extend the psychic tonus model of hemispheric specialization to vision in the occipital lobes.

Neurospect Findings in Patients Exposed to Neurotoxic Chemicals

1994 ◽  
Vol 10 (4-5) ◽  
pp. 561-571
Author(s):  
Gunnar Heuser ◽  
Ismael Mena ◽  
Francisca Alamos
Keyword(s):  
Elderly Patients ◽  
Qualitative Analysis ◽  
Right Hemisphere ◽  
Young Patients ◽  
Chronic Fatigue ◽  
Psychiatric Symptomatology ◽  
Elderly Individuals ◽  
Parietal Lobes ◽  
The Right ◽  
The Brain

Exposures to neurotoxic chemicals such as pesticides, glues, solvents, etc. are known to induce neurologic and psychiatric symptomatology. We report on 41 patients 16 young patients (6 males, 10 females, age 34 8 yrs.) and 25 elderly patients (9 males, 16 females, age 55 7 yrs). Fifteen of them were exposed to pesticides, and 29 to solvents. They were studied with quantitative and qualitative analysis of regional cerebral bood flow (rCBF), performed with 30 mCi of Xe-133 by inhalation, followed by 30 mCi of Tc-HMPAO given intravenously. Imaging was performed with a brain dedicated system, distribution of rCBF was assessed with automatic ROI definition, and HMPAO was normalized to maximal pixel activity in the brain. Results of Xe rCBF are expressed as mean and S.D. in ml/min/100g, and HMPAO as mean and S.D. uptake per ROI, and compared with age-matched controls 10 young and 20 elderly individuals. Neurotoxics HMPAO Uptake Young Elderly R. Orbital frontal R. Dorsal frontal .70 .66 p < 0.05 R. Temporal .64 p < 0.001 R. Parietal .66 .66 We conclude that patients exposed to chemicals present with diminished CBF, worse in the right hemisphere, with random presentation of areas of hypoperfusion, more prevalent in the dorsal frontal and parietal lobes. These findings are significantly different from observations in patients with chronic fatigue and depression, suggesting primary cortical effect, possibly due to a vasculitis process.

The Role of the Right Prefrontal Cortex in Self-evaluation of the Face: A Functional Magnetic Resonance Imaging Study

2008 ◽  
Vol 20 (2) ◽  
pp. 342-355 ◽  
Author(s):  
Tomoyo Morita ◽  
Shoji Itakura ◽  
Daisuke N. Saito ◽  
Satoshi Nakashita ◽  
Tokiko Harada ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Face Recognition ◽  
Inferior Frontal Gyrus ◽  
Video Recording ◽  
Imaging Study ◽  
The Self ◽  
Anterior Cingulate ◽  
Precentral Gyrus ◽  
Self Evaluation ◽  
The Right

Individuals can experience negative emotions (e.g., embarrassment) accompanying self-evaluation immediately after recognizing their own facial image, especially if it deviates strongly from their mental representation of ideals or standards. The aim of this study was to identify the cortical regions involved in self-recognition and self-evaluation along with self-conscious emotions. To increase the range of emotions accompanying self-evaluation, we used facial feedback images chosen from a video recording, some of which deviated significantly from normal images. In total, 19 participants were asked to rate images of their own face (SELF) and those of others (OTHERS) according to how photogenic they appeared to be. After scanning the images, the participants rated how embarrassed they felt upon viewing each face. As the photogenic scores decreased, the embarrassment ratings dramatically increased for the participant's own face compared with those of others. The SELF versus OTHERS contrast significantly increased the activation of the right prefrontal cortex, bilateral insular cortex, anterior cingulate cortex, and bilateral occipital cortex. Within the right prefrontal cortex, activity in the right precentral gyrus reflected the trait of awareness of observable aspects of the self; this provided strong evidence that the right precentral gyrus is specifically involved in self-face recognition. By contrast, activity in the anterior region, which is located in the right middle inferior frontal gyrus, was modulated by the extent of embarrassment. This finding suggests that the right middle inferior frontal gyrus is engaged in self-evaluation preceded by self-face recognition based on the relevance to a standard self.

scholarly journals Morphology of the vertebral artery in Asian population

2014 ◽  
Vol 5 (4) ◽  
pp. 84-88 ◽  
Author(s):  
Maryna Alfaouri-Kornieieva ◽  
Azmy M Al-Hadidi
Keyword(s):  
Vertebral Artery ◽  
Asian Population ◽  
Outer Diameter ◽  
Medical Sciences ◽  
The Third ◽  
Asian Patients ◽  
Distal Loop ◽  
The Right ◽  
Occipital Lobes ◽  
The Brain

Background: Recent clinical trials have shown a rising trend of stroke in Asian population. Approximately 20% strokes of total occur at the vertebrobasilar basin that supplies the occipital lobes of the brain, the cerebellum, and the brainstem. The anatomical features and variability of the third segment of the vertebral artery (VA) in Asians are analyzed in this study. Methods: A prospective cohort study of 68 consecutive Asian patients underwent MRA examination for head and neck in the Department of Radiology of Hospital of University of Jordan from 1.10.2011 to 30.04.2012. The 116 VA were analyzed on the obtained angiograms. Results: The third segment (V3) of the VA was studied according to its conventional division into vertical, horizontal, and oblique parts. The mean outer diameter of the V3 varied up 3.18 ± 0.73 to 4.28 ± 1.08 mm. The parameter prevailed on the left in 91% cases and was greater in males, than in females. The distal loop of the VA projected downward in 26 cases on the right (78%) and in 28 cases on the left (74%). The tortuosity of loop?formations of V3 was evaluated subject to angles between their ascending and descending bends. Conclusion: In comparison with other ethnic groups, the V3 of the VA in Asians has lesser outer diameter, especially along its oblique part; the zero?distance between the occipital bone and horizontal segment of VA occurs more often (up to 26%); the Lang’s III type of V3 variability is the most common in Asians. DOI: http://dx.doi.org/10.3126/ajms.v5i4.6150 Asian Journal of Medical Sciences 2014 Vol.5(4); 84-88

scholarly journals Aberrant Frontostriatal Connectivity in Negative Symptoms of Schizophrenia

2018 ◽  
Vol 45 (5) ◽  
pp. 1051-1059 ◽  
Author(s):  
Dinesh K Shukla ◽  
Joshua John Chiappelli ◽  
Hemalatha Sampath ◽  
Peter Kochunov ◽  
Stephanie M Hare ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Negative Symptom ◽  
Negative Symptoms ◽  
Imaging Study ◽  
Anterior Cingulate ◽  
Functional Magnetic Resonance ◽  
Resting State Functional Connectivity ◽  
Symptom Scale ◽  
Distinct Component ◽  
The Right

AbstractNegative symptoms represent a distinct component of psychopathology in schizophrenia (SCZ) and are a stable construct over time. Although impaired frontostriatal connectivity has been frequently described in SCZ, its link with negative symptoms has not been carefully studied. We tested the hypothesis that frontostriatal connectivity at rest may be associated with the severity of negative symptoms in SCZ. Resting state functional connectivity (rsFC) data from 95 mostly medicated patients with SCZ and 139 healthy controls (HCs) were acquired. Negative symptoms were assessed using the Brief Negative Symptom Scale. The study analyzed voxel-wise rsFC between 9 frontal “seed regions” and the entire striatum, with the intention to reduce potential biases introduced by predefining any single frontal or striatal region. SCZ showed significantly reduced rsFC between the striatum and the right medial and lateral orbitofrontal cortex (OFC), lateral prefrontal cortex, and rostral anterior cingulate cortex compared with HCs. Further, rsFC between the striatum and the right medial OFC was significantly associated with negative symptom severity. The involved striatal regions were primarily at the ventral putamen. Our results support reduced frontostriatal functional connectivity in SCZ and implicate striatal connectivity with the right medial OFC in negative symptoms. This task-independent resting functional magnetic resonance imaging study showed that medial OFC–striatum functional connectivity is reduced in SCZ and associated with severity of negative symptoms. This finding supports a significant association between frontostriatal connectivity and negative symptoms and thus may provide a potential circuitry-level biomarker to study the neurobiological mechanisms of negative symptoms.

scholarly journals Comparing word embedding models for Arabic aspect category detection using a deep learning-based approach

2021 ◽  
Vol 297 ◽  
pp. 01072
Author(s):  
Rajae Bensoltane ◽  
Taher Zaki
Keyword(s):  
Deep Learning ◽  
Vector Representation ◽  
Rule Based ◽  
External Resources ◽  
Unit Model ◽  
Proposed Model ◽  
Feature Based ◽  
The Impact ◽  
Gated Recurrent Unit ◽  
Machine Learning Models

Aspect category detection (ACD) is a task of aspect-based sentiment analysis (ABSA) that aims to identify the discussed category in a given review or sentence from a predefined list of categories. ABSA tasks were widely studied in English; however, studies in other low-resource languages such as Arabic are still limited. Moreover, most of the existing Arabic ABSA work is based on rule-based or feature-based machine learning models, which require a tedious task of feature-engineering and the use of external resources like lexicons. Therefore, the aim of this paper is to overcome these shortcomings by handling the ACD task using a deep learning method based on a bidirectional gated recurrent unit model. Additionally, we examine the impact of using different vector representation models on the performance of the proposed model. The experimental results show that our model outperforms the baseline and related work models significantly by achieving an enhanced F1-score of more than 7%.

scholarly journals Brain tumors and indications for brain imaging in patients with psychiatric manifestations: a case report

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Seyed Alireza Haji Seyed Javadi ◽  
Bahare Rezaei
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Psychiatric Symptoms ◽  
Relevant Information ◽  
History Of ◽  
Response To Stress ◽  
The Right ◽  
Occipital Lobes ◽  
Psychiatric Manifestations ◽  
The Relationship

Abstract Background Studies on the relationship between psychiatric symptoms and brain tumors are ambiguous, as it is not clear whether these symptoms are due to the direct effect of the tumor or a secondary psychological response to stress, resulting from the diagnosis and treatment of the disease; therefore, it is difficult to analyze and retrieve relevant information. Case presentation We present the case of a 43-year-old male patient, who was admitted to a psychiatric emergency room with psychiatric symptoms, such as restlessness and extreme talkativeness, but normal neurological examinations. He showed no response to outpatient treatment and had no history of psychiatric disorders. The onset of symptoms was 2 months before his visit. On neuroimaging, a brain tumor was observed in the right temporal and occipital lobes. Accordingly, the patient was transferred to the neurosurgery ward. Conclusion Factors, such as increased internal pressure on the brain due to a brain tumor or the effect of tumor area, contribute to the occurrence of symptoms, such as restlessness and talkativeness. However, further studies are needed to confirm these findings.

scholarly journals The role of the basolateral amygdala in the perception of faces in natural contexts

2016 ◽  
Vol 371 (1693) ◽  
pp. 20150376 ◽  
Author(s):  
Ruud Hortensius ◽  
David Terburg ◽  
Barak Morgan ◽  
Dan J. Stein ◽  
Jack van Honk ◽  
...  
Keyword(s):  
Basolateral Amygdala ◽  
Complex Structure ◽  
Dorsal Stream ◽  
Imaging Study ◽  
Control Group ◽  
Precentral Gyrus ◽  
Functional Magnetic Resonance ◽  
Context Processing ◽  
The Right

The amygdala is a complex structure that plays its role in perception and threat-related behaviour by activity of its specific nuclei and their separate networks. In the present functional magnetic resonance imaging study, we investigated the role of the basolateral amygdala in face and context processing. Five individuals with focal basolateral amygdala damage and 12 matched controls viewed fearful or neutral faces in a threatening or neutral context. We tested the hypothesis that basolateral amygdala damage modifies the relation between face and threatening context, triggering threat-related activation in the dorsal stream. The findings supported this hypothesis. First, activation was increased in the right precentral gyrus for threatening versus neutral scenes in the basolateral amygdala damage group compared with the control group. Second, activity in the bilateral middle frontal gyrus, and left anterior inferior parietal lobule was enhanced for neutral faces presented in a threatening versus neutral scene in the group with basolateral amygdala damage compared with controls. These findings provide the first evidence for the neural consequences of basolateral amygdala damage during the processing of complex emotional situations.

Abstract TMP56: Differential Effect of Left versus Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Mandip S Dhamoon ◽  
Ying-Kuen Cheung ◽  
Ahmet M Bagci ◽  
Dalila Varela ◽  
Noam Alperin ◽  
...  
Keyword(s):  
White Matter ◽  
Large Population ◽  
Functional Decline ◽  
Frontal Lobes ◽  
White Matter Hyperintensity ◽  
Periventricular White Matter ◽  
Parietal Lobes ◽  
Brain White Matter ◽  
The Right

Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was associated with accelerated long-term functional decline. Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right WMHV asymmetry was associated with functional trajectories. Methods: In the Northern Manhattan MRI study, participants had brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions (brainstem, cerebellum, and bilateral frontal, occipital, temporal, and parietal lobes, and bilateral anterior and posterior periventricular white matter) was determined separately by combining bimodal image intensity distribution and atlas based methods.. Participants had annual functional assessments with the Barthel index (BI, range 0-100) over a mean of 7.3 years. Generalized estimating equations models estimated associations of regional WMHV and regional left-right asymmetry with baseline BI and change over time, adjusted for baseline medical risk factors, sociodemographics, and cognition, and stroke and myocardial infarction during follow-up. Results: Among 1195 participants, mean age was 71 (SD 9) years, 39% were male, 67% had hypertension and 19% diabetes. Greater WMHV asymmetry in the frontal lobes (-3.53 BI points per unit greater WMHV on the right compared to left, 95% CI -0.18, -6.88) and whole brain (-7.23 BI points, 95% CI 0.07, -14.54) was associated with lower overall function. Greater WMHV asymmetry in the frontal lobes (-0.74 additional BI points per year per unit greater WMHV on the right compared to left, 95% CI 0.05, -1.54) and parietal lobes (1.11 additional BI points per year, 95% CI 0.30, 1.93) was independently associated with accelerated functional decline. Periventricular WMHV asymmetry was not associated with function. Conclusions: In this large population-based study with long-term repeated measures of function, greater regional WMHV asymmetry was associated with lower function and functional decline, especially with greater WMHV on the right. In addition to global WMHV, WHMV asymmetry may be an important predictor of long-term functional decline.

Alignment for Advanced Machine Learning Systems

2020 ◽  
pp. 342-382
Author(s):  
Jessica Taylor ◽  
Eliezer Yudkowsky ◽  
Patrick LaVictoire ◽  
Andrew Critch
Keyword(s):  
Machine Learning ◽  
Side Effects ◽  
Objective Function ◽  
Unintended Consequences ◽  
Learning Systems ◽  
Large Impact ◽  
Future Research ◽  
Objective Functions ◽  
Research Areas ◽  
The Right

This chapter surveys eight research areas organized around one question: As learning systems become increasingly intelligent and autonomous, what design principles can best ensure that their behavior is aligned with the interests of the operators? The chapter focuses on two major technical obstacles to AI alignment: the challenge of specifying the right kind of objective functions and the challenge of designing AI systems that avoid unintended consequences and undesirable behavior even in cases where the objective function does not line up perfectly with the intentions of the designers. The questions surveyed include the following: How can we train reinforcement learners to take actions that are more amenable to meaningful assessment by intelligent overseers? What kinds of objective functions incentivize a system to “not have an overly large impact” or “not have many side effects”? The chapter discusses these questions, related work, and potential directions for future research, with the goal of highlighting relevant research topics in machine learning that appear tractable today.

Sign in / Sign up

Export Citation Format

Share Document