I Think Then I Will: The Function of the Cortex in the Process of Decision Making and Initiating Action

Özet Karar verme, mevcut problemi çözüme kavuşturmaya odaklı bir yöneliş, karar verme eylemi ise mevcut seçenekleri değerlendirme, analiz etme ve sonuçlarını takip etme gibi spesifik etkinliklerden oluşan karmaşık bir işlevdir. Karar alabilme kabiliyeti zihinsel analiz, planlama, üst düzey düşünme (koşullardaki değişikliklere uygun olarak cevabı değiştirebilme yetisi gibi), eylemi başlatma ve yürütme gibi bilişsel süreçleri içermektedir. Bu süreç eylem seçimi kapsamında ilişkisel öğrenme, duygusal ve sosyal yönler dâhil olmak üzere çeşitli bileşenlere ayrılmaktadır. Karar vermenin bu farklı yönleri, bilişsel sinirbilim alanındaki araştırmaların odak noktası haline gelmiştir. Özellikle son yıllarda ventromedial prefrontal korteks ve ilgili yapıların karar vermede anahtar bir role sahip olmasının bilişin oldukça karmaşık yönü olduğu düşünülen korteks temelini anlamamızda yol katedildiğini göstermektedir. Bu çalışma ile orbitofrontal korteks ve ventral striatum gibi karar verme süreçlerinde etkin rol alan beyin bölgeleri hakkında yeni perspektifler kazandırmak amaçlanmaktadır. Özellikle, karar verme sürecinin bellek ve öğrenme ile sıkı bir şekilde bağlantılı olduğu giderek daha açık hale gelmektedir. Özünde karar verme, geçmişin ve gelecekteki eylemlerin hafızası arasındaki bağlantı olarak görülebilmektedir. Bu çalışma, karar verme ve eylemi başlatma sürecinde özellikle öğrenme ve hafıza bağlantılarına odaklanarak ve prefrontal korteks içindeki bölgelere özel bir vurgu yaparak bu yapıları gözden geçirmektedir.Decision-making is a complex orientation that is focused on solving the current problem, and act of decision-making is a complex function that consists of specific activities such as evaluating available options, analyzing and tracking their results. The ability to make decisions includes cognitive processes such as mental analysis, planning, higher-order thinking (such as the ability to change the response to changes in circumstances), initiating and executing action. This process is divided into various components, including associative learning, emotional and social aspects, within the scope of action selection. These different aspects of decision-making have been the focus of investigation in recent studies. Especially in recent years, the fact that the ventromedial prefrontal cortex and related structures have a key role in decision making has led to progress in our understanding of the cortex basis, which is thought to be a very complex aspect of cognition. This work has provided fresh perspectives on poorly understood brain regions, such as orbitofrontal cortex and ventral striatum. In particular, it is increasingly clear that decision-making is tightly interlinked with learning and memory. Indeed, decision-making can be seen as the link between memory of the past and future actions. This study reviews these structures in the decision-making process, with a particular focus on learning and memory connections and with a special emphasis on regions within the prefrontal corte

Involvement of the cortico-basal ganglia-thalamocortical loop in developmental stuttering

Stuttering is a complex neurodevelopmental disorder that has to date eluded a clear explication of its pathophysiological bases. In this review, we utilize the Directions Into Velocities of Articulators (DIVA) neurocomputational modeling framework to mechanistically interpret relevant findings from the behavioral and neurological literatures on stuttering. Within this theoretical framework, we propose that the primary impairment underlying stuttering behavior is malfunction in the cortico-basal ganglia-thalamocortical (hereafter, cortico-BG) loop that is responsible for initiating speech motor programs. This theoretical perspective predicts three possible loci of impaired neural processing within the cortico-BG loop that could lead to stuttering behaviors: impairment within the basal ganglia proper; impairment of axonal projections between cerebral cortex, basal ganglia, and thalamus; and impairment in cortical processing. These theoretical perspectives are presented in detail, followed by a review of empirical data that make reference to these three possibilities. We also highlight any differences that are present in the literature based on examining adults versus children, which give important insights into potential core deficits associated with stuttering versus compensatory changes that occur in the brain as a result of having stuttered for many years in the case of adults who stutter. We conclude with outstanding questions in the field and promising areas for future studies that have the potential to further advance mechanistic understanding of neural deficits underlying persistent developmental stuttering.R01 DC007683 - NIDCD NIH HHS; R01 DC011277 - NIDCD NIH HHSPublished versio

White matter developmental trajectories associated with persistence and recovery of childhood stuttering

Stuttering affects the fundamental human ability of fluent speech production, and can have a significant negative impact on an individual’s psychosocial development. While the disorder affects about 5% of all preschool children, approximately 80% of them recover naturally within a few years of stuttering onset. The pathophysiology and neuroanatomical development trajectories associated with persistence and recovery of stuttering are still largely unknown. Here, the first mixed longitudinal diffusion tensor imaging (DTI) study of childhood stuttering has been reported. A total of 195 high quality DTI scans from 35 children who stutter (CWS) and 43 controls between 3 and 12 years of age were acquired, with an average of three scans per child, each collected approximately a year apart. Fractional anisotropy (FA), a measure reflecting white matter structural coherence, was analyzed voxelâ wise to examine group and ageâ related differences using a linear mixedâ effects (LME) model. Results showed that CWS exhibited decreased FA relative to controls in the left arcuate fasciculus, underlying the inferior parietal and posterior temporal areas, and the mid body of corpus callosum. Further, white matter developmental trajectories reflecting growth rate of these tract regions differentiated children with persistent stuttering from those who recovered from stuttering. Specifically, a reduction in FA growth rate (i.e., slower FA growth with age) in persistent children relative to fluent controls in the left arcuate fasciculus and corpus callosum was found, which was not evident in recovered children. These findings provide first glimpses into the possible neural mechanisms of onset, persistence, and recovery of childhood stuttering. Hum Brain Mapp 38:3345â 3359, 2017. © 2017 Wiley Periodicals, Inc.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137362/1/hbm23590.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137362/2/hbm23590_am.pd

A robot model of the basal ganglia: Behavior and intrinsic processing

The existence of multiple parallel loops connecting sensorimotor systems to the basal ganglia has given rise to proposals that these nuclei serve as a selection mechanism resolving competitions between the alternative actions available in a given context. A strong test of this hypothesis is to require a computational model of the basal ganglia to generate integrated selection sequences in an autonomous agent, we therefore describe a robot architecture into which such a model is embedded, and require it to control action selection in a robotic task inspired by animal observations. Our results demonstrate effective action selection by the embedded model under a wide range of sensory and motivational conditions. When confronted with multiple, high salience alternatives, the robot also exhibits forms of behavioral disintegration that show similarities to animal behavior in conflict situations. The model is shown to cast light on recent neurobiological findings concerning behavioral switching and sequencing

La actualización de la información en la memoria de trabajo: diferencias asociadas a la edad y efectos de un programa de entrenamiento.

Esta Tesis Doctoral presenta un conjunto de estudios que intentan profundizar en el conocimiento sobre el funcionamiento del proceso de actualización de la memoria de trabajo y, específicamente, de ciertos componentes implicados. Los trabajos desarrollados se han centrado principalmente en analizar en qué aspectos de la actualización difieren las personas y en qué medida puede entrenarse este proceso. El primer estudio se desarrolló con el objetivo de analizar posibles diferentes asociadas a la edad en cada uno de los componentes. Los resultados indicaron que la recuperación de la información podría determinar en mayor medida estas diferencias. El segundo estudio pretendía examinar el funcionamiento específico de la recuperación. Se comprobó que el acceso a un elemento en la memoria de trabajo implica diferentes subprocesos independientes. Por último, el tercer estudio analizó la efectividad de un programa de entrenamiento. Los resultados muestran el papel de estrategias para la realización de las tareas.This dissertation presents three different studies which were designed to examine the functioning of working memory updating (WMU) and, more specifically, its different components. Two main issues were addressed: age- related changes in WMU and the feasibility of training this process. The first study was carried out to analyze age-related differences in WMU components. Results showed that retrieval was the component that contributed to determine to a greater extent these differences. The second study aimed to examine the specific functioning of retrieval component. It was concluded that accessing an element in working memory could involve at least two independent sub-processes. The third study analyzed the effectiveness of a WMU training program. This experiment showed some specific improvement in a task similar to the ones trained. This gain was explained in terms of learned strategies.Tesis Univ. Jaén. Departamento de Psicología. Leída el 9 de febrero de 2017