Deborah Ely Budding

Consensus Paper: The Cerebellum's Role in Movement and Cognition

While the cerebellums role in motor function is well recognized, the nature of its concurrent role in cognitive function remains considerably less clear. The current consensus paper gathers diverse views on a variety of important roles played by the cerebellum across a range of cognitive and emotional functions. This paper considers the cerebellum in relation to neurocognitive development, language function, working memory, executive function, and the development of cerebellar internal control models and reflects upon some of the ways in which better understanding the cerebellums status as a “supervised learning machine” can enrich our ability to understand human function and adaptation. As all contributors agree that the cerebellum plays a role in cognition, there is also an agreement that this conclusion remains highly inferential. Many conclusions about the role of the cerebellum in cognition originate from applying known information about cerebellar contributions to the coordination and quality of movement. These inferences are based on the uniformity of the cerebellums compositional infrastructure and its apparent modular organization. There is considerable support for this view, based upon observations of patients with pathology within the cerebellum.

From movement to thought: executive function, embodied cognition, and the cerebellum.

This paper posits that the brain evolved for the control of action rather than for the development of cognition per se. We note that the terms commonly used to describe brain–behavior relationships define, and in many ways limit, how we conceptualize and investigate them and may therefore constrain the questions we ask and the utility of the “answers” we generate. Many constructs are so nonspecific and over-inclusive as to be scientifically meaningless. “Executive function” is one such term in common usage. As the construct is increasingly focal in neuroscience research, defining it clearly is critical. We propose a definition that places executive function within a model of continuous sensorimotor interaction with the environment. We posit that control of behavior is the essence of “executive function,” and we explore the evolutionary advantage conferred by being able to anticipate and control behavior with both implicit and explicit mechanisms. We focus on the cerebellums critical role in these control processes. We then hypothesize about the ways in which procedural (skill) learning contributes to the acquisition of declarative (semantic) knowledge. We hypothesize how these systems might interact in the process of grounding knowledge in sensorimotor anticipation, thereby directly linking movement to thought and “embodied cognition.” We close with a discussion of ways in which the cerebellum instructs frontal systems how to think ahead by providing anticipatory control mechanisms, and we briefly review this models potential applications.

Subcortical structures and cognition

Subcortical structures and cognition : , Subcortical structures and cognition : , کتابخانه دیجیتال جندی شاپور اهواز

Adaptation, Expertise, and Giftedness: Towards an Understanding of Cortical, Subcortical, and Cerebellar Network Contributions

Current cortico-centric models of cognition lack a cohesive neuroanatomic framework that sufficiently considers overlapping levels of function, from “pathological” through “normal” to “gifted” or exceptional ability. While most cognitive theories presume an evolutionary context, few actively consider the process of adaptation, including concepts of neurodevelopment. Further, the frequent co-occurrence of “gifted” and “pathological” function is difficult to explain from a cortico-centric point of view. This comprehensive review paper proposes a framework that includes the brain’s vertical organization and considers “giftedness” from an evolutionary and neurodevelopmental vantage point. We begin by discussing the current cortico-centric model of cognition and its relationship to intelligence. We then review an integrated, dual-tiered model of cognition that better explains the process of adaptation by simultaneously allowing for both stimulus-based processing and higher-order cognitive control. We consider the role of the basal ganglia within this model, particularly in relation to reward circuitry and instrumental learning. We review the important role of white matter tracts in relation to speed of adaptation and development of behavioral mastery. We examine the cerebellum’s critical role in behavioral refinement and in cognitive and behavioral automation, particularly in relation to expertise and giftedness. We conclude this integrated model of brain function by considering the savant syndrome, which we believe is best understood within the context of a dual-tiered model of cognition that allows for automaticity in adaptation as well as higher-order executive control.

Sensory Integration, Sensory Processing, and Sensory Modulation Disorders: Putative Functional Neuroanatomic Underpinnings

This paper examines conditions that have variously been called sensory integration disorder, sensory processing disorder, and sensory modulation disorder (SID/SPD/SMD). As these conditions lack readily and consistently agreed-upon operational definitions, there has been confusion as to how these disorders are conceptualized. Rather than addressing various diagnostic controversies, we will instead focus upon explaining the symptoms that are believed to characterize these disorders. First, to clarify the overall context within which to view symptoms, we summarize a paradigm of adaptation characterized by continuous sensorimotor interaction with the environment. Next, we review a dual-tiered, integrated model of brain function in order to establish neuroanatomic underpinnings with which to conceptualize the symptom presentations. Generally accepted functions of the neocortex, basal ganglia, and cerebellum are described to illustrate how interactions between these brain regions generate both adaptive and pathological symptoms and behaviors. We then examine the symptoms of SID/SPD/SMD within this interactive model and in relation to their impact upon the development of inhibitory control, working memory, academic skill development, and behavioral automation. We present likely etiologies for these symptoms, not only as they drive neurodevelopmental pathologies but also as they can be understood as variations in the development of neural networks.

ADHD and giftedness: a neurocognitive consideration of twice exceptionality.

Current models of cognition and behavioral diagnosis emphasize categorical classification over continuous considerations of function and promote the “differential diagnosis” of various conditions according to observational criteria. However, an overemphasis on a purely behavioral, categorical approach to understanding human function fails to address the comorbidity of different disorders and does not include a consideration of overlapping levels of function, from “pathological” through “normal,” to “gifted” or exceptional. The frequent co-occurrence of “gifted” and “pathological” function is thus difficult to understand from a corticocentric and purely behavioral and observational point of view. This article reviews “giftedness” in relation to the diagnosis of attention-deficit hyperactivity disorder, coexistence of which is termed “twice exceptional.” It additionally considers problems in assessing these functions using current neuropsychological tests and methodologies that are presumably based upon a corticocentric model of cognition.

Requiem for a Diagnosis: Attention-Deficit Hyperactivity Disorder

This editorial discusses the diagnosis of ADHD from behavioral and neuropsychological viewpoints. The DSM and clinical neuropsychology offer two completely different nomenclatures while brain-behavior relationships do not easily “map” on to the symptom picture of ADHD. Neuropsychological evaluation offers specificity in identifying and treating individual ADHD presentations, avoiding the heterogeneity inherent in the DSM diagnosis of ADHD.

ADHD and sensory processing disorders: placing the diagnostic issues in context.

Attention-deficit hyperactivity disorder (ADHD) and sensory processing disorders are behaviorally defined conditions that often co-occur, while both diagnoses have been controversial in part due to the constraints of categorical behavioral diagnosis. However, neuroanatomic studies using neuropsychological tests as “probes” have clearly demonstrated that the various symptoms of ADHD are the result of abnormalities in large-scale brain networks. Sensory processing disorders have not yet been grounded within a neuroanatomical substrate. This article reviews sensory processing disorder as a categorically based diagnosis. It discusses certain possible neuroanatomical relationships between the symptoms of ADHD and sensory processing disorders, and suggests that the symptoms of sensory processing disorders be studied within the dimensional framework of research domain criteria.

The Basal Ganglia: Beyond the Motor System—From Movement to Thought

In studying and practising a cortico-centric model of neuropsychology, few students or clinicians likely pay much attention to or fully understand the functions of the basal ganglia, a set of interconnected subcortical nuclei arising from the mammalian forebrain. This is, in part, due to the fact that the anatomical subdivisions of the basal ganglia can seem confusing. Some regions of the basal ganglia can be broken down into multiple components. Several basal ganglia structures feature further subdivisions, and some components of the basal ganglia can have more than one name, based on which structures are grouped together. There are reasons for these differences, which will be described in the course of this chapter.

The Cerebellum: Quality Control, Creativity, Intuition, and Unconscious Working Memory

Cerebellum is a Latin word that means “little brain.” While the cerebellum might be little in gross appearance relative to the neocortex, it is certainly not little in terms of its composition and function. The cerebellum actually contains more neurons than the remainder of the human brain, even though it comprises only about ten percent of total brain weight (Houk & Mugnaini, 2003). The cerebellum also lies outside of the cerebral cortex. Perhaps this is one of the reasons why so little attention has historically been paid to understanding its possible contributions to behavior. From the viewpoint of a cortico-centric bias, regions outside the cortex become less important. The cerebellum has traditionally been viewed as a structure coordinating movement, and until recently, this viewpoint has rarely been given a second thought (Bower & Parsons, 2003).