CNS Vascular System & Motor Learning Lecture 2025 PDF

CNS VASCULAR SYSTEM And Motor Learning Overview of CNS anatomy CNS ADDITIONS The central nervous system is made up of grey matter and white matter. However, grey matter plays the most significant part in allowing humans to function normally daily. Grey matter makes up the outer mos...

CNS VASCULAR SYSTEM And Motor Learning Overview of CNS anatomy CNS ADDITIONS The central nervous system is made up of grey matter and white matter. However, grey matter plays the most significant part in allowing humans to function normally daily. Grey matter makes up the outer most layer of the brain where the cell bodies lie. White matter is where the axons that have more myelin lie. The white matter and grey matter are similar as they are both essential sections of both the brain as well as the spinal cord. The grey matter gets its grey tone from a high concentration of neuronal cell bodies. https://www.ncbi.nlm.nih.gov Neurons Multiple sclerosis= breakdown of the myeline sheaths CNS Circulation There are two paired arteries which are responsible for the blood supply to the brain; the vertebral arteries, and the internal carotid arteries. These arteries arise in the neck and ascend to the cranium. Within the cranial vault, the terminal branches of these arteries form an anastomotic circle, called the Circle of Willis. From this circle, branches arise which supply the majority of the cerebrum. Other parts of the CNS, such as the pons and spinal cord, are supplied by smaller branches from the vertebral arteries. Arterial Circle of Willis The terminal branches of the vertebral and internal carotid arteries all anastomose to form a circular blood vessel, called the Circle of Willis. There are three main (paired) constituents of the Circle of Willis: Anterior cerebral arteries Middle cerebral arteries = most common for stroke. Posterior cerebral arteries MCA=strokes can occur here, stinosis can cause block To complete the circle, two ‘connecting vessels’ are also present: Anterior communicating artery. Posterior communicating artery video Blood Supply to the Cerebrum There are three cerebral arteries; anterior, middle and posterior. They each supply a different portion of the cerebrum. The anterior cerebral arteries supply the region of the brain primarily responsible for motor and sensory of the lower limbs The middle cerebral arteries primarily supply the motor and sensory cortices for the upper limb and face, in addition to supplying Broca’s area in the dominant frontal lobe and Wernicke’s area in the dominant temporal lobe. The posterior cerebral arteries supply blood to the occipital lobe and the medial and inferior aspects of the temporal lobe of the brain; essentially, the back portion of the brain including the visual cortex *Frank Gaillard and Patrick J. Lynch NCMI. NIH Blood Brain Barrier The blood vessels that vascularize the central nervous system (CNS) possess unique properties called the blood–brain barrier. these vessels tightly regulate the movement of ions, molecules, and cells between the blood and the brain. This precise control of CNS homeostasis allows for proper neuronal function and also protects the neural tissue from toxins, pathogens, inflammation and disease. Also provides an obstacle for drug delivery to the CNS Ncbi.nlm.nih.gov Cerebral Vascular Accident - Stroke The brain is sensitive to oxygen starvation. A stroke is an acute development of a neurological deficit, due to a disturbance in the blood supply of the brain. There are four main causes of a cerebrovascular accident: CVA Thrombosis – obstruction of a blood vessel by a locally forming clot. Embolism – obstruction of a blood vessel by an embolus formed elsewhere. Hypoperfusion – lack of blood supply to the brain, due to systemically low blood pressure (e.g shock). Hemorrhage – an accumulation of blood within the cranial cavity. Out of these four, the most common cause is embolism. In many patients, the atherosclerotic embolus arises from the vessels of the neck. Intracerebral Aneurysms An aneurysm is a dilation of an artery, which is greater than 50% of the normal diameter. They are most likely to occur to occur in the vessels contributing to the Circle of Willis. An aneurysm is usually asymptomatic until they rupture. Once ruptured, blood typically accumulates in the subarachnoid space with a subsequent increase in intracranial pressure. Once the artery wall has ruptured, it is life threatening Treatment of an intracerebral aneurysm is surgical emergency.  Cerebrospinal Fluid Cerebrospinal fluid is a clear, colorless body fluid found in the brain and spinal cord. It is produced by specialized ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations. CSF functions 1) to keep the brain tissue buoyant, acting as a cushion or "shock absorber“ 2) to act as the vehicle for delivering nutrients to the brain and removing waste 3) to flow between the cranium and spine and compensate for changes in intracranial blood volume Fluid that is produced in brain and down to spine, absorbed what it makes, stored in ventricals. Acts as shock absorber, help with intercranial fluid loss. CSF Our bodies produce approximately a pint of CSF daily, continuously replacing CSF as it is absorbed. Under normal conditions there is a balance between the amount of CSF that is produced and the rate at which it is absorbed. Hydrocephalus occurs when this balance is disrupted. Although there are many factors that can disrupt this balance, the most common is a blockage, or obstruction, somewhere along the circulatory pathway of CSF. The obstruction may develop from a variety of causes, such as brain tumors, cysts, scarring and infection. VENTRICLES The ventricular system is made up of four ventricles connected by narrow passages. Normally, CSF flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then reabsorbs into the bloodstream. CSF CIRCULATION From the third ventricle it flows down a long, narrow passageway (the aqueduct of Sylvius) into the fourth ventricle. From the fourth ventricle it passes through three small openings (foramina) into the subarachnoid space surrounding the brain and spinal cord. CSF Pressure Intracranial pressure (ICP) is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid (CSF). ICP is measured in millimeters of mercury (mmHg) and, at rest, is normally 7–15 mmHg for a supine child or adult. Little higher if upright Hydrocephalus Hydrocephalus may be congenital or acquired. Congenital hydrocephalus is present at birth and may be caused by either events or influences that occur during fetal development, or genetic abnormalities. Acquired hydrocephalus develops at the time of birth or at some point afterward. This type of hydrocephalus can affect individuals of all ages and may be caused by injury or disease. Hydrocephalus may also be communicating or non- communicating. Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles, which remain open. Non- communicating hydrocephalus — also called "obstructive" hydrocephalus — occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles.  Ventriculoperitoneal Shunt VP Shunt Permanent or semipermanent- needs to be done for growth or infection Ventricle system can not store it External Ventricular Drain EVD not as perminent From stoke- fluid in brain External drain is placed,  Motor Learning (by 6 yr = basic) Ability to learn new movement options Motor learning continues throughout life, provided the environment asks for change AND the CNS has the plasticity to do so. Walking on firm floor, then walking on grass, incline. The difficulty increases and the expectation is a fall. Motor learning will occur in order to acquire the skill to walk on grass etc. since it is part of the environment Reteach motor learning, we have the basic fundamental CNS that are the base of all functional mobility by the age of 6 years. Brain has the ability to create new pathways 3 stages of motor learning Cognitive Stage-learn from your mistakes. "make it look easy" Conscious processing of information Large amount of error Inconsistent attempts/performance Repetition needed *cognitive work includes processing feedback Associative Stage-getting a little bit better from practice, repetition. Decrease in errors of new skill Decreased need for concentration/cognition Skill refinement Repetition/practice Autonomous Stage mainly error free Patterns of movement are non cognitive and automatic Distractions does not impact the activity Motor Control Control of the movement during functional activities (skills acquisition) Neuroplasticity allows us to gain motor function and control after CNS insult. The brain can learn or relearn despite cellular damage Repetitions…the ones that practice over and over will be better  Stages of Motor Skills Acquisition Learning new skills/relearning old ones Feed back and practice Refinement Decrease in error Allow for errors to be self Smooth transitions Change the environment corrected Autonomous Retains the skill and transfers the ability to other environments Weight shift- for pt that lost ability to walk, Class activity – Motor learning PICK A PARTNER ACQUIRE A PEN OR PENCIL PHYSIOLOGIC CHANGES ACROSS THE LIFE SPAN Many biological systems involved in the execution of motor skills and their associated behaviors undergo physiologic changes as a consequence of aging Musculoskeletal System Cardiovascular and Pulmonary System Neurological System Cognitive System Feedback Intrinsic (inherent) feedback Sensory feedback Visual Proprioceptive Tactile/somatosensory Extrinsic (augmented) feedback Verbal Manual Practice of Motor Skills Whole Multiple steps but practiced as a whole Pure Part Learning Steps can be learning in forward or reverse order before whole practice Progressive Sequential Steps are taught sequentially Whole-Part-Whole. Observe, break down, whole practice Options: sitstand, floor stand, step up/downs Practice Schedules Whatever the practice context is, the skill must be eventually practiced as a whole Constant Practice Practice of a tag under a uniform condition Variable practice Practice in a variety of conditions Intermittent/scheduled OP rehab, Home Health, private practice Reduced frequency, type of assist/cueing Reassessment by PT to maximize effectiveness Random HEP. Must be done independently by patient of caregiver SUMMARY OF MOTOR LEARNING IN A PHYSICAL THERAPY CONTEXT Motor skill acquisition, refinement, and retention evolve from a patient’s need to interact with their environment Meet the environmental demands with functional skills that allow the individual to participate in work, play, and leisure activities REFERENCES https://www.ncbi.nlm.nih.gov/