1Listen to the audio lecture while viewing these slides1Psychology 372Physiological PsychologySteven E. Meier, Ph.D.Movement Disorders2Psyc 372 – Physiological PsychologyBackground• Early Stud ies• Found some patients with progressive weakness had problems with nerve cell bodies or peripheral nerves but no problems with muscle fibers.• Other patients had problems muscles with little problems in the nerve cells .• Two important features• Some neurological disorders only affect sensory systems while others affect only motor systems• Neurological problems may o nly affect one component of the neuron Axon vs. Soma3Psyc 372 – Physiological PsychologyMany Types• Nerve-Muscle Synapse Problems• Myasthenia Gravis• Neurogenic and Myopathic Diseases• Amytrophic Lateral Sclerosis (Lou Gehrig Disease)• Mus cular Dyst rophies• Basal Ganglia Disorders•Parkinson’s Disease• Huntington’s Disease• Cerebellar Disorders•Hypotonia•Others4Psyc 372 – Physiological PsychologyMyasthenia Gravis• Means severe weakness of the muscle• Is a functional disorder at the synapse between the motor neuron and skeletal muscle.•Two causes• Autoimmune Disorder• Genetic5Psyc 372 – Physiological PsychologyAutoimmune Type• Antibodies are produced to attack the Nicotinic Ach receptor in the muscle.• Reduces the number of receptors• Muscle becomes weakened6Psyc 372 – Physiological PsychologySome Characteristics• Affects cranial muscles and limb muscles• Eyelids, eye muscles•Legs, Arms• Symptoms vary during the day and between days. • Get remission and exacerbation• No conventional clinical or electromyographic evidence of denervation although muscle weakness is occurring.• Weakness is reversed by drugs that inhibit acetylcholinesterase27Psyc 372 – Physiological PsychologySome Symptoms• Muscle fatigue and weaknesses• Repetitive stimulation of the nerve produces a decrimental response over time.• Patients generally complain of muscle weakness not fatigue• Generally progresses and becomes worse over time8Psyc 372 – Physiological PsychologyTreatment• Use of Anticholinesterases provide symptomatic relief.• e.g., Pyridostigmine• Immunosuppressive Therapies• Suppress immune functioning• Plasmapheresis• Removes plasma and ACh antibodies• Each does not alter the course of the disease9Psyc 372 – Physiological PsychologyOther Treatment•Thymectomy• Remove the Thymus• ½ of patients enter total remission• Have no more problems• Also is used when patients enter severe respiratory distress from MG10Psyc 372 – Physiological PsychologyNeurogenic and Myopathic Diseases11Psyc 372 – Physiological PsychologySymptoms• Appear slower than when a nerve is cut.• Generally symptoms occur as the muscle becomes weak and begins to waste away -Atrophy• Affects limb movement• Lift ing and walking• May also have • Cramps and pain• Mus cle may not be able to relax• Red tinged urine•Others• Does no t influence Sensory Neurons12Psyc 372 – Physiological PsychologyOverview• Neurogenic disorders• May get distal limb weakness • Visible muscle twitches under the skin are a good indicator for neurogenic disorders•Called Fasciculations•Myopathic Disorders• May also get distal limb weakness• Other symptoms313Psyc 372 – Physiological PsychologyMotor Neurons•Lower• Are from the spinal cord and brain stem • Directly innervate skeletal muscles•Premotor• Past called Upper Motor Neurons• Originate in higher brain areas (Cortex)• Synapse on lower motor neurons• Combine with motor neurons in the spinal cord.• Make up the corticospinal tract14Psyc 372 – Physiological PsychologyPremotor and Lower Neurons • Diseases in each group produce distinct symptoms.•Lower•Atrophy• Fasciculations• Decreased muscle tone• Loss of tendon reflexes• Result in weak, wasted and twitching muscles15Psyc 372 – Physiological PsychologyUpper•Symptoms• Muscle Spasticity• Overactive tendon reflexes•Others•Result• Get overactive tendon reflexes16Psyc 372 – Physiological PsychologyDisorders17Psyc 372 – Physiological PsychologyAmytrophic Lateral Sclerosis • Also called Lou Gehrig Disease• Involves both lower and premotor neurons• Characterized by • Atrophy of the muscle• Hardening of the Spinal Cord due to astrocyte increases and scarring of the lateral columns• Premotor neurons degenerate progressively18Psyc 372 – Physiological PsychologySymptoms• Usually begins around age 60• Begins with fine movement difficulties•Playing the piano• Working with tools• Develops into weakness in the limbs• Get an increase in tendon reflexes• Other symptoms as well419Psyc 372 – Physiological PsychologyMuscular Dystrophies• Are inherited• Symptoms begin by or before adolescence• All symptoms are caused by weakness• Weakness becomes more severe• Can also get a delayed relaxation of the muscle – called myotonia20Psyc 372 – Physiological PsychologyTypes• Duchenne• Facioscapulohumeral•Myotonic• Limb-girdle21Psyc 372 – Physiological PsychologyBasal Ganglia Disorders22Psyc 372 – Physiological PsychologyCharacteristics• All have tremor or other involuntary movements.• Have changes in posture and muscle tone• Have slowness of movement without paralysis.• May have diminished movement or excessive movement• Also have cognitive disorders as well23Psyc 372 – Physiological PsychologyStructures and Connections• Consists of the • caudate nucleus, •Putamen • Globus Pallidus•Gets input from • Primary motor cortex • Substantia Nigra24Psyc 372 – Physiological PsychologyOutput•Goes to:• Primary motor cortex• Supplemental motor area• Premotor cortex•Brainstem motor nuclei (ventromedia l pathways ) • Co rtical-basal ganglia loo p• Frontal, parietal, temporal lobes send axons to caudate/putamen• Caudate/putamen projects to the globus pallidus• Globus pallidus projects back to moto r cortex via thalamic nuclei525Psyc 372 – Physiological PsychologyParkinson’s Disease•Is a Hypokinetic Disorder• One of the most common movement disorders26Psyc 372 – Physiological PsychologyMajor Symptoms• Reduced spontaneous movement• Impaired initiation of movementAkinesia• Reduced amplitude and velocity of voluntary movementBradykinesia• Increased muscular rigidity• Tremor at rest• Shuffling gait•Flexed Posture•Impaired