Biological Psychology book by James W. Kalat 10th Edition Chapter 8 Movement PDF

Preview

Summary

This is the summary of Chapter 8: Movement taken from the book of James W. Kalat, 10th edition. Learners should be able to: decompose the different parts within this chapter to achieve a better understanding, have a deeper understanding of how muscles move, and lastly know more about the brain mech...

Description

Title: Movement Objectives: Learners should be able to…      

To decompose the different parts within this chapter to achieve a better understanding. To have a deeper understanding of how muscles move. To know the brain mechanisms of movement. Discuss the neural basis of Parkinson’s and Huntington’s Disease To feel and perceive the topic being discusses in this chapter. To be able to write reflections and essays regarding this chapter.

Content/Discussion

MODULE 8.1 The Control of Movement I.

Muscles and Their Movements 

Three categories of vertebrate muscles include: o Smooth muscles – control the digestive system and other organs. o Skeletal muscles/striated muscles – it controls the movement of the body in relation to the environment. o Cardiac muscles – heart muscles that have properties of skeletal and smooth muscles.



Muscles are composed of many individual fibers. o The fewer muscle fibers an axon innervates, the greater the precision of movement. A neuromuscular junction is a synapse where a motor neuron axon meets a muscle fiber.



  



o In skeletal muscles, axons release acetylcholine which excites the muscle to contract. Movement requires the alternating contraction of opposing sets of muscles called antagonistic muscles. A flexor muscle is any of the muscles that decrease the angle between bones on two sides of a joint, as in bending the elbow or knee. An extensor muscle is any of the muscles that increase the angle between members of a limb, as by straightening the elbow or knee or bending the wrist or spine backward.

Myasthenia gravis is an autoimmune disease, in which the immune system forms antibodies that attack the acetylcholine receptors at neuromuscular junctions o Causes weakness and rapid fatigue of the skeletal muscles.  Fast and Slow Muscles  Skeletal muscle type range from: o Fast-twitch fibers – produces fast contraction but fatigue rapidly. o Slow-twitch fibers – produces less vigorous contraction without fatiguing.  Slow-twitch fibers are aerobic and require oxygen during movement and therefore do not fatigue. o Nonstrenous activities utilize slow-twitch and intermediate fibers.  Fast-twitch fibers are anaerobic and use reactions that do not require oxygen, resulting in fatigue. o Behaviors requiring quick movements utilize fast-twitch fibers.  Muscle Control by Proprioceptors  Proprioreceptors are receptors that detect the position or movement of a part of the body and help regulate movement.  Stretch reflex occurs when muscle proprioreceptors detect the stretch and tension of a muscle and send messages to the spinal cord to contact it.  A muscle spindle is a kind of proprioreceptor parallel to the muscle that responds to a stretch.



II.

The Golgi tendon organ is another type of proprioreceptor that responds to increase in muscle tension. o Located in the tendons at the opposite ends of the muscle. o Acts as a “brake” against excessively vigorous contraction by sending an impulse to the spinal cord where the motor neurons are inhibited.

Units of Movement  Voluntary and Involuntary Movements  Reflexes are involuntary, consistent, and automatic responses to stimuli.  Infants have several reflexes not seen in adults: o Grasp reflex – grasps objects places in the hand. o Babinski reflex – extends big toe and fans others when sole of the foot is stroked. o Rooting reflex – turns head and sucks when cheek is stimulated.  Few behaviors are purely reflexive or non-reflexive and movements vary in their sensitivity to feedback.  Movements Varying in Sensitivity to Feedback  Ballistic movements are movement that once initiated cannot be altered or corrected. o Example: when you thread a needle, you make a slight movement, check your aim, and then readjust, dilation of the pupil.  Sequences of Behaviors  Many of our behaviors consist of rapid sequences, as in speaking, writing, dancing, or playing a musical instrument.  Central pattern generators are neural mechanisms in the spinal cord or elsewhere that generate rhythmic patterns of motor output. o Examples include the mechanisms that generate wing flapping in birds, fin movements in fish, and the “wet dog shake.”  A motor program refers to a fixed sequence of movements that is either learned or built into the nervous system. o Once begun, the sequence is fixed from beginning to end. o Automatic in the sense that thinking or talking about it interferes with the action. o Example: a mouse periodically grooms itself, skilled musicians playing a piece, or gymnast’s routine.

MODULE 8.2 Brain Mechanisms of Movement I.

The Cerebral Cortex

 

The primary motor cortex is located in the precentral gyrus located in the frontal lobe Axons from the precentral gyrus connect to the brainstem and the spinal cord which generate activity patterns to control the muscles.



Specific areas of the motor cortex are responsible for control of specific areas of the body, some overlap exists.



The motor cortex can: o Direct contraction of specific muscles. o Direct a combination of contractions to produce a specified outcome.

 Areas Near the Primary Motor Cortex  Other areas near the primary motor cortex also contribute to movement:  Posterior parietal cortex- respond to visual or somatosensory stimuli, current or future movements and complicated mixtures of a stimulus and an upcoming response. o Damage to this area causes difficulty coordinating visual stimuli with movement.  Primary somatosensory cortex – integrates touch information and movement.  Cells in the following areas are involved in the preparation and instigation of movement:  Prefrontal cortex : o Responds to lights, noises and other sensory signals that lead to movement. o Calculates predictable outcomes of actions and plans movement according to those outcomes.  Premotor contex: o is active during preparation for movement and receives information about a target in space. o integrates information about position and posture of the body and organizes the direction of the movement in space.  Supplementary motor cortex: o Important for organizing a rapid sequence of movements.

 Mirror Neurons  Mirror neurons - are active both during preparation for a movement and while watching someone else perform the same or a similar movement



Some cells respond to hearing an action (e.g., ripping a piece of paper) as well as seeing or doing it.  Cells in the insula (part of the cortex) become active when you see something disgusting, such as a filthy toilet, and when you see someone else show a facial expression of disgust.  Conscious Decisions and Movements  The conscious decision to move and the movement itself occur at two different times.  A readiness potential is a particular type of activity in the motor cortex that occurs before any type of voluntary movement. o Begins at least 500 ms before the movement itself o Implies that we become conscious of the decision to move after the process has already begun  Damage to the primary motor cortex of the right hemisphere leads to the inability to make voluntary movements with the left side.  Some individuals with this condition experience anosognosia and insist they can and do make voluntary movements. o In the absence of the motor cortex, the premotor cortex fails to receive feedback if an intended movement was executed.  Connections From the Brain to the Spinal Cord  Messages from the brain must reach the medulla and spinal cord to control the muscles.  Corticospinal tracts – paths from the cerebral cortex to the spinal cord  We have two such tracts, the lateral and medial corticospinal tracts.  The lateral corticospinal tract - a set of axons from the primary motor cortex to surrounding areas and the red nucleus and allows control of peripheral areas of the body. (hands, fingers, toes) o Red nucleus - a midbrain area with output mainly to the arm muscles.  Axons extend directly to their target neurons in the spinal cord and crosses from one side of the brain to the opposite side of the spinal cord.

 

 

II.

The medial corticospinal tract - includes axons from many parts of the cerebral cortex, not just the primary motor cortex and surrounding areas. Axons go to both sides of the spinal cord and allow control of: o muscles of the neck o shoulders and trunk Enables movements such as walking, turning, bending, standing up and sitting down It also includes axons from the midbrain tectum, the reticular formation, and the vestibular nucleus o Vestibular nucleus - a brain area that receives input from the vestibular system.

The Cerebellum 

One effect of cerebellar damage is trouble with rapid movements that require accurate aim and timing. For example, people with cerebellar damage have trouble tapping a rhythm, clapping hands, pointing at a moving object, speaking, writing, typing, or playing a musical instrument. They are impaired at almost all athletic activities, except those like weightlifting that do not require aim or timing. Even long after the damage, when they seem to have recovered, they remain slow on sequences of movements and even on imaginings of movements (González, Rodríguez, Ramirez, &Sabate 2005).

 Role in Functions Other Than Movement  The cerebellum is not only a motor structure. In one study, functional MRI measure cerebellar activity while people performed several tasks (Gao et al., 1996). When they simply lifted objects, the cerebellum showed little activity. When they felt things with both hands to decide whether they were the same or different, the cerebellum was much more active. The cerebellum responded even when the experimenter rubbed an object across an unmoving hand. That is, cerebellum responded to sensory stimuli even in the absence of movement.

 Cellular Organization  The neurons are arranged in a precise geometrical pattern, with multiple repetitions of the same units.  The Purkinje cells are flat (two-dimensional) cells in sequential planes, parallel to one another.  The parallel fibers are axons parallel to one another and perpendicular to the planes of the Purkinje cells.  Action potentials in parallel fibers excite one Purkinje cell after another. Each Purkinje cell then transmits an inhibitory message to cells in the nuclei of the cerebellum (clusters of cell bodies in the interior of the cerebellum) and the vestibular nuclei in the brainstem, which in turn send information to the midbrain and the thalamus.  Depending on which and how many parallel fibers are active, they might stimulate only the first few Purkinje cells or a long series of them. Because the parallel fibers’ messages reach different Purkinje cells one after another, the greater the number of excited Purkinje cells, the greater their collective duration of response.

III.

The Basal Ganglia 

The term basal ganglia applies collectively to a group of large subcortical structures in the forebrain. In effect, the basal ganglia select a movement by ceasing to inhibit it. This circuit is particularly important for self-initiated behaviors. The basal ganglia seem critical for initiating an action but not when the action is directly guided by a stimulus.

MODULE 8.3 Movement Disorders I.

Parkinson’s Disease 

The symptoms of Parkinson’s disease (also known as Parkinson disease) are rigidity, muscle tremors, slow movements, and difficulty initiating physical and mental activity (M. T. V. Johnson et al., 1996; Manfredi, Stocchi, & Vacca, 1995; Pillon et al., 1996)



II.

Possible Causes: o Thee immediate cause of Parkinson’s disease is the gradual progressive death of neurons, especially in the substantianigra, which sends dopaminereleasing axons to the caudate nucleus and putamen. People with Parkinson’s disease lose these axons and therefore dopamine.

Hungtinton’s Disease 

People with Huntington’s disease also suffer psychological disorders, including depression, sleep disorders, memory impairment, anxiety, hallucinations and delusions, poor judgment, alcoholism, drug abuse, and sexual disorders ranging from complete unresponsiveness to indiscriminate promiscuity (Shoulson, 1990). Th e psychological disorders often develop before the motor disorders, and some individuals in the early stages of Huntington’s disease are misdiagnosed as having schizophrenia.

References:   



Kalat, J. W. (2009). Biological psychology (10th ed.). Belmont, CA: Wadsworth Pub Co. Kreitzer, A. C., & Malenka, R. C. (2007). Endocannabinoid-mediated rescue of striatal LTD and motor deficits in Parkinson’s disease models. Nature, 445, 643–647. (8) Morton, A. J., Wood, N. I., Hastings, M. H., Hurelbink, C., Barker, R. A., & Maywood, E. S. (2005). Disintegration of the sleep–wake cycle and circadian timing in Huntington’s disease. Journal of Neuroscience, 25, 157–163. (9) Morton, A. J., Wood, N. I., Hastings, M. H., Hurelbink, C., Barker, R. A., & Maywood, E. S. (2005). Disintegration of the sleep–wake cycle and circadian timing in Huntington’s disease. Journal of Neuroscience, 25, 157–163. (9)...