BIO PSY CHAP 7

• Vertebrate muscles

  • Smooth muscles
  • Skeletal or striated muscles
  • Cardiac muscles
• Neuromuscular junction


  A synapse between a motor neuron axon and a muscle fiber
• Skeletal muscle types


  • Fast-twitch fibers
  • Slow-twitch fibers
• Fast-twitch fibers


  • Fast contractions and rapid fatigue
• Slow-twitch fibers


  • Less vigorous contractions and no fatigue
  • Aerobic - use oxygen during movements
• Fast-twitch fibers (Anaerobic)

  • Fast-twitch fibers (Anaerobic)use reactions that do not require oxygen at the time but need oxygen for recoveryire oxygen at the time but need oxygen for recovery
• Proprioceptor


  A receptor that detects the position or movement of a part of the body
• Stretch reflex


  1. Muscle is stretched

  2. Spinal cord sends signal to contract it reflexively
• Muscle spindle


  A receptor parallel to the muscle that responds to a stretch
• Golgi tendon organs


  Proprioceptors that respond to increases in muscle tension
• Reflex


  Consistent automatic response to stimuli, insensitive to reinforcements, punishments, and motivations
• Ballistic movement


  Executed as a whole, cannot be altered once initiated
• Central pattern generators


  Neural mechanisms in the spinal cord that generate rhythmic patterns of motor output
• Motor program


  A fixed sequence of movements
• Primary motor cortex


  The precentral gyrus of the frontal cortex, just anterior to the central sulcus, that elicits movements
• Primary motor cortex

  • Does not send messages directly to the muscles, its axons extend to the brainstem and spinal cord
• Cerebral cortex


  • Particularly important for complex actions such as talking or writing, has much less control over reflexive movements
• Posterior parietal cortex


  Monitors the position of the body relative to the world
• Prefrontal cortex


  Important for planning and organizing rapid sequences of movements
• Supplementary motor cortex


  Becomes active after an error in movement, develops ways to inhibit the incorrect movement
• Premotor cortex


  Most active immediately before a movement, receives information about the target and the body's current position and posture
• Prefrontal cortex


  Stores sensory information relevant to a movement, important for considering probable outcomes
• Antisaccade task


  Suppressing the tendency to look toward a moving object and instead looking in the opposite direction
• Mirror neurons


  Active both during preparation for a movement and while watching someone else perform the same or similar movement
• Spinal cord disorders


  • Paralysis
  • Paraplegia
  • Quadriplegia
  • Hemiplegia
  • Tabes dorsalis
  • Poliomyelitis
  • Amyotrophic lateral sclerosis
• Corticospinal tracts


  Paths from the cerebral cortex to the spinal cord
• Lateral corticospinal tract


  Pathway of axons from the primary motor cortex, surrounding areas, and red nucleus, controls movements in peripheral areas like hands and feet
• Medial corticospinal tract


  Includes axons from many parts of the cerebral cortex, midbrain tectum, reticular formation, and vestibular nucleus, controls muscles in the medial parts of the body like trunk and neck
• Cerebellum


  Contributes to many aspects of brain functioning, especially anything that relates to aim or timing
• Cerebellum


  • Does not impair continuous motor activity, receives input from the spinal cord, sensory systems, and cerebral cortex
• Purkinje cells


  Flat (two dimensional) cells in sequential planes, parallel to one another in the cerebellar cortex
• Parallel fibers


  Axons parallel to one another and perpendicular to the planes of the Purkinje cells
• Basal ganglia


  A group of large subcortical structures in the forebrain including the caudate nucleus, putamen, and globus pallidus
• Direct pathway from the striatum


  Inhibits the globus pallidus, which inhibits part of the thalamus, resulting in net excitation
• Readiness potential in the motor cortex begins at least 500 ms before any voluntary movement
• Parkinson's disease


  Results from the gradual loss of dopamine-releasing axons from the substantia nigra to the striatum
• MPTP


  A chemical that destroys neurons that release dopamine, partly by impairing the transport of mitochondria
• L-dopa


  A precursor to dopamine that crosses the blood-brain barrier, used to treat Parkinson's disease
• Huntington's disease


  A severe neurological disorder characterized by rhythmic writhing movements (chorea)
• Huntingtin


  The protein coded by the gene for Huntington's disease, which impairs neurons and glia in several ways