The Sensorimotor System Flashcards
Receptive field
A region of space in which a stimulus will alter that neurons firing rate
Excitatory regions in the receptive field
The area where stimulation increases the neurons firing rate
Inhibitory regions in the receptive field
Stimulation decreases or suppresses the neurons firing rate
Pacinian corpuscles
Senses vibration and pressure, textures
Meissner’s corpuscle
Senses touch and changes in stimuli
Merkel’s discs
Senses touch, edges and isolated points. Part of Meissner’s corpuscle
Ruffini corpuscles
Senses stretching of the skin
Free nerve endings
Sense pain, heat and cold
Sensory adaptation
Progressive decrease in a receptors response to a sustained simulation
Phasic receptors
Adapt/undergo sensory adaptation
Tonic receptors
Do not adapt/undergo sensory adaptation
Dorsal column system
Reports touch information to the brain.
Receptors→axons via spinal cord→synapse on neurons in brainstem→go to different regions of the thalamus where they are emphasized or suppressed
Primary motor cortex (M1)
Organized like map of the body, change firing rate according to the direction of movement
Nonprimary motor cortex
Premotor cortex and supplementary motor area
Premotor cortex
Anterior to M1 and activated when motor sequences are guided by external events
Supplementary motor area (SMA)
Important for initiation of motor sequences especially preplanned
Basal ganglia
Picture
Sensory-discriminative dimension of pain experience
What you feel eg. throbbing
Motivational-affective dimension of pain experience
What you feel emotionally eg. sickening
Cognitive-dimension of pain experience
The overall experience eg. mild
A-delta fibers
Contain TRPM3 which is myelinated, fast conducting and transmits sharp, well-localized pain signals
C fibers
Contain TRPV1 which are unmyelinated, slower conducting, and transmit dull, diffuse, or burning pain signals
Central gray
Electrically activates endorphin-mediated pain control systems blocking the pain signal in the spinal cord
TENS
The delivery of electrical pulses through electrodes attached to the skin, which excite nerves that supply the region to which pain
is referred.
Pyramidal system (corticospinal)
The motor system that includes neurons within the cerebral cortex and their axons, which form the pyramidal tract. Lesions cause paralysis in controlled muscles.
Extrapyramidal system
Includes basal ganglia and some closely related brainstem structures. Axons of this system pass into the spinal cord outside the pyramids of the medulla. Lesions interfere with spinal reflexes and fine-tune motor control
Proprioception
The collection of information about body movements and position in space
Muscle spindle
Responds to stretch, buried in muscles
Golgi tendon organs
Sensitive to tension, detects overloads that may tear muscle
Huntingtons disease
Caused by damage to the caudate and putamen. Characterized by excessive movement, clumsiness and twitches of fingers/face.
Parkinsons disease
Loss of dopaminergic cells in substantia nigra. Characterized by slowed movement, tremors, and reduced facial expressions.
Primary somatosensory cortex (S1)
Where sensory inputs from the body surface are mapped. Receives touch information from opposite side of body, Cells are organized in sensory homunculus
Central modulation of sensory information
The process in which higher brain centers, such as the cortex and thalamus, suppress some sources of sensory information and amplify others.
Neuropathic pain
Pain that persists long after the injury that started it has
healed.
Electromyography (EMG)
The electrical recording of muscle activity.
Antagonist muscle
A muscle that counteracts the effect of another muscle.
Synergist muscle
A muscle that acts together with another muscle.
