Sensorimotor System Flashcards
- a specialized cell that responds to a particular energy or substance in the internal or external environment and converts this energy into a change in the electrical potential across its membrane
receptor cell
- a physical event that triggers a sensory response
stimulus
- the concept that each nerve to the brain reports only a particular type of information
labeled lines
- a local change in the resting potential of a receptor cell in response to stimuli, which may initiate an action potential
generator potential
- the process in which a receptor cell converts the energy in a stimulus into a change in the electrical potential across its membrane
sensory transduction
- a skin receptor cell type that detects vibration and pressure
- tiny onion-like structure embedded in the innermost layer of the skin
- acts as a filter
- vibrations only of 200 or more cycles per second to stimulate sensory nerve endings inside
- texture sensitivity
Pacinian corpuscle (lamellated corpuscle)
- the stimulus intensity that is just adequate to trigger an action potential in a sensory cell
threshold
- a skin receptor cell type that detects light touch, responding especially to changes in stimuli
- localized movement between the skin and a surface
Meissner’s corpuscle (tactile corpuscle)
- a skin receptor cell type that detects light touch, responding especially to edges and isolated points on a surface
Merkel’s disc
- skin receptor cell type that detects stretching of the skin
- sparsely distributed in the skin
movement of fingers or limbs
Ruffini corpuscle
- an axon that terminated in the skin and has no specialized cell associated with it
- detect pain and/or changes in temperature
free nerve ending
- set of specialized receptors and neural mechanisms responsible for body sensations such as touch and pain
somatosensory systems
- stimulus region and features that affect the activity of a cell in a sensory system
- alters neuron’s firing rate
- differ in size, shape, and quality of stimulation that activates them
receptive field
- progressive loss of receptor response as stimulation is maintained
- allows us to ignore unimportant events
sensory adaptation
- receptor in which the frequency of action potentials drops rapidly as stimulation is maintained
phasic receptor
- receptor in which the frequency of action potentials declines slowly or not at all as stimulation is maintained
tonic receptor
- process in which higher brain centers, such as the cortex and thalamus, suppress more sources of sensory information and amplify others
central modulation of sensory information
- somatosensory system that delivers most touch stimuli via the dorsal columns of spinal white matter to the brain
dorsal column system
- strip of skin innervates by a particular spinal nerve
dermatome
- brain region at the top of the brain stem that trade information with the cortex
thalamus
- the region of cortex that receives most of the information about that modality from the thalamus
- located in the postcentral gyrus in each hemisphere (long strip of tissue that lies just posterior to the central sulcus dividing the parietal and frontal lobe)
- receives touch information from opposite side of the body
primary sensory cortex (S1)
- the cortical regions receiving direct projecting from primary sensory cortex for that modality
nonprimary sensory cortex (secondary sensory cortex)
- sensory areas in the brain that process a mixture of inputs from different modalities
association areas
- a neuron upon which information from more than one sensory system converges
- allows different sensory systems to interact
polymodal neuron
- condition in which stimuli in one modality evoke the involuntary experience of an additional sensation in another modality
synesthesia
- the discomfort normally associated with tissue damage
pain
- receptor that responds to stimuli that produce tissue damage or pose the threat of damage
nociceptor
- receptor found in some free nerve endings that opens its channel in response to rising temperatures
transient receptor potential type M3 (TRPM3)
- moderately large, myelinated, and therefore fast-conducting axon that usually transmits pain information
- action potentials in these fibers reach the spinal cord very quickly
A delta (A3) fiber
- small, unmyelinated axons that conducts pain information slowly and adapts slowly
- posses TRPV1
C fiber
- somatosensory system that carries most of the pain information from the body to the brain
- receives its input from the contralateral side of the body
anterolateral system (spinothalamic system)
- peptide transmitter that is involved in pain transmission
- boosts pain signals and remodels pain pathway neurons
substance P
- region of medical cerebral cortex that lies dorsal to the corpus callosum
- part of limbic system
- extent of activation correlates with how much discomfort different people report in response to the same mildly painful stimulus
- different subregions seem to mediate emotional versus sensory aspects of pain
cingulate cortex
- pain that persists long after the injury that started it has healed
- ex. phantom limb pain
neuropathic pain
- absences of or reduction in pain
analgesia
- one of three kinds of endogenous opioids
- relieve pain sensations
endorphin
- delivery of electrical pulses through electrodes attached to the skin, which excite nerves that supply the region to which pain is referred
- may bring dramatic relief lasting for hours
transcutaneous electrical nerve stimulation (TENS)
- potential antagonist of opiates that is often administered to people who have taken drug overdoses
- blocks receptors for endogenous opioids
naloxone
- relief of a symptom that results following a treatment that is known to be ineffective or inert
placebo effect
- the insertion of needles at designated points on the skin to alleviate pain or neurological malfunction
acupuncture
- a single relocation of a body part, usually resulting from a brief muscle contraction
movement
- a simple, highly stereotyped and unlearned response to a particular stimulus
reflex
- complex behavior, as distinct from a simple movement
act
- plan for a series of muscular contractions, established in the nervous system prior to its execution
motor plan
- the electrical recording of muscle activity
electromyography (EMG)
- a muscle that counteracts the effect of another muscle
antagonist
- a muscle that acts together with another muscle
synergist
- neuron that transmits neural messages to muscles (or glands)
motor neuron
- the region where the motor neuron terminal meets its target muscle fiber
- the point where the nerve transmits its message to the muscle fiber
neuromuscular junction
- neurotransmitter that is produced and released bu the autonomic nervous system, by motor neurons, and by neurons throughout the brain
acetylcholine (ACh)
- the motor neurons of the brain and spinal cord, so called because they receive and integrate all motor signals from the brain to direct movement
final common pathway
- body sense
- information about the position and movement of the body
proprioception
- a muscle receptor that lies parallel to a muscle and sends impulse to the central nervous system when the muscle is stretched
- capsule buried within the other fibers of the muscle
contain intrafusal fibers
muscle spindle
- any of the small muscle fibers that lie within each muscle spindle
intrafusal fiber
- a type of receptor found within tendons that sends impulses to the central nervous system when a muscle contracts
- sensitive to muscle tension
- monitoring the force of muscle contractions
- provides second source of sensory information about the muscle
Golgi tendon organ
- the contraction of a muscle in response to stretch of that muscle
stretch reflex
- the motor system that included neurons within the cerebral cortex and their axons, which form the pyramidal tract
- consists of neuronal cell bodies within the frontal cortex and their axons, which pass through the brainstem
pyramidal system (corticospinal system)
- motor system that includes the basal ganglia and some closely related brain stem structures
- axons of this system pass into the spinal cord outside of pyramids of the medulla
extra pyramidal system
- the apparent executive region for the initiation of movement
- primarily the precentral gyrus
- major source of axons forming the pyramidal tract
- organized as a map of the contralateral side of the body
primary motor cortex (MI)
- the strip of frontal cortex, just in front of the central sulcus that is crucial for motor control
precentral gyrus
- frontal lobe regions adjacent to the primary motor cortex that contribute to motor control and modulate the activity of the primary motor cortex
- anterior to MI
emphasizes SMA and the premotor cortex
nonprimary motor cortex
- region of nonprimary motor cortex that receives input from the basal ganglia and modulates the activity of the primary motor cortex
supplementary motor area (SMA)
- region of nonprimary motor cortex just anterior to the primary motor cortex
- activated when motor sequences are guided by external events
premotor cortex
- paralysis; the loss of the ability to move
plegia
- muscular weakness, often the results of damage to motor cortex
paresis
- an impairment in the ability to carry out complex movements, even though there is no muscle paralysis
apraxia
- neuron that is active both when an individual makes a particular movement and when that individual make the same movement
mirror neuron
- a genetic disorder, with onset in middle age, in which the destruction of nasal ganglia results in a syndrome of abrupt, involuntary writhing movements and changes in mental functioning
Huntington’s disease
- a group of forebrain nuclei, including caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres
basal ganglia
- structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement and in some forms of learning
cerebellum
- a loss of movement coordination, often caused by disease of the cerebellum
ataxia
- difficulty of movement in which gestures are broken up into individual segments instead of being executed smoothly
- symptom of cerebellar lesions
decomposition of movement
- a degenerative neurological disorder
- characterized by tremors at rest, muscular rigidity, and reduction in voluntary movement
- caused by loss of the dopaminergic neurons of the substantia nigra
Parkinson’s disease
- a brainstem structure that is a major source of dopaminergic projections to the basal ganglia
substantia nigra