Neuropsychology chapter 5

adaptation

________ is desensitization, the process by which receptors show a progressive decrease in sensitivity.

receptive fields

The ________ are the regions in which a stimulus will alter a sensory neuron's fighting rate.

Stimulus intensity

________ can be encoded by the number and threshold of activated cells.

Meissner

_______ and Pacinian corpuscles are phasic receptors; they respond immediately but stop responding unless there is a change in the stimulus.

S1 cells

________ are arranged as a map of the body; a sensory homunculus.

physical event

A(n) ________ that triggers a sensory response.

association areas

they hold polymodal neurons that hold different neurons and allow them to interact.

Mechanoreceptors

they detect mechanical sensations: differences in pressure.

receptor cells

Molecules that can bind to hormones, drugs, and antigens.

receptor cells

Can sense some stimuli, but not others. Specialized.

stimulus

A physical event that triggers a sensory response.

labeled lines

Tiny receptors all over the body, how the body senses touch

receptor cells

They sort of act as filters, ignoring background noise and converting the stimuli into electrical signals.

labeled lines

We have very distinct ___________, and each sensory receptor has its own pathway up to the brain

Pacinian corpuscles

Skin receptors that respond to vibration and pressure. Located deep in the skin, in the hypodermis layer. Since it's deeper, it needs stronger stimuli like a push or poke

Maisner's corpuscles

Perceives the form of objects that we touch. More sensitive, on the top layer of skin. Responsible for light touch, aware when you brush lightly against something or when you put on a light t-shirt. They need constantly changing stimuli to make you aware of sensations.

receptor cells

Converts energy into a change in the electrical potential across its membrane.

Merkel’s discs

Specialized skin cells, respond to indentations of the skin like poking. Adapts slowly to pressure, record sustained pressure, aka stimuli that are present for longer. More sensitive to touch, at the base of the epidermis but still near the top layer of skin.

Ruffini’s corpuscles

Perceive stretching of the skin when we move. Near the bottom layer of the skin.

Free nerve endings

2 different types, thermoreceptors and nociceptors.

free nerve endings

Thermoreceptors have 2 different types of _______ for perceiving hot and cold.

95, 77, 41

Cold receptors kick in when the temp is under ______ degrees, most stimulated at ______, and turn off at ______ degrees.

86, 113

Hot receptors perceive above _____ degrees, most stimulated at _____ degrees but beyond that pain receptors will take over in order for damage to be avoided to skin.

stimulus

The location of a _____ is determined based on a map-like representation of the position of the activated receptors.

specificity

When poking close spots together without looking, it feels like one poke; when they go farther apart, we notice them as two spots. In order to get ______ in a receptive field, anything outside of the field is inhibited and doesn't fire so that you know exactly where a stimulus was touching you.

sensory adaptation

Stimulus intensity can be encoded by the number and threshold of activated cells. If there are a lot, you’re aware of them. With higher intensities, other sensory neurons are recruited.

adaptation

We can't perceive everything that we are sensing all the time.
_____ is desensitization, the process by which receptors show a progressive decrease in sensitivity.

phasic receptors

The type of receptors that adapt very quickly to the stimulus. Decreases the frequency of action potentials firing. The stimuli are still there, but we stop firing because it is not important.

phasic receptors

Lets us know when there are changes in sensory stimuli, gives us the ability to stop paying attention to constant stimuli like temperature or smells.

tonic receptors

Keeps constant the frequency of action potentials firing.

nociceptors

What type of nerve endings are used for pain detection?

accurate

Sensory systems often shift away from _____ portrayals of reality in order to function; otherwise, you’re overloaded. Noting changes can be more important than exactness.

Central modulation of sensory modulation

When your brain is actively focusing on certain inputs and ignoring others. The cortex and the thalamus are involved in this.

Somatosensory system

We have distinct pathways from sensory receptors that lead from the periphery to the central nervous system.

Dorsal column system

Responsible for delivering touch information. Receptors send axons via the dorsal spinal cord to synapse onto neurons in the brainstem.
Once in the brainstem, they cross the midline and go to the thalamus.

primary sensory cortex

One exists for each modality

nonprimary sensory cortex

Receives direct projections from the primary sensory cortex for that modality

Primary somatosensory cortex (S1)

In the postcentral gyrus. On each hemisphere of the brain that processes touch information from the opposite side of the body.

Primary somatosensory cortex (S1)

Arranged as a map of the body, a sensory homunculus.
We have receptors that help us perceive information, but one type is almost never activated alone; things work in tandem.

sensory homunculus

the imaginary map of neurological connections based on sensory processing

association area

cortical areas that are neither motor or sensory but are thought to be involved in higher processing of information

A delta fiber

Thick and large, myelinated (coated with myelin) axons that register pain. Conducts quickly.

C fiber

Thin and small unmyelinated axons that conduct more slowly. Produces pain.

Anterolateral system (spinothalamic system)

An ascending somatosensorial tract that carries pain and temperature information from the skin to the brain.

Substance P

Peptide that boosts pain signals.

axons

Nerve fibers send _____ into the dorsal horns of the spinal cord.

glutamate

an excitatory substance that is released alongside substance P to boost pain signals and remodel neurons.

cingulate

Pain information is integrated into the _____ cortex.

analgesia

absence of the sense of pain without loss of consciousness

afferent nerves

the axons carried by a sensory nerve that relay sensory information from sensory receptors to regions of the brain. Afferent projections arrive at a particular brain region.

the spinal cord contains a neurological 'gate' that either blocks pain signals or allows them to continue on to the brain

gate control theory

motor plan

a set of muscle commands that we establish before a behavior happens

hierarchy of motor control

1. Skeletal system and attached muscles determine movements
2. Spinal cord controls skeletal muscles
3. The brain stem integrates motor commands
4. Primary motor cortex initiates commands
5. Nonprimary cortex is an additional source for commands
6. Cerebellum and basal ganglia modulate activities via thalamus

synergists

Muscles that act together to move a limb are _____

McGill pain questionnaire aspects of pain

1. Sensory/discriminative
2. Motivational/affective
3. Cognitive/evaluative

Antagonistic muscles

when one muscle contracts, the other stretches

striate muscle

Striped muscles in the skeleton, given appearance by myosin and actin

Most muscles contain a mix of ____ and _____ fibers

fast twitch and slow twitch fibers

fast twitch fibers

contract rapidly but fatigue easily

slow twitch fibers

contract slowly but fatigue slowly

motoneurons

In the spinal cord and brain stem, send action potentials down axons to innervate muscles

motor unit

motor neurons axon and all of its target fibers

motor neuron

_____ are the most common way the brain and spinal cord control muscles

proprioception

the ability to sense the position and location and orientation and movement of the body and its parts

two

How many kinds of proprioceptors?

muscle spindle

A _____ is a capsule that is buried in other muscle fibers. Detects changes in muscle length. A type of proprioception.

golgi tendon organ

Provides us with sensory signals that monitors the force that is generated by a contracting muscle. A type of proprioception.

pyramidal system

Conscious control of muscles from the cerebral cortex to the muscles of the body and face.

hand and jaws

Which two areas take up the most space in the primary motor cortex?

extrapyramidal system

Originate in the brainstem, carrying motor fibers to the spinal cord. They are responsible for the unconscious, reflexive or responsive control of musculature like muscle tone and balance.

somatosensory

the senses of the body

tracts

collections of axons