Proprioception & Somatosensory System and Visual Processing

This set of flashcards covers essential vocabulary related to the proprioception, somatosensory, visual systems, and related brain structures.

Proprioception

The ability to know where your body is in space without looking.

Somatosensory System

How your body feels and senses the world

What are the two key receptors in proprioception?

Muscle spindles, Golgi tendon organs

What do Golgi Tendon Organs detect

muscle tension.

Mechanoreceptors

Sensory receptors that respond to touch, pressure, vibration, and texture.

Aβ fibers

Large myelinated fibers responsible for fast touch

Two Point Discrimination

A measure of spatial acuity, indicating how fine the sensory perception is in different body areas.

Nociceptors

Pain receptors that detect harmful stimuli

Otoliths

detect linear movement and head position.

Semicircular Canals

detect angular (rotational) movement.

Vestibular System

The system in your inner ear that helps with balance, head movement detection, and eye stabilization.

Cerebellum

The part of the brain that helps coordinate movement, smooth execution, and refine motor learning.

Explain Corticospinal Tract

The main pathway for voluntary movement originating from the motor cortex that crosses at the caudal medulla. ends at spinal cord, pyramidal decussation

Population Vector Coding

direction of movement is determined by the combined signals of many neurons

Contrast

The detection of differences in light intensity by ganglion cells in the retina.

Achromatopsia

A condition characterized by the loss of color vision, often due to damage in area V4 of the brain.

Visual Agnosia

Inability to recognize objects despite having clear vision

What are the 4 classes of mechanoreceptors?

Merkel = texture

Meissner = movement

Pacinian = pressure/vibration

Ruffini = stretch

How is nearsighted vision corrected?

Concave lenses that move the image back onto the retina.

Where are most of your cones located?

Fovea

What are the 3 types of eye movements and how do they differ from each other?

Saccades = fast jumps

Smooth pursuit = tracking movement

Fixation = staying still to focus

What is quiet eye?

Final steady gaze before movement

What are the differences between the otoliths and semicircular canals?

Otoliths → linear movement + head tilt

Semicircular canals → rotation

Describe VOR

Head one way eyes go the opposite way

Describe the difference between the vestibulospinal and reticulospinal pathways.

Vestibulospinal pathway, rapid corrections to balance. Reticulospinal Pathway, anticipatory posture control

What are the outputs of the basal ganglia?

Sends signals to the brainstem and motor cortex

How are the direct and indirect pathways different?

Direct= facilitates movement

Indirect = inhibits movement

What are the 3 subdivisions of the cerebellum?

Cerebrocerebellum

Spinocerebellum

Vestibulocerebellum

What are the deep nuclei and what a type of movement are each associated with?

Dentate	Planning
Interposed	Goal-directed movement
Fastigial	Balance

What is apoptosis

Programed cell death

Function of muscle spindles

Detect muscle length

What does rapidly adapting do?

Fires at start & end of movement

What does slowly adapting do

fires through the entire movement

What does the cornea do?

does most of bending

What does the lens do?

Adjusts focus

What does the retina do?

Senses light and converts it to neural signals

What does flat lens shape mean?

Far vision

What does round lens shape mean?

Near vision

What are the two main visual processing pathways?

ventral stream, dorsal stream

What does the ventral stream identify?

Objects

What does the dorsal stream identify?

Location

Right brain is in charge of

left visual field

Left brain is in charge of

right visual field

What is visual neglect?

Can’t attend to one side of space

Why is left side neglect is common?

right hemisphere controls both sides of attention

If hair bends toward kinocilium

depolarization

If hair bends away from kinocilium

hyperpolarization

Parts of the brainstem

midbrain, pons and medulla

Which of the following represents the most direct pathway for the transmission of visual information from the eye to the brain?

Photoreceptor → bipolar cell → ganglion cell→ visual cortex

The best description of the function of the lens is?

Refraction and accommodation

Function of the iris?

Regulates the amount of light entering the eye

Glaucoma of the eye results in what?

Increased ocular pressure due to reduced drainage in the aqueous humor

The spot on the retina with the highest concentration of cones is called what?

fovea

Explain how visual acuity (a sharp image) is obtained in the eye. In your answer clearly identify the main components of the eye that are involved in visual acuity.

the cornea and lens properly refract light so it focuses on the fovea

The topographic map in the primary motor cortex represents parts of the body in terms of

the precision of muscle action required

Parkinson’s disease

originates in the basal ganglia and is hypokinetic in nature

Slowly adapting cutaneous receptors detect ……. while rapidly adapting receptors detect ………..

SA detects object form and pressure, RA detects motion and vibration

What retinal neurons are specialized in detecting differences in light intensity?

Rods and Cones (Ganglion Cells)

What is myopia?

Nearsightedness

Color vision is made possible by what part of the eye?

Cones

Head tilt is detected by …

both otolith organs, the utricle and saccule 

Rank order (from fastest to slowest) the conduction velocity of the following sensory neurons: pain and temperature, proprioceptors, and touch (mechano) receptors. Justify your ordering.

Proprioceptors- Fastest (large diameter and heavily myelinated) 

Mechanoreceptors- Middle (slightly smaller diameter and myelinated) 

Pain and Temperature - Slowest (thinly myelinated)

Describe the different functions of the rods and cones.

Rods= night vision/peripheral vision, Cones= responsible for color vision

Identify a major neuronal type of the cerebellum and discuss its function, incorporating the form of this neuron in you answer.

Ganglion cells, that have no communication with the photoreceptors

What are the differences between anticipatory and compensatory (or reactive) postural control and what brainstem structures regulate these postural control systems?

Anticipatory - Proactive (prepares body for what could happen) - Reticular 

Compensatory- reactive feedback to unexpected perturbations - Vestibular

Explain why visual neglect only happens when there is damage to the right parietal lobe. 

The right parietal lobe controls attention for both left and right visual field 

Explain why elite performers are better visually based on the concept of the quiet eye. 

Because they have a better trained quiet eye 

Which cutaneous receptor in the skin is most likely to help a person to read Braille? Explain your answer.

Merkel cells: This is because they have small reactive field, meaning they have a high spatial resolution, fingertips have the highest spatial resolution in the body,

What is nystagmus?

Involuntary rhythmic oscillation of the eyes

How many cones do we have? What colors do they detect?

3, Red Green and Blue