Psychology condense 1 . Sensory Perception and Thresholds

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Questions and Answers

What is the function of basilar tuning in the cochlea?

It amplifies sound waves before they reach the auditory cortex.

It allows the brain to distinguish between different frequencies of sound. (correct)

It is responsible for the sensation of balance.

It converts sound waves into electrical impulses.

Which type of somatosensation is associated with detecting changes in body position?

Proprioception (correct)

Mechanoreception

Thermoception

Nociception

What describes the phenomenon where receptors cease firing in response to a constant stimulus?

Neural downregulation

Pain modulation

Sensory adaptation (correct)

Sensory amplification

Why is the somatosensory homunculus significant for neurosurgeons?

It allows surgeons to precisely locate and stimulate sensory areas in the cortex. Signup and view all the answers

What is the role of primary auditory cortex in hearing?

It receives auditory information and is sensitive to specific frequencies. Signup and view all the answers

What happens to bipolar cells when glutamate is no longer released?

They turn on. Signup and view all the answers

Which type of photoreceptor is more sensitive to light?

Rods Signup and view all the answers

Where are cones primarily concentrated in the eye?

Fovea Signup and view all the answers

What is the primary function of the magnocellular pathway?

High temporal resolution Signup and view all the answers

What is the role of rhodopsin in rods?

Triggers the phototransduction cascade Signup and view all the answers

How does the brain process visual fields?

Left visual field goes to the right side of the brain Signup and view all the answers

What occurs due to the lack of rods and cones at the blind spot?

No visual perception in that region Signup and view all the answers

What structure is essential for converting light into neural impulses?

Photoreceptor Signup and view all the answers

What happens to the endolymph when a person stops moving?

It continues moving, causing dizziness. Signup and view all the answers

What does the variable 'd'' in Signal Detection Theory represent?

Strength of the detected signal Signup and view all the answers

Which part of the electromagnetic spectrum includes visible light?

Between infrared and ultraviolet rays Signup and view all the answers

What is the primary purpose of rods in the retina?

Facilitating night vision Signup and view all the answers

What initiates the phototransduction cascade in rods when light hits them?

Change in retinal conformation Signup and view all the answers

During phototransduction, what happens to the Na+ channels as cGMP levels decrease?

They close, leading to hyperpolarization. Signup and view all the answers

Which type of cone is NOT one of the three types present in the human retina?

Yellow cones Signup and view all the answers

What is the role of transducin in the phototransduction cascade?

It binds to phosphodiesterase. Signup and view all the answers

What causes sound waves to be created in the air?

The movement of air molecules under pressure Signup and view all the answers

What part of the ear is responsible for transferring vibrations to the cochlea?

Tympanic membrane Signup and view all the answers

Which component of the inner ear is crucial for hearing?

Cochlea Signup and view all the answers

What is the purpose of the hair cells in the cochlea?

To convert mechanical vibrations into electrical signals Signup and view all the answers

During the process of hearing, what happens when the stapes vibrates?

It pushes the fluid in the cochlea Signup and view all the answers

What is the main function of binocular cues in visual perception?

To detect depth and distance Signup and view all the answers

What role do the kinocilia play in the auditory process?

They convert K ion flow to an action potential Signup and view all the answers

What distinguishes low frequency sounds from high frequency sounds in the auditory system?

The response of different hair cells in the cochlea Signup and view all the answers

Which of the following describes the phenomenon where our perception of an object does not change despite its appearance on the retina?

Constancy Signup and view all the answers

What prevents fluid from returning to the oval window after passing through the cochlea?

The organ of Corti's structure Signup and view all the answers

How does the vestibular system primarily contribute to our perception?

By influencing spatial orientation and balance Signup and view all the answers

What does Weber's Law state about the relationship between the just noticeable difference (JND) and the intensity of a stimulus?

JND is directly proportional to the original stimulus intensity Signup and view all the answers

What is the absolute threshold of sensation?

The minimum intensity of stimulus detectable 50% of the time Signup and view all the answers

Which of the following examples would illustrate sensory adaptation?

Noticing a faint smell that fades over time Signup and view all the answers

What role do the otolithic organs play in the vestibular system?

They facilitate the perception of linear acceleration and head positioning Signup and view all the answers

Which of the following best describes motion parallax?

The apparent movement of objects at different distances when the observer moves Signup and view all the answers

Which statement best describes the role of binocular cues in depth perception?

They require both eyes to assess spatial position through retinal disparity and convergence. Signup and view all the answers

What is the main function of sensory adaptation?

To reduce the perception of constant stimuli over time. Signup and view all the answers

How does Weber's Law relate to the perception of weight differences?

It states that the just noticeable difference is a constant percentage of the original weight. Signup and view all the answers

What factors can influence the absolute threshold of sensation?

Previous experiences and environmental variables. Signup and view all the answers

What occurs in the rods when light hits them during the phototransduction cascade?

Rods hyperpolarize and turn off Signup and view all the answers

What is the function of the variable 'c' in Signal Detection Theory?

It refers to the decision-making strategy used Signup and view all the answers

Which of the following describes the role of transducin in the phototransduction cascade?

Transducin binds to phosphodiesterase to influence cGMP levels Signup and view all the answers

Which type of photoreceptor is primarily responsible for visual acuity and color vision?

Cones, which detect bright light and color Signup and view all the answers

What happens to the Na+ channels in rods when cGMP levels decrease during light exposure?

The Na+ channels close, reducing Na+ influx Signup and view all the answers

Study Notes

Sensory Perception

Visual cues include depth, form, motion, and constancy
Binocular cues: retinal disparity (eyes are 2.5 inches apart) and convergence (eyes contract for close objects, relax for distant ones)
Monocular cues: relative size, interposition (overlap), relative height (higher objects appear farther away), shading and contour, and motion parallax (objects farther away move slower)
Sensory constancy: our perception of objects remains constant, even if images on the retina change (e.g., size, shape, color).
Sensory adaptation: receptors desensitize to constant stimuli (e.g., hearing, touch, smell, sight).

Weber's Law

Weber's Law: the ratio of the just noticeable difference (JND) to the intensity of the stimulus is constant (ΔI/I = k).
A 2.05 lb vs. 2 lb weight difference is not noticeable, while a 2.2 lb vs. 2 lb difference is noticeable.
Threshold for change in sensation depends on existing stimulus intensity.

Absolute Threshold

Absolute threshold: minimum intensity of a stimulus needed to detect it 50% of the time.
Factors that influence absolute threshold: expectations, experience, motivation, and alertness.
Subliminal stimuli: stimuli below the absolute threshold of awareness.

Vestibular System

Plays a role in balance and spatial orientation.
Semicircular canals (posterior, lateral, and anterior) detect head rotation, using endolymph in canals. Movement of endolymph causes hair cells to fire.
Otolithic organs (utricle and saccule) detect linear acceleration and head positioning, using Ca crystals. Movement of Ca crystals causes hair cells to fire.

Signal Detection Theory

Used in situations with uncertainty (e.g., discerning important stimuli from background noise).
Variables include signal strength (d') and decision strategy (c). Conservative strategy avoids false alarms (misses are acceptable). Liberal strategy prioritizes true positive, allowing more false alarms.

Bottom-Up and Top-Down Processing.

Bottom-up processing: sensory information influences perception.
Top-down processing; background knowledge influences perception.

Gestalt Principles

The brain groups similar items together.
Reality is often simplified to a most basic form.
Grouping nearby objects
Grouping objects in smooth lines
Objects grouped to be a recognizable whole

Structure of the Eye

Cornea: transparent outer layer that bends light.
Aqueous humor: nourishes eye and maintains pressure.
Pupil and Iris: control the amount of light entering the eye.
Lens: adjusts focus.
Vitreous Humor: jelly-like substance that fills the space behind the lens.
Retina: Contains photoreceptors (cones and rods).
Optic nerve: transmits visual information to the brain.
Macula: contains cones for detailed vision.
Fovea: central part of the macula with the highest concentration of cones for sharp vision.

Phototransduction Cascade

Cones and rods convert light into neural impulses.
Different types of cones detect different colours
Rods are more sensitive for low-light conditions.
11-cis retinal changes shape when light hits it, activating a cascade of events that ultimately lead to hyperpolarization or depolarization.

How the eye works

The photoreceptors (rods and cones), in the retina convert light into a signal.
The brain interprets the signal as images.
Cones detect color vision.
Rods are more sensitive in low-light conditions.
The phototransduction cascade converts light into neural impulses in the photoreceptors.
3 types of cones, and rod detect intensity of light stimulus.

Auditory System

Sound waves are converted into neural signals.
Hair cells on the basilar membrane transduce vibrations into neural signals. Vibrations of the oval window make the basilar membrane vibrate, moving hair cells.
The auditory pathway relays signals from the inner ear to the brain.

Auditory Processing.

Frequency-dependent activation of hair cells across the basilar membrane. Higher frequencies activate hair cells near the base.

Somatosensation

Different types of somatosensation such as touch, temperature, pressure, and position (proprioception).
Somatosensory neurons transmit signals to the brain.
Adaptation: Receptors adapt to constant stimuli over time. Example: receptors in skin adapt to a constant pressure.
Amplification: increase sensitivity, by multiple firings in response to stimuli.

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Description

Explore essential concepts in sensory perception, including visual cues such as binocular and monocular cues, sensory constancy, and sensory adaptation. Additionally, delve into Weber's Law and the absolute threshold for sensation. Enhance your understanding of how we perceive the world around us.