Sensation and Perception Flashcards

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Questions and Answers

What is the difference between distal and proximal stimuli?

Proximal stimuli directly interact with receptors to give information about a distal stimulus.

Define ganglia.

Collections of neuron cell bodies found outside the CNS, involved in transmitting sensory information to the CNS.

Identify the stimuli that each of the following receptors respond to: photoreceptors, hair cells, nociceptors, thermoreceptors, osmoreceptors, olfactory receptors, and taste receptors.

Photoreceptors: visible electromagnetic waves; Hair cells: movement of inner ear fluid; Nociceptors: painful stimuli; Thermoreceptors: changes in temperature; Osmoreceptors: osmolarity of blood; Olfactory receptors: smell volatile compounds; Taste receptors: dissolved compounds.

Define absolute threshold.

The minimum intensity at which a stimulus will be transduced to action potential. Signup and view all the answers

Define threshold of conscious perception.

Minimum intensity for stimuli to be consciously perceived by brain regions that control attention and consciousness. Signup and view all the answers

Define difference threshold.

The just noticeable difference between two stimuli; the minimum amount of change required for a person to detect a difference. Signup and view all the answers

What is Weber's Law?

There is a constant ratio between the change in stimulus magnitude needed to produce a just noticeable difference (jnd) and the magnitude of the original stimulus. Signup and view all the answers

Describe Signal Detection Theory.

Perception can be affected by non-sensory factors, such as experience, motives, and expectations. Signup and view all the answers

Describe the duplicity theory of vision.

The retina contains two kinds of photoreceptors - rods for light and dark detection, and cones for color detection. Signup and view all the answers

Where on the retina is visual acuity highest, and where is there a blind spot?

Visual acuity is best at the fovea, where there are only cones; there is a blind spot where the optic nerve leaves the eye. Signup and view all the answers

Which part of the brain is responsible for aligning the eyes with a loud, sudden noise?

Superior colliculus. Signup and view all the answers

Which cells in the eye detect shape?

Parvocellular cells. Signup and view all the answers

Which cells in the eye specialize in motion detection?

Magnocellular cells. Signup and view all the answers

Which structure of the ear is sensitive to linear motion, and which is sensitive to rotational motion?

Utricle and saccule are sensitive to linear acceleration; the three semicircular canals are sensitive to rotational acceleration. Signup and view all the answers

What are the functions of the lateral geniculate nucleus (LGN) and the medial geniculate nucleus (MGN) in the thalamus?

The LGN receives light input; the MGN receives music (auditory) input. Signup and view all the answers

Describe the place theory of sound perception.

The location of a hair cell on the basilar membrane determines the perception of pitch. Signup and view all the answers

What are the four main modalities of somatosensation?

Pressure, vibration, pain, and temperature. Signup and view all the answers

Describe the gate theory of pain.

Proposes that there is a special mechanism that can turn pain signals on or off to affect whether or not we perceive pain. Signup and view all the answers

Describe the difference between bottom-up and top-down processing.

Bottom-up is data driven, while top-down relies on memories and expectations. Signup and view all the answers

Describe Gestalt principles.

Features such as proximity, similarity, and good continuation that allow the brain to infer missing parts of an incomplete image. Signup and view all the answers

Describe the law of prägnanz.

Perceptual organization will be as regular, simple, and symmetric as possible. Signup and view all the answers

Study Notes

Sensation and Perception Concepts

Distal vs. Proximal Stimuli: Proximal stimuli are the direct interactions with sensory receptors (e.g., heat from a campfire), while distal stimuli are the actual sources (e.g., the campfire itself).
Ganglia: Clusters of neuron cell bodies located outside the central nervous system (CNS) that transmit sensory information to the CNS.

Receptive Fields and Stimuli

Types of Receptors:
- Photoreceptors: Respond to visible light waves.
- Hair Cells: Detect fluid movement in the inner ear, related to hearing and balance.
- Nociceptors: Triggered by harmful or painful stimuli.
- Thermoreceptors: Sensitive to temperature changes.
- Osmoreceptors: Monitor blood osmolarity.
- Olfactory Receptors: Respond to volatile compounds (smell).
- Taste Receptors: Triggered by dissolved substances (taste).

Sensory Thresholds

Absolute Threshold: The minimum intensity required for a stimulus to elicit an action potential.
Threshold of Conscious Perception: The lowest intensity for a stimulus to be perceived consciously by attention-related brain areas.
Difference Threshold: The smallest change in stimulus that can be detected; increases with intensity of the original stimulus.
Weber's Law: States a constant ratio exists between the change needed for a just noticeable difference (jnd) and the original stimulus magnitude.

Perceptual Theories

Signal Detection Theory: Perception influenced by non-sensory factors, including personal experiences and expectations.
Duplicity Theory of Vision: The retina has two types of photoreceptors: rods for light/dark and cones for color.

Vision and the Eye

Visual Acuity: Highest at the fovea (cone-rich area); a blind spot exists where the optic nerve exits (no photoreceptors).
Superior Colliculus: Brain region responsible for eye alignment in response to sudden loud noises.
Parvocellular Cells: Detect shapes and contribute to visual detail.
Magnocellular Cells: Specialize in motion detection.

Auditory and Sensory Systems

Utricle and Saccule: Structures in the ear sensitive to linear motion; semicircular canals detect rotational motion.
Thalamic Nuclei:
- Lateral Geniculate Nucleus (LGN): Processes visual input.
- Medial Geniculate Nucleus (MGN): Processes auditory input.

Sound Perception

Place Theory: Pitch perception is determined by hair cell location on the basilar membrane; higher frequencies vibrate cells near the oval window.

Somatosensory Modalities

Four Main Modalities: Pressure, vibration, pain, and temperature.

Pain Perception

Gate Theory of Pain: Suggests pain perception can be modulated by a mechanism that adjusts pain signal flow.

Processing Methods

Bottom-Up Processing: Data-driven approach relying on sensory input to build a perception from individual components.
Top-Down Processing: Recognizes whole objects based on memories and expectations, subsequently identifying components.

Gestalt Principles

Gestalt Principles: Include elements such as proximity, similarity, and good continuation to infer missing parts in images.
Law of Prägnanz: Perceptual organization favors simplicity, regularity, and symmetry in visual interpretation.

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Description

Test your knowledge of sensation and perception concepts with these flashcards. Learn about the differences between distal and proximal stimuli, as well as the role of ganglia in the nervous system. Ideal for psychology students seeking to enhance their understanding of sensory processes.