Sensation And Perception Flashcards
Perception
The processing of information to make sense of its significance
Sensory receptors
Neurons that respond to stru uni and trigger electrical signals
Ganglia
Collection of neuron cell bodies found outside of the CNS
Once transduction occurs, what happens to the electrical chemical energy ?
It is sent along neural pathways to various projection areas in the brain, which further analyze the sensory input
Photoreceptors
Respond to electromagnetic waves in the visible spectrum (sight)
Hair cells
Respond to movement of fluid in the inner ear structures (hearing, rotational and linear acceleration)
Nociceptors
Respond to painful or noxious stimuli (somatosensation)
Thermoreceptors
Respond to changes in temperature (somatosensation)
Osmoreceptors
Respond to osmolarity of the blood (water homeostasis)
Olfactory receptors
Respond to volatile compounds (smell)
Taste receptors
Respond to dissolved compounds (taste)
Threshold
The minimum amount of stimulus that renders a difference in perception
(3) types of threshold
Absolute threshold
Threshold of conscious perception
Difference threshold
Absolute threshold
The minimum of a stimulus energy that is needed to activate a sensory system
Threshold of conscious perception
The minimum of stimulus energy that will create s signal large enough in size and long enough in duration to be brought into awareness
The difference between the absolute threshold and the threshold for conscious perception is:
A stimulus below the absolute threshold will not be transduced, and thus never reaches the central nervous system
Difference threshold or just-noticeable difference (jnd)
Minimal difference in magnitude between two stimuli before one can perceive this difference
Weber’s law
States that the jnd for a stimulus is proportional to the magnitude of the stimulus and that this proportion is constant over most of the range of possible stimuli
In the MCAT it simply amounts to applying a ratio
(1000 Hz and 1006.8 Hz (0.68% of 1000 Hz)
Signal detection theory
The effects of non sensory factors (such as experiences, motives and expectations) on perception of stimuli
Signal detection theory allows us to explore _______
Response bias
Response bias refers to ?
The tendency of subjects to respond to a stimulus in a particular way due to nonsensory factors
Signal detection experiment consists of:
Many trials
During each trial, a stimulus (signal) may or may not be present
Signal not presented = noise trial
Signal present = catch trial
4 possible outcomes:
Hit: subject correctly perceived the signal
Misses: subject fails to perceive s given signs,
False alarms: subject seems to perceive a signal when non was given
Correct negatives: subject correctly identifies that no signal was given
Adaptation
A decrease in response to a stimulus over time
Pathway for a stimulus to reach conscious perception?
Sensory receptor ➡️ afferent neuron ➡️ sensory ganglion ➡️ spinal cord ➡️ brain
Sensation
The conversion or transduction of physical, electromagnetic, auditory and other information for the internal and external environment into electrical signals in the nervous system
Performed by receptors in the PNS
