Salience (neuroscience)
Encyclopedia
The salience of an item – be it an object, a person, a pixel, etc – is the state or quality by which it stands out relative to its neighbours. Saliency detection is considered to be a key attention
al mechanism that facilitates learning
and survival by enabling organisms to focus their limited perceptual
and cognitive resources on the most pertinent subset of the available sensory data
. Saliency typically arises from contrasts between items and their neighborhood, such as a red dot surrounded by white dots, a flickering message indicator of an answering machine, or a loud noise in an otherwise quiet environment. Saliency detection is often studied in the context of the visual
system, but similar mechanisms operate in other sensory systems.
When attention deployment is driven by salient stimuli, it is considered to be bottom-up, memory
-free, and reactive. Attention
can also be guided by top-down, memory
-dependent, or anticipatory mechanisms, such as when looking ahead of moving objects or sideways before crossing streets. Humans and other animals cannot pay attention to more than one or very few items simultaneously, so they are faced with the challenge of continuously integrating and prioritizing different bottom-up
and top-down influences.
participates in the assessment of salience and context using past memories to filter new incoming stimulus; placing those that are most important into the long term memory. The entorhinal cortex is the pathway into and out of the hippocampus and is damaged early on in Alzheimer's disease
.
The pulvinar
(in the thalamus
) modulates physical saliency in attentional selection.
Attention
Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
al mechanism that facilitates learning
Learning
Learning is acquiring new or modifying existing knowledge, behaviors, skills, values, or preferences and may involve synthesizing different types of information. The ability to learn is possessed by humans, animals and some machines. Progress over time tends to follow learning curves.Human learning...
and survival by enabling organisms to focus their limited perceptual
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
and cognitive resources on the most pertinent subset of the available sensory data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
. Saliency typically arises from contrasts between items and their neighborhood, such as a red dot surrounded by white dots, a flickering message indicator of an answering machine, or a loud noise in an otherwise quiet environment. Saliency detection is often studied in the context of the visual
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
system, but similar mechanisms operate in other sensory systems.
When attention deployment is driven by salient stimuli, it is considered to be bottom-up, memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
-free, and reactive. Attention
Attention
Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
can also be guided by top-down, memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
-dependent, or anticipatory mechanisms, such as when looking ahead of moving objects or sideways before crossing streets. Humans and other animals cannot pay attention to more than one or very few items simultaneously, so they are faced with the challenge of continuously integrating and prioritizing different bottom-up
Bottom-up
Bottom-up may refer to:* In business development, a bottom-up approach means that the adviser takes the needs and wishes of the would-be entrepreneur as the starting point, rather than a market opportunity ....
and top-down influences.
Neuroanatomy of salience
The hippocampusHippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
participates in the assessment of salience and context using past memories to filter new incoming stimulus; placing those that are most important into the long term memory. The entorhinal cortex is the pathway into and out of the hippocampus and is damaged early on in Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
.
The pulvinar
Pulvinar
The pulvinar nuclei are a collection of nuclei located in the pulvinar thalamus. The pulvinar part is the most posterior region of the thalamus....
(in the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
) modulates physical saliency in attentional selection.
Salience in psychology
Distinctiveness, prominence, obviousness. The term is widely used in the study of perception and cognition to refer to any aspect of a stimulus that, for any of many reasons, stands out from the rest. Salience may be the result of emotional, motivational or cognitive factors and is not necessarily associated with physical factors such as intensity, clarity or size.External links
- iLab at the University of Southern California
- Scholarpedia article on visual saliency by Prof. Laurent IttiLaurent Ittithumb|right|Laurent IttiLaurent Itti is a computational neuroscientist. He received his MS in "Image Processing" from the École Nationale Supérieure des Télécommunications de Paris in 1994, and a PhD in Computation and Neural Systems from Caltech in 2000...