Salience (neuroscience)

This article is about salience in cognitive neuroscience. For other uses, see Salience.

The salience (also called saliency) 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 attentional 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.

Neuroanatomy of salience

The hippocampus 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.^{[citation needed]}
The pulvinar (in the thalamus) 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.

See Also

Latent Inhibition

External links

• Itti L, Koch C (March 2001). "Computational modelling of visual attention". Nat. Rev. Neurosci. 2 (3): 194–203. doi:10.1038/35058500. PMID 11256080. 
• iLab at the University of Southern California
• Scholarpedia article on visual saliency by Prof. Laurent Itti