Levels of Sensory Processing

Somatosensory Cortex

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Attention!!

fMRI images of a subject cued to expect a stimulus in a particular portion of the visual field show right hemisphere activation in the

cingulate cortex.

What is attention??

• Traditional information processing views: Based on limits to simultaneous processing.

• Mechanisms exist to filter, gate, select or inhibit.

• Prevailing view for years: Bottleneck

• A basic conversion from massive parallel input to a limited or serial processing mode.

Sequel to information processing:

• Hi degree of parallel processing

• Flexible allocation of resources

• Attention interacts with motor output.

Along came Posner and Boies

• Attention is not a unitary phenomenon.

• Alertness or Readiness to take in information (concentration, vigilence)

• Selective Attention – search a display or an environment for a particular target.

A. SPATIAL ATTENTION (3 components). Covert and overt.

“Attentional Stimuli”

• Are responded to more rapidly

• Give rise to an increase or a decrease in neuronal responses

• Have signature ERPs (P300, N200, N400)

• Can be reported with a lower threshold of occurence

• Will be remembered better

Attentional Stimuli - continued

• Increased learning of the stimulus

• A bias to respond to that stimulus

• Note – many behavioral indications involve change in accuracy and latency. The pattern of change is taken as an indication of attention or NOT.

Impaired Response Inhibition

• Stroop

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