ATTENTION

Attention: the process by which certain information is selected for further processing and other information is discarded.

• Reasons why we pay attention:

o The stimulus grabs our attention (bottom-up) → attention is involuntarily captured by external stimuli

(REFLEXIVE/EXOGENOUS attention).

o We are actively searching for it (top-down) → attention is voluntarily directed according to our goals and

thoughts (VOLUNTARY/ENDOGENOUS attention).

SELECTIVE ATTENTION

Selective attention: the process of picking out and maintaining focus on a particular quality, object, or event, and ignoring

other stimuli or characteristics of the stimuli due to limited capacity to process all information.

• OVERT attention: when the focus of attention corresponds with eye fixation and with what is suggested by

posture and head movements.

o Voluntary (top-down) attention: attention driven by current goals & behaviors

o Reflexive (bottom-up) attention: attention driven by a stimulus

• COVERT attention: the focus of attention is not accompanied by eye or head movements.

ANATOMY OF ATTENTION

Cortical regions:

• FRONTAL LOBE: ventral and superior prefrontal cortex. Maintaining vigilance

• PARIETAL LOBE: representation of spatial information, involved in top-down

attention control of spatial orientation.

• FRONTOPARIETAL NETWORK: reorienting attention.

Subcortical regions involved in attention

• SUPERIOR COLLICULUS: involved in directing eye-movement.

ATTENTION DEFICITS

Balint’s syndrome: only one or a small subset of available objects is perceived at the same time, although

patients can see each object when presented individually.

• Caused by bilateral damage to posterior parietal and occipital cortices.

• Problems with object based attention (rather than spatial atten tion as in the case of neglect).

Hemispatial neglect (neglect): reduced attention to one (usually left) side of the scenes and objects, as though they do not

exist. Affects the side contralateral to the side of damage.

• Typically caused by damage to the right parietal regions .

• Inaccurate determination of midline (line cancellation/bisection test).

• Applies to both external and internally generated (e.g., memory

representations) objects and scenes.

• Patients are usually unaware of their abnormal condition.

• A disorder of attention, not low-level perception.

o Still activates visual regions in occipital lobes that they claim not to be aware of.

o They are often able to detect objects on the left if cued there (and can improve in the long run).

o Affects auditory and tactile judgments, not only vision.

ATTENTION CONTROL NETWORKS

DORSAL (FRONTO-PARIETAL) attention network

• Frontal and parietal areas.

• Concerned primarily with the control of spatial attention.

• Involved in voluntary attention to goal-directed locations and targets.

VENTRAL attention network

• Temporoparietal junction and ventral frontal cortex.

• Involved in stimulus-driven control (e.g., attending to unexpected stimuli) that is

needed for disengaging and re-orienting attention to attend to novel stimuli.

ATTENTION TESTS

• Attentional Capacity: WAIS Digits Span Forward/ Backward

• Working memory/Mental tracking: WAIS Digits Span Backward

• Concentration/Focused Attention: Stroop

• Divided Attention: Trail Making Test