1. Background

The paper included many biology, psychology and neuroscience related words and phrases. The following sections provide several brief brain anatomy and attention related definitions and descriptions (note that a complete description of brain anatomy is beyond the scope of this discussion).

1.1 Attention Defined

What exactly is attention? It is used rather broadly in various contexts and is not always explicitly defined in large amount of literature related to it. This may lead to confusion, especially to those new to the field or to researchers from other disciplines (for example computer scientists!) examining the literature. So, as a first step to this discussion, attention will be defined. Naturally, the first place to obtain a definition is the dictionary! According to [14], attention is defined as follows:

the process whereby a person concentrates on some features of the environment to the (relative) exclusion of others.
the work of caring for or attending to someone or something; "no medical care was required"; "the old car needed constant attention".
a general interest that leads people to want to know more; "She was the center of attention".
a courteous act indicating affection; "she tried to win his heart with her many attentions".
the faculty or power of mental concentration; "keeping track of all the details requires your complete attention".
a motionless erect stance with arms at the sides and feet together; assumed by military personnel during drill or review; "the troops stood at attention".

As the definitions above indicate, there are several meanings of attention which are not necessarily relevant to the human attention system (e.g. 2, 3, 6). Jenkin and Harris [2] provide the following definition of attention with respect to the human attentional system:

Attention implies allocating resources, perceptual or cognitive, to some things at the expense of not allocating them to something else.

According to [9], the visual attention system involves at least the following components:

The selection of a region of interest in the visual field.
The selection of feature dimensions and values of interest.
The control of information flow through the through the network of neurons that constitute the visual system.
The shifting from selected region to the next.

Finally, the attentional system can by subdivided into two systems. The anterior attention system and the posterior attention system. The following subsections describe each of these systems in greater detail.

1.1.1 Posterior Attention System [5]

Directs attention to regions of the visual field.
Compares information in memory to the current input to try and "make sense" of it.
Involved in both implicit (or covert e.g. attention we are unaware of) and explicit (or overt e.g. attention we are aware of).
As an analogy, this attention system can be considered as a spotlight: it helps us focus on an object or group of subjects while suppressing the signals coming from everything else.

1.1.2 Anterior Attention System [5]

Responsible for the attention we are aware of., the subjective experience.
Detection of events.

1.2 Anatomy Related Definitions

1.2.1 Parietal Lobe

According to [12], the parietal lobes is involved in planning, organizing, problem solving, selective attention, personality and a variety of "higher cognitive functions" including behavior and emotions. Furthermore, it contains the primary sensory cortex which controls sensation (touch, pressure). Figure 1 [12] illustrates the location of the parietal lobe in the human brain.

Figure 1. Diagram of the Human Brain with the Parietal, Occipital and Temporal Lobes Reprinted from [brain injury link].

1.2.2 Occipital Lobe

As shown in figure 1, the occipital lobe is the region of the brain containing the visual cortex (the location where all visual information is processed). The occipital lobe is the final destination for visual information [11]. The occipital lobe is also used in the visual recognition of shapes and colors and damage to this lobe can cause visual deficits [12].

1.2.3 Superior Colliculus

The superior colliculus allows for orienting to multiple sensory stimulus [11] and concerned with where the stimulus is, not what the stimulus is. Figure 2 illustrates the location of the superior colliculus in the brain.

Figure 2. Diagram of the Human Brain with Several Vision Related Parts. Reprinted from [13]

1.2.4 Pulvinar Nucleus

The pulvinar nucleus (see figure 2), directs visual attention to some particular location, allowing for more detailed information processing at that location, essentially filtering out irrelevant information. Receives information from many other brain areas including the parietal and occipital lobes.