Attention is a complex mental process that allows individuals to focus on specific information while filtering out irrelevant stimuli. This ability is fundamental for navigating daily life, enabling effective work, learning, and interaction with the environment. Rather than being controlled by a single brain region, attention involves a sophisticated interplay of various areas working in concert.
Key Brain Regions for Attention
The prefrontal cortex, particularly the dorsolateral prefrontal cortex (DLPFC), plays a significant role in executive functions related to attention. Located in the front part of the brain, this region helps in planning, decision-making, and managing distractions, contributing to selective and sustained attention in complex tasks. The parietal lobes, found near the top and back of the brain, are also involved in attention, specifically with spatial awareness and directing attention toward objects in the environment. These lobes work with the prefrontal cortex to maintain focus and shift attention as needed.
The thalamus, a small structure deep within the brain, filters sensory input and relays it to appropriate brain areas, influencing conscious awareness of sensory information. The brainstem, particularly the reticular activating system (RAS), regulates alertness and wakefulness, helping to maintain focus and responsiveness. The subthalamic nucleus contributes to how humans redirect thoughts and attention when distracted.
The Brain’s Attentional Networks
Attention relies on distributed networks of interconnected brain regions rather than isolated areas. These networks allow for the dynamic control of attention based on current cognitive demands. Two primary networks are the dorsal attention network (DAN) and the ventral attention network (VAN).
The dorsal attention network, also known as the dorsal frontoparietal network, is primarily composed of the intraparietal sulcus (IPS) and frontal eye fields (FEF). This network mediates goal-directed, voluntary control of visuospatial attention, enabling individuals to consciously choose what to focus on. It is involved in top-down selection of stimuli and responses.
The ventral attention network, sometimes called the visuospatial attention network, is lateralized to the right hemisphere and includes the temporoparietal junction (TPJ) and the ventral frontal cortex (VFC). This network is involved in detecting unattended or unexpected stimuli and triggering shifts of attention, often described as stimulus-driven or bottom-up processing. It acts as the brain’s “radar,” helping to reorient attention to new or interesting events. While the DAN focuses and guides attention, the VAN plays a role in shifting focus between tasks and responding to unexpected cues.
Chemical Messengers of Attention
Neurotransmitters are chemical messengers that play a significant role in modulating activity within the brain regions and networks involved in attention. These chemicals influence how neurons communicate, thereby affecting attentional processes.
Dopamine
Dopamine is a neurotransmitter involved in motivation, attention, and reward processing. It helps regulate how individuals perceive and respond to stimuli, impacting their ability to sustain focus on tasks. Low levels of dopamine can impair concentration, organization, and time management.
Norepinephrine
Norepinephrine, also known as noradrenaline, affects alertness and arousal. This neurotransmitter helps the brain remain alert and responsive to stimuli. It can alter network activity in attention and working memory through arousal activation, particularly in the frontoparietal network.
Acetylcholine
Acetylcholine governs memory, learning, motivation, and attention. It is a neurotransmitter in many brain regions, influencing various cognitive processes. Fluctuations in acetylcholine levels can affect short-term memory, processing speed, and word recall.