Whether you’re daydreaming at work or mindlessly checking your phone, it can feel nearly impossible to keep your attention focused on the task at hand. But like building muscle, improving focus and concentration takes time and practice.
Voluntary attention is the ability to control and consciously direct one’s focus of attention towards desired goals or objects. It is different from involuntary attention, which is triggered by salient stimuli. Both types of attention can be controlled by the nervous system, but they operate through a separate process.
Attention is an important cognitive process that involves the selection and processing of relevant information from sensory input, memory stores, and plans for action. This information is then fed into the brain networks that make decisions about what to pay attention to, and for how long.
It is believed that the neural mechanisms underlying attention are divided into two independent systems: voluntary and involuntary, also known as top-down and bottom-up processes. Both systems are necessary to perform a variety of tasks, from processing sensory input to making complex decisions.
A recent study used a predictive spatial cueing paradigm to examine the differences between involuntary and voluntary attention. Participants were asked to press a key when they saw a face appear in one of two locations, to the right or left of fixation. In blocks that required voluntary attention, the face was presented in a location that predicted where it would appear (80% probability) while in the other blocks the target appeared in a random location. Both voluntary and involuntary attention led to faster RTs, but only the former induced gamma-band responses, suggesting that the two processes operate through distinct neural mechanisms.
In addition, the study compared the effects of manipulating the availability of the neurotransmitter acetylcholine in the prefrontal cortex on these behavioral measures. A low dose of the muscarinic antagonist attenuated the cue-target association and the difference in RTs between the two conditions, but did not affect the cue-target interaction or gamma-band responses. These results suggest that the presence of acetylcholine in the cerebral cortex correlates with the ability to allocate visual spatial attention in a goal-oriented manner and that the absence of it is associated with involuntary capture of attention by salient stimuli.
The research described here was performed in the Emei music frog (Nidirana daunchina). Electroencephalographic recordings were obtained from the telencephalon, diencephalon and mesencephalon of the animals during the broadcasting of acoustic stimuli evoked by either a binary playback with silence replacement or an equiprobably random playback paradigm. The amplitudes of SPN and N1 elicited by predictable stimuli were analyzed to determine whether these peaks reflected a top-down modulation of attention by the thalamus or a bottom-up control by the mesencephalon. It was found that the SPN peaks recorded in the telencephalon during experiments recruiting voluntary attention were larger than those recorded in the mesencephalon during the same experiment, reflecting top-down control over auditory perception by thalamus-based mechanisms. The N1 peaks recorded in the mesencephalon were smaller than those in the telencephalon, consistent with a bottom-up, reflexive mechanism for capturing attention by external events. Both thalamus-based mechanisms require activation to be effective and can be modulated by attentional load. Consequently, the thalamus appears to provide an interface between the prefrontal and mesencephalic attentional network.