Page 32 - JCBP-2-2

Journal of Clinical and
Basic Psychosomatics Cognitive modulation of baroreceptor afferents

into interoceptive neural signals and regulate blood reporting that cardiac systole (baroreceptor activation)
pressure through a negative feedback mechanism known selectively inhibits automatic responses that involve little
as the baroreflex. Reduced baroreflex function has been cognitive control but facilitates complex sensorimotor
3,4
observed in cardiovascular disease (CVD), Parkinson’s responses that require top-down resources and attentional
disease, spinal cord injury, and depression. Moreover, control. 24,25 Specifically, in a task involving sensorimotor
5-8
baroreceptor dysfunction may serve as a mechanism incompatibility and multi-sensory stimuli, baroreceptor
through which depression contributes to CVD. 9,10 afferents inhibited incompatible responses to auditory

The somatic symptoms of such diseases influence stimuli but, surprisingly, facilitated compatible responses,
cognition through the afferent pathway of cardiovascular and Larra et al. (2020) attributed these findings to the
activity. The interceptive neural signals generated by suppression of residual activation in response to auditory
25
baroreceptor activation inhibit information processing stimuli in the cerebral hemisphere. This explanation
at cortical levels. Specifically, during cardiac systole, was further supported by the null results in the trials
11
25
the blood enters the aorta and activates baroreceptors, with tactile stimuli. Adelhöfer et al. (2020) found that,
which are encoded by the nucleus solitary tract (NST) in an emotional Stroop task, frontal EEG was influenced
and decrease the efficiency of sensory input processing. by baroreceptor afferents in congruent trials but not in
Conversely, during cardiac diastole, baroreceptors keep incongruent trials, providing further insight into the
24
quiescent, exerting no influence on central processing. effects of task complexity. As such, cognitive demanding
12
This mechanism is mediated by the autonomic nervous elements in a task may override the neuromodulation
system (ANS) and contributes to the integration of ANS effect of baroreceptor afferents. 24
control and cognition. In healthy individuals, fluctuations Under mental workload, cognitive resources are
in interoceptive states help in coping with environmental influenced by the underlying processes related to working
demands, optimizing cognitive processes and behavior. In memory (WM). 26,27 WM is a psychological construct that
13
contrast, unstable blood pressure, tachycardia, and altered describes the mental process of holding information in
circulatory system functioning linked to ANS dysregulation conscious storage and manipulating it. 28,29 Loading WM
contribute to the negative outcomes of mental disorders, by a concurrent task taxes cognitive resources, which
including anxiety, phobia, and depression. 1,2,9,10 would resemble a complex sensorimotor task (e.g.,
In laboratory assessments, cortical inhibition by incongruent Stroop trials and sensorimotor incompatible
baroreceptor afferents manifested as cardiac cycle time tasks). In WM processes, the dorsolateral prefrontal cortex
effects on sensorimotor processing. In general, response (DL PFC) is activated for cognitive regulation of sensory
speed (often indicated by reaction time [RT]) is faster when processing. 26,27,30,31 Prior studies suggest the important role
the stimulus is delivered at cardiac diastole as compared of the DL PFC in cognitive control of bottom-up, automatic
to systole. 14-16 Notably, RTs vary as a linear function of information processing. 26-32 Therefore, it is possible that
the temporal location of the stimulus in a cardiac cycle. different levels of WM load, associated with various
17
Physiologically, baroreceptors activate during the time specific task requirements in sensorimotor processing, may
window of 90–390 ms after the electrocardiography contribute to the modulation of response requirements
(ECG) R-wave, with their peak afferent neural output and complexity on cardiac cycle time effects, 24,25 given that
lasting approximately 250 ms. Accordingly, to induce concurrent WM load decreases cognitive resources linked
16
cardiac cycle time effects, stimuli are typically delivered to DL PFC.
around 250–300 ms (the early cardiac cycle phase, or Further, in sensorimotor tasks, mean and median RTs
cardiac systole) and 500–550 ms (the late cardiac cycle have been traditionally used as the metrics for response
phase, or cardiac diastole) after the ECG R-wave in studies speed. However, these metrics fail to capture trial-by-trial
manipulating cardiac timing. 16-19 RT variability, 33,34 which may mask potential cardiac timing
35
While cardiac cycle time effects have been observed effects on sensorimotor processing. One way to overcome
in various sensorimotor tasks, a wide range of factors has the limitation of the traditional metrics of response speed
been found to modulate these effects, including stimulus is ex-Gaussian modeling that teases responses with very
characteristics and experimental design, resulting in long RTs (the exponential tail of the RT distribution)
inconsistent findings. 20-23 Therefore, an essential step apart from faster responses in the Gaussian (normally
toward establishing cardiac timing effects as an easy distributed) portion. 36,37 In particular, the proportion
and effective assessment of baroreceptor function is of slow responses, estimated with the parameter tau (τ),
identifying factors that may influence these effects. One is believed to indicate top-down, effortful attentional
such factor is response complexity, with recent studies processes. 38,39 Conversely, parameters mu (μ) and sigma

Volume 2 Issue 2 (2024) 2 https://doi.org/10.36922/jcbp.2248