On the synchrony of stopping motor responses and delaying heartbeats

Development of a Classical Conditioning Task for Humans Examining Phasic Heart Rate Responses to Signaled Appetitive Stimuli: A Pilot Study

Cardiac responses to appetitive stimuli have been studied as indices of motivational states and attentional processes, the former being associated with cardiac acceleration and latter deceleration. Very few studies have examined heart rate changes in appetitive classical conditioning in humans. The current study describes the development and pilot testing of a classical conditioning task to assess cardiac responses to appetitive stimuli and cues that reliably precede them. Data from 18 adults were examined. They were shown initially neutral visual stimuli (putative CS) on a computer screen followed by pictures of high-caloric food (US). Phasic cardiac deceleration to food images was observed, consistent with an orienting response to motivationally significant stimuli. Similar responses were observed to non-appetitive stimuli when they were preceded by the cue associated with the food images, suggesting that attentional processes were engaged by conditioned stimuli. These autonomic changes provide significant information about classical conditioning effects in humans.

Listen to Your Heart: Examining Modality Dominance Using Cross-Modal Oddball Tasks

The current study used cross-modal oddball tasks to examine cardiac and behavioral responses to changing auditory and visual information. When instructed to press the same button for auditory and visual oddballs, auditory dominance was found with cross-modal presentation slowing down visual response times more than auditory response times (Experiment 1). When instructed to make separate responses to auditory and visual oddballs, visual dominance was found with cross-modal presentation decreasing auditory discrimination, and participants also made more visual-based than auditory-based errors on cross-modal trials (Experiment 2). Experiment 3 increased task demands while requiring a single button press and found evidence of auditory dominance, suggesting that it is unlikely that increased task demands can account for the reversal in Experiment 2. Auditory processing speed was the best predictor of auditory dominance, with auditory dominance being stronger in participants who were slower at processing the sounds, whereas auditory and visual processing speed and baseline heart rate variability did not predict visual dominance. Examination of cardiac responses that were time-locked with stimulus onset showed cross-modal facilitation effects, with auditory and visual discrimination occurring earlier in the course of processing in the cross-modal condition than in the unimodal conditions. The current findings showing that response demand manipulations reversed modality dominance and that time-locked cardiac responses show cross-modal facilitation, not interference, suggest that auditory and visual dominance effects may both be occurring later in the course of processing, not from disrupted encoding.

Response inhibition on the stop signal task improves during cardiac contraction

Motor actions can be facilitated or hindered by psychophysiological states of readiness, to guide rapid adaptive action. Cardiovascular arousal is communicated by cardiac signals conveying the timing and strength of individual heartbeats. Here, we tested how these interoceptive signals facilitate control of motor impulsivity. Participants performed a stop signal task, in which stop cues were delivered at different time points within the cardiac cycle: at systole when the heart contracts (T-wave peak, approximately 300 ms following the R-wave), or at diastole between heartbeats (R-wave peak). Response inhibition was better at systole, indexed by a shorter stop signal reaction time (SSRT), and longer stop signal delay (SSD). Furthermore, parasympathetic control of cardiovascular tone, and subjective sensitivity to interoceptive states, predicted response inhibition efficiency, although these cardiovascular and interoceptive correlations did not survive correction for multiple comparisons. This suggests that response inhibition capacity is influenced by interoceptive physiological cues, such that people are more likely to express impulsive actions during putative states of lower cardiovascular arousal, when frequency and strength of cardiac afferent signalling is reduced.

Topography and timing of activity in right inferior frontal cortex and anterior insula for stopping movement

Stopping incipient action activates both the right inferior frontal cortex (rIFC) and the anterior insula (rAI). Controversy has arisen as to whether these comprise a unitary cortical cluster-the rIFC/rAI-or whether rIFC is the primary stopping locus. To address this, we recorded directly from these structures while taking advantage of the high spatiotemporal resolution of closely spaced stereo-electro-encephalographic (SEEG) electrodes. We studied 12 patients performing a stop-signal task. On each trial they initiated a motor response (Go) and tried to stop to an occasional stop signal. Both the rIFC and rAI exhibited an increase in broadband gamma activity (BGA) after the stop signal and within the time of stopping (stop signal reaction time, SSRT), regardless of the success of stopping. The proportion of electrodes with this response was significantly greater in the rIFC than the rAI. Also, the rIFC response preceded that in the rAI. Last, while the BGA increase in rIFC occurred mainly prior to SSRT, the rAI showed a sustained increase in the beta and low gamma bands after the SSRT. In summary, the rIFC was activated soon after the stop signal, prior to and more robustly than the rAI, which on the other hand, showed a more prolonged response after the onset of stopping. Our results are most compatible with the notion that the rIFC is involved in triggering outright stopping in concert with a wider network, while the rAI is likely engaged by other processes, such as arousal, saliency, or behavioral adjustments. Hum Brain Mapp 39:189-203, 2018. © 2017 Wiley Periodicals, Inc.

Response Inhibition After Traumatic Brain Injury (TBI) in Children: Impairment and Recovery

Children who experience traumatic brain injury (TBI) often show cognitive impairments postinjury, some of which recover over time. We examined the recovery of motor response inhibition immediately following TBI and over 2 years. We assessed the role of injury severity, age at injury, and lesion characteristics on initial impairment and recovery while considering the role of pre-injury psychiatric disorder. Participants were 136 children with TBI aged 5-16 years. Latency of motor response inhibition was measured with the stop-signal task within 1 month of the injury and again at 3, 6, 12, and 24 months. The performance of the TBI participants at each measurement occasion was standardized with 117 children of similar age, but without injury. Residualized latency scores were calculated. Growth curve analyses showed an initial impairment in response inhibition and improvement over the 2 years following injury. Younger TBI patients were initially more impaired although they exhibited greater recovery of response inhibition than did older TBI patients. Longer duration of coma, but not reactivity of pupils or Glasgow Coma Scale score, predicted initial deficit. Lesion characteristics or pre-injury attention deficit hyperactivity disorder did not predict initial impairment or recovery. Replication with longitudinal testing of a comparison group of children sustaining extracranial injury is necessary to confirm our findings.

Mental rotation delays the heart beat: Probing the central processing bottleneck

We tested the hypothesis that mental rotation would delay response-related processing as indicated by transient slowing of the heart beat. Thirty college-age subjects (half female) were presented with normal and mirror image letters rotated at 0, 60, 120, and 180 degrees. Three letters were assigned to a right-hand response; a separate three to a left-hand response. Responses were only required for letters in one orientation, mirror or normal. Continuous measures of interbeat interval (IBI) of the heart, respiration, and muscle tension were collected. Performance results were largely consistent with prior findings. Greater angular displacement of the stimuli was associated with greater lengthening of IBI immediately after the stimulus. IBI was influenced equally by angle of rotation in respond and inhibit trials. The lengthening of IBI was interpreted as due to a delay in response selection and execution due to mental rotation.

Heart rate and sustained attention during childhood: age changes in anticipatory heart rate, primary bradycardia, and respiratory sinus arrhythmia

This study examined age changes in three aspects of heart rate responsivity elicited in an auditory oddball task; anticipatory heart rate change, primary bradycardia, and respiratory sinus arrhythmia. Three age groups (5-, 7-, and 9-year-old boys) were presented with series of target (15%) and standard (85%) tones. The results were consistent with the findings reported previously in the adult literature. Heart rate decreased in anticipation of the target tone. The morphology of anticipatory deceleration was somewhat different for the 5-year-olds compared to the older children. Stimuli presented during the early part of the cardiac cycle induced added deceleration, but this primary bradycardia did not differ between age groups. Respiratory sinus arrhythmia did not discriminate between age groups but was suppressed during the performance of the oddball task relative to base level. It was concluded that these three aspects of heart rate responsivity show developmental constancy rather than change.

Is it important that the mind is in a body? Inhibition and the heart

The hypothesis is advanced that certain inhibitory processes necessarily involve autonomic adjustments. Such adjustments would represent a constraint on information processing imposed by the location of the mind in a body. Evidence is reviewed showing that motoric inhibition is related to a transient delay in heartbeat generation. The delay is shown to further depend upon when inhibition occurs in the cardiac cycle. It is argued that this form of interaction between central and autonomic nervous system processing may be common. Central nervous system processes that may control inhibition and integrate information processing with motoric and autonomic processes are discussed.