Biomedical subjects

Eric Buckolz

Publications and source records attributed to Eric Buckolz.

11 recordsLinked to original sources

PubMed2006

The contribution of peripheral and central vision in the control of movement amplitude.

Past research has revealed that central vision is more important than peripheral vision in controlling the amplitude of target-directed aiming movements. However, the extent to which central vision contributes to movement planning versus online control is unclear. Since participants usually fixate the target very early in the limb trajectory, the limb enters the central visual field during the late stages of movement. Hence, there may be insufficient time for central vision to be processed online to correct errors during movement execution. Instead, information from central vision may be processed offline and utilised as a form of knowledge of results, enhancing the programming of subsequent trials. In the present research, variability in limb trajectories was analysed to determine the extent to which peripheral and central vision is used to detect and correct errors during movement execution. Participants performed manual aiming movements of 450 ms under four different visual conditions: full vision, peripheral vision, central vision, no vision. The results revealed that participants utilised visual information from both the central and peripheral visual fields to adjust limb trajectories during movement execution. However, visual information from the central visual field was used more effectively to correct errors online compared to visual information from the peripheral visual field.

Adolescent↗

PubMed2006

The locus and modulation of the location negative priming effect.

Responding to the location of a target is slower when it appears at a recent distractor location [ignored-repetition (IR) trial] than when it arises at a new position [control (CO) trial], defining the location negative priming (NP) effect. On IR trials, both the distractor location and response are from the prior trial, and the locus question asks whether the delayed responding that arises is caused by the reused distractor position (i.e., a location locus) or the need to execute a distractor output (i.e., a response locus). A location NP procedure was used, incorporating a many:1 location-to-response mapping design, along with a response cue on some trials. A response locus for the location NP effect was indicated. Distractor-turned-target responses took longer to initiate than new outputs (many:1 paradigm), and valid response cues reduced distractor response interference and the location NP effect. Importantly, a possible S-R compatibility problem within the many:1 S-R paradigm was not supported.

Conditioning, Operant↗

PubMed2006

Programming strategies for rapid aiming movements under simple and choice reaction time conditions.

Increases in reaction time (RT) as a function of response complexity have been shown to differ between simple and choice RT tasks. Of interest in the present study was whether the influence of response complexity on RT depends on the extent to which movements are programmed in advance of movement initiation versus during execution (i.e., online). The task consisted of manual aiming movements to one or two targets (one- vs. two-element responses) under simple and choice RT conditions. The probe RT technique was employed to assess attention demands during RT and movement execution. Simple RT was greater for the two- than for the single-target responses but choice RT was not influenced by the number of elements. In both RT tasks, reaction times to the probe increased as a function of number of elements when the probe occurred during movement execution. The presence of the probe also caused an increase in aiming errors in the simple but not choice RT task. These findings indicated that online programming was occurring in both RT tasks. In the simple RT task, increased executive control mediated the integration between response elements through the utilization of visual feedback to facilitate the implementation of the second element.

Adolescent↗

PubMed2005

Can the location negative priming process operate in a proactive manner?

The location negative priming (NP) effect refers to the fact that the processing of a current target stimulus (probe trial) is delayed when it appears at a location that has recently contained a distractor event (prime trial), relative to when it occurs at a previously unoccupied position. One view is that the process causing the NP effect involves the inhibition of the internal representation of the prime-distractor event, and that the future processing of target stimuli that involve this event are prolonged because this distractor inhibition is persistent. In this study, we examined the possibility that the NP process (inhibition) could act proactively; specifically asking whether inhibition could be allocated to a location merely predicted to hold a future distractor event. To do this, we cued the probe distractor's location using an otherwise traditional location NP paradigm. No evidence of a proactive NP process was obtained. Probe-trial target latency was the same whether it appeared at the cued distractor location or at a new location, but was delayed when it occupied the prime-distractor location (NP effect). The location NP process is seemingly a reactive one, applying inhibition only when an actual distractor is present, much as past theories have implied.

Attention↗

PubMed2004

The utilization of visual feedback from peripheral and central vision in the control of direction.

Past research has demonstrated that both peripheral and central vision play an important role in the control of movement direction. However, it has been unclear whether the benefits of these sources of information are due to adjustments in the limb trajectory during movement execution (i.e., online) or modification in motor commands prior to movement initiation (i.e., offline). In the present paper, we analyzed the variability in limb trajectories in a directional aiming task to examine the relative contributions of peripheral and central vision in both the planning and execution of movements. The point of gaze was manipulated to vary where in the limb trajectory information was gained from central and peripheral vision. Analysis of the variability in directional error at various stages of the movement revealed that participants utilized information from early in the trajectory during movement execution when it appeared in both peripheral and central visual fields. Information from late in the trajectory was used offline to improve the programming of subsequent movements regardless of where this information was available in the visual field.

Adult↗

PubMed2004

The influence of distractor-only prime trials on the location negative priming mechanism.

Two experiments were conducted that examined the influence of distractor-only prime trials on the "location" negative priming (NP) effect. In all experiments, the probe trial always lacked a distractor. We showed that the predictable absence of a probe distractor caused the elimination of the location NP effect when the prime trial contained both a target and a distractor event (T + D-->T), but not when the prime contained only a to-be-ignored distractor event (D-->T) (Milliken, Tipper, Houghton, & Lupianez, 2000). The preservation of the NP effect seen with the distractor-only prime trials (D-->T) was not the result of its lacking a prime-trial selection, nor was it the consequence of its representing a higher level of episodic similarity than the T + D-->T condition. Finally, the location NP effect observed for the D-->T condition is seemingly consistent with the view that location NP and the inhibition-of-return effects share a common underlying process (Milliken et al., 2000).

Adult↗

PubMed2004

The use of a distractor-assigned response slows later responding in a location negative priming task.

Responding to a target's location takes longer when that location has recently contained a distractor event (ignored-repetition [IR] trial) relative to when it has been unoccupied (control trial). This is known as the location negative priming (NP) effect. We aimed to determine whether the elevated reaction time observed for IR trials was due to the reuse of a distractor location (location locus) and/or to the need to execute a (just inhibited) distractor response (response locus). We isolated these loci latency effects by using many-to-one and one-to-many location-response assignments. Our results showed that reusing a distractor location hastened target processing at that position (facilitative location locus), whereas the production of a distractor response was associated with a time cost (interfering response locus). Accordingly, part of the latency elevation seen with IR trials results from the need on these occasions to execute ajust inhibited (distractor) response, and, hence, the location NP effect has a response locus.

Attention↗

PubMed2003

Children with developmental coordination disorder (DCD) and their ability to disengage ongoing attentional focus: more on inhibitory function.

Children with developmental coordination disorder (DCD), along with their Control counterparts, completed two endogenous, spatial precue tasks. When the precue arrow was informative (.80) with respect to target location, the spatial precue effect results demonstrated that children with DCD take significantly longer than Control individuals to volitionally disengage (inhibit) attention from an endogenously cued location (i.e., a disengagement inhibition deficit). When the precue was uninformative (.25), we found, contrary to a common assumption, that the precue arrow automatically moved attention in the direction of the arrow, and, in addition, that DCD children may also be less able to inhibit the precued-induced urge to move attention (i.e., an initiation inhibition deficit). This type of inhibitory difficulty was also indicated for manual response inclinations produced on catch trials. Overall, DCD children appeared to have an elevated difficulty suppressing the initiation of incorrect, stimulus-provoked movement urges, be they manual or attention in nature.

Attention↗

PubMed2002

Conflicting sources of spatial information in a distance-reproduction task.

Previous research has shown that the reproduction of a criterion distance is biased towards previously coded endpoints. The purpose of this research was to illustrate that, in addition to the retention of endpoint information, the presence of conflicting sources of spatial information within a trial causes systematic response biases in distance reproduction. Three experiments were conducted in which participants performed rapid aiming movements on a digitising tablet that translated to movement of a cursor on a computer monitor. The required movement amplitude in all three experiments was 20 cm. In experiment 1, the location of the home and target positions on the monitor was fixed, but the initial position of the hand was varied randomly from trial to trial. In experiment 2, the change in position of the limb was matched by a corresponding change in the location of the monitor display. In experiment 3, the initial position of the limb was fixed, but the location of the display on the monitor varied from trial to trial. The results of experiments 1 and 2 showed that error varied as a function of the initial position of the limb. However, this effect was greater in experiment 1, where the mapping between the location of the monitor display and limb position varied from trial to trial. There was also an effect of varying the location of the monitor display in experiment 3, but this was smaller than varying initial limb position in experiment 1. These findings suggest that both the retrieval of previously specified endpoints and conflicts in the coding of spatial information contributed to the observed response biases in distance reproduction.

Adolescent↗

PubMed2002

On the ability of children with developmental coordination disorder (DCD) to inhibit response initiation: the simon effect.

The ability of children with developmental coordination disorder (DCD) to inhibit the initiation of an incorrect manual response urge was examined using a typical Simon task. While the size of the Simon effect was the same for both DCD (N = 20) and Control (N = 20) groups of children, showing no difference with respect to the time needed to complete the inhibition an unwanted response, children with DCD produced significantly more errors of the type which reflected a reduced ability to successfully effect the inhibition operation when it was required. This result is consistent with some earlier findings pointing to an inhibitory deficit for children with DCD (Wilson & Maruff, 1999).

Child↗

PubMed2002

Influence of probe-trial selection on the location negative priming effect.

Using the location variant of the typical negative priming procedure, participants were cued (100% reliable) before (Experiment 1) or after (Experiment 2) the prime trial as to whether a distractor would or would not accompany the target on the probe trial. The crucial results were that on cued trials, the predictable absence, produced the removal of the negative priming effect (disengagement), and that this disengagement of the priming process, motivated by the predictable absence of a probe-trial distractor, could take place on-line. These findings demonstrated the "selection-state" dependency (probe trial) of the location negative priming process, supporting inhibition-based and episodic retrieval models in their contention that the ultimate function of this process is to enhance the efficiency of future distractor processing, and hence selection. The disengagement results revealed an adaptive feature of a process that can be detrimental or irrelevant to upcoming processing.

Adult↗