A series of expert lectures will address the potential of brain stimulation in the field of Experimental Psychology.
|Date||30 April 2015|
|Time||14:00 - 18:00|
Several experts will discuss the current state and future directions of the field. The goal of these expert lectures is to have an in-depth discussion on the use and additional values of brain stimulation techniques in Experimental Psychology.
14.00 - 14.25 - Ilja Sligte
Enhancing visual short-term memory with electrical brain stimulation
At any instant, we are bombarded with a massive influx of visual information. For a fraction of a second, people hold on to the majority of the input in so-called iconic memory. Thereafter, only 3-4 objects can be maintained in visual working memory. In this talk, I will present data showing that iconic memory capacity can be boosted by about 10% by stimulating visual cortex (Oz) with transcranial direct current stimulation. Visual working memory can be enhanced by 8% by stimulating the parietal lobe bilaterally (P3/P4) with transcranial random noise stimulation. Thus, it seems that different forms of visual memory can be enhanced by simply flipping the switch of a low-voltage battery.
14.25 - 14.50 - Birte Forstmann
Transcranial direct current stimulation does not influence the speed-accuracy tradeoff in perceptual decision making: Evidence from three independent replication studies
In perceptual decision-making tasks, human subjects can trade the speed of their decisions for accuracy by modulating their response caution. Neuroimaging studies have shown that this speed-accuracy tradeoff is implemented in a cortico-basal ganglia network, with an important role for the pre-supplementary motor area (pre-SMA). Here we stimulated pre-SMA with anodal and sham transcranial direct current stimulation (tDCS) over FCZ to test whether subjects’ response caution, as measured with a quantitative cognitive model, can be modulated by brain stimulation. Subjects performed a cued version of the random dot motion task instructing them to respond either quickly or accurately. Individual response caution was quantified by the threshold parameter as estimated by the diffusion decision model. Using Bayesian hypothesis testing, three independent experiments revealed substantial evidence for no influence of anodal tDCS stimulation on response caution. These findings shed new light on the recent controversy surrounding the replicability of anodal tDCS (Horvath, Forte, & Carter, 2014b) and suggest that the effects of tDCS stimulation might be limited to the domain of motor execution.
14.50 - 15.15 - Dilene van Campen
Action conflict under control
Performing a goal-directed action requires one to perceive the environment and act upon changes within this environment. Sometimes, the environment automatically triggers a particular action. Response inhibition refers to the processes needed to overcome such an unwanted action. In this talk I will discuss several transcranial magnetic stimulation approaches to investigate the physiological mechanisms of the motor cortex during a conflict task and the involvement of the inferior frontal cortex.
15.15 - 15.45
Coffee and tea break
15.45 - 16.10 - Thierry Hasbroucq
Deep brain stimulation of the subthalamic nucleus
Reaction Time (RT) distribution analyses suggest that deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves impulse control in Parkinson's disease (PD) patients. We used electromyographic (EMG) methods to test this notion in the context of a classic version of the Simon task. STN DBS specifically impaired the proficiency to suppress subliminal response impulses, thereby contradicting interpretations based on RT distribution analyses.
16.10 - 16.35 - Birgit Stürmer
Processing internal and external signals for performance monitoring
We often detect our errors just because we recognize afterwards on the basis of internal signals that something went wrong during response selection. External signals, however, are also important sources of information for performance monitoring. With the present study we recorded event-related brain potentials to investigate whether relating one´s performance to external signals affects internal performance monitoring. Participants performed a cognitive conflict task in which responses were followed by emotional faces, whose expression was related to performance. Instructions given to half of the participants mentioned a relationship between their task performance and the upcoming face expression. When the instructions indicated a relation the error-related negativity (Ne/ERN) to erroneous responses was smaller and the N170 to faces was larger as compared to the not instructed group. Taken together, referring to an emotional facial expression increased processing of external signals and concurrently reduced processing of internally generated signals of performance monitoring.
16.35 - 17.00 - Wim Notebaert
Motor evoked potentials reveal automatic response tendencies in the absence of a response
Automatic motor activation on the basis of irrelevant information has been demonstrated in congruency tasks and prime-target designs by means of RT differences (faster RTs for congruent compared to incongruent trials), event-related potentials (LRPs) and recently, motor evoked potentials (increased MEP on incongruent trials for the non-response hand). In this project, we want to investigate motor activation (and the modulation of this activation) in the absence of a response or task. The blueprint for this project comes from imitation research and I will present a recent imitation study where we showed automatic motor activation in the absence of a response, and the modulation of the activation by means of instructions. I will present a second TMS study where we observed automatic motor activation on the basis of the spatial words LEFT and RIGHT, in the absence of a response, that is by passively looking at the words. I will also briefly discuss initial attempts to modulate this activation.
17.00 - 17.25 - Rogier Mars
Studying inferior frontal cortex interactions using TMS
The inferior frontal cortex (IFC) has been identified as a crucial hub in neural networks implementing cognitive control in the human brain. However, how IFC exerts its influence remains largely unknown. In the number of recent studies, we have used TMS to study how manipulating activity of IFC affects activity in other parts of the brain. We show that IFC has very specific influences on other brain regions that are highly dependent on the cognitive state of the participant. First, IFC can influence posterior sensory areas facilitating the selection of relevant loci of attention. Second, a different part of IFC influences the motor cortex during the selection and inhibition of motor responses. Third, by using a novel paired-pulse paradigm, we can strengthen the pathway between IFC and the motor cortex, which affects both the interactions between these areas as those across the wider motor network.
17.30 - 18.00