BioPsy-Colloquium, 1 - 3 pm ct, GAFO 05/425
Katja Doerschner (Brain and Perception, Bilkent University, Ankara):The role of image motion in the perception of object qualities.
Fakultät für Psychologie
Phone: +49 234 - 32 28213
Fax: +49 234 - 32 14377
News & Views
Imagine a Mouse and an Elephant: Hemispheric Asymmetries of Imagination
Do you remember how Mowgli was dancing with Baloo on the floor of the Indian rain forest? Can you imagine one of the immortal cartoons when Asterix and Obelix where returning to their village from one of their victorious battles against the Roman army? All of these scenes have one aspect in common: The smaller person is drawn on the left, creating an ascending object sequence from left to right. After encountering much similar visualizations, psychologists from the Izmir University of Economics and from the Ruhr University Bochum pondered about the possibility that this phenomenon could be explained by the mental number line. In the mental number line numbers are represented along a left-to right-oriented continuum. Consequently, smaller object are placed on the left, creating an ascending size order from left to right. To test this idea, sixty-four participants were instructed to imagine stimulus-pairs that were staggered from those showing very prominent intra-pair size differences (e.g., elephant vs. mouse) to very low size differences (e.g., orange vs. apple). Indeed, pairs of objects were imagined with the smaller one being placed on the left. In addition, the tendency to imagine the bigger object on the right side increased directly proportional to the size difference of the two stimuli. Such a bias was also present with numbers such that the participants imagined smaller and larger numbers on the left and the right sides, respectively. Together, these findings could imply that the left-to-right orientation observed in imagined objects may share the same cognitive mechanism as the mental number line. Thus, the fact that Baloo is dancing on right side of the jungle and that Obelix walks on the right side of Asterix could reflect a common cognitive mechanism that biased the imagination of the various artists who sketched these immortal scenes with a specific orientation.
News & Views
A three-dimensional digital atlas of the starling brain
Because of their sophisticated vocal behaviour, their social nature, their high plasticity and their robustness, starlings have become an important model species that is widely used in studies of neuroethology of song production and perception. Since magnetic resonance imaging (MRI) represents an increasingly relevant tool for
comparative neuroscience, a 3D MRI-based atlas of the starling brain becomes essential. Using multiple imaging protocols, scientists from the University of Antwerp in Belgium, Université Rennes in France, and from the Biopsychology Department of the RUB delineated several sensory systems as well as the song control system. This starling brain atlas can easily be used to determine the stereotactic location of identified neural structures at any angle of the head. Additionally, the atlas is useful to find the optimal angle of sectioning for slice experiments, stereotactic injections and electrophysiological recordings. The starling brain atlas is freely available for the scientific community.
De Groof, G., George, I., Touj, S., Stacho, M., Jonckers, E., Cousillas, H., Hausberger, M., Güntürkün, O., Van der Linden, Annemie, A three-dimensional digital atlas of the starling brain, 2016, Brain Structure and Function, 221, 1899-1909.
News & Views
Farewell to Sarah Starosta
Unbelievable but true: Sarah Starosta has left the lab for a postdoc stay in New York. Sarah was an indispensable part of the Biopsychology since time being. It is very, very sad to part, but the lab of Adam Kepecs in New York is a great place to be and Sarah will certainly make the next big academic leap there. Leaving Bochum to whatever place is always sort of descend. But leaving for New York is certainly among the more acceptable options.
Hey Sarah: We will miss you a lot!!!!
News & Views
Motivational control of sign-tracking behaviour
Learning and motivation are two psychological processes allowing animals to form and express Pavlovian associations between a conditioned stimulus (CS) and an unconditioned stimulus (UCS). However, most models have attempted to capture the mechanisms of learning while neglecting the role that motivation (or incentive salience) may actively play in the expression of behaviour. There is now a body of neurobehavioural evidence showing that incentive salience represents a major determinant of Pavlovian performance. This article presents a motivational model of sign-tracking behaviour whose aim is to explain a wide range of behavioural effects, including those related to partial reinforcement, physiological changes, competition between CSs, and individual differences in responding to a CS. In this model, associative learning is assumed to determine the ability to produce a Pavlovian conditioned response rather than to control the strength and the quality of that response. The model is in keeping with the incentive salience hypothesis and will therefore be discussed in the context of dopamine’s role in the brain.
News & Views
A GABAergic Tecto–Tegmento–Tectal Pathway in Pigeons
Previous studies have demonstrated that the optic tecta of the left and right brain halves reciprocally inhibit each other in birds. In mammals, the superior colliculus receives inhibitory γ-aminobutyric acid (GABA)ergic input from the basal ganglia via both the ipsilateral and the contralateral substantia nigra pars reticulata (SNr). This contralateral SNr projection is important in intertectal inhibition. Because the basal ganglia are evolutionarily conserved, the tectal projections of the SNr may show a similar pattern in birds. Therefore, the SNr could be a relay station in an indirect tecto–tectal pathway constituting the neuronal substrate for the tecto–tectal inhibition. To test this hypothesis, neuroscientists from the Biopsychology performed bilateral anterograde and retrograde tectal tracing combined with GABA immunohistochemistry in pigeons. Suprisingly, they found out that the SNr has only ipsilateral projections to the optic tectum, and these are non-GABAergic. Inhibitory GABAergic input to the contralateral optic tectum arises instead from a nearby tegmental region that receives input from the ipsilateral optic tectum. Thus, a disynaptic pathway exists that possibly constitutes the anatomical substrate for the inhibitory tecto–tectal interaction. This pathway likely plays an important role in attentional switches between the laterally placed eyes of birds.