1 - 3 pm, GAFO 05/425, Christine Schwab (Universität Wien): Social learning and innovation in wild and captive crows.
1 - 3 pm, GAFO 05/425, Jonas Rose (Tierphysiologie, Universität Tübingen): Capacity and control of working memory.
Fakultät für Psychologie
Phone: +49 234 - 32 28213
Fax: +49 234 - 32 14377
News & Views
CATEGORIES IN THE PIGEON BRAIN: A REVERSE ENGINEERING APPROACH
Pigeons are well capable to categorize visual stimuli. Now scientists of the biopsychology adopted a reverse engineering approach to study categorization learning in a novel way. Instead of training pigeons on predefined categories, they simply presented stimuli and analyzed neural output in search of categorical clustering on a solely neural level. They presented artificial, easily distinguishable colored shapes and grating while recording from the nidopallium frontolaterale (NFL), a higher visual area in the avian brain. They computed representational dissimilarity matrices to reveal categorical clustering based on the neural data. This revealed that colored shapes and gratings were differentially represented in the brain. This study gives proof-of-concept that this reverse engineering approach – namely reading out categorical information from neural data – can be quite helpful in understanding the neural underpinnings of categorization learning.
News & Views
‘Wanting’, ‘liking’, and their relation to consciousness
Most animal and human behaviors emanate from goal-directedness and pleasure seeking, suggesting that they are primarily under conscious control. However, ‘wanting’ and ‘liking’ are believed to be adaptive core subcortical processes working at an unconscious level and responsible for guiding behavior towards appropriate rewards. Here we examine whether ‘wanting’ is an inherent property of conscious goals and ‘liking’ an intrinsic component of conscious feelings. We argue that ‘wanting’ and ‘liking’ depend on mechanisms acting below the level of consciousness, explaining why individuals often struggle to enhance or refrain their motivations and emotions by means of conscious control. In particular, hyperreactivity of subcortical ‘wanting’ systems has been tied to pathological behaviors such as drug addiction and gambling disorder. In addicts, cognitive processes intended to curb drug-seeking wage a constant battle against subcortical urges to take more drug that often ends in relapse following repeated assaults. Nevertheless, we suggest that in non-pathological contexts, ‘wanting’ and ‘liking’ interact with major cognitive processes in order to guide goal-directed actions.
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Are birds “natural split-brains”? – Anatomical analysis of the anterior commissure in pigeon
In birds which do not possess a corpus callosum the anterior commissure (AC) constitutes the main interhemispheric pathway at telencephalic level. However no detailed description of the topographic organization of the AC has been performed till now. This information is not only necessary for a better understanding of interhemispheric transfer in birds, but also for a comparative analysis of the evolution of commissural systems in the vertebrate classes. Therefore researchers from the Biopsychology Department examined the fiber connections of the AC. The main differences in the interhemispheric connectivity between birds and mammals are found at two levels of structural organization. First, the AC in birds differs from the corpus callosum and the AC of mammals in its proportion of homotopic reciprocal to heterotopic unidirectional projections. In contrast to the situation in mammals, in birds only a small amount of cells interconnect the two hemispheres in a homotopic and reciprocal fashion. Instead, most of the cells project heterotopically and in unidirectional manner. Second, in birds the absolute majority of pallial areas do not participate by themselves in interhemispheric exchange. Instead, a rather small cluster of cells is key for commissural interactions. Thus, the colloquial statement that birds are “natural split-brains” is wrong, when the pallial areas are considered that interhemispherically interact via the AC. It is true, however, when taking into account how small the proportion of pallial neurons is that constitutes interhemispheric exchange.
News & Views
The Circuitry of Hunger and Sleep
Serotonin 1A receptors play a key role in eating and sleeping. Their combined action explains why we get sleepy after a good meal. But what is the circuitry of this system? To analyze that in birds, scientists from Brazil and Germany (Bochum and Düsseldorf) joint forces and revealed the distribution of 5-HT1A receptors in the hypothalamus and brainstem of birds and analyzed their potential roles in sleep and feeding. 5-HT1A receptors are concentrated in brainstem areas like periventricular hypothalamus, preoptic nuclei and circumventricular organs that receive dense serotonergic projections. Delivering of ventricular serotonin produced a complex pattern of neuronal activations in the 5-HT1A receptor-enriched preoptic hypothalamus and the circumventricular organs, which are related to drinking and sleep regulation, but only modestly affected the activity of serotonergic neurons themselves. The same procedure induced feeding and sleeping. Further detailed experiments revealed that serotonin induces feeding and sleeping by presynaptic binding to 5-HT1A receptors that are localized in periventricular diencephalic circuits.
dos Santos, T. S., Krüger, J., Melleu, F. F., Herold, C., Zilles, K., Poli, A., Güntürkün, O., Marino-Neto, J., Distribution of serotonin 5-HT1A-binding sites in the brainstem and the hypothalamus, and their roles in 5-HT-induced sleep and ingestive behaviors in rock pigeons (Columba livia), Behav. Brain Res. 2015, 295: 45-63.
News & Views
Cryptochrome 1b - A possible inductor of visual lateralization in pigeons?
The visual system of adult pigeons shows a lateralization of object discrimination with a left hemispheric dominance on the behavioural, physiological and anatomical levels. The crucial trigger for the establishment of this asymmetry is the position of the embryo inside the egg, which exposes the right eye to light falling through the egg shell. As a result, the right-sided retina is more strongly stimulated with light during embryonic development. However, it is unknown how this embryonic light stimulation is transduced to the brain as the classic photoreceptors, rods and cones, are not yet functional. Scientists from the biopsychology department now identified a photoreceptive protein inside the retina of pigeons which is also expressed during the critical phase of asymmetry induction. This protein, Cryptochrome 1b, is expressed in retinal ganglion cells. A tracing study revealed that such Cryptochrome 1b containing ganglion cells project to the optic tectum, a primary visual area in the pigeon brain. The projection pattern and the presence of Cryptochrome 1b during the critical phase of asymmetry induction suggests that Cryptochrome 1b could indeed be the missing photoreceptive instance responsible for inducing asymmetries in the visual system of pigeons.