Welcome to Gyrus

Dear future authors,

you can find the list of our available topics in this link.

Please note that the topics, depending on the part of the journal to which they belong, are classified into several groups in the document (sheets: Issue Topic, Topics by Sections, Editor's Choice).

In order to apply for a certain topic, please enter your personal data and your e-mail address in the appropriate columns next to the preferred topic. Afterwards contact us by e-mail on This email address is being protected from spambots. You need JavaScript enabled to view it..

In case you have your own idea and/or have come up with a different topic feel free to contact us as well!

Guidelines are available here.


The newest articles are available in "Epub ahead of print" digital form.

Feel free to access full text under the "New Issues" section in sidebar.

Issue Topic

Rhythmic variations of mood

Article by Augustin Mutak

Abstract
In this article, an overview of studies on circadian (daily), circaseptan (weekly) and circannual (yearly) variations of positive affect, negative affect and total mood is given. Studies on circadian mood rhythms, which were mostly focused on fluctuations of positive and negative affect, indicate that positive affect displays circadian variations, while negative affect does not. Such findings are linked to predictive and reactive homeostasis, respectively. The function of positive affect could be to energize the organism to be more active during the middle of the day, while the function of negative affect could be to respond to immediate threats which can appear during any time of the day. Research on circaseptan mood rhythms often also explored total mood in addition to positive and negative affect. Current findings show that mood is higher during the weekend than during the working week. It is possible that such variations are culturally determined, however, more research is needed to reach stable conclusions. Studies on circannual mood rhythms were mostly focused on seasonal affective disorder (SAD). SAD rates are highest in the winter, although a smaller number of patients report depressive symptoms during the summer months. Predictive homeostasis is also thought to be the underlying evolved mechanism responsible for SAD since SAD makes the organism less active, thus reducing the quantity of food the organism needs to consume in the winter months when the sources of food are scarce. An overview of differences between yearly fluctuations of SAD rates and suicide rates is given.
KEYWORDS:
affect, circadian clocks, circaseptan, periodicity, seasonal mood disorder

To see the full article click here.

Basic Neuroscience

What color are your letters? – an insight into synesthesia

Article by Andrea Paulik

Abstract
Tuesday is a dark shade of blue. The sound of a train tastes like strawberries. For people with synesthesia, sensations in two modalities are experienced when only one is stimulated. Synesthesia can theoretically bind any two senses and there are 60 currently known synesthetic combinations, but research has largely focused on two of the most common variants in which auditory tones and colorless numbers produce vivid colors. It is commonly said that synesthesia is an involuntary, automatic, consistent and idiosyncratic condition, meaning that it does not happen consciously and that sensations evoked by stimuli do not change over time. It also means that no two people will have the exact same experience. For scientists, synesthesia presents an intriguing problem and more research is being conducted with the sole purpose of discovering where it originates from and how it works in the human brain. There are two main competing neurological hypotheses for synesthesia: crossmodal transfer (CMT) and neonatal synesthesia (NS). CMT is based on the idea that different sensory modalities and their functions are located in separated areas or modules of the brain, which are „cross-activated“ in synesthetes. NS is based on an assumption that ordinary neural pruning in human development fails to occur, leaving the individual with an originary, synesthetic brain.
KEYWORDS:
cognitive neuroscience, crossmodal transfer, multisensory integration, perception, synesthesia

To see the full article click here.

Psychiatry & Psychology

Menstrual cycle and cognitive functions

Article by Anamaria Novak

Abstract
Menstrual cycle is characterized by fluctuations of the main ovarian sex hormones, estradiol and progesterone. Estradiol reaches its peak around day 12 of the average 28-day cycle, during the late follicular or preovulatory phase, while progesterone peaks in the mid luteal phase. In animals, estradiol has been shown to induce neurogenesis and increase spinal density in the hippocampus, as well as potentiate dopaminergic signaling in the prefrontal cortex. In women, studies have shown that sex hormones, while not effecting overall learning ability, do modulate certain cognitive functions. Most prominent of these is the preference for response strategy in 4/8 virtual maze task during early and late follicular phase, as opposed to spatial strategy, which women are statistically more likely to use during mid to late luteal phase. In addition, when tested on a verbal memory test, women in the ovulatory phase, when estradiol levels are high, recalled significantly more words during the first five trials, after interference trial and after time delay when compared to women in luteal phase of the cycle. This suggests that high estradiol levels are associated with beneficial effects on working memory, which could, in part, be explained by its agonist-like effects on dopamine signaling in prefrontal cortex. 
KEYWORDS:
cognition, estradiol, progesterone, spatial memory, working memory

To see the full article click here.

Neurosurgery

Pediatric hydrocephalus: causes, symptoms and treatment modalities

Article by Alisa Junaković

Abstract
Hydrocephalus may be defined as building up of the cerebrospinal fluid (CSF) within the brain ventricles. It can be divided into obstructive and communicating hydrocephalus or classified by etiology into congenital and acquired hydrocephalus. The patient usually presents with macrocephaly, increased irritability, headache, setting-sun sign, spasticity of the lower extremities, positive Macewen sign, and signs of increased intracranial pressure like papilledema. The most common causes of congenital hydrocephalus are malformations of the brainstem, usually aqueductal stenosis, Dandy-Walker malformation, Arnold-Chiari malformation type 1 and type 2, or agenesis of the foramen Monroi. Common reasons for developing obstructive hydrocephalus are brain tumors (medulloblastoma), intraventricular hemorrhage and subarachnoid hemorrhage. In general, hydrocephalus may develop due to obstruction of the outflow of CSF, overproduction of the cerebrospinal fluid or poor reabsorption. CT and MRI are well-known imaging techniques that are used in diagnosing hydrocephalus, including ultrasonography through the anterior fontanelle, and, less frequently, cerebral angiography. Sometimes, if X – linked hydrocephalus is suspected, genetic testing is needed. EEG is performed in the case of seizures. Most patients are treated with surgery. Medications, such as diuretics acetazolamide and furosemide, are used to postpone and delay the surgical process. The most common surgery is shunting and its purpose is to make a communication between the brain ventricles and a drainage cavity (pleura, peritoneum, right atrium). The most commonly performed are ventriculoperitoneal (VP) and ventriculoatrial (VA) shunts. The alternative to shunting is called ETV – endoscopic third ventriculostomy, whose major advantage over shunting is decreased risk for possible infections.
KEYWORDS:
cerebrospinal fluid (CSF), endoscopic ventriculostomy, intracranial pressure, neurosurgery, pediatric hydrocephalus, ventriculoatrial shunt, ventriculoperitoneal shunt

To see the full article click here.