TR Dizin İndeksli Yayınlar Koleksiyonu / TR Dizin Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14365/4
Browse
4 results
Search Results
Article Citation - Scopus: 2Behavioral Immune System and Trypophobia(Klinik Psikiyatri Dergisi, 2022) Ozturk, Suleyman; Ceylan, Deniz; Demir, Ayse Banu; Kazdagli, Hasan; Erdeniz, BurakPathogens, which are the source of infectious diseases, have imposed a strong selection pressure on human evo-lution as one of the most important causes of human death during the natural selection process. As a result of this, it is assumed that a variety of adaptations have evolved against infection threats and one of these adap-tations is the physiological immune system. However, activation of the physiological immune system can be quite costly for organisms in some cases, and therefore it has been recently proposed in evolutionary psychology that an adaptive system called behavioral immune sys-tem may have evolved in association with the proactive functional processes against pathogen threats. Furthermore, it was hypothesized that a number of psy-chopathologies might develop as a result of maladaptive processes affecting the functionality of this system, and one of these psychopathologies might be trypophobia. Trypophobia refers to a psychological disorder in which individuals experience aversion and disgust at excessive levels toward clusters of small objects such as holes and bumps. Following this, the current review was estab-lished within the framework of three distinct goals. Firstly, this review aimed to discuss the evolutionary basis and mechanisms of the behavioral immune system. Secondly, the review aimed to discuss the characteristic features and the etiological explanations of trypophobia. Finally, the review aimed to discuss how potential changes in the behavioral immune system might lead to the development of trypophobia.Article Citation - WoS: 2Citation - Scopus: 2Neural Correlates of Opponent Processes for Financial Gains and Losses(Ege Univ, 2019-06-24) Erdeniz, Burak; Done, JohnObjective: Functional imaging studies offer alternative explanations for the neural correlates of monetary gain and loss related brain activity, and their opponents, omission of gains and losses. One possible explanation based on the psychology of opponent process theory suggests that successful avoidance of an aversive outcome is itself rewarding, and hence activates brain regions involved in reward processing. In order to test this hypothesis, we compared brain activation for successful avoidance of losses and receipt of monetary gains. Additionally, the brain regions involved in processing of frustrative neutral outcomes and actual losses were compared in order to test whether these two representations are coded in common or distinct brain regions. Methods: Using a 3 Tesla functional magnetic resonance imaging machine, fifteen healthy volunteers between the ages 22 to 28 were scanned for blood oxygen level dependent signal changes while they were performing a probabilistic learning task, wherein each trial a participant chose one of the two available options in order to win or avoid losing money. Results: The results confirmed, previous findings showing that medial frontal cortex and ventral striatum show significant activation (p<0.001) not only for monetary gains but also for successful avoidance of losses. A similar activation pattern was also observed for monetary losses and avoidance of gains in the medial frontal cortex, and posterior cingulate cortex, however, there was increased activation in a mygdala specific to monetary losses (p<0.001). Further, subtraction analysis showed that regardless of the type of loss (i.e., frustrative neutral outcomes) posterior insula showed increased activation. Conclusion: This study provides evidence for a significant overlap not only between gains and losses, but also between their opponents. The results suggested that the overlapping activity pattern in the medial frontal cortex could be explained by a more abstract function of medial frontal cortex, such as outcome evaluation or performance monitoring, which possibly does not differentiate between winning and losing monetary outcomes.Review Article Citation - WoS: 2Citation - Scopus: 2Neuroanatomy of Postural Stability: Links To Parkinson's Disease(Turkish Neurological Soc, 2019-03-01) Erdeniz, Burak; Selvaraj, David; Bulut, MervePostural stability is a complex task that requires the integration of many sensory inputs to produce an appropriate response for every environmental situation. The balance systems employ both reactive and anticipatory strategies to maintain the body's center of mass. The body's ability to maintain stability is limited by biomechanical constraints, such as the bodies' internal representation of position in space. The balance system has multiple internal representations of verticality including those in the vestibular and somatosensory cortexes that serve to orient the body and help to maintain balance. Moreover, the balance system uses cognitive resources to integrate sensory inputs. These cognitive resources are used to produce the appropriate motor responses in situations when the balance system is malfunctioning. Parkinson's disease (PD) is characterized by many motor symptoms, such as resting tremors, bradykinesia, and rigidity. PD is generally characterized by two subcategories of symptoms: the tremor type and the postural instability gait difficulties type (PIGD). Previous studies showed that the PIGD type is less responsive to current treatments, which include L-dopa. Thus, a better understanding of the balance system and how it affects the production of postural deficits is needed to better treat individuals suffering from the PIGD type of PD. Here, we review the candidate neural mechanism involved in balance, and inferences are made on how these balance networks may be affected by PD.Article Citation - WoS: 2Citation - Scopus: 1Towards Automaticity in Reinforcement Learning: a Model-Based Functional Magnetic Resonance Imaging Study(Turkish Neuropsychiatry Assoc-Turk Noropsikiyatri Dernegi, 2019) Erdeniz, Burak; Done, JohnIntroduction: Previous studies showed that over the course of learning many neurons in the medial prefrontal cortex adapt their firing rate towards the options with highest predicted value reward but it was showed that during later learning trials the brain switches to a more automatic processing mode governed by the basal ganglia. Based on this evidence, we hypothesized that during the early learning trials the predicted values of chosen options will be coded by a goal directed system in the medial frontal cortex but during the late trials the predicted values will be coded by the habitual learning system in the dorsal striatum. Methods: In this study, using a 3 Tesla functional magnetic resonance imaging scanner (fMRI), blood oxygen level dependent signal (BOLD) data was collected whilst participants (N=12) performed a reinforcement learning task. The task consisted of instrumental conditioning trials wherein each trial a participant choose one of the two available options in order to win or avoid losing money. In addition to that, depending on the experimental condition, participants received either monetary reward (gain money), monetary penalty (lose money) or neural outcome. Results: Using model-based analysis for functional magnetic resonance imaging (fMRI) event related designs; region of interest (ROI) analysis was performed to nucleus accumbens, medial frontal cortex, caudate nucleus, putamen and globus pallidus internal and external segments. In order to compare the difference in brain activity for early (goal directed) versus late learning (habitual, automatic) trials, separate ROI analyses were performed for each anatomical sub-region. For the reward condition, we found significant activity in the medial frontal cortex (p<0.05) only for early learning trials but activity is shifted to bilateral putamen (p<0.05) during later trials. However, for the loss condition no significant activity was found for early trials except globus pallidus internal segment showed a significant activity (p<0.05) for later trials. Conclusion: We found that during reinforcement learning activation in the brain shifted from the medial frontal regions to dorsal regions of the striatum. These findings suggest that there are two separable (early goal directed and late habitual) learning systems in the brain.