Can biological quantum networks solve NP-hard problems?

There is a widespread view that the human brain is so complex that it cannot be efficiently simulated by universal Turing machines. During the last decades the question has therefore been raised whether we need to consider quantum effects to explain the imagined cognitive power of a conscious mind. This paper presents a personal view of several fields of philosophy and computational neurobiology in an attempt to suggest a realistic picture of how the brain might work as a basis for perception, consciousness and cognition. The purpose is to be able to identify and evaluate instances where quantum effects might play a significant role in cognitive processes. Not surprisingly, the conclusion is that quantum-enhanced cognition and intelligence are very unlikely to be found in biological brains. Quantum effects may certainly influence the functionality of various components and signalling pathways at the molecular level in the brain network, like ion ports, synapses, sensors, and enzymes. This might evidently influence the functionality of some nodes and perhaps even the overall intelligence of the brain network, but hardly give it any dramatically enhanced functionality. So, the conclusion is that biological quantum networks can only approximately solve small instances of NP-hard problems. On the other hand, artificial intelligence and machine learning implemented in complex dynamical systems based on genuine quantum networks can certainly be expected to show enhanced performance and quantum advantage compared with classical networks. Nevertheless, even quantum networks can only be expected to efficiently solve NP-hard problems approximately. In the end it is a question of precision - Nature is approximate.Comment: 38 page

The cognitive neuroscience of visual working memory

Visual working memory allows us to temporarily maintain and manipulate visual information in order to solve a task. The study of the brain mechanisms underlying this function began more than half a century ago, with Scoville and Milner’s (1957) seminal discoveries with amnesic patients. This timely collection of papers brings together diverse perspectives on the cognitive neuroscience of visual working memory from multiple fields that have traditionally been fairly disjointed: human neuroimaging, electrophysiological, behavioural and animal lesion studies, investigating both the developing and the adult brain

Brain maturation during adolescence and young adulthood - an EEG study

Objective: Adolescence is a period of major maturational changes in the brain. It is particularly the maturation of the frontal cortex and its interactions with other brain regions that dominates this late stage of development and has important implications for the cognitive abilities during the entire adult life. Methods: In this thesis, developmental changes in the delta (0 - 4 Hz), theta (4 - 7 Hz) and gamma (28 - 48 Hz) frequency bands were investigated in adolescents (13 - 15 years) and adults (20 - 27 years) during resting and cognitive states. Four tasks were conducted: the spontaneous EEG (eyes-open), the ambiguous task, the unambiguous task and the visual oddball task. During the ambiguous task, participants were exposed to the Stroboscopic Ambiguous Motion (SAM) paradigm. SAM is a multistable stimulus that, when viewed continuously, induces internally-generated changes in the perceived direction of motion. For the unambiguous task, a modified version of the SAM was used. In this case, the perceived direction of motion was controlled externally. In the visual oddball task, randomly interspersed targets had to be identified in a train of frequent non-targets. Single-trial amplitudes of delta, theta and gamma activity obtained during the spontaneous EEG were compared between the groups to assess general maturational changes in the developing brain. The task-related enhancement of the oscillatory activity was compared between the groups in order to assess developmental changes in task performance. Results: The previous findings of delta and theta amplitudes decreasing with age during the spontaneous EEG were replicated. Similarly to previous studies, our results also indicate that for spontaneous EEG gamma amplitudes do not profoundly differ between adolescents and adults. Moreover, the present study supports previous findings from adult research which have established a functional relationship between delta, theta and gamma activities and higher cognitive processes. It has further been found that the developmental changes correlated with task difficulty. Only for the - most challenging - ambiguous task the gamma oscillations were found to reflect a change in task-related cortical processing during adolescence, whereas no age-related differences of gamma responses were detected for less demanding tasks (the unambiguous and visual oddball tasks). The event-related theta responses were found to increase with age for the ambiguous and visual oddball tasks and did not depend on age for the unambiguous task. Furthermore, the event-related delta responses increased with age for all tasks. Conclusions: The main finding of this study is that functional networks of delta, theta and gamma activity undergo maturational changes during adolescence. The found differences in the task-related activations may indicate a protracted development of higher-order cognitive processes during adolescence. The developmental changes of task-related activations seem to vary with task difficulty and frequency band. Significance: Systematic studies on developmental changes of brain oscillations in cognitive tasks are still infrequent and specifically the time period of adolescence has been rarely investigated. The typical age of onset for mental disorders, such as schizophrenia, is the late stages or shortly after the onset of adolescence, rendering the outcome of brain maturation during this period of immense importance for life-long mental health. Thus, it is critical to extend our understanding of the mechanism behind the appearance of cognitive functions during adolescence

Investigation of brain networks for personalized rTMS in healthy subjects and patients with major depressive disorder: A translational study

Depression is a complex psychiatric disorder with emotional dysregulation at its core. The first line of treatment includes cognitive behaviour therapy and pharmacological antidepressants. However, up to one third of patients with depression fail to respond to these treatment interventions. The past decades have seen an increasing use of repetitive Transcranial Magnetic Stimulation (rTMS) in clinical studies, as an alternative treatment for depression. Several large-scale, multicentre randomized controlled trials have led the Food and Drugs Administration (FDA), USA to approve two rTMS protocols for clinical application in the treatment of depression - 10 Hz rTMS and intermittent Theta Burst Stimulation (iTBS). However, only 30-50% of patients receiving rTMS respond to the treatment. The large variability in response to rTMS likely stems from multiple reasons, one being the targeting method currently employed for delivering rTMS at the left dorsolateral prefrontal cortex (DLPFC). Previous functional connectivity studies have shown that stimulation at left DLPFC targets with larger negative correlation to the subgenual anterior cingulate cortex (sgACC) may result in greater therapeutic response than those with lower negative correlation. However, current use of rTMS ignores functional connectivity in choosing the left DLPFC target, thus largely discarding functional architectural differences of the brain across subjects. Furthermore, despite widespread clinical use of rTMS, the basic network mechanisms behind these rTMS protocols remain elusive. This work presents a novel personalization method of left DLPFC target selection based on their negative functional connectivity to the sgACC. The default mode network (DMN) is a large-scale brain network commonly involved in self-referential thought processing and plays an essential role in the pathophysiology of depression. I use the novel personalization method and identical study designs to delineate DMN mechanisms from a single session of 10 Hz rTMS and iTBS in healthy subjects. Arguably, an understanding of basic mechanisms of clinically relevant rTMS protocols in healthy subjects will help improve the current therapeutic effect of rTMS, and possibly expand the therapeutic role of rTMS. My work shows, for the first time, strong but different modulations of DMN connectivity by single personalized sessions of 10 Hz rTMS and iTBS. Such modulations can be predicted using the personality trait harm avoidance (HA). Given that initial results show that the method is robust and reproducible, its adaptation to patient cohorts is likely to result in improved therapeutic benefits. Therefore, the novel method of personalization is translated to clinical setting by using accelerated iTBS (aiTBS) in patients with depression. Additionally, a comparison is made between effects resulting from personalized and nonpersonalized (10-20 EEG system F3 position) aiTBS in patients with depression. By evaluating the DMN, and heart rate variability, I show precise modulatory effects of personalized aiTBS, which is not seen in the standard aiTBS group. The work presented here introduces an important method to reduce variability and increase precision in rTMS modulation by personalizing the left DLPFC target selection. Even though DMN and cardiac effects already point towards the advantage of personalization, the still preliminary analysis fails to show significant differences in treatment response. Lack of greater therapeutic benefits viii from personalized aiTBS in this ongoing study probably stems from a still limited sample size. In case personalization proves clinically advantageous to standard iTBS by the final sample size, this work can sediment the first step towards systems medicine in the field of psychiatry.2022-02-0

The Impact of Neurofeedback on Women Diagnosed with PTSD: A Multiple Case Study

The purpose of this study was to examine how women diagnosed with PTSD experienced neurofeedback (NFB) using quantitative and qualitative data. The quantitative data included pre- and post-test scores on the quantitative electroencephalogram (QEEG), the Davidson Trauma Scale, and the Inventory of Altered Self-capacities. The qualitative data illuminated participants’ experiences with NFB and their observations about the changes that occurred during and after NFB. The participants in this study included three women who received at least 20 sessions of NFB to treat their PTSD. The results indicated that two participants achieved a significant reduction in their PTSD symptoms and improvements in their concentration, sustained attention, and ability to calm themselves down. The third participant observed limited reductions in her depression and anxiety symptoms and improvement in her concentration and sustained attention. Participants also shared that understanding NFB before beginning treatment would have helped them to acquire self-regulation skills. Results also implicated that negative effects could occur from overtraining and standardized NFB protocols. Recommendations were made for the use of individualized NFB protocols to address clients’ unique symptoms and EEG patterns. Future studies should utilize mixed-method or qualitative methods to investigate the impact of NFB combined with bottom-up approaches such as somatic experiencing therapy, trauma-sensitive yoga, and eye movement desensitization and reprocessing (EMDR). Recommendations were also made to investigate treating PTSD new NFB protocols based on the triple network model. تهدف الدراسة إلى الكشف عن تأثير العلاج بالتغذية الراجعة العصبية على النساء المشخصات باضطراب كرب ما بعد الصدمة باستخدام البيانات الكمية والنوعية. تضمنت البيانات الكمية الدرجات القبلية والبعدية للتخطيط الكمي الكهربائي للدماغ ومقياس ديفيدسون للصدمات وقائمة جرد القدرات الذاتية المتغيرة. وقد أظهرت البيانات النوعية تجربة المشاركات للعلاج بالتغذية الراجعة العصبية وملاحظاتهن حول التغيرات التي حدثت أثناء وبعد العلاج. كانت عينة الدراسة ثلاث سيدات تلقيّن على الأقل عشرين جلسة تغذية راجعة عصبية لعلاج اضطراب كرب ما بعد الصدمة. أشارت النتائج إلى انخفاض كبير في أعراض اضطراب كرب ما بعد الصدمة لدى مشاركتين ، بالإضافة إلى تحسن التركيز واستمراية الانتباه والقدرة على التهدئة عند الاستثارة. و كان انخفاض أعراض الاكتئاب والقلق لدى المشاركة الثالثة محدودًا في حين تحسّن مستوى التركيز واستمرار الانتباه لديها. أوضحت المشاركات أن فهم إجراءات العلاج بالتغذية الراجعة العصبية قبل بدء العلاج يساعد على اكتسابهن لمهارات الضبط الذاتي. كما أشارت النتائج إلى أن الآثار السلبية يمكن أن تحدث من الإفراط في التدريب أواستخدام بروتوكولات علاجية موحدة. تم تقديم توصيات لاستخدام بروتوكولات فردية وفقا لأعراض كل فرد وأنماط تخطيط الدماغ لديه. وقد أوصت الدراسة بإجراء دراسات مستقبلية تجمع بين المنهج الكمي والنوعي لاكتشاف تأثير الجمع بين العلاج بالتغذية الراجعة العصبية ومناهج (من أسفل إلى أعلى) مثل علاج الخبرة الجسية ، والعلااج بإزالة التحسس وإعادة المعالجة باستخدام حركة العين. كما أوصت الدراسة بإجراء دراسات مستقبلية لاختبار بروتوكولات جديد في العلاج بالتغذية الراجعة العصبية لعلاج اضطراب مابعد الصدمة استنادا على نموذج شبكة الدماغ الثلاثية