PSYCH 004: Neural Development and Neurogenesis

PSYCH 030: Learning Theory and Psychosis, Anxiety, and Addiction

At its core, the brain is a learning system - constantly updating itself based on experience. This chapter explores how fundamental learning mechanisms, when altered, can give rise to psychiatric conditions such as psychosis, anxiety, and addiction. In this episode, we examine key principles of learning theory, including classical conditioning, operant conditioning, and reinforcement learning. These processes allow the brain to predict outcomes, assign value, and adapt behaviour accordingly. We explore how these mechanisms can become distorted. In anxiety, neutral stimuli may acquire excessive threat value through conditioning. In addiction, reward learning becomes hypersensitised, driving compulsive behaviour despite negative consequences. In psychosis, aberrant assignment of salience may lead to unusual beliefs and perceptions. A central theme is that these conditions are not random - they follow identifiable patterns rooted in how the brain learns from experience. The same systems that allow adaptation can, under certain conditions, produce maladaptive outcomes. This chapter reframes psychiatric disorders as disturbances of learning - where prediction, reinforcement, and meaning assignment have shifted in ways that reshape behaviour and experience. Key Takeaways * The brain uses learning mechanisms to adapt to its environment. * Key processes include classical conditioning, operant conditioning, and reinforcement learning. * Anxiety can arise from maladaptive threat learning. * Addiction involves dysregulated reward learning and reinforcement. * Psychosis may reflect altered salience and prediction processes. * Learning systems are adaptive but can produce maladaptive patterns. * Understanding these mechanisms supports more targeted interventions. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 029: Neuropsychiatry of Self

The sense of self feels immediate and unquestionable - yet it is a construction. This chapter explores the neuropsychiatry of self, examining how brain systems generate the experience of being a coherent, continuous individual. In this episode, we examine how networks such as the default mode network contribute to self-referential processing - enabling reflection, autobiographical memory, and the sense of continuity across time. The self is not located in a single region, but emerges from coordinated activity across distributed systems. We explore different dimensions of selfhood: the minimal self (immediate experience), the narrative self (identity over time), and the social self (how we relate to others). These layers interact to produce the experience of “I”. Disruptions in these systems can lead to profound alterations in experience - from depersonalisation and dissociation to the fragmentation seen in psychosis. These are not simply cognitive disturbances, but shifts in the very structure of subjective experience. This chapter challenges assumptions. The self is not fixed - it is dynamic, constructed, and dependent on underlying neural processes. Understanding this opens new ways of thinking about both normal experience and psychiatric disorder. Key Takeaways * The sense of self is constructed through distributed brain networks. * The default mode network plays a key role in self-referential processing. * Selfhood includes minimal, narrative, and social dimensions. * Continuity of identity emerges from integration across time and memory. * Disruptions can lead to depersonalisation, dissociation, and psychosis. * The self is dynamic, not fixed. * Psychiatry must engage with subjective experience as well as biology. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 028: Functional Brain Connectivity and Psychopathology

The brain is not simply a collection of regions, but a network defined by how those regions communicate. This chapter explores functional connectivity - the dynamic relationships between different parts of the brain - and how alterations in these patterns contribute to psychopathology. In this episode, we examine how brain regions coordinate their activity over time, forming networks that support functions such as attention, self-referential thinking, and emotional regulation. Key systems, including the default mode network, salience network, and executive control network, operate in balance to maintain coherent mental function. We explore how disruptions in connectivity - whether through excessive synchrony, reduced integration, or abnormal switching between networks - can lead to psychiatric symptoms. Disorders such as depression, schizophrenia, and anxiety can be understood as disturbances in these patterns of communication. A central insight is that dysfunction does not necessarily lie within individual regions, but in the relationships between them. Connectivity becomes the organising principle of mental life. This chapter invites a relational perspective: to understand the mind not as a static structure, but as a dynamic network - where coherence depends on communication, and disorder emerges when that communication breaks down. Key Takeaways * Functional connectivity refers to coordinated activity between brain regions. * Brain function relies on networks such as default mode, salience, and executive systems. * Mental processes emerge from dynamic interactions between regions. * Psychopathology can reflect disrupted connectivity rather than focal abnormalities. * Both excessive and reduced connectivity can be problematic. * Network balance and switching are critical for adaptive function. * Psychiatry increasingly adopts a network-based understanding of the brain. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 027: Radiotracer Imaging with Positron Emission Tomography and Single Photon Emission Computed Tomography: Fundamental Principles, Methodology and Role in Neuropsychiatric Research

While MRI shows structure and EEG captures electrical activity, radiotracer imaging reveals something different: the brain’s molecular activity in action. This chapter explores PET and SPECT - techniques that allow us to track specific biological processes in vivo. In this episode, we examine how radiolabelled tracers bind to particular receptors, transporters, or metabolic pathways, enabling us to visualise neurotransmitter systems and functional activity. These methods provide a window into processes such as dopamine transmission, glucose metabolism, and receptor availability. We explore how PET and SPECT have advanced our understanding of psychiatric disorders - particularly in areas such as schizophrenia, addiction, and mood disorders - by linking symptoms to underlying neurochemical dynamics. A key strength of these techniques is specificity. Unlike broader imaging methods, radiotracer studies can target particular systems, offering insights into mechanisms at a molecular level. However, these approaches are complex, resource-intensive, and primarily research tools. Interpretation requires caution, and findings are often probabilistic rather than definitive. This chapter highlights a powerful idea: that understanding the mind requires not only seeing the brain, but tracing the chemistry that animates it. Key Takeaways * PET and SPECT use radiotracers to visualise molecular processes in the brain. * These techniques can assess neurotransmitter systems, receptor binding, and metabolism. * They provide high biochemical specificity compared to other imaging methods. * Radiotracer imaging has advanced understanding of disorders such as schizophrenia and addiction. * These methods are primarily used in research rather than routine clinical practice. * Interpretation is complex and findings are not always definitive. * Molecular imaging links symptoms to underlying neurochemical processes. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]

PSYCH 026: Electroencephalography in Psychiatry

If imaging reveals structure, electroencephalography (EEG) captures activity in real time. This chapter explores how electrical signals generated by neuronal populations can be recorded from the scalp, offering a dynamic view of brain function. In this episode, we examine how EEG reflects synchronised activity across neural networks, producing patterns that can be analysed in terms of frequency, amplitude, and coherence. These rhythms - from slow delta waves to fast gamma activity - represent different states of brain function. We explore how EEG is used clinically, particularly in epilepsy and sleep medicine, but also its growing role in psychiatric research. Subtle alterations in brain rhythms have been associated with conditions such as schizophrenia, depression, and attention disorders. A key theme is temporal resolution. Unlike structural imaging, EEG captures the brain as it unfolds moment by moment - revealing patterns of timing, synchrony, and disruption that are otherwise invisible. However, EEG also has limitations. Its spatial precision is limited, and interpretation requires careful contextualisation. It offers a window into function, but not a complete map. This chapter highlights the importance of timing in brain activity - showing that when signals occur, and how they synchronise, is as important as where they originate. Key Takeaways * EEG records electrical activity from neuronal populations in real time. * Brain activity is reflected in rhythmic patterns across different frequencies. * EEG provides high temporal resolution but limited spatial precision. * It is widely used in epilepsy and sleep medicine, with growing psychiatric applications. * Altered brain rhythms are associated with various psychiatric conditions. * EEG reveals patterns of synchrony, timing, and network dynamics. * Functional insight requires careful interpretation within clinical context. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe [https://drmanaankarray.substack.com/subscribe?utm_medium=podcast&utm_campaign=CTA_2]