PSYCH 005: Cellular and Synaptic Basis of Neural Signalling

PSYCH 015: Basic Science of Sleep

Sleep is often treated as absence - a passive state where the brain switches off. This chapter challenges that notion, revealing sleep as an active, highly organised process essential for brain function and mental health. In this episode, we explore the architecture of sleep - its stages, cycles, and regulatory systems. Non-REM and REM sleep represent distinct physiological states, each contributing differently to restoration, memory consolidation, and emotional processing. We examine how sleep is governed by two interacting systems: the circadian rhythm and the homeostatic drive. Together, they determine when we sleep, how deeply, and for how long. Disruptions to either system can destabilise the entire process. Sleep is not merely restorative - it is transformative. During sleep, the brain reorganises information, processes emotional experiences, and clears metabolic by-products. It is a period of recalibration, not inactivity. Clinically, disturbances in sleep are both symptoms and drivers of psychiatric disorders. Insomnia, hypersomnia, and altered sleep architecture are closely linked to mood disorders, anxiety, and psychosis. This chapter reframes sleep as foundational - not optional, but integral to how the brain maintains coherence and resilience. Key Takeaways * Sleep is an active, structured process essential for brain function. * Non-REM and REM sleep serve distinct roles in restoration and processing. * Sleep is regulated by circadian rhythms and homeostatic drive. * It supports memory consolidation, emotional regulation, and metabolic clearance. * Disruptions in sleep can both reflect and contribute to psychiatric disorders. * Sleep architecture (timing, depth, cycles) is clinically significant. * Rest is not passive - it is a critical component of neural health and function. 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 014: Chronobiology, Circadian Rhythm, and Psychiatry

The brain does not function in a constant state - it operates in rhythms. This chapter explores chronobiology and circadian systems, revealing how internal biological clocks organise sleep, energy, cognition, and emotional regulation across the day. In this episode, we examine the circadian system as a master regulator, synchronising physiological and psychological processes with environmental cues such as light and darkness. The suprachiasmatic nucleus acts as a central pacemaker, coordinating peripheral systems and maintaining temporal order. We explore how disruptions in these rhythms - whether through lifestyle, illness, or intrinsic vulnerability - can profoundly affect mental health. Sleep disturbances, mood instability, and cognitive changes are not random; they often reflect underlying temporal dysregulation. Conditions such as depression, bipolar disorder, and anxiety can be understood, in part, as disorders of rhythm - where timing, not just content, has gone awry. This chapter invites a subtle but powerful shift: to consider not only what the brain is doing, but when it is doing it - and how misalignment in time can alter the entire landscape of experience. Key Takeaways * Circadian rhythms regulate sleep, mood, cognition, and physiological processes. * The suprachiasmatic nucleus acts as the central biological clock. * Environmental cues (especially light) synchronise internal rhythms. * Disruptions to circadian systems can significantly impact mental health. * Sleep disturbances are often both symptoms and drivers of psychiatric disorders. * Mood disorders, particularly bipolar disorder, are closely linked to rhythm dysregulation. * Timing and synchronisation are as important as biological mechanisms themselves. 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 013: Immune–Brain Interactions in Psychiatry

The brain does not operate in isolation from the body’s defence systems. This chapter explores the evolving understanding of how the immune system and the brain interact - not only in illness, but as part of normal regulation of mood, behaviour, and cognition. In this episode, we examine how immune signalling molecules, particularly cytokines, influence brain function. These signals can alter neurotransmission, neural plasticity, and circuit activity - effectively shifting how the brain processes information. We explore the concept of “sickness behaviour” - a coordinated response to inflammation characterised by fatigue, low mood, reduced motivation, and social withdrawal. While adaptive in acute illness, similar patterns may become maladaptive when immune activation is prolonged or dysregulated. This provides a powerful framework for understanding aspects of depression, as well as emerging links between inflammation and other psychiatric conditions. The boundary between physical and mental illness becomes increasingly blurred - revealing shared biological pathways. This chapter invites a reframing of psychiatric symptoms: not solely as disorders of the brain, but as states influenced by systemic processes - where the immune system becomes an active participant in shaping experience. Key Takeaways * The immune system and brain interact through signalling molecules such as cytokines. * Immune activation can influence neurotransmission, plasticity, and neural circuits. * “Sickness behaviour” reflects adaptive responses that can resemble depressive symptoms. * Chronic or dysregulated inflammation may contribute to psychiatric disorders. * The distinction between physical and mental illness is increasingly blurred. * Immune–brain interactions offer new perspectives on mechanisms and treatment targets. * Psychiatry must consider systemic biology, not just brain-specific 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 012: Psychoneuroendocrinology

The mind does not exist in isolation from the body. This chapter explores psychoneuroendocrinology - the interface between brain, hormones, and behaviour - and how internal physiological states shape emotional and psychological experience. In this episode, we examine how the brain communicates with the endocrine system, particularly through the hypothalamic–pituitary–adrenal (HPA) axis. This system translates perception into physiological response, mobilising the body in the face of challenge and restoring balance afterwards. We explore how hormones such as cortisol act not only on the body, but back on the brain - influencing mood, cognition, memory, and perception. Stress is therefore not just a psychological experience, but a whole-body process with neural consequences. A central theme is regulation. Acute stress can be adaptive, sharpening attention and preparing for action. Chronic or dysregulated stress, however, can alter neural systems, impair resilience, and contribute to disorders such as depression, anxiety, and trauma-related conditions. This chapter reframes psychiatric symptoms as embodied phenomena. The boundary between mind and body dissolves - replaced by a continuous feedback loop in which each shapes the other. Key Takeaways * Psychoneuroendocrinology studies the interaction between brain, hormones, and behaviour. * The HPA axis is central to the stress response. * Hormones such as cortisol influence both body and brain function. * Stress responses can be adaptive in the short term but harmful when chronic or dysregulated. * Brain and endocrine systems operate in continuous feedback loops. * Dysregulation contributes to mood, anxiety, and trauma-related disorders. * Psychiatric symptoms are often embodied, not purely psychological. 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 011: Intraneuronal Signalling

While synapses transmit signals between neurons, the real transformation happens within. This chapter explores intraneuronal signalling - the complex cascade of intracellular processes that determine how a neuron responds to incoming information. In this episode, we move inside the neuron to examine how signals are not simply received, but interpreted. Neurotransmitters bind to receptors, triggering intracellular pathways involving second messengers, protein kinases, and gene transcription. These cascades shape everything from immediate responses to long-term changes in structure and function. We explore how the same external signal can produce different outcomes depending on the internal state of the neuron. Context matters - receptor subtype, intracellular environment, and prior activity all influence how a signal is processed. This is where short-term communication becomes long-term adaptation. Intraneuronal signalling underpins plasticity, learning, and memory, but also vulnerability. Dysregulation at this level can alter how information is processed, contributing to psychiatric conditions in ways that are not visible at the level of synapses alone. This chapter reveals a deeper layer of complexity: the brain is not just a network of connections, but a system of interpretive units, each transforming signals into meaning. Key Takeaways * Intraneuronal signalling involves intracellular cascades triggered by receptor activation. * Second messengers and protein kinases play key roles in signal transduction. * Neurons interpret signals rather than simply transmitting them. * The same neurotransmitter can produce different effects depending on intracellular context. * These processes link short-term signalling to long-term changes such as gene expression and plasticity. * Dysregulation can alter how signals are processed, contributing to psychiatric disorders. * Understanding intracellular pathways is key to deeper mechanistic insight in psychiatry. 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]