Alexithymia and Interoception
Stress and Neck Pain
The Accessory XI nerve, a cranial nerve, is vital for controlling the trapezius muscle, which facilitates various neck and shoulder movements. When stress occurs, this muscle can tense up, leading to neck discomfort. Interestingly, in quadrupeds like cats, the trapezius muscle is crucial for lifting the head; this adaptation aids grazing animals in responding to external stimuli. Additionally, the short-term memory (STM) muscles also contribute to raising the head, illustrating the complexity of our muscular system's evolution and functionality.
The Complex Terrain of Muscle Contraction - Insights from Disability
(Based on topic covered in Neuroanatomy Class along with some additional disability perspectives. )
In the world of biology, muscle contraction is a fundamental process, enabling us to move and function. The way our muscles contract, however, can lead to various consequences, especially when disrupted by factors like bacterial infections.
Muscle contractions are driven by motor units. Whether the contraction is strong or weak depends on how many of these units are activated. So a fine precise motor action requires small number of units activated and need little strength.
Understanding muscle pain takes us to the basics of cellular respiration. Muscles, like all cells, need oxygen, which is supplied through arteries. When a muscle contracts and restricts this oxygen supply, it creates a problem. The muscle cells continue to function, breaking down glucose in the absence of oxygen. However, this process produces lactate, leading to a burning sensation, indicating the body's distress.
This pain can have severe consequences. In intense muscle contractions, essential muscles like the diaphragm, responsible for breathing, can weaken. Chest muscles may become so tense that they hinder the natural process of inhaling and exhaling.
In the complexity of our body's workings, this delicate balance between muscle contraction and relaxation defines our abilities. Understanding these intricacies not only enhances our knowledge of our biological marvel but also emphasizes the need to appreciate and preserve the balance that allows us to move and function seamlessly.
There exists a parallel narrative, one that often goes unnoticed — the experience of autistics. Consider a autistic whose sensory perceptions are heightened and processed differently. The involuntary muscle contractions experienced by autistics might not only induce physical discomfort but also trigger heightened sensory responses, amplifying the distress. In such cases, the pain isn't merely a physiological phenomenon; it extends into the realms of sensory overload, creating an overwhelming and sometimes unbearable experience.
Consciousness
Nature of Consciousness and Quantum Physics. Both Sanathana Dharma and Buddhism assert that consciousness isn't a byproduct but a fundamental aspect of reality. This perspective aligns, to some extent, with certain interpretations of quantum mechanics, which propose that consciousness plays a role in the process of quantum measurement or wave function collapse.
Meditation, Mindfulness, and Neuroscience: Neuroscientific research into the effects of meditation—a practice central to both Sanathana Dharma and Buddhist traditions—has shown that it can induce significant changes in areas of the brain associated with attention, emotion regulation, and self-awareness.
Levels and States of Consciousness: The Mandukya Upanishad, outlines different states of consciousness, including waking, dreaming, deep sleep, and a transcendent state known as "Turiya." Modern neuroscience also explores various states of consciousness, such as REM sleep, deep sleep, and altered states induced by substances or meditation. Buddhist meditation practices often aim to transcend ordinary states of consciousness and attain enlightened states. Neuroscientific studies on accomplished meditators have reported unique brainwave patterns and states of consciousness.
Interconnectedness: Both Sanathana Dharma and Buddhist philosophies emphasize the interconnectedness of all things. This idea has resonances with holistic perspectives in science, especially in fields like ecology and certain interpretations of quantum physics which emphasize non-locality and entanglement.
Plasticity and Transformation: Both Sanathana Dharma and Buddhist traditions emphasize the possibility of transforming one's mind and consciousness. The idea of neuroplasticity in modern neuroscience—that the brain is malleable and can be changed through experiences, especially practices like meditation—aligns with this.
Phenomenal Experience: Buddhism, particularly in schools like Yogacara, delves deep into the nature of experience, cognition, and perception. These explorations find parallels in cognitive science and phenomenological approaches in modern philosophy of mind.
Phrenology according to Gall. A Historical Curiosity
The prevailing view of the era was dominated by religious or philosophical beliefs rather than empirical research. Gall's ideas challenged long-held beliefs about the nature of the mind and the brain and landed in a lot of hot water.
And the hot water was not just religions, but also social. Phrenology also had practical implications, as some individuals and organizations began using it for character assessment in various contexts, such as education and employment. This raised ethical and legal questions about the fairness and validity of making judgments about people based on phrenological assessments.
Gall's most notable contribution was his intricate neuroanatomy diagram, which depicted the brain as a series of localized faculties or organs, each responsible for a particular aspect of personality or behavior. The size of these organs corresponded to a person's character traits and abilities. Obviously this is quite incredulous by today's standards - a historical curiousity.
- Firmness (in frontal lobe) Development of this area in the frontal lobe was associated with determination, willpower, and the ability to persevere in the face of challenges.
- Immortality: linked to religious and moral tendencies, as well as a sense of spirituality.
- Veneration (Parietal Love): related to feelings of respect, admiration, and reverence for authority figures or ideals
- Destructiveness (in lower back of brain): aggressive and combative behaviors, as well as a propensity for violence.
- Benevolence (frontal love): linked to kindness, empathy, and a compassionate nature.
- Acquisitiveness (forehead): desire for material wealth and possessions.
- Wit (Frontal Lobe): responsible for humor, quick thinking, and cleverness.
- Love of Offspring (back of brain):linked to parental instincts and the love and care of one's children.
- Secretiveness (Upper back of brain): associated with the tendency to keep secrets and be discreet.
- Self-Esteem (upper back of head): related to self-confidence, pride, and a sense of self-worth.
The Brain is Never Zero
In the realm of thoughts, wonders reside
Brain pulses ceaselessly, a relentless tide
Neurons fire, synapses alight
The brain is never zero, its brilliance ignites.
EEG Capping
Felt like a soggy swim cap. Not the most comfortable feeling but tolerable.
To clarify, in this photo I'm trying on the cap to see what it feels like as I will likely be using neuroimaging methods (EEG, fMRI etc) in my own research design and I will be studying issues in autism.
Review v Meta Analysis
A meta-analysis is a specific type of research synthesis that involves combining and analyzing quantitative data from multiple studies to generate more robust conclusions. Researchers identify relevant studies, extract relevant data from each study, and statistically analyze the combined data to derive overall effect sizes or estimates of the relationship between variables. Meta-analyses often include a systematic review of the literature as a first step to identify relevant studies for inclusion.
Mental Time Travel
In this task, the individual's present moment serves as a reference point from which they situate and retrieve personal versus general events. Personal events refer to specific episodic memories from the individual's own life, such as a birthday party or a family trip, while general events are more abstract and can be shared by multiple individuals, such as historical events or holidays.
The MTT task taps into several cognitive processes and neural mechanisms associated with mental time travel. It requires the retrieval of specific episodic memories or the construction of plausible future scenarios. The task engages memory processes, including recall and recognition, as well as imagination and prospective thinking.
Neuroimaging studies have shown that the neural substrates underlying MTT involve a network of brain regions.
- PFC: cognitive control and executive function required for retrieving and manipulating temporal information.
- Hippocampus and MTL: formation and retrieval of episodic memories
The MTT task has been used in research to investigate individual differences in the capacity for mental time travel and how it relates to various cognitive processes, such as autobiographical memory, imagination, planning, and self-projection. It has also been employed to examine the effects of aging, neurodegenerative diseases, and psychiatric disorders on mental time travel abilities.
Depersonalization and Autism
- Loss of body ownership /disembodiment feelings / somatosensory distortions/ loss of agency: distressing feelings of being 'spaced out', detached from one's self, body, and the world (observing yourself from a distance).
- atypical 'flat' time perception (alterations in perception, including disruptions in the perception of time. )
Research findings on DPD and atypical time perception in the NT population
- Distorted perception of time: Tendency to overestimate the duration of time intervals, perceiving time as slower than it actually is which can contribute to the overall sense of detachment (1,2)
- Neural correlates of time perception: fMRI studies show differences in brain activity and connectivity patterns in regions associated with time processing, eg: PFC and parietal cortex (3,4)
- Role of attentional processes: Difficulties in allocating attention appropriately, leading to a reduced ability to accurately perceive and process temporal information (5,6)
- Emotional factors: Emotional states, eg anxiety and stress, can modulate time perception, leading to temporal distortions. DP folks often experience heightened levels of anxiety and emotional distress, which may contribute to their altered perception of time. (1,2)
- Both involve atypical sensory processing suggesting a potential shared underlying connection.
- Overlap in Symptoms: Though there are distinct dx criteria, both share some overlapping symptoms, such as a sense of detachment from oneself, difficulties with emotional regulation, and social challenges.
- Neurobiological Factors: Though the specific mechanisms and neural circuits may differ, both potentially involve alterations in brain functioning and connectivity.
- Impact on Functioning: Co-occurrence may exacerbate the challenges in everyday functioning especially in areas of social interactions and emotional well-being.
- 17% autistics met the diagnostic criteria for DPD, compared to 2% non-autistic (7)
- Compared to controls, autism+DPD more likely to have
- higher anxiety and depression (8)
- more difficulty with social interaction and communication (9)
- more repetitive behaviors and special interests (10)
Self Referencing and Self Projecting
- Self-Referencing: general capacity of using one's own position in time to estimate/situate events in time. This skill relies on internal cues such as memory and self-awareness to place events within a temporal framework. By referencing our own experiences and the temporal context in which they occurred, we can make sense of the timing and sequence of events in our environment.
- Self-Projecting: ability to mentally move back and forward in time, maintaining the competence of correctly situating events in time. This skill allows us to anticipate future events, plan our actions, and make decisions based on the temporal context. Self-projecting skill involves mental time travel, where we can mentally simulate and project ourselves into different points in time, drawing upon past experiences and knowledge to predict and shape future events.
Personal Space v PPS
[Concepts in Sensorimotor Research]
Personal Space v PPS
Personal space refers is a social construct - refers to the physical or psychological distance individuals prefer to maintain between themselves and others. It is the immediate area surrounding a person that they consider as their own.
Peri-personal space is a neuroscience construct to describe the area immediately surrounding the body that is within reach of the individual. It encompasses the space where individuals feel they can manipulate/reach using their limbs / body parts.
Past research has indicated autistics as having a very constrained PPS.
Principle of inverse effectiveness
Ergo, when the individual sensory cues are relatively weak or have low impact, the brain tends to rely more on multisensory integration to enhance the perception and processing of the stimuli. eg: people with hearing loss exhibit increased visual abilities, and increased crossmodal activation within the auditory cortex.
The principle of inverse effectiveness highlights the advantage of combining multiple sensory inputs in situations where the individual senses may provide limited or unreliable information. By integrating sensory cues from different modalities, the brain can enhance the overall perception and make more accurate judgments about the external environment. This principle has been observed across various species and sensory domains and is believed to reflect a fundamental property of multisensory processing.
MBNCA Connectome Dataset
https://www.biorxiv.org/content/10.1101/2023.03.10.532036v1
Interaural differences
- ITD (interaural time difference): time delay between the arrival of sound at each ear. ITD is greatest for sounds coming from the side of the head and is zero for sounds coming from directly in front or behind the listener.
- ILD (interaural level difference): amplitude difference between the sound waves arriving at each ear. ILD is greatest for sounds coming from directly to one side of the listener and is zero for sounds coming from directly in front or behind the listener.
Some studies have reported differences in how autistics process interaural differences, including reduced ability to integrate auditory and visual information, as well as altered auditory and multisensory temporal processing.
Interoception and exteroception
Interoception refers to the sense of the internal state of the body. It helps us understand and feel what's going on inside our bodies, like feeling hungry, thirsty, or perceiving our heartbeat. Interoceptive awareness contributes to emotional regulation and self-awareness.
Exteroception refers to the perception of the external environment through our senses like vision, hearing, touch, taste, and smell. These senses help us navigate and interact with the world around us.
Research findings in autism:
Autistics often exhibit differences in sensory processing, which may include atypical interoceptive and exteroceptive perception. Findings (examples below) suggest that atypical interoceptive and exteroceptive processing may be significant factors in understanding the behavioral and sensory symptoms in individuals with autism.
- This review explores the role of oxytocin in interoception and its potential implications for autism. The authors propose that atypical interoceptive processing, potentially linked to altered oxytocin functioning, could contribute to the social and emotional difficulties experienced by autistics. (1)
- This study found that adult autistics exhibited significantly lower interoceptive awareness compared to NT adults. The authors suggest that this might be related to the difficulties in social and emotional processing seen in autism (2).
- This review discusses various neurophysiological findings in sensory processing, including exteroception, in autistics. The authors highlight that altered sensory processing may contribute to the core features of ASD, such as social communication and repetitive behaviors (3)
Temporal Binding Window and Autism
In autistics, research suggests alterations in the TBW due to difficulties in accurately perceiving and integrating sensory information across different modalities, leading to difficulties in forming a unified perception of the world.
One aspect of the TBW that has been extensively studied in relation to autism is audiovisual integration. Typically, individuals are sensitive to the relative timing of auditory and visual stimuli and can perceive them as belonging to a single event when presented within a certain temporal proximity. However, studies have shown that autistics may have a broader or more extended TBW. This means that they require a longer temporal proximity between auditory and visual stimuli to perceive them as synchronized.
This winder TBW has implication in terms of social communication and interaction since the perception of synchrony is crucial for understanding and interpreting non-verbal cues such as facial expressions, gestures, and vocal intonations. Difficulties in integrating sensory information across different modalities can also contribute to sensory processing issues commonly observed in individuals with autism, such as hypersensitivity or hyposensitivity to certain stimuli.
TBW may also influence higher-level cognitive processes such as attention, perception of causality, and the ability to predict and anticipate events. Disruptions in these processes can impact the ability to understand the temporal structure of events and may contribute to difficulties with executive functioning.
Ventriloquism Effect in Multisensory Integration
The ventriloquism effect can also occur in other situations where there is a mismatch between the visual and auditory information, such as when watching a movie with dubbed audio, or when hearing a person speak on a phone or speaker. The brain uses contextual cues to determine the location of the sound source and can be influenced by visual information, leading to the perception of the sound coming from a different location.
There is some evidence to suggest that autistics may process sensory information differently than neurotypicals, including the processing of auditory information and less fooled by the ventriloquism effect which may suggest that autistics have difficulty integrating information form different senses (which has implication in terms of social interactions).
Other studies have suggested that individuals with autism may have heightened sensitivity to certain auditory stimuli and may experience difficulty in filtering out irrelevant sounds. This hypersensitivity to sound could potentially interfere with the integration of visual and auditory information, leading to a weaker ventriloquism effect.
However the caveat is that research on the relationship between autism & ventriloquism effect is ongoing and not fully understood. So nothing is set in stone.