Showing posts with label Neuroscience. Show all posts
Showing posts with label Neuroscience. Show all posts

Alexithymia and Interoception

Alexithymia and interoception are intertwined aspects of emotional processing, yet they represent different dimensions of self-awareness. 

Alexithymia characterizes individuals who struggle to recognize and articulate their emotions, often leading to difficulties in interpersonal relationships and emotional expression. On the other hand, interoception pertains to the awareness of internal bodily sensations, providing individuals with valuable information about their emotional states. 

The ability to accurately interpret these internal cues is essential for emotional regulation and understanding. In the context of alexithymia, impaired interoceptive awareness can exacerbate the challenges faced by individuals, making it harder for them to connect their emotional experiences with physiological responses. Consequently, addressing both alexithymia and interoception is crucial in enhancing emotional intelligence and overall well-being.

And yes, both are issues seen in autism. 

Stress and Neck Pain

Insights from Neuroanatomy class. 

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.

Tetanus, caused by bacteria, takes this natural muscle contraction process to an extreme, forcing every single motor fiber in a muscle to contract simultaneously, causing intense pain that is hard to put into words.

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.

Understanding muscle contraction through the lens of disability offers profound insights into the human experience. It urges us to delve deeper, to acknowledge the diverse ways in which individuals perceive and process pain. In doing so, we foster empathy and compassion, paving the way for inclusive healthcare practices that cater to the unique needs of every individual, irrespective of their physical or neurological differences. 

Consciousness

The exploration of consciousness is a central theme in both  Buddhism and Sanathana Dharma (Hinduism) philosophies, and modern scientific inquiry has begun to intersect with some of these ancient concepts. While there are parallels, there are also significant differences in the methodologies, foundational assumptions, and goals of spiritual traditions and scientific inquiry. The intersections, however, provide fertile ground for scientific enrichment.

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.

Self and Non-self:  Sanathana Dharma philosophy's exploration of the self through concepts like "Atman" (individual soul) and its relationship with "Brahman" (universal consciousness) can be seen in parallel with the scientific exploration of individual consciousness and its relationship with the world. Buddhism's concept of "Anatta" (non-self) proposes that there's no continuous, unchanging self. This idea resonates with certain findings in neuroscience, suggesting that the perception of a continuous "self" is an emergent property of various neural processes and not localized in one part of the brain. 

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 18th century consensus on the brain was steeped in ancient beliefs that depicted it as an formless mass governing bodily functions. Franz Josef Gall, challenged this orthodoxy: the brain wasn't a mere lump of flesh but the very seat of our mental faculties, with distinct regions governing specific functions. This revolutionary idea laid the foundation for what we now recognize as "phrenology." While Gall's phrenological theories have been largely discredited in modern neuroscience, his work marked a significant shift in the study of the brain.  Gall's work also contributed to the development of techniques for brain mapping and the understanding of cognitive processes.


Landing himself in plenty of hot water. 
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. 

His beliefs were seen as a direct challenge to established religious doctrines, suggesting that human behavior and personality were products of physical attributes, not divine intervention. This incurred the wrath of religious authorities who deemed phrenology heretical. In 1805, Gall was banned from practicing phrenology in Prussia by the Prussian government, which considered his ideas subversive and potentially dangerous. He was eventually expelled from Prussia but that did not deter him from promoting phrenology elsewhere. He continued to travel and lecture about his theories in other European countries, where phrenology gained a following and influence, particularly in France and the UK.

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  garnered both acclaim and criticism from his contemporaries. One notable figure was Johann Spurzheim, Gall's collaborator and rival, who further popularized phrenology and took it to international audiences. Another contemporary of interest is Marie-Jean-Pierre Flourens, a French physiologist who advocated for a more holistic view of brain function, emphasizing the importance of the brain as a whole rather than isolated "organs." Other scientific peers cast doubts upon his theories, criticizing the lack of empirical evidence and the inherently subjective nature of his observations. Phrenology, in their eyes, was more pseudoscience than genuine scientific inquiry. 

Gall's Neuroanatomy Diagram: A Window into the Mind
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

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

 

EEG capping from a neuroimaging researcher perspective at the Vanderbilt EEG research lab 
(rather than as a half sedated patient in a hospital clinic).

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

I continue to learn....as I navigate grad school

Review vs Meta-Analysis
A review paper /literature review, provides a comprehensive overview and evaluation of existing research on a particular topic. It involves gathering information from multiple sources, such as research articles, books, and other relevant publications, and synthesizing the findings to summarize the current state of knowledge on the topic. Review papers typically do not involve statistical analysis or original data collection.

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

The concept of mental time travel (MTT) refers to the ability of individuals to mentally project themselves backward in time to relive or remember past events, as well as forward in time to imagine or anticipate future events. It is a cognitive process that allows us to mentally simulate and navigate through temporal experiences beyond the present moment.

The MTT task is a neuroscience measure designed to assess an individual's capacity for mental time travel. It typically involves presenting participants with a series of event cues and asking them to generate specific events from their own personal past or future that are related to each cue. For example, participants may be shown cue words such as "graduation" or "vacation" and then asked to recall a specific past event or imagine a specific future event related to each cue.

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


What is  Depersonalization Disorder (DPD)
  • 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)
Caveat: This is a complex phenomena and further research is needed to fully understand underlying mechanisms.

Reasons why DPD may co-occur with autism
  • 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.
Research Findings in Autism and Implications
  • 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)
Caveat: Research is all over the place when it comes to autism, so nothing is set in stone.
 

Self Referencing and Self Projecting

[Concepts in Sensorimotor Research]

Within the context of multisensory integration, self-referencing and self-projecting skills play important roles in our perception of time. 
  • 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.
Both self-referencing and self-projecting skills are closely intertwined with our sensory experiences. Our senses provide us with temporal information through various cues. For example, visual stimuli provide temporal cues through motion and changes in spatial patterns, while auditory stimuli provide temporal cues through changes in pitch, intensity, and rhythm. By integrating these sensory cues with our self-referencing and self-projecting abilities, we can accurately perceive and situate events in time.

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

[Concepts in Sensorimotor Research]

The principle of inverse effectiveness is a phenomenon observed in multisensory integration, which refers to how our brain combines information from multiple sensory modalities, such as vision, hearing, and touch. According to this principle, the strength or effectiveness of multisensory integration is greatest when the individual unisensory cues are weak or ineffective on their own.

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. 

This principle suggests that the brain optimally integrates sensory information from multiple modalities to improve perception and increase sensitivity, particularly in situations where the sensory cues are less informative or ambiguous.

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

 




Researchers at the University of Melbourne have created a dataset that maps connectivity in 40,000 brains. The dataset, called the Melbourne Brain Network Connectivity Atlas (MBNCA) includes data on the structure and function of the brain, as well as information on the participants' demographics and health. The data in the MBNCA dataset comes from a variety of sources, including brain scans, genetic data, and behavioral data.

The MBNCA includes data from over 1,000 autistic individuals; making it one of the largest datasets of its kind. The MBNCA is freely available to researchers and may be a good resource to to study autistic brains to identify potential biomarkers and gain other insights.

https://www.biorxiv.org/content/10.1101/2023.03.10.532036v1



Interaural differences

[Concepts in Sensorimotor Research]

Interaural differences refer to the differences between the sound signals that reach each ear. These differences are caused by the time delay and the amplitude difference of the sound waves that reach each ear.
  • 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.
The brain processes these interaural differences to determine the location of the sound source and create a spatial auditory image, which helps us to perceive the world around us in three dimensions.

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. 

The caveat being, more research is needed in this area for better understanding. Nothing is set in stone when it comes to autism. 

Interoception and exteroception

[Concepts in Sensorimotor Research]

Interoception and exteroception are two types of sensory perception.

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

[Concepts in Sensorimotor Research]

Temporal binding window (TBW) refers to the specific time frame during which the brain integrates and processes information from different sensory modalities. It is the period in which the brain combines and links stimuli occurring close in time and attributes them to a single event. This window is crucial for the perception of synchrony and the formation of coherent perceptual experiences.

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

[Concepts in Sensorimotor Research]

The ventriloquism effect is a fascinating example of multisensory integration, the process by which the brain combines information from different senses to create a unified percept. The brain is integrating information from the visual and auditory senses to create the perceive that the sound is coming from a location (the dummy's mouth) that is different from the actual source of the sound.

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.

Cellular Neuroscience grade

I made an A in this super tough Cell Neuroscience course, filled with baffling weekly quizzes; a course which consumed most of my life this semester. 
OMG.