Mechanisms of Change
The malleable, adaptive nature of our biopsycho selves
‘We shall have to find a contact point with biology.’ Freud
Freud’s assertion strikes a chord with many of us who accept the premise that we are no more than our biology and yet also embrace everything else that we are, our memories, thoughts, contradictions, and emotions; our creative streaks, our habits and unconscious motivations and our tendencies to anger or to tears. But how does everything we are, the richness, depth and wonderful complexity of us arise out of 1.4kg of rather wet, grey substrate?
Over 100 years ago Freud began his Project for a Scientific Psychology and tried to link his knowledge about the brain with the observations he made in psychology. The immeasurable gulf between these levels of explanation led him to abandon his Project in favour of psychoanalysis, the task of observing and explaining psychological phenomena. Despite distancing himself from the neuro-scientific theories of the time in order to preserve impartiality for psychoanalysis, Freud believed that psychoanalysis was a science that would someday be reconciled with basic neuroscience. That day is almost upon us and “The Neuropsychotherapist” brings you the very latest neuroscientific research that is relevant to the endeavours of psychotherapy and counselling.
Mechanisms of ChangeWe are at an exciting place in the evolution of psychotherapy where we are beginning to see scientific evidence for neural changes mediated through talking therapy alone. Psychotherapists witness and their clients experience, profound change as a result of the psychotherapeutic endeavour suggesting that psychotherapy can bring about actual changes in the brain. The nature of these changes has been long been mysterious but advances in neuroscience are now demonstrating that the brain is much more dynamically adaptive and malleable than was previously believed. From the level of the genes to the degree of functional connectivity between brain regions, scientists are discovering that our brains are incredibly plastic and adaptively responsive to environments, relationships and even odours! The Mechanisms of Change department is interested in the adaptive, malleable nature of our neurobiology and what implications the latest research has for the way we practice and evaluate psychotherapy.
Adaptive changes within the brain occur at many levels, from the molecular where the influence of chemical groups on DNA alters gene expression, through neural and glial plasticity which allow us to learn and remember, to changes in functional connectivity between regions of the brain which help us to articulate and moderate our emotional and stress responses. Mechanisms of Change spans the breadth of adaptive changes that occur in the brain and body, covering epigenetics, neurogenesis, synaptic and white matter plasticity and changes in functional connectivity between brain regions.
Epigeneticsinvolves the addition of small chemical groups, such as methylations, either directly to the DNA or to the histone proteins that the DNA wraps around. These ‘epigenetic marks’ may be transient but can also be inherited by our children and even by their children. These tiny molecular modifications act like volume controls over the transcription of particular genes. What makes epigenetics a hot topic is that our experiences in the world, our food, the care we receive as infants and the variety of opportunities we have to socialise or learn or to participate in new activities, all leave their marks on our genes. Science has demonstrated that our genes learn through our experiences. Is psychotherapy an experience that makes an epigenetic mark?
Neurogenesisis a multi-stage process of generating and integrating new neurons into the existing network of the dentate gyrus. Neurogenesis occurs in the hippocampus which is a region associated with learning, memory and emotion and in rodents the rate and success of neurogenesis is intricately linked with hippocampal dependent learning. Adult neurogenesis recapitulates the developmental trajectory of embryonic neurogenesis with the new neurons going through a period of hyper-excitability where they also have enhanced plasticity. This enhanced neural plasticity contributes to ‘pattern separation’ which is thought to underlie our ability to separate closely spaced memories. Exposure to extreme stress, such as the stress that causes Post Traumatic Stress Disorder reduces neurogenesis and consequently impairs pattern separation perhaps leading to the integration and over-generalisation of fear memories that is a characteristic feature of PTSD. Depression is also associated with reduced neurogenesis and this finding spawned the neurogenic theory of depression and consistent with this is the finding that most anti-depressant treatments from medication to electroconvulsive therapy enhance neurogenesis. Exercise and the experience of an enriched environment also stimulate neurogenesis. If psychotherapy can be thought of as a type of environmental enrichment, perhaps one which offers novel emotional experiences, it may enhance neurogenesis or alternatively psychotherapy may require neurogenesis so that new therapeutic experiences can be integrated into the existing neural network.
Synaptic plasticityThe human brain is thought to be made up of 100 billion neurons each of which may make 7-10000 synaptic connections to other neurons, meaning that there is a truly awesomely huge number of synapses in the human brain! Synapses are dynamic neural connections that transmit a one way de-polarising signal from a pre-synaptic to a post-synaptic neuron. The synapse strength is highly regulated and can be strengthened or weakened to make it more or less likely that the post-synaptic neuron is depolarised. In addition synapses can be gained through synaptogenesis or lost through regulated processes such as synaptic pruning or through neurodegeneration. The number, pattern and strength of these dynamically changing synaptic connections has been termed ‘our connectome’ by Sebastian Seung who in his TED talk ‘I am my connectome’, popularised the idea that our thoughts, feelings and memories, our identities, are held as activation patterns within the neural network of the brain.
In 1949 the neuropsychologist, Donald Hebb theorised that learning was a process of increasing the efficiency of impulse transmission or synaptic strength between two neurons that are active at the same time; the succinct and ubiquitously quoted version is, neurons that fire together wire together. In 1973 Bliss and Lomo realised Hebb’s prediction with the discovery of long-term potentiation (LTP), demonstrating a persistent increase in the strength of hippocampal synapses following high frequency stimulation. A compelling degree of correlation between drugs that block or enhance LTP and have the same effect on learning and memory has led to widespread acceptance of LTP and its complement LTD, (long-term depression) as being the cellular mechanisms of learning and memory.
As we learn throughout our lives and are constantly creating new memories and forgetting old ones the cellular mechanism of learning and memory must be similarly flexible. As the strength of the synapse between neurons dynamically changes in response to the pattern of their firing, this requirement is met, and the capacity of synapses to change in this way is referred to as synaptic plasticity. A simple metaphor, popularised by Seung, to illustrate synaptic plasticity is to think of the pattern of activation of particular neurons within a network like water trickling down a mountain. The more a pattern of neurons fire together, the stronger the synapses between them becomes, rather like the water wearing a deeper groove that eventually becomes a stream bed. In order to change the course of the water an alternative groove must be worn, and similarly with synaptic plasticity, we can strengthen the synapses between neurons in a different activation pattern following new experiences or new learning. Psychotherapy is a new experience of a relationship for a client and the repeated experiences within this benevolent relationship such as being empathised with, attuned to and valued enable new grooves to be worn, and a new representation of relationships to be formed and carried into the world as a more positive anticipation, and expectation of future relationships.
White matter plasticitycan be thought of as being the next level of up from synaptic plasticity as the myelin sheathes around the neuron’s axon which form white matter are also dynamically regulated by neuronal activity, experience and learning. Myelin is generated by glial cells of the nervous system and forms an insulating multi-layered wrap around axons which increases the speed and efficiency of transmission of the electrical impulse down the axon. Myelination of axons and axonal tracts continues until humans reach their thirties and occurs latest in the brain regions that are highly neuro-plastic and consequently most modifiable by experience such as the pre-frontal cortex, a region associated with executive function, decision making and social competence. Myelin and changes in myelination can now be visualised allowing us to see how myelination changes with experiences, including playing the piano and learning to juggle as well as the practice of meditation. Intelligence quotients and working memory ability also correlate with the extent of myelination in the areas of the brain relevant for the particular task. Emotional and social experiences also affect myelination as in animal studies, social isolation reduces myelination in the frontal cortex accompanied by social and memory deficits whereas environmental enrichment paradigms lead to increased myelination and improved cognitive performance. These findings are consistent with findings in humans; neglected children have reduced myelination of their corpus callosum, whereas premature born babies that have an enriched program of individualised care have have increased myelination in their frontal lobes and at 9 months old perform better in behavioural tests. Interestingly, many people suffering with a variety of psychiatric disorders also have structural differences in their white brain matter.
Essentially myelination occurs in response to neural activity and increases the efficiency of impulse transmission down the most active neural pathways. If we were to continue with the water metaphor for synaptic plasticity, myelin would be a pipe to increase the flow and reduce the loss of the water. In order to change the way the water flows, not only does a competing groove, (neural pathway) have to be built, (activated) it has to be used over and over to make building the myelin ‘pipe’ biologically worthwhile. The effect of repeated experiences or practice can be seen readily in the brains of musicians, as the degree of myelination correlates with the number of hours of practice. Thus repeated positive relational experiences in psychotherapy may act as creating and then repeatedly ‘practising’ the activation of new neural pathways. It would be wonderful to be able visualise the psychotherapeutic change by imaging our plastic white matter if anyone has a spare research grant?
Functional connectivityDifferent regions of the brain are specialised for different tasks; the amygdala as part of the limbic system, is the seat of emotional processing, the hippocampus is important for memory formation and spatial navigation, and the pre-frontal cortex is considered vital for executive function and for driving socially acceptable behaviours. These regions are specialised within themselves but also connect with each other and these ‘between region’ connections can now be visualised using various imaging techniques. It is frequently, although not universally the case, that synchronously activated brain regions, considered to be functionally connected, are also structurally connected through bundles of myelinated axons called white matter tracts. Both structural and functional connections can be imaged using distinct magnetic resonance imaging methods. Imaging studies have demonstrated that the functional connectivity between various brain region changes throughout development, with age, and differs between males and females. Connections between the amygdala and the pre-frontal cortex of the brain are important in how we process our emotions and thus it is unsurprising that early life stressors such as abuse impact the connectivity between these brain regions, or that people who suffer with depression, PTSD or many other mental health problems also have altered connectivity between their amygdala and pre-frontal cortex. Allan Schore suggests that increased integration and connectivity between higher and lower right brain regions is the hallmark of a secure attachment and is also a predictor of infant mental health. This fortuitous state of an integrated right brain is achieved through myriad rewarding interactions between a mother and her ‘securely attached’ infant where their right brains are in harmony or ‘affective synchrony’. As adults, attachment patterns (described by Ainsworth and Bowlby) are modifiable through new experiences of relationship, including within the psychotherapeutic relationship. Fortunately, the orbitofrontal cortex which underlies many of our attachment related interpersonal skills, including our capacity to empathise and to reflect upon ours or other’s emotional states, remains plastic and is thus modifiable by new relationship experiences even in adulthood. Greater activity in the orbitofrontal cortex and increased connectivity to subcortical regions has already been linked to successful psychological treatments, so the prospect of visualising a psychotherapeutically mediated change in attachment pattern through a correlating change in functional connectivity between brain regions is almost within reach.
The brain is the organ of adaption. At every level in our brains, from the molecular and epigenetic through neurogenesis and neuroplasticity to the connections between regions of our brain, adaptive changes occur. In the widest sense, the brain perceives our environment to anticipate it and adapts so that we may thrive, or at least survive, and reproduce. An important aspect of our environment are our relationships, which at the very beginning of our lives are crucial for our survival when we are babies depending entirely on the caring relationship we have with our mother or caregiver. Our brains are profoundly shaped by and adapt to, our relationships with our primary carer, creating representations of relationships and attachment patterns that will probably be maintained throughout our lives. If our relational experiences are positive and our brains are changed by that relationship in all and more than the ways described above, we may achieve right brain integration and benefit from having a secure attachment with our caregiver, but if our experiences are not so positive, neglectful, or even abusive, our brains will adapt to reflect and anticipate these experiences. For better or worse we carry the ways our brains have adapted and the experiences of our primary relationships out into the world where they linger as the anticipations and expectations, even in the creations, of the relationships we forge with our partners and our own children, often despite our conscious determination to break free of our pasts. Clearly, as babies, we cannot choose the relationship we will have with our primary caregiver, nor can we prevent our brains from adapting to the relational experiences we have had; however, armed with the information that experiences can change brains we can, as adults, make choices about what kinds of relational experiences we would like to have and actively seek out those experiences. The experience of psychotherapy offers our brains a positive relational world to experience and thus may ameliorate some of the effects of previous negative relational experiences. Through a multitude of new and repeated experiences of empathy, attunement and repair after ruptures in the psychotherapeutic relationship, our brains adapt to this new paradigm of relationship which may be taken out into the world as a healthier anticipation and therefore creation of future relationships. Although it is unlikely that psychotherapists will be able to scientifically validate their efforts through visualising the changes in their individual clients’ brains through the psychotherapeutic relationship it perhaps heartening to understand that the experience of relationship has the power to change the brain at every level from the expression of genes through to the connectivity between brain regions. The profound changes experienced by the client and witnessed by the psychotherapist are real even if they are still not easily measurable by neuroscience.
Department Editor: Dr. Haley Peckham
Haley has a degree in philosophy, and Masters degrees in Philosophy of Cognitive Science, and Molecular Neuroscience and a PhD in Neuroscience from the Uni of Melbourne.
Email: [email protected]