link: synapse modification



theme: The focal point for the biological basis of learning is the contact point between nerve cells or 'neurons' i.e. the 'synapse'. New synapses grow and develop to create neural networks with experiences of learning. Creation of neural networks is a function of 'synapse modification' or 'neuroplasticity'.

"Learning occurs as a result of changing the effectiveness of synapses so that their influence on other neurons also changes... Learning is a function of the effectiveness of synapses to propagate signals and initiate new signals along connecting neurons. Learning and experience change the structure of the neural networks." (Geoffrey Hinton, "How Neural Networks Learn from Experience," Scientific American, 267:3, September 1992, 145.)

THE BRAIN IS MADE UP OF NEURONS CONNECTED AT THE SYNAPSES TO FORM 'NEURAL PATHWAYS'. The brain is the biological organ of learning... the basis of mental processes which underlie mental functioning as 'thought', or 'mind'. The thinking patterns of the mind consist of 'analysis' - interrelated processes of remembering and comparing mental data and 'synthesis' - organizing, integrating, evaluating, detecting relationships and making connections. Analysis and synthesis are based on the structural patterns of of interconnections 'nerve cells' or 'neurons'. (The number of neurons in the brain - perhaps about 100 billion - is fixed at birth.) Neurons are connected to forthe corresponding patterns of  'nerve circuits'... 'neural circuits' ...'neural networks'   ...'neural pathways' throughout the cortex of the brain.

The formation of neural pathways results from neuron activity -  propagation of electrical stimuli or 'nerve impulses' along the neurons and the 'two process mechanism' of transmission across their connections between them - specialized points of contact - the 'junctional connections' or 'neural junctions' i.e. 'synapses'.

SYNAPSES FUNCTION IN THE FLOW OF INFORMATION WHICH IS THE BASIS FOR LEARNING At the synapse, nerve impulses are converted to chemical processes which excite or inhibit activity in the connecting neuron depending on their strength (intensity) which determines the molecular events at the synapse (synaptic activity). Depending on the occurrence of excitation or inhibition synapses are either strengthened or weakened. New synapses can be created. Established synapses can deteriorate. As a result of this process of 'synapse modification' neural pathways are altered. Alteration of neural pathways involves the physiological process of continuity of information from one part of the brain to another i.e. 'information flow'. Information flow is a function of the propagation of nerve impulses along the neurons and their transmission from one neuron to another across the gaps which separate them, the 'synaptic clefts'. The effectiveness of synapses to initiate or 'fire' the propagation of new signals on connecting neurons involving a series of complex molecular events and depends on nerve impulses which are strong enough to increase the strength or 'potency' of other synapses so that  their influence enhances the creation of new synapses and new pathways. When stimuli are not strong enough then synapses regress. Formation of new synapses depends on stimulation through activity. Changes in neural pathways and the creation of new ones constitute the biological basis for 'learning' and the retention of learning or 'memory'.

Synapse modification is the 'trace of learning' or 'memory trace' or 'engram'.

NEURAL TISSUE HAS THE ABILITY TO CHANGE or 'LEARN': 'NEUROPLASTICITY' The capacity of neural tissue for long lasting modification at the synapses is known as 'neural plastic capability', 'neural plasticity' or 'neuroplasticity'. New synapses grow and develop through 'synaptogenesis' a physiological process which accounts for the 20-fold increase in the number of synapses - to more than 1,000 trillion - in the first months of life. (The number of possible synaptic connections is greater than the number of atoms in the universe.) The growth and development of new synapses produces changes in the structure of functional neural pathways and the creation of new ones. Neuroplasticity - the structural basis for the function of learning and retention of learning or 'memory' - includes microstructural changes in established synapses or 'synaptic connections' ... 'spine synapses' on the dendrites of neurons in the cerebral cortex and the hippocampus..., enlargement or 'hypertrophy' and ramification of existing synapses. Learning and memory are functions of natural physiological processes of 'brain functioning'. Formation of synapses in the cortex is 'function-dependent'. Evidence is provided in the comparison studies of rats raised in 'rich environments' and 'poor environments' (Marion Diamond). Diamond's studies indicate that experiential learning is a function of stimuli which are intense ...strong enough to produce nerve impulses of sufficient intensity to ensure their transmission across the synaptic clefts and their propagation along connecting neurons.   

 "We are led to conjecture that the structural basis of memory lies in the enduring modifications of synapses, the functional connections between nerve cells. These would involve microstructural changes such as the 'hypertrophy' (increase in size) when memory is stored and regression of synapses in forgetting. The efficacy of synapses could be increased with conditioned activation or 'potentiation.' (John Carew Eccles 1957. "The Physiology of Nerve Cells" Johns Hopkins Press Baltimore 209-211)

As a natural physiological function of the brain the process of learning is enhanced by physiological factors such as nutrition, sleep, exercise... i.e. 'health' as 'wholeness' or 'wellness'.

EXPERIENTIAL LEARNING  INVOLVES STIMULI WHICH ARE STRONG ENOUGH TO ESTABLISH NEW SYNAPTIC CONNECTIONS BETWEEN NEURONS IN THE CORTEX Knowledge of the role of stimulation on synapse modification is directly related to educational methodology.The effectiveness of synapses is modified or altered by experience. In experiences of learning the stimulation of nerve impulses at the synapse enhances the influence of neurons on each other and causes new synapses to form and grow... 'experiential learning'. Experiential learning as 'successful learning' is a function of synaptic activity which involves stimuli strong enough to establish new synaptic connections between the neurons in the cortex of the brain. When new synaptic connections are established then changes are brought about in the structure of existing nerve networks and nerve circuits and learning results.

Stimulation from interest or 'curiosity' ...'intrinsic motivation' based on intrinsic motives for learning which are rooted in the instinct for self-preservation i.e. 'human needs. This is of particular significance to learning theory.

IMPLICATIONS FOR EDUCATION Successful learning is a result of the natural functioning of the brain. Learning is brain-based... 'brain functions' are the basis of learning. 'Brain based learning' or 'natural learning' is a function of the generation of nerve impulses at the synapse, their propagation at definite rates along the axons of neurons and their transmission across the synaptic clefts... optimal brain functioning or 'optimal learning' or 'optimalearning'. Optimalearning is a function of the creation and enhancement of synaptic transmission ...facilitated by teaching to the brain's potential for holistic learning with the use of teaching methods which are compatible with brain functioning or 'brain-compatible'... Teaching methods which stimulate... enhance the formation of synaptic connections also enhance learning... 'brain-based learning'. Methods which enhance the formation of synaptic connections are compatible with the natural functioning of the brain i.e. 'brain-compatible'. Brain compatible teaching methods enhance learning i.e. 'facilitative teaching'. Facilitative teaching engages the learner's intrinsic motives for learning or 'human needs' i.e. 'intrinsic motivation'. Intrinsic motivation enhances learning... involves the psychological value of the human capacity for creativity and productivity or 'work'. Meaningful work engages the human potential for self-development ... development of 'moral consciousness' or 'conscience' i.e. 'self-actualisation'. Education for self-actualisation is 'holistic education'. Holistic education increases the scope of so-called 'traditional education' as 'schooling'. Education as schooling involves teaching methods which are not compatible with the natural functioning of the brain. They are antagonistic to natural brain functioning or 'brain-antagonistic'.

Brain-antagonistic methods of teaching and 'conditioned learning' actually inhibit experiential or 'real learning' because they inhibit the formation of new synaptic connections in the cortex of the brain.