Lesson 3 - Powers of the mind.pdf

POWERS OF THE MIND NUCLEUS / NEURON - Also called nerve cells or brain cell - Basic functional units in the nervous system - At birth, there is about 100 billions neums, however as we grow older, neurons die and lessen in our brain - Receive signal or information (Sensony Neun) - In...

POWERS OF THE MIND NUCLEUS / NEURON - Also called nerve cells or brain cell - Basic functional units in the nervous system - At birth, there is about 100 billions neums, however as we grow older, neurons die and lessen in our brain - Receive signal or information (Sensony Neun) - Integrate incoming signals to determine whether or not me information should be Passed along (Interneuron) - Communicate signals to target cells such as offer neurons or muscle (motor neuron) Parts of a Neuron Dendrites- Receive signals from other neurons, muscles or sense organs and pass the signals towards the cell body. Cell Body- Also Known as Soma, this contains the nucleus; provides fuel, manufactures chemicals, and maintains the neuron in working order Axon- Carries signals away from the cell body to neighboring neurons, organs or muscles Myelin Sheath- Fatty material that insulates an oxygen/ axon; prevents interference from electrical signals from adjacent axons. Terminal Button- Region where neurotransmitters are stored Synapse- Small gap between the terminal button and its adjacent organ, muscle or cell body Synaptic Vesicles- Spherical membrane packages that store neurotransmitter molecules ready for releases near synapses Neurotransmitters- Molecules that are released from active neurons and influence the activity for other cells Neural Communication Electrical Transmission(dendrites to axon) Also known as conduction Mechanism that involves the communication of the cell body with its own terminals via the axon (intracellular signaling) Involves electrical signals (action potentials) along axons to achieve long distance and rapid communication Chemical transmission Communication between neurons (intercellular signaling) that occurs in the synapses by the process of neurotransmission Lock and key model Although there are many different NTs, each has a unique chemical key that fits and open certain locks or receptors Neurogenesis (Prenatal)-process by which neurons are generated from neural stem cells and progenitor cells Neurogenesis (Adult)-Regeneration of new adult neurons in the dentate gyrus of the hippocampus All events that are remembered have a number of features that are not encoded. In a “high-resolution” memory, more details about the event are remembered; while the memory may not be perfect, it is much higher fidelity. In a “low-resolution” memory, less about the original event is encoded within memory, perhaps focusing on a lower number of features or coarse representations Neuroplasticity Brain’s ability to grow and change The brain is plastic throughout our lives The brain can be ‘re-wired’ in many ways: –Mental activity (thought, feeling, or action –Creation of neural structures –Repetition of mental activity –Strengthening neural connections Learning and Neural Communication Learning occurs when two neurons communicate with each other (i.e. neurons have “learned” when one neuron sends a message to another neuron) (Hannaford, 1995) -Everytime we learn, our neurons (dendrites) make connections -The more often we access the neural network, the stronger the connections become. -We learn best by association. -The more often we access the neural network, the synapses become stronger as well. Long Term Potentiation (LTP) The more neurons “fire”, the more the axons and dendrites grow accustomed to each other, thereby, making connections easier to make. Practice and repetition makes it permanent! Practice and repetition build double connections Faster, stronger, double connections last a very long time; hence, we remember what we learn better. Effects of practice on myelination Practice causes the dendrites to grow thicker with a fatty coating of myelin. A study by Bengtsson et al (2005) reveals that training can induce myelination if it is in a period wherein the fiber tracts are still under maturation. The thicker the dendrites, the faster the signals travel. The myelin coating also reduces interference. Practice and repetition builds stronger synaptic connections Practice enables signals to cross the synapse because the contact area becomes wider and more neurotransmitters are stored there. Neural Pruning Process that involves synapse, axon and dendrite elimination that occurs between early childhood and the onset of puberty to increase the efficiency of neuronal transmissions Neurons may lose their connecting powers especially if neurons are not used at appropriate times during brain development Apoptosis Programmed cell death that occurs through a series of events termed apoptosis and is an appropriate and essential event during brain development –Neurons that are extra –Neurons that have fulfilled their functions, –Neurons that have lose their connecting powers and –Neurons that fail to obtain life-preserving chemicals (neurotrophic factors) Later in life, inappropriate neuronal cell death may result from pathological causes such as traumatic injury, environmental toxins, cardiovascular disorders, infectious agents, or genetic diseases Neuronal Death: Apoptosis vs. Necrosis Neuronal death can occur by either necrosis or apoptosis. Necrosis is analogous to neuronal assassination, in which neurons explode and cause an inflammatory reaction after being destroyed by poisons, suffocation, or toxins such as glutamate. On the other hand, apoptosis is akin to neuronal suicide and results when the genetic machinery is activated to cause the neuron to literally "fade away" without causing the molecular mess of necrosis. The Effects of Neurotrophic Factors (NFs) The process of making dendritic connections on an undeveloped neuron may be controlled by various growth factors, which act to promote the branching process and thus the formation of synapses on the dendritic tree. The Effects of BDNF The Brain-Derived Neurotrophic Factor (BDNF) is a protein that increases the growth of the axons and dendrites. ANATOMY OF BRAIN Forebrain Highest center; perceives sensations, initiates voluntary movement, provide awareness of emotions, memory, thinking, planning, language abilities and other higher mental functions Midbrain Reward or pleasure center (stimulated by food, sex, money, music, attractive faces, and some drugs); visual and auditory reflexes, reticular formation (arouses the forebrain so that it is ready to process information from the senses) Pons Sleep and arousal Medulla Respiration, heart rate, blood pressure Cerebellum Coordination of movement, equilibrium, procedural memory Lobes of the Cortex Frontal lobe Emotions, judgements, voluntary movement, guide to the degree of complexity and motor capabilities Parietal lobe Body sensory (touch, pain, pressure, temperature); spatial reasoning Occipital lobe Sense of vision Temporal lobe Sense of hearing