Chapter 9: Biologic basis of practice Flashcards
The biologic basis of behavior, emotions and cognition
Emotions have a biologic basis. Symptom expression is a term referring to the behavioural symptoms seen in mental illness and the link to the neurobiologic basis of the symptom. Psychiatric symptoms are often indicators of central nervous system problems.
Genetics
Schizophrenia bipolar or panic disorders have an increased risk of passing it on to their children. Animal models have greatly increased the ability of researchers to understand the influence of genetics and symptom expression in psychiatric disorders. The human genome project not the complete set of human genes. There are 30,000 genes in the human genome with a brain accounting for only 1% of the bodies DNA. The half map is a catalogue of common human genetic variations. A gene or part of a gene can be altered When this occurs commonly it has affect on human behaviour it is called a polymorphism. Schizophrenia people are at risk for 22Q 11.2 deletion Which has been linked to abnormalities such as cranial focal and cardiovascular alterations.
Population genetics
Population genetics trace given disorders within groups of people, it involves the analysis of Genetic transmission of a trait within families and populations to determine risk and patterns of transmission. It includes family studies twin studies and adoption studies. Few traits are completely irritable. Colour blindness and blood types are examples. A strong genetic contributions exist for most psychiatric disorders. More than one gene exists in producing the disorder. The disorder develops from genes interaction which produces a risk factor and environmental influences that lead to the expression of the illness.
Epi-Genetics
Epi-Genetics is the study of the mechanisms by which genetic inheritance is modified without any change in the organisms genetic DNA sequence. The Eppy genome marks the genome through Friday processes such as DNA methylation or histone acetylation which upper down regulates gene expression.
Risk factors
Genetic susceptibility suggests that an individual may be at increased risk for psychiatric disorder. Learning more about risk factors will lead to preventative care practices.
Current research approaches and advance
Comparative which explores and compare his behavior across animal nervous system‘s from a simple primitive cord like structure to the large complex structure of the human brain. Developmental, studies nervous system structure within an individual or species of animal across different stages of development. Chemo architectural, identifies difference in location of neurochemicals such as neurotransmitters throughout the brain. Cytoarchitectural, identifies differences or variations in cell types structure and density throughout the brain, mapping these variations by location. Functional, identifies location of predominate control over various behavioural functions within the brain.
Brains are more plastic during infancy and early childhood when large adaptive learning tasks should normally occur.
Neuroimaging
Structural neural imaging
• Computed tomography
X-ray beam passed through the head and cereal slices. Computers measure the strength of the beam that results from absorption. Degree of energy absorbed is related to its density. Good at detecting skull fractures and injuries. Relatively safe and non-evasive. Use of contrast medium improves results but may cause for allergic reaction.
• Magnetic resonance imaging
Uses a magnetic field to magnetize hydrogen Adams. The magnetic field is an interrupted impulses causing the molecules to turn.This creates a tiny electric signal which produces the image. Produces greater resolution than a CT. Creates a three dimensional image that allows for gross determination of white and grey areas. However patients may experience headache, dizziness, claustrophobia.
• Diffusion tensor magnetic resonance imaging
Produces information on white matter pathways. Can identify what is happening at the fibre bundle level. It is a special type of MRI. Based on the microscopic movement of water protons and tissues. Used to Investigate white matter changes in schizophrenia dementia and other illnesses.
Functional neuroimaging
• Single photon emission computed tomography SPET
Measuring regional cerebral blood flow. Uses radio scopes that produce only one photon. Data is collected as a three dimensional volume. Less expensive than PET. However there is less resolution and sensitivity than PET
• Positron emission tomography PET
Uses positron emitting isotopes to image brain functioning. Studies cerebral metabolism blood flow and specific neural chemicals. However images appear blurry lack anatomical detail.
• Functional magnetic resonance imaging fMRI
Images neural activity. Shows sequential images of blood flow in the brain as it is happening. However images aren’t as good as MRI. But it is non-invasive
• Magnetic resonance spectroscopy MRS
Uses same equipment as fMRI by altering scanning parameters the signal represents a specific chemical in the brain. However it has limited spatial resolution especially with molecules that occur in low concentrations.
Bridging the structural function gap
MRS and fMRI are examples of imaging procedures that detail structure and function at the same time. Magnetoencephalopathy MEG records Magnetic fields generated by neuronal activity. Trans cranial magnetic stimulation TMS painlessly delivers an alternating current through a metal coil placed around the scope. The current causes a magnetic field to be generated which changes firing along neurons. Areas of the brain may be inhibited or excited.
Cerebrum
Largest part of the brain. The cortex or outer most surface makes up 80%. Contains gyri and sulci. These increase the surface area the longitudinal fisher separates the cerebrum into right and left. Do you hemispheres are connected by the corpus callosum that allows information to be exchanged quickly.
Left and right hemispheres
For 95% of people the left hemisphere is dominant. The right hemisphere provides input into receptive nonverbal communication, spatial orientation and recognition, intonation of speech and aspects of music, facial recognition expression of emotion and nonverbal learning and memory. The left hemisphere is involved with verbal language functioning, receptive and expressive speech control, Temporel order and sequencing, numerical symbols, verbal learning, and memory.
Cerebrum lobes of the brain
Frontal lobes
Make up 1/4 of the entire cerebral cortex. The precentral dries contains the primary motor area. Frontal lobe contains Brokas area which controls the motor function of speech. Frontal lobe contains personality, working memory, executive function, intellect and speech. Insight judgment reasoning concept for my shin problem-solving Abstraction and self-evaluation Are all executive functions. Think of Phineas Gauge.
Parietal lobes
The post central gyrus contains the primary somatosensory area. Posterior areas of the bridal lobe coordinate visual and somatosensory info. The pride lobes contribute to the ability to recognize objects calculate right recognize fingers draw and organize special directions. They are important for speech and maintaining focussed attention
Temporal lobes
Contain the primary auditory and olfactory areas. When Ricky’s area is primarily responsible for receptive speech. Temporal lobe’s integrate sensory and visual information. The hippocampus contributes to memory. Other internal structures modulate mood and emotion
Occipital lobes
Primary visual area. Occipital lobe’s are involved in visual integration of information, colour vision, object and facial recognition and the ability to perceive objects in motion and judge distance
Association cortex
Allows the lobes to work in an integrated manner. Areas of one lobe often share functions with an area of the adjacent lobe. When nerve fibres are related to the same sensory modality they are referred to as association areas.
Cerebrum subcortical structures
Basil ganglia
Contains interconnected cell bodies or nuclear which include the cot a nuclear us, putamen, Globus pallidus, claustrum, subthalamus, and substantia nigra. The basal ganglia are involved with motor functions, learning and programming of behaviours that are repetitive and overtime become automatic. Parkinson’s disease is the most common disorder of the basal ganglia.
Pituitary
Has two parts the anterior and posterior pituitary. The anterior pituitary contains granular epithelial tissue where the posterior contains neural tissue. When stimulated the posterior releases oxytocin and vasopressin. The interior produces several different hormones such as growth hormone thyroid stimulating hormone, follicle stimulating hormone prolactin. Together with the pituitary gland the hypothalamus functions as one of the primary regulators of many aspects of the endocrine system. It’s involved in the control of visceral activities such as body temperature arterial blood pressure, hunger, thirst, fluid balance, gastric mortality and secretions
Limbic system
Basic emotions, needs, drives and instincts begin and are modulated in the limbic system. It is involved with emotions and aspects of memory. Changes to the limbic system can play a significant role in major mental disorders such as schizophrenia depression and anxiety disorders. The limbic system is composed of the hypothalamus, thalamus, hippocampus, amygdala, and limbic midbrain nuclei
Hippocampus
Involved in forming and sorting memories especially the emotion attached to a memory. Neurons in the hippocampus continue to form throughout life. Destruction of the left hippocampus impairs verbal memory. Damage to the right hippocampus results in difficulty with recognition and recall of complex visual and auditory patterns. Deterioration of the hippocampus is seen in Alzheimer’s disease and is a hallmark of memory disfunction
Thalamus
Composed of several distinct something with Eli. Called the relay switch in centre of the brain. Functions as a regulatory structure to rely all sensory information except smell sent to the CNS from the PNS. The thalamus prevents the cortex from becoming overloaded with sensory stimuli.
Hypothalamus
Basic human activities such as sleep rest patterns, body temperature and physical drives are regulated by the hypothalamus. Disfunction of the hypothalamus produces symptoms such as appetite and sleep problems. Nerve cells in the hypothalamus secretes hormones such as anti-diuretic hormone
Amygdala
Connected to areas of the brain involving smell. Is involved in modulating aggression fear anxiety and sexuality. Dysregulation of the amygdala and erratic firing can lead to impulsive acts of aggression and violence and the scene in bipolar mood disorder’s. The amygdala is the part of the brain most affected by psycho active drugs
Limbic midbrain nuclei
A collection of neurons that play a role in the biological basis of addiction. Pleasure centre or reward centre of the brain. They function to chemically reinforce certain behaviours ensuring the repetition. The reinforcement of activities such as nutrition procreation and nurturing young are all aspects of ensuring the survival of the species. However the limbic midbrain nucleus can reinforce unhealthy or risky behaviour such as drug abuse.
Other central nervous system structures
Extrapyramidal motor system
controls muscle tone, common reflexes and automatic voluntary motor functioning such as walking. Dysfunctioning such as Parkinson’s disease.
Pineal Body
The pineal body remains a mystery. Contain secretory cells that release the neural hormone melatonin and other substances. Thought to have Regulatory functions within the endocrine system. Melatonin is associated with sleep and emotional disorders and me modulate immune function.
Locus Coeruleus
Nor epinephrin containing neurons that connects to every part of the brain. Has an influence in the regulation of attention, time perception, sleep rest cycles, arousal, learning, pain and mood. Most involved with processing new unexpected and novel experiences. Disfunction may explain why individuals become addicted to substances and seek risky behaviours despite knowing negative consequences
Brain stem
Composed of the midbrain, ponds and medulla and has important life-sustaining function. Nuclei of numerous neural pathways to the cerebellum are in the brain stem and involved in mediating symptoms of emotional dysfunction.
Cerebellum
Controls movements and postural adjustments. Regulates postural balance and positioning and receives information from all parts of the body including muscles, joints, skin and visceral organs as well as from any parts of the CNS
Autonomic Nervous System
Contains efferent or motor system neurons which affect target tissue such as cardiac muscles smooth muscles and glands. The two main neurotransmitters are acetylcholine and norepinephrine. Is divided into the sympathetic and parasympathetic nervous system’s. They are involved in fight or
Glial cells
Three types of glial cells astrocytes, oligodendrocytes, and micro glial cells. There are five times the number of astrocytes in the brain as neurons. Astrocytes regulate blood flow and form the blood brain barrier. Astrocyte dysfunction may be related to anxiety addictive behaviors depression and schizophrenia. Oligodendrocytes produce the myelin sheath. Damage to the myelin sheath is common in multiple sclerosis. Microglia are the immune cells of the brain.
Neurons and nerve impulses
Responsible for receiving, organizing and transmitting information. Each neuron has a cell body which holds the nuclear us. Neurons are very interconnected and might receive signals from more than 10,000 sources. Most neurons only have one axon but numerous dendrites. 100 billion cells are nerve cells. The firing of a nerve cell produces an electrical impulse. An action potential is a nerve impulse. The membrane is depolarized and a threshold value is reached which triggers the sodium channels which makes the cell become positively charged inside and negatively charged outside.
Neurotransmitters Cholinergics
The synaptic cleft is a junction between one nerve and another. Neurotransmitters directly and indirectly control ion channels. Neuromodulators are chemical messengers that make the target cell membrane more or less susceptible to the effects of neurotransmitters. Excitatory neurotransmitter‘s reduce the membrane potential and enhance the transmission of the signal. Inhibitory neurotransmitter‘s have the opposite effect and slow down nerve impulses. Neurotransmitters are stored in small vessels near the terminal end of the neuron when stimulated the vessels fuse and release the neurotransmitters into the synapse where they bind on the receptor site of the postsynaptic neuron. Many psychopharmacologist agents such as antidepressants act by blocking the reuptake of the neurotransmitter.
Receptor activity
Receptors have the capacity to change developing either a grade or a supersensitivity or less called a sub sensitivity response to the neurotransmitter. The change in sensitivity is most commonly caused by the effect of a drug. These may account for the long term severe effects of psycho pharmacology drugs and the loss of effectiveness of a given medication.
Receptor subtypes
Each specific chemical messenger requires a specific receptor on which the chemical can act. Neurotransmitters may produce different affects at different synaptic sites. These are receptor subtypes. Dopamine has five different subtypes.
Principles of Neuroplasticity
- Use it or lose it
Brain circuits not used in task performance overtime Can decay. - Use it and improve it
Through extended training brain plasticity can be induced - Learning Something New
Repeating something already learned does not induce plasticity but learning something new will - Repeat, Repeat, REpeat
Repeating a new or relearn skill may be needed to induce long-term changes - Be intense but not too intense
Training to intensely can worsen things balance as needed - Brain age matters
Plasticity occurs more easily in younger brains - Timing Matters
Certain types of plasticity change follow a pattern - A little can go a long way
Plasticity in one set of neurons can promote ongoing development in the same or other areas of the brain - Make it important
Motivation and attention are important mediators - Plasticity in one form can block a different plasticity within the same circuit
Developing brain circuits to do one skill may block learning another
