Lecture 4 Flashcards
Abnormalities or damage to the ____ or sensory systems can cause deficits in:
Communication
Learning
Behaviour
Motor
brain
Structures of the _____
Two parts: Brain and the spinal cord
Protective factors: Skull, Vertebrae, Meninges and CSF
CSF drains into the lymphatic or vascular system
CSF is a filtration by-product of blood. Filters out metabolites, drugs, and substances.
Brain and spine work together to carry out functions such as behaviors and body maintenance.
Blood supplied through Intercranial artiers/carotid arteries
Circle of Willis
CNS
3 types of non-neural supports cells called Glia
Microglia- macrophages
Astrocytes – nutrition
Oligodendrocytes – form myelin sheaths (protect axons)
Gray Matter – neurons (body of a nerve cell)
White matter – Axons
Brain to spinal cord are the main pathway for the peripheral nervous system
CNS
3 types of non-neural supports cells called Glia
Microglia
Astrocytes
Oligodendrocytes
Microglia
macrophages
Astrocytes
nutrition
form myelin sheaths (protect axons)
Oligodendrocytes
neurons (body of a nerve cell)
Gray Matter
White matter
Axons
Brain to spinal cord are the main pathway for the _____ nervous system
peripheral
3 parts of the ____
Somatic nervous system
Afferent and Efferent
Autonomic nervous system
Sympathetic and
Parasympathetic
Enteric nervous system
PNS
Neurons – transmit and process information
Neuroglia – perform housekeeping
Synapses – chemical and electrical Dendrites – receive signals
Axons – send signals
Cells of the brain
transmit and process information
Neurons
perform housekeeping
Neuroglia
chemical and electrical
Synapses
receive signals
Dendrites
send signals
Axons
Stored in vesicles and diffuse across the synaptic cleft to bind to receptor molecules in the dendrite
Ionotropic and metabotropic
GABA is the main inhibitory transmitter.
Transmitters can also include: Fatty acids, peptides and catecholamines
Neurotransmitters
External _____
Brain stem
Lobes
Parietal, Temporal, Occipital, Frontal
Olfactory bulb
Brain structures
Internal ____
Limbic system:
Amygadala, hypothalamus, hippocampus
Basal ganglia – limbic and motor functions
Cerebral Cortex
Brain structures
Before _____ to __ years
Begins at conception
Extremely vulnerable at this point
Brain growth spurt begins in the last trimester of pregnancy to 2 years
Birth; 2
Factors
Lack of oxygen
Traumatic physical injury
Lack of essential fatty acids, folic acid or other vital nutrients
Infections
Drugs
Toxins (Maternal use of alcohol)
Stress
Lack of stimulation
These all affect normal development.
Stages of development
Developing fetuses are more vulnerable due to:
Rapid development
Chemical exposure
Blood-brain barrier is not mature
Systems for detoxifying and excreting not fully developed
More years of which a problem can be developed
Stages of development
means the connections between neurons can form, strengthen, weaken or disappear
Plasticity
Infants emotions begin to develop
10 – 18 months
Key components for emotion
Limbic system – responses to stress and formation of memories
Emotion and sensory perception (smelling, hearing, seeing, feeling, and
tasting)
Vital for survival, growth, development, and the experience of bodily pleasure
10-18 months
Puberty is a critical time for typical brain development
Marked by changes in neuroendocrine function
Levels of sex hormones increase
Effect the structure and function of the maturing nervous system
Influence development of steroid-dependent behaviours
Affect stress reactivity
Changes in the neuronal circuitry involve steroid-hormone-induced sculpting of certain synapses as well as the pruning of others
Adolescence
Characterized
Challenges in memory
Requires more time to learn new tasks
Intelligence, abstract thinking, verbal expression remain the same
Life experiences
Wisdom - Makes more rationale and flexible Lifestyle is important in preservation of memory
Aging
Separates the brain and surrounding tissues
Contains: neurons, astrocytes, microglia from the circulating blood
Regulates the transport of nutrients
Signals molecules into the brain
Maintains proper biochemical conditions
Blocks circulating bacteria and pathogens
Defends against infection
Genes are activated and protein recruits white blood cells
Blood brain barrier
Communication system between
Hypothalamus and pituitary gland
Various types of stress activate HPA in the CNS and the PNS and the sympathetic nervous system in the PNS
Abnormal functioning of the HPA axis resulting in different types of
IDD, in mental illness and challenging behaviours
As well as physical illness such as cardiovascular disease.
HYPOTHALAMIC-PITUITARY- ADRENAL AXIS AND STRESS
▶ ______ are more common in developing nations
▶ 1% of the population (although likely underestimated). Only 0.5% are severe.
▶ 1/6 children in the US are thought to have a disorder (autism, ADHD, seizures, hearing loss, learning disorders etc (this was back in the early 2000’s)
▶ 25%-50% of developmental disorders are thought to be genetic
▶ Four factors contributing to IDD
▶ Biomedical
▶ Social
▶ Behavioral
▶ educational
Disabilities
human bodies contain 46 chromosomes; 23 from mother and 23 from father
Genetics
abstract traits such as intelligence, personality, aggression, and sexual
orientation are encoded in a person’s DNA
Nature
behavioral aspects of humans originates from the environmental factors of
upbringing
Nurture
study of changes in gene activity; caused by things other than the genes themselves.
Epigenetics
(Neuroplasticity) changes in neural connections that occur in the brain when people learn new things or memorize new information
Brain Plasticity
Appropriate responsiveness of the stress system to stressors is necessary for a sense of well-being, adequate performance of tasks, and positive social interactions
HYPOTHALAMIC-PITUITARY- ADRENAL AXIS AND STRESS
Inappropriate responsiveness of the stress system may impair growth and development and may account for many endocrine, metabolic, autoimmune, and psychiatric disorders affecting IDD
HYPOTHALAMIC-PITUITARY- ADRENAL AXIS AND STRESS
Three different approaches:
Brain bank – techniques applied to brain tissues collected at autopsy
Neuroimaging and Electrophysiological – studies the brains of the living
Neuropsychological Assessments – cognitive, intellectual, language, visual-perceptual, scholastic, motor, sensory, and emotional/behavioural abilities
Measuring brain activity
techniques applied to brain tissues collected at autopsy
Brain bank
studies the brains of the living
Neuroimaging and Electrophysiological
cognitive, intellectual, language, visual-perceptual, scholastic, motor, sensory, and emotional/behavioural abilities
Neuropsychological Assessments
Studies the ways in which a person’s mental state influences
development or expression of a disorder, disease, or injury
Studies the relationship between psychological processes and the nervous and immune systems
Communication between the brain, the stress response, and the immune system is maintained by molecules called cytokines and neurohormones.
Carry messages from cells to the brain and immune system and back to the brain
PSYCHONEUROIMMUNOLOGY
Neurogenesis – formation of new neurons
May play a role in erasing old memories and making way for new ones
Defective adult neurogenesis in mouse models of certain IDD
Down syndrome
Rett syndrome
Paves the way for new treatment approaches
Cognitive deficits
Unusual behaviors
Neurogenesis in adult brain
Brain plasticity (neuroplasticity) refers to the brain’s ability to reorganize itself by
forming new neural connections.
Plasticity occurs throughout life in response to learning, injury, and environmental changes.
Types of Plasticity:
Synaptic Plasticity: Changes in the strength of connections between neurons.
Structural Plasticity: Changes in the number or structure of neurons and synapses.
Importance:
Vital for learning, memory, and recovery from brain injuries.
Enhanced during childhood but continues throughout life.
NEUROPLASTICITY
The brain consists of large numbers of neurons that communicate with each other through electrical and chemical signaling.
Sights and sounds are encoded
Movements are planned
Commands are communicated
To learn is to modify the signaling between neurons, by creating new connections or changing the strength with which signaling occurs
Learning and memory in the brain
Allows for the visualization of brain structure and function.
Used in both research and clinical settings to diagnose disorders and study cognitive processes.
MRI (Magnetic Resonance Imaging): High-resolution images of
brain structures.
fMRI (Functional MRI): Detects brain activity by measuring blood flow.
PET (Positron Emission Tomography): Measures metabolic
activity in the brain.
EEG (Electroencephalogram): Records electrical activity in the brain.
Brain imaging
Neurodevelopmental disorders:
Often associated with deficits in neuronal plasticity
Fragile X syndrome (FXS)
Disruption of a single gene
Spines remain immature; failed to form fully functioning
synapses
Decreased efficiency of neural networks during early brain development
BRAIN PLASTICITY IN THE CONTEXT OF DISEASE AND INSULT
Traumatic Brain Injuries – caused by external forces large enough to affect the structure and functioning of the brain
Primary Brain Injuries – caused by impact
Secondary Brain Injury – raised intercranial pressure, edema, and ischema
Effects the brains functioning for months or years
BRAIN PLASTICITY IN THE CONTEXT
OF DISEASE AND INSULT
At critical periods of development the brain undergoes important structural changes
Earlier interventions have higher probability of success
The young brain; targeted behavioural interventions
Cognitive behavioural therapy (CBT) effective in pediatric OCD
Increasing gray matter in frontal cortex
CBT targets brains ability to rewire itself
BOOSTING PLASTICITY AS TREATMENT
Exercise
Improving fitness increases overall brain health
Decreases inflammation and pathological processes
Important processes that support brain plasticity
Aerobic exercises
Cardiorespiratory fitness
Contribute to healthy brain aging
BOOSTING PLASTICITY AS TREATMENT
▶ Fetal Vulnerability – substances and agents that induce physical deformities in the fetus and CNS
- Teratogens
Biomedical
▶ Genetic Causes – variable in their expression
▶ Most common genetic disorders:
▶ Down Syndrome
▶ 22q11.2 deletion Syndrome
▶ Fragile X Syndrome
Biomedical factors
▶ Inborn Errors of Metabolism
▶ 89 potentially treatable genetic disorders (Inborn Errors of Metabolism)
▶ Can not turn food into energy
▶ Phenylketonuria (PKU)
▶ Galactosemia
▶ Hunter Syndrome
▶ Lesh-Nyhan Syndrome
Biomedical factors
▶ _____ Chromosome Disorders and Imprinting Disorders
▶ Abnormalities in the number of sex chromosomes –cause mild intellectual disabilities and physical anomalies
▶ Turner Syndrome
▶ Klinefelter Syndrome
▶ Two different but related developmental disorders
▶ Prader-Willi Syndrome
▶ Angelman Syndrome
▶ Both are related to deletions or duplications in chromosome 15
Sex
________ – thyroid hormone deficiency ** most easily treated thing in the world in our part of the world
▶ Genetic mutations or iodine deficiency (easily treated)
Congenital Hypothyroidism
______ single nucleotide mutations and loss of function
mutations
▶ Autism Spectrum Disorders (ASD)
De Novo
– mutation in mitochondrial DNA (not common)
▶ Can be maternally inherited
▶ Myoclonic epilepsy with ragged red fibers
▶ Mitochondrial Myopathy, encephalopathy, lactic acidosis, and stroke syndrome – a progressive neurodegenerative disorder
Mitochondrial disorders
▶ Ethnic Origin – may influence the chances of a child being affected by or being a carrier of a genetic disability
▶ Survival Advantage – phenomenon associated with recessive mutant genes
▶ Sickle Cell Anemia – Red blood cells are sickle shaped
▶ Beta Thalassemia – body cannot make the beta chains of
hemoglobin
▶ Being the carrier of only one mutant gene is an advantage
Other Factors that Affect Genetic Causes of Disability
▶ Maternal malnutrition prior to conception
▶ Protein – energy undernutrition and deficiencies of certain vitamins (folic acid, vitamin B12, Vitamin A) and minerals (iodide, zinc, iron)
▶ Economic, social, and cultural factors
Malnutrition
▶ Required by the body to make new cells
▶ Folic acid deficiency is a risk factor for neural tube defects (Spina Bifida) and Anencephaly (missing or reduced amount of brain tissue)
▶ Vitamin B12 Deficiency is a risk factor for neural
tube defects
Folic Acid and B12 Deficiencies
Vitamin ___ Deficiency and Excess
▶ Crucial for normal nervous system development
▶ Important for proper function of the immune system
▶ Leading cause of preventable blindness in children
▶ Risk of disease and death from severe infections accompanied by diarrhea and measles
A
Vitamin __ Deficiency
▶ Is a prohormone
▶ Known as the “sunshine vitamin”
▶ D sufficiency is essential for preventing rickets in children
▶ Contributes to abnormal fetal development
D
_____ Deficiency
▶ Helps to prepare the immune system to do its job
▶ Has been associated with adverse postnatal behavioural outcomes
Iodine
Complications of ______ in infants:
▶ Developmental delays
▶ Behaviour disturbances – decreased motor activity
▶ Social interaction and attention to tasks
▶ Compulsive eating of non-food items
(PICA) (caused by)
▶ Irreversible impairment of learning ability
iron deficiency anemia
▶ Can result in problems with attention, memory, learning, social behavior, and intellectual ability
▶ Toxic threats include:
▶ Methylmercury
▶ Polychlorinated biphenyls (PCB’s)
▶ Ethanol
▶ Lead
▶ Arsenic
▶ Tolulene
▶ Manganese
▶ Flouride
▶ Pesticides (DDT, DDE)
Toxic Threats
Maternal Obesity and ______
▶ Increased risk of neural tube defects
▶ Type II diabetes some have it before pregnancy and some develop it during known as gestational diabetes
▶ Maternal diabetes diagnosed at 26 weeks gestation creates a significant risk factor for ASD
Diabetes
Abnormal ______ Function
▶ Three types of thyroid disorders that affect fetal development:
▶ Hyperthyroidism – makes too much thyroid hormone
▶ Hypothyroidism – thyroid doesn’t make enough thyroid hormone
▶ Congenital Hypothyroidism - Results in permanent developmental delay and growth defects
Thyroid
▶ Can result in emotional problems, symptoms of ADHD, ASD, or impaired cognitive development
Maternal Stress
▶ Intrauterine or Perinatal
▶ Toxoplasmosis
▶ Other (Syphillis, varicella-Zoster, Parvovirus B19)
▶ Rubella
▶ Cytomegalovirus
▶ Herpes Virus
▶ Human Immunodeficiency Virus (HIV)
▶ Zika Virus
▶ Teratogen causing microcephaly
▶ Rh Disease in the newborn
▶ Pre-term delivery and low birth weight
Infections
▶ Premature Cutting of the Umbilical Cord
▶ Cord clamped before babies first breath and before the cord stops pulsating
▶ Decreases baby hemoglobin levels and iron stores causing anemia
▶ Advanced Parental Age
▶ Trisomy 21, 13, and 18 are three syndromes associated with increased maternal age
▶ Brain Injury
▶ Brain injury is a common cause of cerebral palsy
▶ Falls
▶ Child battery
▶ Bicycle, scooter or sports
▶ Complications during delivery
Maternal Metabolic Affects
▶ Sensory impairments, challenging behavior, mental health are very common in people with DID
▶ Sensory impairment -> decreased sensory exposure -> underdeveloped area of the brain = more challenging behavior
Co-Occurrence of Sensory Impairments and IDD
▶ 3 to 4 times more likely
▶ People with ASD – severe disabilities, sensory impairments and communication disorders
▶ Increased risk of having co-morbid mental health disorders
▶ ADHD
▶ Schizophrenia
▶ Depression
▶ Bipolar Disorder
Co-Occurrence of Sensory Impairments and IDD
▶ New born screening programs
▶ Immunization programs
▶ Access to early comprehensive prenatal care
▶ Counselling women with PKU to use a restricted diet
▶ Removal of lead from the environment
▶ Safe storage of toxins
▶ Use of child safety seats, bicycle helmets and sports helmets
▶ Installation of pool fencing
▶ Measures to avoid drunk driving
▶ And many more……
IDD and Prevention
