International Brain Bee Syllabus 2012 Department of Neurosciences, Universiti Sains Malaysia

Transcription

1 BRAIN DEVELOPMENT The cells of the nervous system connect with one another in trillions of remarkably specific patterns that form and change over the course of an organism s life. These connections develop among various types of neurons, a process that begins in the embryo. Knowing how the brain is put together is essential for understanding its ability to reorganize in response to external influences or injury. Scientists hope that new insight into brain development will lead to treatments for those with learning disabilities, brain damage and neurodegenerative disorders and will help us understand aging. The nervous system develops from embryonic tissue called the ectoderm. The first sign of the developing nervous system is the neural plate that can be seen at about the 16th day of development. Over the next few days, a "trench" is formed in the neural plate - this creates a neural groove. By the 21st day (week 3) of development, a neural tube is formed when the edges of the neural groove meet. The front part of the neural tubes goes on to develop into the brain and the rest of the neural tube develops into the spinal cord. Neural crest cells become the peripheral nervous system. By fourth weeks, major regions of the human brain can be recognized in primitive form, including the forebrain, midbrain, hindbrain, and optic vesicle (from which the eye develops). Irregular ridges, or convolutions, are clearly seen by six months.

2 International Brain Bee Syllabus 2012 Neuron is the basic working unit of the nervous system, specialized in transmitting information throughout the body. Basic Structure of a Neuron Dendrites Cell body Nucleus Neurons Transmit Messages in the Brain Axon These specialised cells are the informationprocessing units of the brain responsible for receiving and transmitting information. Each part of the neuron plays a role in the communication of information throughout the body. They come in many shapes and sizes enabling them to conduct specialized functions such as storing memories and controlling our muscles. Myelin sheath Direction of impulse Axon terminals The neurons are composed of cell bodies, dendrites and axons. Dendrites are tree-like extensions at the beginning of a neuron. They receive information from other neurons and transmit electrical stimulation to the cell body. Cell body contains nucleus and cytoplasm, and is the cell s control center. The electrically excitable axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals. The larger the axon, the faster it transmits information. Some axons have an outer layer called myelin sheath that speeds the messages along the pathway. These myelinated axons transmit information much faster than other neurons. Neurons Communicate Via the Synapse Information from one neuron flows to another neuron across a small gap called a synapse. At the synapse, electrical signals are translated into chemical signals (called neurotransmitter) in order to cross the gap. Neurotransmitter is released from the axon terminal after an action potential has reached the synapse. The neurotransmitter then crosses the synaptic gap to reach the receptor site of the other cell or neuron. Then, in a process known as reuptake, the neurotransmitter attaches to the receptor site and is reabsorbed by the neuron.

3 Frontal Parietal Cerebral cortex is the largest and most advanced part of the brain. It is divided into two hemispheres, right and left. The right being more concerned with the artistic and creative ability, while the left is more concerned with analytical aspects. Each half of cerebral cortex is divided into four lobes: Frontal Lobe Reasoning Problem-solving Personality and emotion Motor control Memory Parietal Lobe Pain processing Touch sensation Cognition Movement and orientation Speech Temporal Lobe Auditory and sensation Language recognition Emotion Long-term memory Speech Occipital Lobe Visual sensation and processing Cerebellum Temporal Brain Stem Cerebellum Occipital Located right underneath cerebral cortex and below the brainstem, cerebellum is the second biggest part of the brain (1/8 the size of cerebral cortex). The cerebellum is similar to the cerebral cortex in some ways, where it is divided into hemispheres and has a cortex that surrounds these hemispheres. The cerebellum s main job is to control balance, movement, and coordination (how your muscles work together). Because of your cerebellum, you can stand upright, keep your balance, and move around. Cerebellum is also said to be involved in learning. Major Internal Structures Forebrain Hypothalamus Thalamus Midbrain The forebrain is credited with the highest intellectual functions (i.e. thinking, planning, and problem-solving). The hippocampus is involved in memory. The thalamus serves as a relay station for almost all the information coming into the brain. Neurons in the hypothalamus serve as relay stations for internal regulatory systems by monitoring information coming in from the autonomic nervous system and commanding the body through those nerves and the pituitary gland. Hippocampus Amygdala Pons Hindbrain Cerebellum Medulla Oblongata On the upper surface of the midbrain are two pairs of small hills, colliculi, collections of cells that relay specific sensory information from sense organs to the brain. The hindbrain consists of the pons and medulla oblongata, which help control respiration and heart rhythms, and the cerebellum, which helps control movement as well as cognitive processes.

4 YEAR Schizophrenia Parkinson Multiple sclerosis Major depression / bipolar disorder Huntington s disease Autism Alzheimer s ADHD Tourette Syndrome

5 PET Imaging techniques PET MRI Gene diagnostics Alteration of chromosome structure (e.g: Huntington's Disease) Alteration of chromosome number (e.g: Down Syndrom) MRS fmri MRS MRI MEG MEG Optical Imaging Techniques fmri Optical Imaging Techniques

6 NEURAL DISORDERS CLINICAL FEATURES EPIDEMIOLOGY/ PREVALENCE CAUSES/FACTORS TREATMENT Addiction Alcohol Club drugs Marijuana Nicotine Opiates Psychostimulants Alzheimer s Disease Earliest stages Progress symptoms Final stages Amyotrophic lateral Sclerosis (Lou Gehrig s Disease) Paralysis Respiratory failure Anxiety Disorders Obsessivecompulsive disorder Panic disorder Phobias Social anxiety disorder Generalized anxiety disorder Post-traumatic stress disorder

7 Attention Deficit Hyperactivity Disorder Excessively inattentive, hyperactive or impulsive behaviours Autism Communication difficulties Absent, delayed or abnormal language Impaired social skills Narrow, obsessive interests or repetitive behaviours Common symptoms: Mental retardation, seizures and behavioral abnormalities Bipolar Disorder Deep depression and manic highs with a return to relatively normal functioning in between Have increased risk of suicide Brain Tumors Seizures Headache Vomiting Visual disturbances Impaired mental functioning

8 Down Syndrome Mild to moderate intellectual disabilities Low muscle tone Upward slant to the eyes A flat facial profile Enlarged tongue Increased risk of congenital heart defects Respiratory problems Digestive tract obstruction Dyslexia Learning disability (reading) Huntington s Disease Earliest stages: Involuntary jerking movements of the limbs, torso and facial muscles Progress symptoms Final stages Major Depression Sadnesso Hopelessness Pessimism Loss of interest in life Reduced emotional wellbeing

9 Multiple Sclerosis Numbness Fatigue Blurred vision Clumsiness Slurred speech Weakness Loss of coordination Pain & tremors Loss of bladder control Memory and cognitive problems Depression Neurological AIDS Affected immune and nervous system Dementia Mental problems Neurological Trauma Head or spinal cord injuries Edema or swelling Ischema Pain Chronic or debilitating headache Pain arthritis Neuropathic pain Parkinson s Disease Slowness of movement Muscular rigidity Tremor Postural instability

10 Schizophrenia Disturbances in thinking, emotional reaction and social behavior Chronic illness and personality change Delusions Hallucinations Thought disorder Seizures and Epilepsy Two types: Generalized epilepsy and partial epilepsy Occurrence of unprovoked seizures Stroke Paralysis (one side or whole of the body) Loss of speech Tourette Syndrome Motor and vocal tics (repetitive, involuntary movements or utterances that rapid, sudden and persist for more than one year

11 Trophic factors Cell and gene therapy DRUG Engineered antibodies Small molecules and RNAs

12 Major Concerns Personal responsibility and punishment Diagnosis, treatment and enhancement Social behavior Prediction Informed consent in research Effective and ethical science communication and commercial enterprise For further reading, please download Brain Facts: A Primer on the Brain and Nervous System at