Central Nervous System Flashcards
Brain and Behaviour
The Central Nervous System (CNS) is comprised of
Brain and Spinal Cord
The Spinal Cord links to…
Muscles and organs
The Spinal Cord is divided into
4 major divisions, 30 segments
What are the 4 major divisions of the spinal cord?
- Cervical (C1-C8)
- Thoracic (T1-T12)
- Lumbar (L1-L5)
- Sacral (S1-S5)
The fibers entering the dorsal portion of the spinal cord transmit…
sensory information into the CNS
The fibers exiting the ventral portion of the spinal cord transmit….
motor information out from the CNS
Damage to the spinal cord results in:
A loss of communication and control (e.g., quadriplegia, paraplegia)
Partial damage to the spinal cord results in:
Paresis (weakness)
What is the role of the skull and cranial meninges?
Protection of the brain
What are the three layers of the cranial meninges
(Outside in): Dura mater, arachnoid mater, pia mater
What is contained within the sub-arachnoid space?
Arteries, veins, and trabeculae
What is the role of the ventricles in the brain/the cerebral ventricular system?
Produce and surround you brain in cerebrospinal fluid
What is the role of cerebrospinal fluid?
- To maintain the brains buoyancy
- To protect the brain from infection
- To regulate cerebral blood flow
What is the cerebrum?
The largest part of the brain, divided into two hemispheres (see image)
Neurons transmit information via
electrochemical signals
Space between two neurons
Synapse
Parts of a neuron
cell body/soma, dendrites (which receive signals), and an axon (which transmits signals)
Role of neurotransmitters
Facilitate transmission of information across synapses
What is a myelin sheath?
Insulation of the neuron’s axon, speeds up transmission, made up of glial cells
Neurotransmitter responses can be either
Excitatory (increase the likelihood of post-synaptic neuron firing) or inhibitory (decrease the likelihood of firing)
Norepinephrine
Fight or flight response, regulates mood and alertness
Dopamine
Motivation, pleasure, reward, and movement, lack associated with schizophrenia, Parkinsons and tourettes
Serotonin
Influences mood, sleep, appetite and emotional regulation, too much: schizophrenia, autism, food restriction. Too little: bulimia, ptsd, OCD
Acetylcholine (Ach)
Attention, learning, memory, sleep, muscle contraction
GABA
Inhibitory neurotransmitter, reducing anxiety and regulating sleep. Damage to basal ganglia where GABA is secreted = Huntington’s
Glutamate
Excitatory neurotransmitter, learning and formation of long-term memory
Hippocampus
part of limbic system
involved in memory formation, transition of short-term to long-term memory
Amygdala
Part of limbic system
Proesses olfactory info, processing emotions
Thalamus
interior
relays information between cortex and the brainstem (brain’s sensory switchboard), regulates attention and perception
Basal Ganglia
subcortical, encloses the thalamus
responsible for motor output, emotion, cognition, and eye movements
Received input from the cerebral cortex and sending information out to the thalams
if damaged, difficulties with coordination and rhythm of movement (extrapyramidal syndromes)
Brain Stem (incl. + function)
incl., midbrain, pons, medulla
sits underneath the thalamus
regulated autonomic functions (breathing, heart rate, etc.)
reticular formation (in medulla) regulates alertness, consciousness and pain
Cerebellum
Behind brainstem
Divided into superior, middle, and inferior cerebella penducles
Regulation of movement, automatic and rhythmic movements, coordination of limbs, and postural control
incld. cognitive functions (learning + attention)
Vulnerable in multiple sclerosis, lesions result in motor incoordination
The Frontal Lobe Includes
The primary motor cortex, premotor cortex, orbitofrontal cortex, prefrontal cortex
The frontal lobe is responsible for
attention, cognition, reasoning, problem solving, voluntary movement
Damage to the primary motor cortex results in
difficulties in motor learning
Premotor cortex is responsible for
limb movements, includes mirror neurons
Prefrontal and orbitofrontal cortexes are responsible for
executive functioning (incl. reasoning, judgement, planning)
Deficits in the prefrontal cortex are seen in
ADHD, schizophrenia
Broca’s area
responsible for speech + comprehension, damage here results in Broca’s aphasia
Temporal Lobes incl.
superior, middle, and inferior temporal gyri
Superior temporal gyri is responsible for
primary auditory processing, aka Heschl’s convolution
Auditory Association Cortex is responsible for
Further auditory processing specific to language comprehension, aka Wernicke’s area. Wernicke’s aphasia related to difficulties extracting meaning from spoken language
Parietal Lobes
Site of primary somatosensory processing. Integrates sensory information to create a sensory picture of ourselves and our work
lesions here result in hemisensory (one-sided) loss
Occipital Lobes
Responsible for visual processing
Primary visual (striate) cortex = color and movement processing
Peristriatal regions = further visual processing and integration
lesions = cortical blindness
Central Nervous System Stages
- Proliferation
- Migration
- Differentiation (neurons develop axons and dendrites)
- Myelination
- Synaptogenesis
CT
Computed Tomography, structural. Computed ‘slices’ of the brain. Used to find: tumors, blood clots, MS
MRI
Magnetic Resonance Imaging, uses magnetic fields and radio waves to create structural images of the brain
PET
Positron Emission Tomography, uses radioactive tracer to indicate regional bloodflow. Used to identify: cerebrovascular disease, Alzheimer’s, schizophrenia. Functional test.
fMRI
Functional Magnetic Resonance Imaging, uses contrast similar to MRI to provide detailed imaging of brain activity.
Ataxia
Poor muscle control and clumsy movements
Medulla
Part of hindbrain, responsible for vital functions, damage here can result in death
Reticular Activating System (RAS)
Runs through the brain stem, hind, mid, and forebrain. Responsible for wakefulness, consciousness, and arousal. Damage here can result in coma-like sleep.
Thalamas integrates all senses minus
olfactory - governed by the amygdala
Wernicke-Korsakoff Syndrome
Defenciency in thymine, often due to chronic alcoholism.
1. Wernicke encephalopathy, slurred speech, ataxia, abnormal eye movements
2. Korsakoff Syndrome, amnesia, confabulation
Suprachaismatic Nucleus (SCN)
Located in hypothalamus, involved in sleep-wake cycles and circadian rhythms.
The amygdala attached emotions to
memories
Kluvar-Bucy Syndrome
Results from lesions to amygdala. Reduces fea/aggression, increases docility, oral fixations and hypersexuality
