Lecture 1 - Level of Lesions Flashcards
What is the Spinal Cord’s main function ?
- Simple reflexes in limbs & torso
- Extension to touch & flexion to pain
- Transmission of sensory (dorsal root) & motor (ventral root) information
What are the 5 types of nerves present in the Spinal Cord ?
- Cervical (7)
- Thoracic (12)
- Lumbar (5)
- Sacral (5)
- Coccygeal (4)
What symptoms do you expect when the Spinal Cord is disconnected from the brain ?
- Paraplegia (cut below cervical segments)
- Quadriplegia (cut extending into cervical segments)
What are the components of the Hindbrain ?
- Myelencephalon : Lower Brain Stem (Medulla, Reticular Formation & Cranial Nerves)
- Metencephalon : Cerebellum & Pons
What’s the reticular formation’s main function ?
- Consciousness
- Arousal
- Control sleep/waking
- Contains nuclei for noradrenaline, acetylcholine, serotonin & many others
What’s the cranial nerves’ main function ?
- Regulatory & autonomic reflexes
- Posterior = motor, Anterior = sensory
What’s the Medulla’s main function ?
- Relays sensory information to thalamus
- Control vital functions (breathing & cardiovascular system)
What symptoms do you expect when the Lower Brain Stem (Myelencephalon) is disconnected from the brain ?
- Sensory input cannot reach the rest of the brain : low consciousness, narcolepsy, muscle rigidity, persistent vegetative state
What symptoms to expect if the Reticular Formation is damaged ?
Unconsciousness
What symptoms do you expect if the Medulla is damaged ?
Stops breathing & heartbeat
What’s the Cerebellum’s main functions ?
- Motor coordination & motor learning (sensory receptors of trunk & limbs)
- Integration of motor functions with mental processes
- Posture & balance (inputs from vestibular system)
What symptoms fo you expect if the Cerebellum is damaged ?
- Problems with equilibrium & postural reflexes
- Impairement of skilled motor activity
What’s the Pons’ main functions ?
- Relay sensory information to cerebellum & thalamus
- Subconscious somatic & visceral motor centers
What are the components of the Midbrain ?
- Mesencephalon : Upper Brain Stem (Tectum, Tegmentum, Pariaqueductal Gray)
What’s the Tectum’s main functions ?
- Superior Colliculus : receives sensory information from the eyes
- Inferior Colliculus : receives sensory information from the ears
What’s the Pariaqueductal Grey’s main functions ?
Pain responses
What’s the Tegmentum’s main functions ?
- Red Nucleus : limb movement
- Substantia Nigra : connection to Basal Ganglia & Limbic System + Dopamine projection neurons
What’s the Midbrain’s main function ?
- Sensory-motor connections
- Orienting behaviour to visual, auditory & noxious information
- Response in relation to value of objects
What symptoms do you expect when the Midbrain is disconnected from the rest of the brain ?
- Problems with self-initiated behaviours and habituation to stimuli
- Overall drowsy state
- Behaviours are not energetic
What are the components of the Forebrain ?
- Diencephalon : Hypothalamus, Thalamus & Epithalamus
- Telencephalon : Basal Ganglia, Limbic System & Neocortex
What’s the Hypothalamus’ main function ?
- Autonomic & endocrine (hormones) regulation
- Motivated behaviour (feeding, sexual, emotional)
What’s the Thalamus’ main function ?
- Composed of 20 nuclei
- Relay station from one cortical region to another
- Connect sensory systems to the cortex
What’s the Epithalamus’ main function ?
- Regulation of sleep/wake cycle
- Regulation of hunger/thirst
What symptoms do you expect when the Diencephalon is disconnected from the rest of the brain ?
- Quasi-emotional phenomena (energetic but inappropriate & excessive behaviors, unchecked & ongoing rage, pathological uncontrolled laughter or crying, constant aimless activity)
- Problems in goal-directed behaviors
What’s the components of the Basal Ganglia ?
- Caudate Nucleus
- Putanem
- Globus Pallidus
What’s the Basal Ganglia’s main function ?
- Regulate movements
- Associative learning
- Control of movement (not production)
- Connect sensory & motor regions
- Adjust movement to environment
- Receives input from (dopaminergic) Substantia Nigra & Tegmentum
- Reciprocal connections with cortex
What symptoms do you expect when the Basal Ganglia is disconnected from the cortex ?
- Problems with adaptation of behavior to environmental changes
- Problems with planning & complex behavioral patterns
What symptoms do you expect when the Basal Ganglia is damaged ?
- Excessive movement : Huntington’s disease, Tourette syndrome
- Loss of movement : Parkinson’s disease
- Learning deficits, stimulus-response associations : gambling, druf addiction, impulsivity
What are the motor symptoms of Huntington’s disease ?
- Chorea (uncontrolled movement)
- Slurred speech
- Loss of coordination
What are the cognitive & emotional symptoms of Huntington’s disease ?
- Memory & concentration problems
- Impulsivity & disinhibition
-Mood swings, depression, irritability - Development of dementia
What leads to Huntington’s disease ?
- Genetic mutation that results in death of brain cells in Basal Ganglia & Frontal Lobes
What are the main structures of the Limbic System ?
- Amygdala
- Hippocampus
- Cingulate Cortex
- Fornix
What’s the Limbic System’s main function ?
- Memory, learning & spatial behavior
- Emotional control of behavior
- Stimulus-outcome association
What’s the Neocortex’ main function ?
- Make plans
- Combine movement sequences
- Generate complex goal-directed behaviors
Where are positioned the Sensory Areas ?
Posterior of the central sulcus
Where are positioned the Motor Areas ?
Anterior of the central sulcus
How many Cortical Layers are ?
6
