NS Flashcards
Whats the peripheral NS?
Autonomic nervous system
Somatic nervous system
Whats the autonomic NS?
Regulates body‘s internal environment
Controls involuntary muscles (heart, intestines)
- Afferent: internal sensory signals to CNS
- Efferent: motor signals from CNS to internal organs
Unconscious and automatic
What’s somatic NS?
Interacts with external environment
Controls voluntary muscles and conveys sensory information to the CNS
- Afferent: from skin, skeleton muscles, etc. to CNS
- Efferent: motor signals from CNS to skeleton muscles
Conscious and voluntary
What’s the autonomic NS?
Sympathetic NS
Parasympathetic NS
What’s the sympathetic NS?
Prepares the organs for vigorous activity (“fight-and-flight”)
Increases breathing and heart rate, decreases digestive activity
What’s the parasympathetic NS?
Promotes energy-conserving, non-emergency functions
Generally does the opposite of sympathetic activities
Whats the spinal cord?
Within the spinal column
- Communicates with sense organs and muscles below the head
Segmented structure
- SN: enters
- MN: exits
If cut, brain loses sensation from that segment and all segments below!
Simple, reflexive behaviours can take place on the level of the spinal cord
What are the brain divisions?
Forebrain - cerebral hemisphere
Midbrain - brain stem
Hindbrain - spinal cord
Whats in the hind brain?
Medulla
- Tracts carrying signals between rest of the brain and body
- Controls some vital reflexes (breathing, heart rate, vomiting, salivation, coughing, sneezing)
Reticular formation
- Plays important role in arousal, sleep, attention, movement, cardiac and circulatory responses …
Pons
- Axons from each side of the hemisphere cross (pons – Latin bridge)
Cerebellum
- Important sensorimotor structure
- Seems also involved in cognitive functions (e.g. crossmodal attentional shifts, timing)
What’s in the midbrain?
Tectum
- SC: visual function
- IC: auditory function
Tegmentum
- sensorimotor function, part of the system that deteriorates in Parkinson’s disease
Whats in the forebrain - diencephalon
Thalamus
- Sensory relay except for olfactory information
Hypothalamus
- Important for regulation of motivated behaviours
- Regulates release of hormones from pituitary gland
Whats in the forebrain - Telencephalon?
Largest division of the human brain
Initiates voluntary movement, interprets sensory input, mediates complex cognitive processes
Main parts: cerebral cortex, basal ganglia, limbic system
Basal ganglia
- Several structures that play a major role for voluntary motor responses
- EX: Pathway from substantia nigra to striatum is deteriorated in Parkinson’s disease
What’s the limbic system?
Regulation of motivated behaviours and emotions
Amygdala, hippocampus, cingulate cortex and others
Whats the cerebral cortex?
Outer surface of cerebral hemispheres
Deeply convoluted to increase surface of the cortex
- Large furrows – fissures
- Small furrows – sulci (sing. sulcus)
- Ridges between furrows - gyri (sing. gyrus)
Neurons communicate across hemispheres mainly through the corpus callosum (bundle of axons)
What’s the occipital lobe?
Main input from thalamic nuclei that receive visual input
Posterior pole = primary visual cortex (V1, striate cortex)
Destruction of V1 causes blindness in related part of the visual field
Whats the parietal lobe?
Area posterior to central sulcus
Postcentral gyrus = primary somatosensory cortex
- Receives main input from touch sensations & muscle stretch receptors
- Sensory Homunculus
Also areas which are relevant for spatial information, numerical information, attentional processes
Lesions in the right PL often result in hemispatial neglect – disregard of the contralesional world
Whats the temporal lobe?
Primary target for auditory information
Left TL relevant to understand spoken language (YT)
Medial part: Memory (Hippocampus)
Inferior part: Complex aspects of vision (perception of movement, recognition of faces and places – FFA/PPA
What’s the frontal lobe?
Area anterior to central sulcus
precentral gyrus = primary motor cortex
- Movement control
- Motor homunculus
Anterior portion – prefrontal cortex
- Receives and integrates input from all sensory systems
- Higher cognitive functions (working memory, planning …)
- Prefrontal lobotomy – surgical disconnection of the prefrontal cortex from the rest of the brain (1940s/50s)
How do neurons develop?
5 processes in the development of neurons
- Production of neurons and glia from stem cells
- Neurons move toward their eventual destinations in the brain
- Growth of axon and then dendrites
- Myelination, continues for decades
- Formation of synapses, continues throughout life (synaptogenesis)
Neurons are not formed after birth
- Two exceptions: Olfactory neurons and hippocampus neurons
What are mechanisms of recovery for brain damage?
Regrowth of axons - PNS only
Formation of new axon branches in response to the loss of axons (sprouting)
Increased sensitivity to remaining neurotransmitters (denervation supersensitivity)
- Compensation
- Chronic pain
Reorganisation of sensory representations
- Axons representing another body part sprout into synaptic sites originally innervated by an amputated body part
- Can lead to a phantom limb
Learned adjustments in behaviour
- Identification and training of spared abilities
