Neurons and the Brain Flashcards
Central Nervous System (CNS) (Zentralnervensystem)
The CNS is the central information processing system formed by the brain and the spinal cord. It collects and distributes data throughout the body.
Peripheral Nervous System (PNS) (Peripheres Nervensystem)
The peripheral nervous system transmits signals between sensory organs, muscles and internal organs and the CNS.
Cerebrum (Großhirn)
largest and uppermost portion of the brain and accounts for sensory integration, voluntary motion and higher-level cognitive functions. It is split into two hemispheres that are connected by the corpus callosum (Balken).
Corpus callosum (Balken)
Connects two hemispheres of cerebrum (inner part)
Cerebral cortex (Großhirnrinde) aka gray matter (graue Substanz)
Is the folded outer layer of the cerebrum that
is mainly comprised of cell bodies.
white matter (weiße Substanz)
The inner part of the cerebrum, it is a core of nerve fibers that connect the cortical regions
The surface of the cerebral cortex is
subdivided based on three anatomical
features
Gyri (sg. Gyrus) (Windungen)
Gyri are the crests (Kämme) formed by the
convoluted surface of the cerebral cortex.
Sulci (sg. Sulcus) (Furchen)
A sulcus is the fissure (Spalt) between two
neighboring sulci.
Lobes (Lappen)
On each hemisphere, two major sulci
divide the cerebral surface into a frontal,
parietal, temporal and occipital lobe
Diencephalon (Zwischenhirn), four sub-structures
- Epithalamus: production of the hormone
melatonin (biological clock) - Thalamus: relay and distribution of sensory and
motor signals to the different regions of the
cerebral cortex - Hypothalamus: Control of autonomic functions
(temperature regulation, appetite), behavior, and
hormone production - Subthalamus
Midbrain (Mesencephalon) (Mittelhirn)
The midbrain is involved in the control of eye movements (including visual reflexes for e.g. object tracking), auditory processing, and visual processing
Pons
The pons is comprised of nerve fibers that connect the medulla oblongata and the cerebral cortex with the cerebellum. It further transmits sensory and motor signals between the brain and the facial region.
Medulla Oblongata (Verlängertes Mark)
The medulla oblongata connects the brain with the spinal cord
Autonomic Nervous System (Vegetatives
Nervensystem)
The autonomic nervous system is responsible for homeostasis (self-regulation) and operates largely unconsciously.
Subsystems of Autonomic Nervous System
Sympathetic nervous system (Sympathikus):
connection of the internal organs to the brain; preparation of the organism for stress (e.g. increase of heart rate and blood flow to the muscles, sweating due to heat
Parasympathetic nervous system (Parasympathikus)
mainly cranial nerves (Hirnnerven) and lumbar (Lenden-) spinal nerves (Rückenmarksnerven); sets the body to resting state and increases digestive functions
Brain Networks as a network
The brain is a highly complex network of interconnected cells and modules
Connectivity is both static (anatomical connectivity) and dynamic (functional connectivity, dependent on the current cognitive task)
Brain networks can be described as graphs and analyzed with graph theory
The endocrine system (Hormonsystem)
Regulatory systems that works in parallel to the nervous system by secreting hormones
Myths about the Human Brain
Only ten percent of the brain are used
Every part of the brain is used but not all parts are used at once (which would result in epilepsy).
The brain does not produce new neurons in adults
In certain brain areas, new neurons are produced throughout life.
The size of the brain is related to intelligence
The brains of elephants and whales are much larger than those of humans
The Encephalization Quotient
Measures brain size relative to body size across species
PCA – A “Mapping” to the Nervous System in the Cycle of cognitive processing
Perception - Sensory Organs
Cognition - Brain
Action - Spinal Cord and Muscles
Frontal lobe (Frontallappen)
short-term memory, action planning, movement control
Parietal lobe (Scheitellappen)
somatic sensation, body image
Occipital lobe (Hinterhauptlappen)
vision
Temporal lobe (Schläfenlappen)
hearing, learning, memory, emotion
Neocortex
Center of higher cognitive functions and intelligence
Neocortex six layers
Layer I: Molecular Layer (Molekularschicht)
Dendrites of cells located in deeper layers and axons that travel through this layer in other areas of the cortex
Layer II: External Granular Cell Layer (äußere Körnerzellenschicht) Small pyramidal-shaped cells. Projections to other cells within the same and to other cortical areas.
Layer III: External Pyramidal Cell Layer (äußere Pyramidenschicht)
Similar to Layer II. However, neurons located deeper in the layer are “typically larger than those located more superficially.”
Layer IV: Internal Granule Cell Layer (innere Körnerzellenschicht) Large number of small spherical neurons.
Layer IV is the “main
recipient of sensory input from the thalamus” and sometimes divided into three sub-layers.
Layer V: Internal Pyramidal Cell Layer (innere Pyramidenschicht)Pyramidal cells that are large than those in
Layer III. Neurons in
this area project to other cortical areas and subcortical structures and form the major output pathways of the cortex.
Layer VI: Multiform Layer (multiforme Schicht) Layer with heterogeneous neurons which blends into the white
matter.
Basal Ganglia (Basalganglien)
The basal ganglia are a group of nuclei (Kerne) (clusters of neurons) located beneath the cerebral cortex. The function of the basal ganglia is mainly related to the motor system where they are engaged in the planning, selection, execution and learning of actions.
Hippocampus
The hippocampus is a brain region with a sea horse-like shape. It is involved in the formation of episodic long term memories.
Amygdala
The amygdala is a group of nuclei related to the analysis of the emotional or motivational significance of stimuli.
Distinctive Features of the Human Brain
Neuron morphology: the pyramidal neurons in the human cortex have the most elaborate and spine-rich dendritic trees
Electrical properties of neurons: the pyramidal neurons in the human cortex
have a very low membrane capacity, which significantly enhances signal transmission
Sequence processing: compared to other species, humans have superior capabilities of learning sequences of stimuli
