Module A: Development Flashcards
How many neurons are estimated to comprise the human brain?
10^12
How long has it been understood that the qualities of human experience come “from nothing else but the brain”?
Since as early as the fourth century BCE (testimony of Hippocrates)
What prominent, controversial neuroanatomist in 18th century Germany advocated that all behaviour arose from the brain?
Franz Josef Gall (1758-1828).
- Advocated that all behaviour emanated from the brain
- Suggested that particular regions of the cortex were responsible for specific functions, and that the center for each function developed with use
- Was frequently frustrated by his peers’ adherence to notions of Cartesian dualism
Who was responsible for the discovery of a localized area of the frontal lobe required for the production of speech?
Pierre Paul Broca (1824-1880)
- Discovered Broca’s area by post-mortem examination of a patient who could understand language but was unable to speak
A certain famous histological stain discovered in the 19th century (and still in use today) used silver chloride solution to reveal key anatomical elements of neurons.
Who was its inventor? What did the stain reveal? What was the importance of the discovery?
The Golgi stain was discovered by (no surprise) Camillo Golgi, an Italian histologist.
It revealed that neurons have multiple parts:
- a central somatic region (the “cell body”)
- neurites - extensive processes that radiate out from the cell
He used the results as evidence to argue that neurites from different cells fused together to form a CONTINUOUS network
Santiago Ramon y Cajal was a prominent Spanish histologist in the 19th century. What significant (and later proved correct) theory did he advocate about neuronal networking?
Cajal used the Golgi stain to argue that neurons are NOT CONTINUOUS (as Golgi had claimed) but instead that they must communicate via contact.
This was proven correct in the 1950s with electron microscopy and the discovery of the synapse.
What broad function is attributed to the precentral gyrus?
Primary motor cortex.
What substructure of the brain comprises the primary somatosensory cortex?
The postcentral gyrus.
What is grey matter composed of?
Neuron cell bodies and their supporting glia.
What is the primary composition of white matter?
Axons (primarily myelinated axons) and their supporting glial cells.
What is the “motor homunculus”?
A map of the precentral gyrus (primary motor cortex) representing functional divisions of the cortex.
Areas of the body with finer control and greater motor function take up a greater proportion of the homunculus and thus a greater amount of space on the cortex.
There is also a sensory homunculus representing functional divisions of the sensory cortex (postcentral gyrus).
What is the function of the arcuate fasciculus?
It is a bundle of axons that connects Wernicke’s and Broca’s areas.
Damage to this structure will result in conduction aphasia, where a sufferer is fully capable of understanding what they are hearing, but they have difficulty repeating what was actually said.
What is the area of the forebrain that is responsible for interpreting the sensory aspects of speech and sound?
Wernicke’s area.
It may be found on the posterior section of the superior temporal gyrus, on the dominant hemisphere, posterior to the primary auditory cortex.
Where is Broca’s area located? What function does it serve?
Broca’s area is located posteriorly in the inferior frontal gyrus, roughly anterior to the pre-motor cortex.
It is responsible for the motor aspect of speech production, and is also linked to speech comprehension.
A lesion here may result in non-fluent (expressive) aphasia. Patients with this condition are typically able to comprehend words, and sentences with a simple syntactic structure, but are more or less unable to generate fluent speech.
Name the three broad forms of fibrous connections found within the brain and their respective functions.
- Association fibres: same-hemisphere connections.
- Commissural fibres: cross-hemisphere connections.
- Projection fibres: brain-spinal cord or brain-muscle connections.
Which area of the brain is responsible for processing vision?
The primary visual cortex, located mid in the far posterior of the occipital lobe (this is the occipital cortex).
Where, in the brain, is Exner’s area located, and what is its function?
Exner’s area is located posteriorly in the superior frontal gyrus, just anterior to the primary motor cortex (precentral gyrus).
It is responsible for motor control of the hand (thus its close proximity to the motor cortex).
What region of the cortex is primarily responsible for reading? Where can it be found?
The supramarginal gyrus, responsible for reading, is located immediately anterior to another area of the brain with related function. What is this area called, and what is its function?
The angular gyrus. It is involved in interpretation of written language.
What is the corpus callosum? What does it do?
It is an extremely large bundle of white matter (axonal tracts) connecting the left and right hemispheres of the brain.
