#2: Neuroanatomy Flashcards
Why should we study neuroanatomy? (2 main reasons)
It is the gateway to understanding brain functions and disorders, and knowing which structures are affected by disease is essential for diagnosis and treatment of disorders
What is the pathway of information that we gather?
SENSORY SIGNALS (from senses) then NEURAL PROCESSING (in brain) then MOTOR COMMANDS (sent to periphery) then ACTIONS
What is it called when the brain adapts after injury? What is involved in this process?
Plasticity, the brain has an endogenous ability to change the nervous system in response to damage (this is capitalized on by modern therapeutics). When a part of the brain is injured resulting in loss of function, the opposite hemisphere (the equivalent site in the other hemi) can take on the function that was lost overtime and restores somewhat normal functioning
What are the subdivisions of the CNS? (5)
Cerebral cortex (contains 4 main lobes), the brainstem (pons, medulla, midbrain), the diencephalon, and the spinal cord, as well as the cerebellum (mini brain)
What results when the brain stem is damaged?
The brainstem is responsible for many life-sustaining functions such as breathing and heart rate, therefore damage here usually results in death.
What are the parts of the cerebral cortex? Lobes and structures
Longitudinal fissure, central sulcus, precentral gyrus (primary motor cortex), postcentral gyrus (somatosensory cortex), sulcus (grooves), gyri (crests), temporal lobe (hippo and amy), parietal lobe, occipital lobe (contains V1)
What are the functions of the frontal lobe?
Shaping personality, organizing behaviour, planning, short term memory, memory retrieval, distinguishing reality and falsity, critical for behavioural control
Who is Phineas Gage? Why is he important?
He was a construction worker, and when a stick of dynamite went off in front of him he had a rod blasted through his head and completely destroyed his frontal lobe, and he underwent a complete change in personality. This study of him played a major role in developing our understanding of the localization of brain functions.
What is the function of the parietal lobe? Which visual processing pathway is it involved in?
Somatosensation (through post-central gyrus), visuomotor guidance of behaviour (object recognition, as well as object location and orientation), orienting ourselves in the environment, attention and body awareness.
What are the two major pathways for visual processing? What areas are in common between these pathways?
DORSAL STREAM
VENTRAL STREAM
Both of these begin in V1 in the occipital cortex, and they end in the frontal association cortex
What pathway does the dorsal stream of visual processing follow?
V1 to the parietal association cortex. Here we also get somatosensory information coming in, and then projecting to the frontal association area where judgements are made
What type of visual processing does the dorsal stream control? What visual disorder is associated with damage to this stream and associated area?
This is the vision for action stream, so it controls orienting and moving towards a stimulus/object (reaching and grasping). Damage to this stream via damage to the parietal lobe results in object ataxia. This results in inaccurate preshaping of grasp, misorientation of hand, misdirected reach.
Patient RV had parietal lobe damage therefore had object ataxia
What type of visual processing does the ventral stream control? What visual disorder is associated with damage to this stream and associated areas?
This is the vision for perception stream. And it controls recognition of objects and identification (what stream). Damage to this stream via damage to the temporal lobe results in visual form agnosia. You cannot identify what an object is, yet you can still grasp or draw it.
Patient DV: hypoxia due to CO poisoning, resulted in diffuse cortical damage in the ventrolateral occipital region (no damage to V1)
What pathway does the ventral stream follow?
V1 (occipital lobe) to the temporal association area where somatosensory and auditory information also come in, and then to the frontal association area where judgements are made.
What is hemineglect?
This is when there is unilateral damage to the parietal lobe (damage to one hemisphere) that causes you to neglect things on the side opposite to the damage (RT parietal damage results in LT visual field neglect)
