Lecture 2: Basic Neuroanatomy Flashcards
What is essential for diagnosis and treatment of disorders?
Knowing which brain structures are affected by disease
What is the function of the human brain?
To process multiple sensory signals from the external environment
What processes the multiple sensory signals from the external environment in the human brain?
The four cortical lobes
What do the 4 cortical lobes do with the sensory signals it receives from the external environment?
It processes the sensory info and sends it to the motor cortex to generate motor commands and movements which constitute behaviour
What is the ultimate goal of the nervous system?
To generate motor actions that constitute behaviour
Which brain regions are recruited when playing violin?
The auditory system and auditory cortex and is passed down to the frontal cortex and the premotor and primary motor cortex
What is significant about playing the violin?
Multiple brain regions are recruited
Why is it a challenge to diagnose and locate the site of function when something goes down in the brain regions?
Because multiple brain regions are used for different functions
What is Plasticity?
The ability of the brain to adapt and take over when a different portion of the brain is damaged
What are the 5 major subdivisions of the CNS?
- Cerebral cortex
- Diencephalon
- Brainstem
- Cerebellum
- Spinal Cord
What are the parts of the brainstem?
- Midbrain
- Pons
- Medulla
What are the two main Sulci of the brain?
- Central Sulcus
* Lateral Sulcus
What does the Central Sulcus separate?
The frontal lobe and the parietal lobe
What does the Lateral Sulcus separate?
The frontal lobe and the temporal lobe
Sulci: ______; Gyri:_______
Sulci: Grooves
Gyri: Crests
What does the Precentral Gyrus contain?
The Primary Motor cortex
What does the Postcentral Gyrus contain?
The primary somatosensory cortex (sensation)
What are the functions of the frontal lobe?
- Short term memory
- Behavioral organization and planning
- Memory retrieval
- Distinguishing reality vs. falsity
- Shaping Personality
What occurred surrounding the Phineas Gage case?
His frontal lobe was damaged cause a change in his personality causing him to be an unpleasant person. This case played a major role in developing our understanding of the localization of brain functions and the frontal lobe in personality
What is the function of the Parietal lobe?
- Somatosensation
- Visuomotor guidance of behavior (ex. recognition of object location and orientation)
- Attention
- Body awareness
Which lobe of the brain is responsible for visuomotor guidance of behavior?
The parietal lobe
What are examples of the visuomotor guidance of behavior?
Recognition of an object location or orientation
What are the two major pathways for Visual Processing?
- Dorsal stream
* Ventral stream
Where does the Dorsal Stream end?
In the parietal association cortex
Where does the Ventral stream end?
In the temporal association cortex in the temporal lobe
Where do both visual processing pathways originate?
The Primary Visual Cortex (V1)
Where in the brain is V1 located?
The occipital cortex
Where do visual signals from the eyes go?
V1
What is the Dorsal stream important for?
Vision for action
What does damage to the dorsal stream do?
Disrupts visuomotor tasks involving actions linked to object locations ex. Reaching for an object
What is Optic Ataxia?
A disorder in translating vision into action
Which stream is object ataxia associated with?
The Dorsal Stream
What occurs when the cells of the parietal cortex are monitored in a monkey looking at a fixed point with a stimulus off to the side?
When the monkey is not attending to the visual stimulus there are mild action potentials. When the monkey looks at the stimulus there is more intense firing. When the monkey touches the stimulus, there is most intense firing
What does the monkey with the stimulus tell us?
That the posterior parietal lobe can be activated by attention and action
What can the posterior parietal lobe be activated by?
Attention and action
What is a characteristic of optic ataxia?
Difficulties with visually guided reaching and grasping. What a person sees can not be coordinated with motor movement
What are things that a person with optic ataxia may do?
They may not form their hand properly clasp an object or they may orient their hand in the wrong way to fit through a slot
What was the problem with RV who has Optic Ataxia?
She couldn’t perform visually guided reaching properly but she perform manual estimation without reaching. She couldn’t use visual information from her eyes to control movement
What is the Ventral Stream important for?
Vision for Perception (object recognition)
What does Damage to the inferior temporal lobe cause?
Impaired recognition of objects
What is Visual form agnosia?
Damage to the inferior temporal lobe that impair recognition of objects
Damage to which part of the brain causes visual form agnosia?
The inferior temporal lobe
Which stream is visual form agnosia associated with?
The ventral stream
What did patient DF with visual form agnosia do?
They had no problem reaching to put a disk in its place but they had issues matching the orientation of the disk to a slot
Injury to which part of the brain results in visual agnosia?
The medioventral temporal cortex
How do people with injury to the medioventral temporal cortex (visual agnosia) function with recognizing and drawing images?
Some can copy images fine but are unable to identify them and some were unable to copy images but could draw them from memory
Why aren’t some people with visual form agnosia able to copy a picture but can draw it from memory?
Because they have no conscious experience of vision but are able to imagine an object
Which stream is visual agnosia associated with?
The ventral stream
What is altered in visual form agnosia?
Perception (like object recognition and how we see things)
What is intact in visual form agnosia?
Action
What does damage to the ventral stream cause?
Visual form agnosia
What is altered with Optic Ataxia?
Action
What is intact in optic ataxia?
Perception
Which stream is damaged in optic ataxia?
The dorsal stream
What does damage to the dorsal stream cause?
Optic Ataxia
What does Hemineglect result from?
Unilateral damage to the parietal lobe
What is hemineglect?
When an individual ignores one half of their visual space
What is the Hippocampus important for?
- Learning and remembering facts and events
- Spatial navigation
- Forming associative memories of spatial and non-spatial information
What are associative memories?
When we make an association between events occuring in close timing
What is the function of the amygdala?
- Emotional expression
- Forming proper associations between emotions and behavior situations
- Fear learning
What does damage to the hippocampus cause?
Anterograde amnesia and impaired consolidation of memory
What is Anterograde amnesia?
The inability to make new memories
What are intact with damage to the hippocamus?
Old memories and motor skills
Why are old memories intact with anterograde amnesia?
Because they are stored in the neocortical regions
Why are motor skills still intact with damage to the hippocampus?
Because they are stored outside the hippocampus
What is enough to cause anterograde amnesia?
Damage to the CA1 alone
What does the hippocampus of an individual with Alzheimer’s look like?
They have a massive loss of neurons in CA1
What is Urbach-Wiethe Disease?
The calcification of the amygdala and medial temporal lobes
What occurs in Urbach-Wiethe disease?
There is a failure to process fearful expressions
