Week 1 Functional Neuroanatomy Flashcards
What are the layers of the meninges?
(Brain) Pia mater (Subarachnoid space) Arachnoid layer Dura mater (Skull)
What are the 4 (5) lobes of the brain and their basic functions?
Forebrain – neocortex
• Frontal lobes – motor executive function, memory, speech production
• Temporal lobes – auditory, speech comprehension, memory, visual perception
• Parietal lobes – somatosensory, visual perception, integration of stimuli
• Occipital lobes – vision
Insula
What are the various views of the brain?
Dorsal - from the top Ventral - from the bottom Lateral - towards the side Medial - towards the middle Superior - above/top Inferior - below/bottom Anterior - front Posterior - back
What are the four ventricles and what do they do?
Two lateral ventricles
Third ventricle
Fourth ventricle
Filled with CSF
Provides buoyancy for 1.4kg brain
Tumours can grow inside ventricles – very hard to operate – 3rd ventricle is colloid cyst - adopt wait and see approach
As passages are narrow, fluid can build up – hydrocephalus – intracranial pressure can lead to pressure on thalamus and other structures - bizarre behaviour as will begin to push on those areas ie use a shunt and example of behaving like a dog.
What is grey matter?
Cell bodies - may be organised into nuclei (outside of cortex)
What is white matter?
Axons (inside of cortex)
What are the main functions of the Medulla Oblongata & Pons?
Regulates basic functions such as heart rate, respiration, blood pressure, swallowing, eye movement
Reticular Formation: arousal & sleep/wake cycle
Where do the cranial nerves enter the brain?
Nuclei of 5-12 enter at Medulla Oblongata & Pons
Nuclei of 3 and 4 enter in tegmentum (midbrain)
What are the main functions of the Medulla Oblongata & Pons?
Regulates basic functions such as heart rate, respiration, blood pressure, swallowing, eye movement
Pons-
o Superior to medulla and anterior to cerebellum
o Main connective bridge between brain and cerebellum – point of synapse (connection between neurons) for some cranial nerves
o Control centre for eye movements and vestibular functions (balance)
o Superior olive – auditory info from ear to brain, both ears converge
Reticular Formation: arousal & sleep/wake cycle - diurnal rhythm
Damage - loss of consciousness, vegetative state, death, coma
What is the main functions of the Cerebellum?
Balance & coordination and learning of skill movements, muscle tone, cognitive and motor sequencing (esp. timing). Whole body in space rather than fine motor skills
• Sequencing as a motor program – automatic so use procedural memory ie dancing
Where is the midbrain, what are the structures of the midbrain, and their functions?
Small, superior to hindbrain (Pons)
- Tectum (roof) dorsal
- Superior colliculi (nuclei for visual function)
- Inferior colliculi (nuclei for auditory function)
- Orienting - orient to visual and auditory info – well developed in animals – combine info to locate threats/food etc
-Tegmentum (floor) ventral
*Nuclei of 3rd 4th cranial nerves (eye movement)
*Ventral TA: natural reward circuitry (motivation, social affiliation)
• high activation when doing rewarding things
• damaged with unnatural things ie substance abuse (meth and heroin) changes biological structure and reduces natural rewards like seeing family
What are the structures and functions of the diencephalon (between brain)?
Thalamus
Not passive but adds extra info and projects to relevant part of cortex, processes basic info
Comprise pairs of nuclei projecting to the cortex
Relay station for sensory signals – lateral (visual), medial (auditory) geniculate nuclei, dorsal (memory) and ventral posterior nuclei (sensory)
Hypothalamus
Regulates hormone release from the pituitary gland (HPA)
Mediates ANS function and behaviour (e.g., flight/flight, hunger and sexual drives)
Damage can alter desire for food and water ie priest who drank all the water from the vases
Where is the limbic system, what is the limbic system and what structures does it house?
Ventral/inferior to the cortex
Circuitry of midline structures that circle the thalamus:
Hypothalamus
Mammillary bodies
Cingulate gyrus (Anterior Cingulate – also part of PFC)
Hippocampus
Amygdala (almond) – primary processing of emotion (emotional significance but not response)
What is the basal ganglia and what structures does it house?
Collection of subcortical grey matter
- Caudate nucleus (striatum)
- Lentiform nucleus
- Globus pallidus (pale globe)
- Putamen (striatum)
- Substantia nigra (dopamine producing)
- Limbic: Nucleus accumbens and ventral tegmental area (dopaminergic pathways)
What is the basal ganglia and what structures does it house?
Collection of subcortical grey matter
- Caudate nucleus (striatum)
- Lentiform nucleus
- Globus pallidus (pale globe)
- Putamen (striatum)
- Substantia nigra (dopamine producing)
- Limbic: Nucleus accumbens and ventral tegmental area (dopaminergic pathways)
o Controlled and fluid movements – initiating and fine movement
o Important for voluntary control of motor function, procedural and reward learning, executive functions, emotion
What is the cerebral cortex?
- Frontal Lobes (motor, executive function, behavioural regulation, memory, speech production)
- Temporal Lobes (audition, speech comprehension, emotion, memory, visual perception)
- Parietal Lobes (somatosensory, visual perception, multi-modal integration of stimuli)
- Occipital Lobes (vision)
Insula – part of CC folded deep in lateral sulcus: consciousness, interoceptive awareness, self-awareness, emotion (contagion), body homeostasis, pain
What is the cerebral cortex?
o Bark, outer layer of brain
- Frontal Lobes (motor, executive function, behavioural regulation, memory, speech production)
- Temporal Lobes (audition, speech comprehension, emotion, memory, visual perception)
- Parietal Lobes (somatosensory, visual perception, multi-modal integration of stimuli)
- Occipital Lobes (vision)
Insula – part of CC folded deep in lateral sulcus: consciousness, interoceptive awareness, self-awareness, emotion (contagion), body homeostasis, pain
Develops during adolescence
Mindfulness training an increase
What is the visual pathway?
Eye Optic nerve Optic chiasm Optic tract Lateral geniculate nucleus Thalamus (relay station) Primary visual cortex in occipital lobe
Where does visual information get processed?
Right sides of both eyes is processed in the left PVC
Left sides of both eyes is processed in the right PVC
- Contralateral
What happens with occipital lobe damage?
Contralateral loss of visual sensation and recognition (small = scotoma; large = anopia) (LH = RF, RH = LF)
Perceptual problem: difficulties in discriminating visual objects that are different in sizes, shapes, orientations, and colours
What is visual agnosia?
inability to combine visual impression into complete patterns and interpret these
What is object agnosia? What are the two types?
Apperceptive: Inability to develop a “percept” of objects (failure to recognise objects, cannot copy, cannot match)
Associative (failure to recognise objects despite intact perception – can copy/match objects but not identify) – failure to associate visual representation with meaning
What is prosopagnosia?
inability to recognise faces
What is prosopagnosia?
Inability to recognise faces
Bilateral damage to the
occipital-temporal junction (fusiform)
Disorder is dissociable from
facial emotion recognition and
object agnosia
What are dissociations and double dissociations?
Assumptions about brain function based upon the pattern of people’s intact abilities and impairments within the same functional domain.
Person A has an impairment in word pronunciation (phonological skills) and intact understanding of word meanings (semantics) = dissociation
Person B has an impairment in semantics and intact phonological abilities
Evidence from Person A+B = double dissociation
Suggests that these abilities are subserved by different brain regions (and can be selectively damaged)
What are the areas of parietal visual area?
Tertiary area
Right: contralateral neglect, inability to consciously attend to objects in the left visual space despite intact visual pathways and cortex (spatial attentional problem) - not conscious attention
Left/bilateral – multimodal integration (temporo-parietal junction) = visual/auditory/tactile & motor
Affects reading, writing, maths and skilled movements (alexia/dyslexia, agraphia, acalculia, apraxia)
What are the three main areas of the parietal lobe for somatosensory processing?
Primary area: recognition of sensory stimuli from contralateral side of the body
Secondary area: tactile perception, touch discrimination and body sense
Tertiary area (TPJ): integration of stimuli (visual, auditory and somatosensory); guiding movement in space and spatial representation
What are tactile processing disorders?
Primary area (somatosensory strip)
- Loss or alteration of sensation of touch,
pain, temperature and body sense on
contralateral side of the body
Secondary area
- Partial or complete inability to recognise somatosensory stimuli. 2 types
Loss of ability to recognise objects by touch
Loss of knowledge or sensory awareness of one’s own body or bodily condition
What are the three hierarchical zones of motor function?
Tertiary zone: Formation of behavioural intention – prefrontal cortex
Secondary zone: Preparation and organisation of motor programmes – premotor areas of frontal lobes
Primary zone: execution of motor programmes – motor cortex (input from thalamus and basal ganglia) and spinal cord
What happens with damage to the primary motor area?
impairment of motor functioning (speed, movement and strengths) in limb and digits – extensive damage = hemiplegia - can do the major movement but not with strength
Contralateral