18.2.1 Forebrain Neuroanatomy Flashcards
Cerebrum
Gray matter
Cell bodies
White matter
Axons
Cerebral cortex
Outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain
Frontal lobe
Frontal lobe
Frontal lobe functions
- Conscious movement of the body (M1)
- Reward
- Attention
- STM tasks
- Goals
- Prioritisation
Damage to frontal lobe
Problems with memory, behavioural changes and reduced ability to plan
Temporal lobe
Temporal lobe
Temporal lobe functions
- Decoding visual and auditory input into meanings for retention
- Language comprehension
Damage to temporal lobe
- Aphasia
- Reduced hearing
- Memory impairment
Parietal lobe
Functions of the parietal lobe
- S1; processing sensory information
- Left side; language, maths, interpreting signals
Damage to the parietal lobe
- Sensory deficits; numbness, difficulty perceiving/localising input
- Cognitive deficits in attention, problem-solving
Occipital lobe
Occipital lobe
Occipital lobe functions
- Visual processing
Damage to occipital lobe GRT
Problems with vision
Insular lobe (insula)
Insula
Insula
Insula
Functions of the insula
- Taste
- Emotion
- Vestibular
Insula
Damage to the insular
- Apathy
- Loss of libido
- Inability to tell fresh food from rotten
Limbic lobe
Gyrus
Ridge on the surface of the brain, increasing its surface area and surrounded by sulci
Precentral gyrus
In which lobe is the precentral gyrus
Frontal
Precentral gyrus function
Primary motor cortex (M1); initiation and control of voluntary motor movements
Homunculus of the precentral gyrus
Face laterally and legs/feet medially
Lesion to precentral gyrus
Contralateral loss/weakness of voluntary motor function
Postcentral gyrus
In which lobe is the postcentral gyrus?
Parietal
Postcentral gyrus function
Primary somatosensory cortex (S1); processing somatosensory information like touch, pressure, temperature and pain
Homunculus of the postcentral gyrus
Face laterally and legs/feet medially
Lesion to the postcentral gyrus
Contralateral sensory deficit
Hippocampus
Hippocampus
Yellow
Dentate gyrus
In which lobe is the dentate gyrus?
Temporal
Gyrus capable of neurogenesis
Dentate gyrus
Dentate gyrus functions
- Formation of new memories
- Pattern separation
Lesions of the dentate gyrus
- Memory deficits
Orange
Parahippocampal gyrus
In which lobe is the parahippocampal gyrus?
Limbic/medial temporal
11
Parahippocampal gyrus
Parahippocampal gyrus
Blue
Uncus of parahippocampal gyrus
Lesion to the parahippocampal gyrus
Deficits in memory and spatial navigation
Cingulate gyrus
Structure 4
Cingulate gyrus
Which structures project to the cingulate gyrus? (2)
- Hippocampus
- Ventral anterior and ventral lateral nuclei of thalamus
In which lobe is the cingulate gyrus?
Limbic
Cingulate gyrus functions
- Emotional processing
- Pain perception
In which lobe is the superior temporal gyrus?
Temporal
Superior temporal gyrus function
- Primary auditory cortex
- Speech (Wernicke’s area)
Superior temporal gyrus
Concerning the cerebral cortex and its connections, what function is associated with the superior temporal gyrus?
Speech
Lesion of left superior temporal gyrus
- Receptive aphasia
- Deficit in processing sound
Orbitofrontal gyrus
Orbitofrontal gyrus functions
- Decision making
- Emotional processing
- Social behaviour
Lesions to orbitofrontal gyrus
Impulsivity, inappropriate social behaviour and difficulty regulating emotions
Wernicke’s area
Effects of a lesion to Wernicke’s area
Receptive (sensory) aphasia
Function associated with Wernicke’s area
Language comprehension
Broca’s area
Effects of a lesion to Broca’s area
Motor/expressive aphasia
Function associated with Broca’s area
Speech production
Primary visual cortex (V1)
Site of V1
Banks of post-calcarine sulcus
3
Primary visual cortex (V1)
3
Primary visual cortex (V1)
Sulcus
Ridge between gyri
Longitudinal sulcus
Longitudinal sulcus divides
Two cerebral hemispheres along the saggital plane
Central sulcus
Central sulcus divides
- Frontal and parietal lobes
- M1 and S1
Lateral sulcus
Lateral sulcus divides
Frontal and temporal lobes
Parieto-occipital sulcus
Calcarine sulcus
Calcarine sulcus divides
Occipital lobe into superior and inferior halves
Cingulate sulcus
Cingulate sulcus divides
Frontal and parietal lobes from cingulate gyrus
Tract
Bundle of axons grouped together with similar origin, destination and function
3 main tracts of forebrain
- Internal capsule
- Optic radiations
- Cerebral peduncles
Internal capsule
Internal capsule
5 and 6 show
Anterior and posterior limbs of the internal capsule
5 shows
Internal capsule
Internal capsule fibres run where
Ascending and descending fibres running between the cerebral cortex and the brainstem/spinal cord
Origin of internal capsule fibres
Cerebral cortex
Destination of internal capsule fibres
Brainstem
Which structure contains fibres that connect the thalamus directly to the cerebral cortex?
Internal capsule
Posterior limb of internal capsule - lesion
Contralateral motor/sensory deficits:
- Increased muscle tone
- Exaggerated reflexes
- Spacsticity
- Babinski sign present
Posterior limb of the internal capsule - functions
Connects thalamus and sensory/motor cortices; involved in transmission of sensory and motor information between brainstem and cerebral cortex
Anterior limb of internal capsule - functions
Connects thalamus and frontal lobe (inc. prefrontal cortex); functions related to executive control, attention and emotion
Anterior limb of internal capsule - lesion
Cognitive/emotional deficits
5 shows
Optic radiations
Fibres highlighted in green are
Optic radiations
Region highlighted green is
Optic radiations
Arrow 4 points to
Optic radiations
Optic radiations origin
Lateral geniculate nucleus
Optic radiations
Transmission of visual information from the thalamus to the visual cortex
Optic radiations destination
Visual cortex (occipital lobe)
Optic radiations - lesion
Visual field deficits/blindness in contralateral visual field
Cerebral peduncles
B shows
Cerebral peduncles
6 is
Cerebral peduncles
11 is
Cerebral peduncles
Cerebral peduncles run to/from
Ascending and descending fibres between the brainstem and cerebral hemispheres
Cerebral peduncles carry info relating to what
Sensory/motor info
Cerebral peduncles lesion
Contralateral motor/sensory deficit including hemiparesis/hemiplegia, spasticity and ataxia
Commissure
Connection between hemispheres
2 major commissures in the brain
- Corpus callosum
- Anterior commissure
Corpus callosum
Corpus callosum
Corpus callosum
4 shows
Corpus callosum
5 shows
Corpus callosum
1 shows
Corpus callosum
4 and 6 show
Corpus callosum
Corpus callosum connects
Two cerebral hemispheres
Functions of corpus callosum
Integration; motor coordination, sensory integration and cognitive processing
Difficulty with fine motor coordination, impaired sensory integration, cognitive deficits
Corpus callosum lesion
Which vessel follows the curvature of the corpus callosum?
Anterior cerebral artery
Anterior commissure
3 shows
Anterior commissure
3 shows
Anterior commissure
6 shows
Anterior commissure
Anterior commissure connects
Temporal lobes
Anterior commissure lesion
Deficits in the processing of olfactory info and visual/auditory info
Anterior commissure fibres function to
Carry olfactory information and integrate visual/auditory information
This gorg schematic shows
Basal ganglia
Basal ganglia
Group of subcortical structures found deep in the white matter of the brain; form part of the extrapyramidal motor system
Describe the role of the basal ganglia in one adjective
Inhibitory
Component nuclei of the basal ganglia
- Striatum
- Globus pallidus
- Subthalamic nucleus
- Substantia nigra
Structure highlighted green
Head of caudate nucleus
Structure highlighted green
Body of caudate nucleus
Structure highlighted green
Tail of caudate nucleus
1 shows
Head of caudate nucleus
2 shows
Head of caudate nucleus
4 shows
Head of caudate nucleus
Structure highlighted green
Putamen
5 shows
Putamen
1 shows
Putamen
2 shows
Putamen
Striatum components (4)
- Caudate nucleus
- Putamen
- Nucleus accumbens
- Olfactory tubercle
Main function of nucleus accumbens
Reward system; addiction, feelings
Nucleus accumbens has strong connections to which pathway
Mesolimbic dopamine pathway of the ventral segmental area
Structure highlighted green
Olfactory tubercle
Structure highlighted green
Nucleus accumbens
Ventral striatum is composed of
Nucleus accumbens and olfactory tubercle
Ventral striatum is considered to be part of which brain system
Limbic system
Dorsal striatum is composed of
Caudate nucleus and putamen
Striatum is part of which lobe
Insular lobe
Fibres of which forebrain tract run through the striatum, separating the putamen and caudate nucleus and giving the structure its striped appearance
Internal capsule
Striatum + Globus pallidus =
Corpus striatum
The striatum receives what from where
Excitatory glutamatergic inputs from the cerebral cortex
Body of caudate nucleus arches over which structure
Thalamus
Where does the caudate nucleus terminate?
Amygdala
The rostral potion of the caudate nucleus is continuous with which structure
Putamen
Caudate nucleus functions
Integration of sensory information about spatial position of body; fine tunes motor response to stimuli accordingly (motor planning)
A 35-year-old man visits his physician because he had been experiencing sporadic involuntary movements and was becoming increasingly uncoordinated. Genetic testing revealed that the man had Huntington’s disease, an autosomal dominant disease caused by a loss of GABA-ergic neurons in the basal ganglia. Which of the following structures is most affected by this disease?
A. Caudate nucleus/putamen
B. Globus pallidus
C. Substantia nigra
D. Subthalamic nucleus
E. Thalamus
A - Caudate nucleus/putamen
Caudate nucleus transmits information where
Thalamus
Putamen lies laterally to which structure
Globus pallidus
Putamen lies medially to which structure
External capsule
Putamen and globus pallidus Aare separated by what
Medial medullary lamina
Function of putamen
Regulation of motor functions
2 shows
Globus pallidus
3 shows
Globus pallidus
Globus pallidus components
Internal (GPi) and external (GPe)
Globus pallidus is divided by what
Internal medial medullary lamina
Globus pallidus is separated from the inferior thalamus by which structure
Subthalamuc nucleus
Lenticular nucleus is composed of
Putamen and globus pallidus
Globus pallidus receives inhibitory GABAergic input from where
Striatum
Globus pallidus transmits fibres to where
Thalamic nuclei
Function of globus pallidus
Fine tuning movement
Lesion of globus pallidus may
Chorea; excessive and involuntary movements
Structure highlighted green
Subthalamic nucleus
Structure highlighted green
Substantia nigra
6 shows
Substantia nigra
5 shows
Thalamus
Substantia nigra is a collection of what
Dopaminergic neurons
Dorsal portion of the substantia nigra
Pars compacta
Ventral portion of substantia nigra
Pars reticulata
Melanin-containing neurons that give the substantia nigra its characteristic dark colour can be found in which part of the structure
Pars compacta
Output of substantia nigra arises where
Pars compacta
Input of substantia nigra is to where
Pars reticulata
Pars compact gives output to
Striatum
Death of dopaminergic neurons in the substantia nigra is characteristic of what disease
Parkinson’s
Substantia nigra receives input from where
Subthalamic nucleus
Lesion to the substantia nigra may
- Tremors
- Rigidity
- Bradykinesia
- Difficulty initiating movement
Major efferents of the basal ganglia (2)
Neurons projecting to the thalamus and brainstem from the GPi and pars reticula of the substantia nigra
Major afferents to the basal ganglia (4)
- Corticostriatal pathway (from cerebral cortex)
- Nigrostriatal (from substantia nigra)
- Thalamostriatal (from thalamus)
- Reticular formation
“Input nuclei” of basal ganglia
Striatum and subthalamic nucleus
“Output nuclei” of basal ganglia
Internal globus pallidus and pars reticulata of substantia nigra
“Modulatory nucleus” of basal ganglia
Pars compacta of substantia nigra
“Connecting nucleus” of the basal ganglia
External part of the globus pallidus; connects input nuclei to output
Structure highlighted green
Thalamus
Thalamus
Substantia nigra components
Pars compact and pars reticulata
4 shows
Thalamus
Thalamus
1
Thalamus
1
Thalamus
2
Thalamus
Which structure shows the thalamus?
6
1 shows
Pulvinar of the thalamus
Thalamus function
Relay and integrate motor and sensory impulses between higher centres of brain and periphery
Thalamus receives information about which senses
All but olfaction
6 shows
Hypothalamus
Which structure is the hypothalamus?
12
7 shows
Hypothalamus
Mammillary bodies
2 shows
Mammillary body
Mammillary bodies are found on the inferior surface of which structure
Hypothalamus
Mammillary bodies are a part of which system
Limbic
Role of mammillary bodies
Memory and spacial navigation
Pineal gland
2 shows
Pineal gland
Pineal gland is which number
2
Pineal gland produces what
Melatonin
Pineal gland is also known as
Epiphysis
The pituitary gland lies in which bone
Hypophyseal fossa of the sphenoid bone
Pituitary gland is connected to the hypothalamus by which structure
Infundibular stalk
2 shows
Pituitary gland
8 shows
Pituitary gland
Structure highlighted green
Amygdala
3
Amygdala
Where in the brain is the amygdala located?
In the medial temporal lobe, anterior to the hippocampus
Functions associated with the amygdala
Fear response, hunger and eating behaviours, cardiorespiratory functions
Lesion of the amygdala
- Lack of visual recognition
- Excessive reactions to visual stimuli
- Reduced fear/aggression
- Eating abnormal amounts when not hungry
- Amnesia/aphasia
Major connections of amygdala
Afferents include: Thalamus, sensory cortices, hippocampus
Efferents include: hypothalamus, brainstem, prefrontal cortex
