Brain Anatomy Flashcards
Our understanding of function including behaviour is greatly helped by understanding the physical object(s)…
that deliver that function.
Function is an emergent property of signals in networks. Networks = ?
Neuroanatomy
Anatomical network for..
visual information processing
Tasks engage ..
neuroanatomical networks
Brain has a long…
evolutionary history
Name the factors to vertebrate brain evolution
Our brain is very different to that of our distant vertebrate ancestors.
Mainly in terms of the size and proportion of various parts.
The basic structure, anatomy and connectivity is incredibly well preserved.
What did the brain start as and how has it developed?
Started as a tube then developed into gyri and coils.
What does evolution do?
It modifies what is already there.
Preservation of brain architecture also tells us that…
the major survival issues for us also tells is that major survival issues for us as a species are not all that different to those of our ancestor species.
defence as a functional system
pain -> spinal cord -> escape -> motor
Loom -> Sensorimotor midbrain -> Avoidance -> Autonomic
Learned threat -> cortex + Limbic system -> Endocrine Avoidance -> Defence related output
What does a hierarchy of functional systems provide?
Increasingly sophisticated competences. Multiple systems acting together.
What part of the brain does cognitive analyses belong to ?
Frontal cortex -> Response suppression -> Motor, autonomic and endocrine output
What part of the brain does context belong to?
Hippocampus and septum -> Amygdala -> Conditioned emotion responses -> Motor, autonomic and endocrine output
What part of the brain does complex neural stimuli belong to?
Sensory cortex -> Amygdala -> Conditioned emotional responses -> Motor, autonomic and endocrine output
What part of the brain deals with neural stimuli?
Thalamus -> amygdala ->Conditioned emotional response -> Motor, autonomic and endocrine output
What part of the brain deals with species specific threat stimuli?
Midbrain and Hypothalamus -> Motor, autonomic and endocrine output
What part of the brain deals with sudden distal stimuli?
Hindbrain -> Motor, autonomic + Endocrine output
What part of the brain deals with noxious or contact stimuli?
Spinal cord -> Motor, autonomic + endocrine output
Name the direction and planes
Coronal (frontal) section Horizontal section Mid saggital (medial) section Superior - dorsal Anterior Posterior Inferior- ventral Dorsal Ventral Lateral Dorsal Ventral Medial
CNS:
Brain Spinal Cord
Peripheral nervous system:
Division located outside the skull and spine
Somatic (of the body) nervous system:
Skin
Muscles
Joints –>Afferent nerves (CNS)
Eyes
Autonomic (unconscious/ automatic) nervous system:
Internal –> afferent nerves
organs
State the vertebral column in spinal cord regions
Cervical Nerve Region - Head and neck, diaphragm, arms and hands
Thoracic Nerve Region - Chest muscles, breathing and abdominal muscles
Lumbar Nerve Region - Legs and Feet
Sacral Nerve Region - Bowel and Bladder Control and Sexual Functions
Dorsal root is …
Ventral root is …
Afferent (affected by the world) [Sensory]
Efferent (having an effect on the world) {Motor}
What are the subdivisions of the brain in the CNS?
Forebrain - Telenecephalon -> Cerebral cortex, basal ganglia and the limbic cystem
DIenecephalon
Thalamus
Hypothalamus
Midbrain -> Mesencephalon (tegmentum, tectum)
Hindbrain -> Metencephalon (pons, cerebellum)
Myelencephalon (medulla)
What was the old brain involved in?
autonomic and low level sensorimotor control.
What is the function of the medulla (myelencephalon)?
It contains tract signals between the rest of the brain and the body.
Contain caudal part of the reticular formation
- Low level sensorimotor control eg balance.
- Involved in variety of vital functions - sleep/wakefulness
Motor plant: movement, maintenance of muscle tone. Various cardiac, circulatory, respiratory and excretory reflexes.
What is the function of the pons?
Relay from cortex and midbrain to the cerebellum
Contains millions of neural fibres
Pontine reticular formation (pattern generators) - e.g. for walking
What is the function of the cerebellum?
Smaller than the brain but contains as many neurons as all the rest of the CNS.
‘Motor errors’ between intended movement and actual movement - adjusts synaptic weights to eliminate error
Online correction can take place during the movement: motor learning
Thought exclusive for motor coordination- recently implicated in cognitive and affective/emotional function.
Tectum function?
Visual/spatial and auditory frequency maps.
Superior Colliculus - Sensitive to sensory change- orienting/ defensive movements
Inferior Colliculus - Similar but for auditory events.
What are the structures of Tegmentum?
The Periaqueductal gray
Red nucleus
Substantia nigra
What is the function of the Periaqueductal gray as part of the tegmentum?
Role in defensive behaviour
Role in analgesia
Role in reproduction
What is the function of Tegmentum - Red Nucleus?
Target of cortex and cerebellum, projects to spinal cord
Role in pre-cortical motor control (especially arms and legs)
What is the function of the Tegmentum- Substantia nigra?
Part of the basal ganglia Role in defensive behaviour Role in analgesia Role in production Dopamine cells in the substantia nigra.
Diencephalon is made up of the…
hypothalamus and thalamus
What is the function - Diencephalon: Thalamus - relay structure?
Specific nuclei: relay signals to cortex/limbic system for all sensations
Non-specific: Role in regulating state of sleep and wakefulness and levels of arousal
Important relays from basal ganglia and cerebellum back to cortex.
What is the function of the Hypothalamus - Diencephalon?
Regulates the pituitary gland which regulated hormonal secretion; interface between brain and hormones
Role in hormonal control of motivated behaviour
including hunger, thirst, temperature, pain, pleasure and sex
What are the structures part of the forebrain - cerebral cortex (subcortical)?
Under the cortex portions:
Basal Ganglia
Limbic system
What is white matter?
Fibers/ Axons
What is in gray matter?
It’s made up of six layers and cell bodies.
What is the biggest part of the brain in primates?
Gray matter and white matter.
Name the cortical lobes- cerebral cortex?
Central Sulcus - Central fissure Frontal Lobe} Parietal Lobe} Lateral fissure Occipital Lobe} Temporal Lobe}
Name subcortical structures?
Basal ganglia and limbic system.
Name 6 cortical layers
- Molecular Layer
- External granular layer
- External pyramidal layer
- Internal granular layer
- Internal pyramidal layer
- Multiform layer: Three multiform layer
- Precentral gyrus
- Postcentral gyrus
- Superior temporal gyrus
Cerebral cortex - Frontal lobe -
Largest part of the human - Main difference with non-human primates and other mammals.
What is the function of the precentral gyrus?
Motor instructions sent from the cerebral cortex to muscles controlling hand and feet.
Primary motor cortex…
contain many of the cells giving origin to the descending motor pathways - involves in the initiation of voluntary movements.
Premotor and supplementary motor areas…
Higher level motor plans and initiation of voluntary movements.
When lesions disrupt it effects?
Executive planning
Judgemental roles
Emotional modulators
Control of behaviour
Prefrontal cortex: generating sophisticated behaviour options that are mindful of consequence
Broca’s area: Left hemisphere production of written and spoken language.
Cerebral cortex - Parietal lobe?
Contains the postcentral gyrus which receives sensation from the rest of the body. Maintains representations of the body’s and of the heads position in space.
Permits complicated spatiotemporal predictions
Cerebral cortex - temporal lobe?
Contains the primary auditory cortex
Inferotemporal cortex Recognition faces and objects
Plays important roles in integrating sensory information from various parts of the body
Interface between cortex and limbic system- association of affect/ emotion with things.
Cerebral cortex- occipital lobe?
- Contain visual cortices
- Dorsal stream for movement
- Ventral stream - vision for identification
Forebrain - subcortical structures - basal ganglia?
Group of structures
Loop of organization
Structures thought to be involved in motor function since involved in movement disorders.
Work at uni of sheff showed role in action selection and reinforcement learning.
Subcortical structures - limbic system
Group of structures
Structures involved in emotion motivation and emotional association with memory.
Limbic system influences the formation of memory by integrating emotional state with stored memories of physical sensations.
Limbic system structures?
Amygdala - involved in associating sensory stimuli with emotional impact
Hippocampus - involved in memory
Fornix - Shaped bundle of fibres, carries signals from the hippocampus to the mammillary bodies and septal nucleus.
Cingulate gyrus - Linking behavioural outcomes to motivation and autonomic control atrophied in schizophrenia
Septum- Involved in defence and aggression
Mammillary body - Breast shaped important for the recollection of memory in amnesia
