Major Brain Structures Flashcards
List the lobes of the cerebral cortex
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
Frontal lobe
Impulse control, cognitive flexibility, risk/reward processing, judgment, language, memory, motor function, problem solving, sexual behavior, socialization and spontaneity, attention
Parietal lobe
Integrating sensory information and manipulation of objects
Occipital lobe
Processing of local orientation, spatial-frequency and colour properties
Temporal lobe
Speech/language functions (predominantly in left hemisphere), audition, episodic memory, visual processing, object recognition, face recognition
List 5 specific regions of the cerebral cortex
- Pyriform cortex
- Prefrontal cortex
- Entorhinal cortex
- Cingulate cortex (cingulate gyrus)
- Motor cortex
Pyriform cortex
Critical role in olfaction. Analogous to association cortex of other senses. Links olfactory components with other brain functions.
Prefrontal cortex
Critical role in regulation of cognitive processes such as working memory, cognitive flexibility and inhibitory control
Entorhinal cortex
Involved with the medial temporal lobe memory system; has many reciprocal connections with cortical and subcortical regions.
Cingulate cortex (cingulate gyrus)
Involved in the generation of emotional responses. In the past, this was a common target area for lobotomy in psychiatric patients.
Motor cortex
Divided into primary motor cortex, premotor cortex and the supplementary motor area. These areas work together to plan and execute movements.
Commissures (function + list 4 major ones)
Allow for communication between left and right hemispheres
- Corpus callosum
- Hippocampal commissure
- Posterior commissure
- Anterior commissure
Corpus callosum
The main bridge for communication between hemispheres
Hippocampal commissure
A small portion of each fornix crosses here
Posterior commissure
Made up of fibres originating mainly from thalamic nuclei
Anterior commissure
Part of the olfactory tract crosses here
Ventricles (function + list 3 major ones)
Interconnected fluid-filled cavities that produce cerebrospinal fluid, which then act to cushion and protect the brain and spinal cord.
- Lateral ventricles
- Third ventricle
- Fourth ventricle
Lateral ventricles
Found in forebrain; neurons are produced here during development and in adulthood
Third ventricle
Found in midbrain
Fourth ventricle
Found in hindbrain
List the telencephalon (cerebrum) structures
- All of the cerebral cortex is part of the cerebrum
- Olfactory bulb
- Hippocampus/Hippocampal formation
- Basal ganglia
- Amygdala
Olfactory bulb
Important component of olfactory system; analogous to primary cortex of the other senses; extracts different components of odours and then passes this information on to the pyriform cortex.
Hippocampus/Hippocampal formation (general function)
A memory centre in the brain; responsible for spatial memory and navigation, and some types of non-spatial memory such as contextual memory and episodic memory. Damage to this structure produces both retrograde and anterograde amnesia.
What are the subregions of the hippocampus?
- Dentate gyrus
- Cornu ammonis
- Subiculum
* Each region may play a different role in memory processing, and their unique functions are an area of active research in neuroscience
Dentate gyrus
Subregion of the hippocampus; primarily made up of granule cells (excitatory) and basket cells (inhibitory). One of the few regions that adult neurogenesis (birth of new neurons) occurs. Neurogenesis in this region has been suggested to play a role in depression.
Cornu ammonis
Subregion of the hippocampus; primarily pyramidal cells
Subiculum
Subregion of the hippocampus; mostly pyramidal cells
Basal ganglia (general function)
A set of nuclei crucial for voluntary motor functions, behavioural routines (including procedural learning and addiction), and plays a role in cognition and emotion.
List 4 specific structures of the basal ganglia
- Caudate nucleus
- Putamen
- Nucleus accumbens
- Globus pallidus
Caudate nucleus
Structure of the basal ganglia; together with the putamen, forms the dorsal striatum. This region is important for voluntary movement.
Putamen
Structure of the basal ganglia; receives input from sensory and motor areas and projects to globus pallidus. Important for some types of reinforcement and motor learning.
Nucleus accumbens
Structure of the basal ganglia; receives lots of dopaminergic input from the ventral tegmental area. Involved in motivation and reward processing.
Globus pallidus
Structure of the basal ganglia; main inhibitory output from the basal ganglia to thalamus. Also important for posture control.
Amygdala
Responsible for the production of fear and anger related behaviours and involved in fear memories
List the diencephalon structures
- Thalamus
- Hypothalamus
- Pineal body
Thalamus
Relay and integration station for all sensory inputs (except olfactory input) before continuing to cerebral cortex. Sensory and motor inputs are also processed here.
Lateral geniculate nucleus
One of the many nuclei of the thalamus. It receives visual information from the retina (perhaps cancelling out redundant or unnecessary information) and relays it to the primary visual cortex.
Hypothalamus
Responsible for maintaining homeostasis of factors such as blood pressure, temperature, electrolyte balance, body weight
Mammillary nuclei
Appear to play a role in memory formation as their damage produces anterograde amnesia but the exact role is unknown
Posterior pituitary gland
Made of axons directly projecting from the hypothalamus, and releases oxytocin and vasopressin into the bloodstream
Anterior pituitary gland
Separate gland connected to the hypothalamus by blood vessels, and known as the “master gland” due to its regulation of other endocrine functions. Releases into the bloodstream a range of hormones that regulate the activity of gonads, adrenal glands, thyroid and adipose tissue.
Pineal body
A small endocrine gland. Contains photoreceptors and is stimulated by darkness to produce melatonin and this process is inhibited by light. Melatonin plays an important role in maintenance of the circadian rhythm.
List the midbrain (mesencephalon) structures
- Superior colliculus
- Inferior colliculus
- Cerebral peduncle
- Substantia nigra
- Ventral tegmental area
Superior colliculus
Part of the visual and auditory system that helps to orient the head to something that is seen or heard
Inferior colliculus
Part of the auditory system that integrates sound localization information from different dimensions
Cerebral peduncle
Descending fibre pathway from the brain to the spinal cord
Substantia nigra
Synthesizes the neurotransmitter dopamine. Neurons here contain the pigment melanin, which gives this region a dark appearance.
Ventral tegmental area
Medial to substantia nigra and rich in dopamine neurons; important for cognition, motivation and reward processing
List the hindbrain (rhombencephalon) structures
- Medulla
- Cerebellum
- Pons
- Reticular formation
Medulla
Controls vital reflexes (ie. heartbeat, respiration, vomiting)
Cerebellum
Important for motor coordination and procedural memory
Pons
Consists of fibres from the cerebellum crossing from left to right hemispheres
Reticular formation
A distributed set of numerous small nuclei. Involved in maintaining wakefulness and sleep. One subregion is the raphe nuclei (dorsal raphe).
Raphe nuclei
A subregion of the reticular formation, also known as the dorsal raphe; releases serotonin to other regions of the brain.
List 4 fibre tracts
- Optic chiasm
- Optic tract
- Olfactory tract
- Fornix
Optic chiasm
Location where part of each optic nerve crosses to the other side of the brain. This cross means the left visual field is processed in the right side of the brain and the right visual field in the left.
Optic tract
Segment of the optic nerve that connects the optic chiasm and the lateral geniculate nucleus. Carries visual information from the retina.
Olfactory tract
Responsible for transmission of olfactory information from the olfactory bulbs to primary olfactory cortex
Fornix
Fibre bundle that connects the hippocampus with the mammillary nuclei and the septal nuclei
Anterior
from Ante (before). Towards front or head. Synonymous with rostral (means beak)
Posterior
from Post (after). Towards back or tail. Synonymous with caudal (means tail)
Dorsal
from Dorsum (back). Think of a shark’s dorsal fin. Up or on top of. Synonymous with superior
Ventral
from Venter (belly). Down, below, or on the bottom. Synonymous with inferior
Medial
from Medius (middle). Towards the midline. Synonymous with nasal (means nose)
Lateral
from Latus (side). Away from midline. Synonymous with temporal (means temple)
Ipsilateral
from Ipsi (self or same). On the same side of the body (e.g., right eye and right ear)
Contralateral
from Contra (against, opposite to) on the opposite side of the body (e.g., right eye and left eye)
Sagittal sections
divide the brain parallel to the midline.
Coronal sections
divide the brain perpendicular to the midline.
Horizontal sections
divide the brain parallel to the anterior-posterior axis. These are often seen in CT and MRI scans.
Tract
a set of axons within the CNS, also known as a projection. (e.g., if axons extend from the cell bodies in the Ventral Tegmental Area (VTA) to the Prefrontal Cortex (PFC), we would say that fibers “project” from the VTA to the PFC).
Nerve
a set of axons that connect between the periphery and the CNS. (e.g., a nerve may connect between the CNS to a muscle gland, or from sensory organs to the CNS)
Nucleus
a cluster of neuron cell bodies within the CNS (ex. The Caudate “Nucleus” is a region in the brain that is part of the dorsal striatum).
Ganglion
a cluster of neuron cell bodies, usually outside the CNS, as in the sympathetic nervous system.
Gyrus
a protuberance (bump, peak) on the surface of the brain
Sulcus
a fold or groove that separates one gyrus from another
Fissure
a long deep sulcus.
Meninges
tough, durable membrane that covers the brain
