PSY 511

Neuroanatomy

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Fun

Resources

Harvard Brain Atlas

http://www.med.harvard.edu/aanlib/cases/caseNA/pb9.htm

Brain anatomy through dance

Directional terms

• Anterior/Posterior
• Medial/Lateral
• Superior/Inferior
• Dorsal/Ventral
• Rostral/Caudal

Bipeds vs. quadripeds

https://upload.wikimedia.org/wikipedia/commons/thumb/0/00/1303_Human_Neuroaxis.jpg/800px-1303_Human_Neuroaxis.jpg

Image axes

• Horizontal/Axial
• Coronal/Transverse/Frontal
• Sagittal (from the side)

Supporting structures

Meninges (outside -> in)

• Dura mater (‘tough mother’)
• Arachnoid membrane
• Subarachnoid space
• Pia mater (‘gentle mother’)
• Cerebrospinal fluid (CSF) between Arachnoid membrane and Pia Mater

Ventricular system

• Also known as cerebral ventricles
• Lateral (1st & 2nd)
  • Forebrain/telencephalon
• 3rd
  • Diencephalon
• Cerebral aqueduct
  • Midbrain
• 4th
  • Hindbrain

• Ventricles filled with cerebrospinal fluid (CSF)
  • CSF clears metabolites during sleep (Xie et al., 2013)?
  • Blockage of CSF flow -> hydrocephalus

Blood Supply

• Carotid & basilar arteries converge on Circle of Willis
• Anterior, Middle, and Posterior Cerebral arteries main output

https://previews.123rf.com/images/hfsimaging/hfsimaging1208/hfsimaging120800005/14672522-drawing-of-the-blood-vessels-at-the-base-of-the-brain-called-the-circle-of-willis.jpg

https://teachmeanatomy.info/wp-content/uploads/Schematic-of-the-Circle-of-Willis.jpg

https://teachmeanatomy.info/wp-content/uploads/Regional-Blood-Supply-to-the-Cerebrum-1024x380.jpg

By <a href=“//commons.wikimedia.org/wiki/User:BruceBlaus” title=“User:BruceBlaus”>BruceBlaus</a> - <span class=“int-own-work” lang=“en”>Own work</span>, CC BY-SA 4.0, Link

Blood/brain barrier

• Cells forming blood vessel walls tightly packed
• Active transport of molecules typically required

(Abbott, Rönnbäck, & Hansson, 2006)

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(Abbott, Rönnbäck, & Hansson, 2006)

Area Postrema

• In brainstem, blood-brain barrier thin
• Chemoreceptors (chemical receptors) detect toxins, trigger emesis if necessary

(Begg & Woods, 2013)

Organization of the Nervous System

https://www.pastmedicalhistory.co.uk/the-nervous-system-of-harriet-cole/

• Central Nervous System (CNS)
  • Brain
  • Spinal Cord
  • (Everything encased in bone)
• Peripheral Nervous System (PNS)
  • Somatic division
  • Autonomic division
    • Sympathetic
    • Parasympathetic

Organization of the CNS

Major division	Ventricular Landmark	Embryonic Division	Structure
Forebrain	Lateral	Telencephalon	Cerebral cortex
			Basal ganglia
			Hippocampus, amygdala
	Third	Diencephalon	Thalamus
			Hypothalamus
Midbrain	Cerebral Aqueduct	Mesencephalon	Tectum, tegmentum
Hindbrain	4th	Metencephalon	Cerebellum, pons
	–	Mylencephalon	Medulla oblongata

• Forebrain, midbrain, hindbrain terminology derives from embryonic stages in CNS development.

https://upload.wikimedia.org/wikipedia/commons/c/c8/6_week_embryo_brain.jpg

Hindbrain

https://upload.wikimedia.org/wikipedia/commons/thumb/5/54/EmbryonicBrain.svg/1200px-EmbryonicBrain.svg.png

• Hindbrain: structures adjacent (or caudal to) 4th ventricle
  • Medulla oblongata
  • Cerebellum
  • Pons

http://webspace.ship.edu/cgboer/medial-labelled.gif

Medulla oblongata

• Cardiovascular regulation
• Muscle tone
• Fibers of passage
  • Ascending fibers (from body), a.k.a. afferents
  • Descending fibers (exiting brain), a.k.a., efferents

https://upload.wikimedia.org/wikipedia/commons/6/69/1311_Brain_Stem.jpg

Cerebellum

• “Little brain”
• Dorsal to pons
• Movement coordination, simple learning (classical conditioning)
• Largest number of neurons in the brain

Pons

• Bulge on ventral brain stem
• Neuromodulatory nuclei
  • Nucleus (anatomically discrete cluster of neurons
  • Neuromodulators: neurotransmitters that modulate/alter function of other neurons
  • e.g., Serotonin (5-HT), norepinephrine (NE), acetylcholine (ACh), dopamine (DA)
• Relay to cerebellum

Midbrain

• Tectum (roof), dorsal
• Tegmentum (floor), ventral

http://antranik.org/wp-content/uploads/2011/11/the-brain-stem-mid-brain-left-lateral-view-superior-colliculus-inferior-cerebellar-peduncle.jpg

Tectum

• “Roof” of the midbrain
• Superior and inferior colliculus (colliculi is plural for ‘little hill’)
• Superior colliculus: Reflexive orienting of eyes, head, ears (superior colliculi)
  • Input from FEF, parietal lobe
  • Output to cranial nerve nuclei (III, IV, VI) in tegmentum, pons
• Inferior colliculus: Auditory processing (from brainstem to auditory thalamus)

Tegmentum

• “Floor” of the midbrain
• Species-typical movement sequences
• Neuromodulatory nuclei
  • Norepinephrine (NE)
  • Serotonin (5-HT)
  • Dopamine (DA) – from ventral tegmental area (VTA)

Forebrain

• Diencephalon
• Telencephalon

Diencephalon (‘between brain’)

• Thalamus
• Hypothalamus

Thalamus

• Input to cortex
• Functionally distinct nuclei
  • Lateral geniculate nucleus (LGN), vision
  • Medial geniculate nucleus (MGN), audition
  • Pulvinar, attention?

Hypothalamus

• Five Fs: fighting, fleeing/freezing, feeding, and reproduction
• Controls pituitary gland (“master” gland)
  • Anterior pituitary (indirect release of hormones)
    • e.g., Corticotropin Releasing Hormone (CRH) -> release of cortisol from Adrenal Cortex (adjacent to kidney)
  • Posterior pituitary (direct release of hormones)
    • Oxytocin
    • Vasopressin (aka, Arginine Vasopressin – AVP; Anti-diuretic Hormone – ADH)

Telencephalon

• Basal ganglia
• Hippocampus, amygdala
• Cerebral cortex

Basal Ganglia

• Skill and habit learning
• Linked to Tourette syndrome, obsessive-compulsive disorder (OCD), addiction, movement disorders
• Example: Parkinson’s Disease

• Striatum
  • Caudate nucleus
  • Putamen
• Globus pallidus
• Subthalamic nucleus
• Substantia nigra (tegmentum)

Hippocampus

• Hippocampus means “sea horse”

https://theconversation.com/explainer-what-happens-in-the-hippocampus-32589

• Medial to lateral ventricles
• Store memories of specific facts (semantic memory) or events (episodic memory)
• Place memory in non-human animals (& humans?)
• Fornix (axon fiber bundle) projects to (mammillary bodies of) hypothalamus

Amygdala (“almond”)

• Physiological state, behavioral readiness, affect
• NOT the fear center! (LeDoux, 2015).
• Projection to hypothalamus

Cerebral Cortex

• Cerebral hemispheres
• Groove (sulcus or sulci)
• Bumps (gyrus or gyri)
• Grey vs. white matter
• Lobes

Lateral view

Medial view

Nissl stain

Lobes of the cerebral cortex

• Frontal
• Temporal
• Parietal
• Occipital
• Names derive from underlying bones of the skull

Longitudinal fissure

• Also known as superior longitudinal fissure
• Divides the cerebral hemispheres

Lateral sulcus/fissure

• Also known as Sylvian Fissure
• Divides frontal from temporal lobe

Central sulcus

• Also known as Rolandic Fissure or Fissure of Rolando
• Divides frontal from parietal lobe

Frontal lobe

• Anterior to central sulcus
• Superior to lateral fissure
• Dorsal to temporal lobe

• Primary motor cortex (M-I or M1)
  • Precentral gyrus

https://en.wikipedia.org/wiki/Precentral_gyrus

• Secondary motor areas
  • Supplementary motor cortex (SMC)
  • Frontal eye fields (FEF)
• Prefrontal cortex
  • Planning, problem solving, working memory…?
• Secondary olfactory cortex

(Saive, Royet, & Plailly, 2014)

Figure 1. Schematic view of the human olfactory system. The primary and secondary olfactory cortices are represented in blue and green, respectively. Amyg, amygdala; Ento, entorhinal cortex; Hipp, hippocampus; OFC, orbitofrontal cortex; PC, piriform cortex; Thal, thalamus (adapted from Royet et al., 2014).

(Saive, Royet, & Plailly, 2014)

• Basal forebrain
  • Nucleus accumbens (NAcc), part of ventral striatum

Cingulate Gyrus

• Anterior cingulate cortex (ACC)

Inferior Frontal Gyrus (IFG)

• Home to Broca’s Area

Middle Frontal Gyrus (MFG)

• Home to Dorsolateral Prefrontal Cortex (DLPFC)

Superior Frontal Gyrus (SFG)

• Brodmann Area 8
• Frontal Eye Fields (FEF)

https://en.wikipedia.org/wiki/Frontal_eye_fields

Temporal lobe

• Ventral to frontal, parietal lobes
• Inferior to lateral fissure

• Primary auditory cortex (A-I or A1)

https://en.wikipedia.org/wiki/Auditory_cortex

Superior Temporal Sulcus

• Object, face recognition; biological motion processing
• Language processing

Inferior Temporal Gyrus (ITG)

• Continuation of ventral visual processing stream

https://en.wikipedia.org/wiki/Inferior_temporal_gyrus

Entorhinal Cortex (ER)

• Storage of memories about events, objects
• Amygdala, hippocampus

Parietal lobe

• Caudal to frontal lobe
• Dorsal to temporal lobe
• Posterior to central sulcus

• Primary somatosensory cortex (S-I or S1)
  • information from sensors in skin, muscles, tendons, joints and viscera
• Post-central gyrus

https://en.wikipedia.org/wiki/Postcentral_gyrus

• Perception of spatial relations, action planning

Inferior Parietal Lobule

• e.g., language, mathematical operations, body image, etc.

Superior Parietal Lobule

• damage to can cause spatial hemi-neglect

https://en.wikipedia.org/wiki/Superior_parietal_lobule

Occipital lobe

• Caudal to parietal & temporal lobes

• Primary visual cortex (V1)
• Secondary visual areas (V2…V7)

Insular cortex (insula)

• medial to temporal lobe
• deep inside lateral fissure

• Primary gustatory cortex
• Self-awareness, interpersonal experiences, motor control, interoception

(Namkung, Kim, & Sawa, 2017)

Brodmann Areas

• Korbinian Brodmann

• Cytoarchitectonic (cellular architecture) differences in cerebral cortex
• Numbered areas, e.g. V1 == Area 17

White matter pathways

• Brainstem
• Projection fibers
• Association fibers
• Commissural fibers

(Oishi, Faria, Zijl, & Mori, 2010), Chapter 3, Figure 1.

Brainstem projections

• Corticospinal tract (descending/efferent)
• Dorsal column/medial lemniscus (ascending/afferent)
• Superior/inferior cerebellar peduncles (from/to cerebellum)

(Oishi, Faria, Zijl, & Mori, 2010), Chapter 3, Figure 8.

Projection fiber tracts

• Internal capsule
  • Thalamic radiation
  • Cortico-{pontine, bulbar, reticular} tracts

(Oishi, Faria, Zijl, & Mori, 2010), Chapter 3, Figure 11.

Cortical white matter tracts

• Superior/inferior longitudinal fasciculus
  • Arcuate fasciculus part of sup. long. f.
• Superior/inferior fronto-occipital fasciculus
• Cingulum, fornix (hyp-hip), stria terminalis (hyp-amyg)

Commissural fibers

• Corpus callosum
• Anterior commissure (AC)
• Posterior commissure (PC)

Anterior, Posterior Commissures

Spinal cord

• Spinal column w/ vertebrae
• Moving rostral -> caudal…
• Cervical (8), thoracic (12), lumbar (5), sacral (5), coccygeal (1)
• Spinal segments & 31 nerve pairs
• Cauda equina

• Spinal segments (rostral to caudal) ennervate specific body segments
• When focusing on the skin, these are called dermatomes

• Dorsal/Ventral
  • Dorsal root (sensory)
  • Ventral root (mostly motor)
• Grey (interior) vs. white matter (exterior)
  • Cerebral cortex opposite (grey exterior, white interior)

Organization of the PNS

• Somatic division
• Autonomic division (Autonomic Nervous System)

Somatic division

Cranial nerves

• Afferents (input), efferents (output), or mixed
• Innervate head and neck
• Olfactory (I), optic (II), (VIII) auditory, vagus (X), etc.
• Spinal nerves

Spinal nerves

Autonomic nervous system

• CNS & PNS components
• Controls “vegetative functions”
  • Limited voluntary control
• Three divisions
  • Sympathetic
  • Parasympathetic
  • Enteric (gut, intestinal tract)

• Bipolar (continuum) vs. bivariate autonomic space (Berntson, Cacioppo, & Quigley, 1991)

Sympathetic division

• Prepares body for action
• “Fight or flight”
• Spinal cord
  • ganglion chain along spinal column to End organs
• Neurotransmitters (NTs)
  • Preganglionic: ACh
  • Post: NE

Parasympathetic division

• “Around” sympathetic
• Restorative function
• “Rest & digest”
• Spinal cord (or Vagus n. from Xth cranial n.) -> ganglia near end organs -> end organ
  • NT: ACh

Illustrative measures of ANS function

• Heart rate variability

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Neurovisceral_integration_model.png/330px-Neurovisceral_integration_model.png

• Galvanic skin response (GSR)
• Pupillary response

https://upload.wikimedia.org/wikipedia/commons/a/a5/Gray840.png

• electrogastrogram (EGG) for ENS (Al Taee & Al-Jumaily, 2020)

Fig. 1. Gastric pacesetter potentials or slow waves originate from the pacemaker area on the greater curve. Pacesetter potentials travel in a circumferential and aboral direction at a rate of approximately 3 cycles per minute (cpm). The cutaneously recorded electrogastrogram shows 3-cpm wave pattern. The fundus has no rhythmic electrical activity.

(Al Taee & Al-Jumaily, 2020)

References

Abbott, N. J., Rönnbäck, L., & Hansson, E. (2006). Astrocyte-endothelial interactions at the blood-brain barrier. Nature Reviews. Neuroscience, 7(1), 41–53. https://doi.org/10.1038/nrn1824

Al Taee, A., & Al-Jumaily, A. (2020). Electrogastrogram based medical applications an overview and processing frame work. In Hybrid intelligent systems (pp. 511–520). Springer International Publishing. https://doi.org/10.1007/978-3-030-14347-3\_50

Begg, D. P., & Woods, S. C. (2013). The endocrinology of food intake. Nature Reviews. Endocrinology, 9(10), 584–597. https://doi.org/10.1038/nrendo.2013.136

Berntson, G. G., Cacioppo, J. T., & Quigley, K. S. (1991). Autonomic determinism: The modes of autonomic control, the doctrine of autonomic space, and the laws of autonomic constraint. Psychological Review, 98(4), 459–487. https://doi.org/10.1037/0033-295X.98.4.459

LeDoux, J. (2015, August 10). The Amygdala Is NOT the Brain’s Fear Center. Psychology Today. Retrieved from https://www.psychologytoday.com/blog/i-got-mind-tell-you/201508/the-amygdala-is-not-the-brains-fear-center

Namkung, H., Kim, S.-H., & Sawa, A. (2017). The insula: An underestimated brain area in clinical neuroscience, psychiatry, and neurology. Trends in Neurosciences, 40(4), 200–207. https://doi.org/10.1016/j.tins.2017.02.002

Oishi, K., Faria, A. V., Zijl, P. C. van, & Mori, S. (2010). MRI atlas of human white matter. Academic Press.

Saive, A.-L., Royet, J.-P., & Plailly, J. (2014). A review on the neural bases of episodic odor memory: From laboratory-based to autobiographical approaches. Frontiers in Behavioral Neuroscience, 8, 240. https://doi.org/10.3389/fnbeh.2014.00240

Xie, L., Kang, H., Xu, Q., Chen, M. J., Liao, Y., Thiyagarajan, M., … others. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373–377. https://doi.org/10.1126/science.1241224