04 functional neuroanatomy

Functional NeuroanatomyProf. Nahla NagyProf. Psychiatry

Ain Shams University

The brain is formed of three general areas:

the brain stem, the cerebellum, the cerebral cortex.

The brain stem is involved with: autonomic control of processes like

breathing and heart rate (panic attacks).

conduction of information to and from the peripheral nervous system.

The cerebellum is responsible for: balance and coordination of

movement. Cognitive functions

The cerebral cortex is divided into two hemispheres connected by the corpus callosum.

The right side of the brain is the creative side

The left hemisphere is involved more in analytical processing.

The language—both Broca’s Area, an area important to language syntax, and Wernicke’s Area, a region critical to language content, reside on the left side of the brain.

The occipital lobe, located at the back of the brain, is the seat of the primary visual cortex, the brain region responsible for processing and interpreting visual information.

The temporal lobe is a major processing center for language and memory.

The parietal lobe houses the somatosensory cortex and plays an important role in touch and spatial navigation.

The frontal lobe, is the brain region that separates

humans from our primate cousins. This lobe is the seat of executive function, with a hand in reasoning, decision-making, integration of sensory information, and the planning and execution of movement.

Subcortical structures: The thalamus responsible for

integrating sensory information The basal ganglia for processing risk

and rewards Both are strongly connected to the

neocortex (frontal lobe)and share information in both a bottom-up and top-down fashion.

Current estimates suggest the brain has approximately 86 billion neurons.

The brain is made up of two types of matter: gray and white.

Gray matter consists of the cell bodies and dendrites of the neurons, as well as supporting cells called astroglia and oligodendrocytes.

White matter, however, is made up of mostly of axons sheathed in myelin, an insulating-type material that helps cells propagate signals more quickly. It’s the myelin that gives the white matter its lighter color.

Recent studies show that white matter architecture is important in processes like learning and memory.

Obsessive-compulsive disorder

Functional imaging studies indicated functional deficits in frontostriatal networks,mainly the orbitofrontal leading to an imbalance in direct and indirect feedback loops and a disinhibition of thalamocortical activity.

Neurochemical studies have shown that OCD is linked to changes in the serotonin and dopamine system.

The primary parts of the limbic system include the hypothalamus, amygdala, hippocampus, septal nuclei, and anterior cingulate gyrus.

Also important in the function of the limbic system is the limbic striatum, which includes the nucleus accumbens, ventral caudate nucleus and the putamen . The nucleus accumbens (NA) has been implicated as an especially important structure of the brain reward pathway because drugs of abuse target it. Other structures important in brain reward include the amygdala and the ventral tegmental area (VTA).

Core Structures of the Reward System

The core structures of the brain reward pathway is located in the limbic system

Conceptually, the function of the limbic system is to monitor internal homeostasis, mediate memory, mediate learning, and experience emotion.

It also drives important aspects of sexual behavior, motivation, and feeding behaviors .

Neuroanatomy of depression

Decision making

Neuroanatomy of ADHD

Alzhiemer’s Dementia

Borderline Personality Disorder

BPD patients demonstrated functional changes in the amygdala, fusiform gyrus, primary visual areas, superior temporal gyrus (STG), and premotor areas.

These findings suggest that BPD patients show greater amygdala activity and heightened activity of visual processing regions in the processing of negative social emotional pictures .

Posttraumatic Stress Disorder

Brain regions that play an important role in PTSD include hippocampus, amygdala, and medial prefrontal cortex.

Cortisol and norepinephrine are two neurochemical systems that are critical in the stress response

MCQ MODEL

The following are true about the trigeminal nerve:

a. it supplies the muscle of mastication b. its ganglion lies on the apex of the petrous bone

c. emerges from the brain stem between the pons and the medulla

d. emerges from the brain stem as separate sensory and motor roots

e. innervates all the teeth of the upper jaw

6) A54 year-old man has become forgetful, preoccupied, withdrawn, irritable and dishevelled. His physical examination was normal. The patient had been with his company for twenty-two years and was considered an excellent employee. Which of the following is the most likely diagnosis: a) multi-infarct dementia b) hypothyroidism c) schizophrenia d) alcoholism e) major depression

______, which covers most of the axon, is important because it ______.

Myelin; facilitates the release of neurotransmitter

Synovial fluid; facilitates electrical conduction of nerve cells

Membrane potential; increases conduction of nerve impulses

Cerebrospinal fluid; increases conduction of nerve impulses

Neurotransmitters can inhibit or excite neurons. ______, for example, is inhibitory whereas ______ is excitatory.

Glutamate; GABA GABA; glutamate Serotonin; dopamine None of the above is correct

occipital lobe of cerebral cortex has: a. Visual area. b. Auditory area. c. Motor area. d. Somatic sensory area.

cerebellum controls the following function:

a. Feeding. b. Sensation. c. Body posture and equilibrium. d. Sleep.

sensory cortex has a large area for impulses from:

a. Lips. b. Shoulder. c. Abdomen. d. Lower limbs.

Inability to vocalize the words indicate lesion in:

a. Brain stem. b. Broca's area. c. Motor area. d. Thalamus.

hypothalamus controls: a. Water intake (thirst). b. Body temperature. c. Food intake (appetite). d. All of the above.

Essay Questions

Discuss the neural circuits involved in addiction

How enviromental factors can affect gene expression of psychiatric disorders.

Thank YOU