functional neuroanatomy of brain

FUNCTIONAL NEUROANATOMY OF BRAIN

Presented by: Dr. Karrar Husain

Moderator: Dr Piyush P Singh

• The brain, and the brain alone, is the source of our pleasures, joys, laughter, and amusement, as well as our sorrow, pain, grief, and tears.

Hippocrates, ca. 400

HUMAN BRAIN• Human brain substantially greater in size (350g vs 1200g).

• The prefrontal cortex 3.5 % of the total cortical volume in cats and 11.5% in monkeys but close to 30 % in humans brain.

• Relative representation of other regions is decreased in the human brain; (primary visual cortex 1.5 percent of the total area in humans but its close to 17% in monkeys.

CELLS• Human brain 1011 nerve cells

• Neurons four morphologically identified regions

• 1) The cell body, or soma containing the nucleus; considered the metabolic center of the neuron.

• 2) The dendrites, processes arising from the cell body, branch extensively; serve as the major recipient zones of input.

• 3) The axon, a single process that arises from a specialized portion of the cell body (the axon hillock) and conveys information to other neurons

• 4) The axon terminals, fine branches near the end of the axon that form contacts (synapses).

THE CEREBRUM

Cerebrum -The largest division of the brain. It is divided into two hemispheres, each of which is divided into four lobes.

Cerebrum

Cerebrum

Cerebellum

Cerebral cortex• Cerebral Cortex - The outermost layer of gray matter

making up the superficial aspect of the cerebrum.

• cerebral cortex, several millimeters thick, covers the cerebral hemispheres 22.5 billion neurons 165 trillion synapses

• 90 percent of the total cortical area neocortex, which has a six-layered structure

• Rest is allocortex and consists of the paleocortex and the archicortex, regions that are restricted to the base of the telencephalon and the hippocampal formation, respectively.

Cerebral Cortex

Cerebral Cortex

Cerebral Features:

• Sulci – Small grooves dividing the gyri

– Central Sulcus – Divides the Frontal Lobe from the Parietal Lobe

• Fissures – Deep grooves, generally dividing large regions/lobes of the brain

– Longitudinal Fissure – Divides the two Cerebral Hemispheres

– Transverse Fissure – Separates the Cerebrum from the Cerebellum

– Sylvian/Lateral Fissure – Divides the Temporal Lobe from the Frontal and Parietal Lobes

• Gyri – Elevated ridges “winding” around the brain.

Gyri (ridge)

Fissure

(deep groove)

Sulci (groove)

Longitudinal Fissure

Transverse Fissure

Sylvian/Lateral Fissure

Central Sulcus

Specific Sulci/Fissures:

Lobes of the Brain

•Frontal•Parietal•Occipital•Temporal

* Note: Occasionally, the Insula is considered the fifth lobe. It is located deep to the Temporal Lobe.

Lobes of the Brain - Frontal• The Frontal Lobe of the brain is located deep to the Frontal Bone of the skull.

• It plays an integral role in the following functions/actions:

- Memory Formation

- Emotions

- Decision Making/Reasoning

- Personality

Frontal Lobe - Cortical Regions

• Orbitofrontal Cortex – Site of Frontal Lobotomies

• Primary Motor Cortex (Precentral Gyrus) – Cortical site involved with controlling movements of the body.

• Broca’s Area – Controls facial neurons, speech, and language comprehension. Located on Left Frontal Lobe.

– Broca’s Aphasia – Results in the ability to comprehend speech, but the decreased motor ability (or inability) to speak and form words.

• Olfactory Bulb - Cranial Nerve I, Responsible for sensation of Smell

* Desired Effects:- Diminished Rage- Decreased Aggression- Poor Emotional Responses

* Possible Side Effects:- Epilepsy- Poor Emotional Responses- Perseveration (Uncontrolled, repetitive actions, gestures, or words)

Primary Motor Cortex/ Precentral Gyrus

Broca’s Area

Orbitofrontal Cortex

Olfactory Bulb

Lobes of the Brain - Parietal Lobe

• The Parietal Lobe of the brain is located deep to the Parietal Bone of the skull.

• It plays a major role in the following functions/actions:

- Senses and integrates sensation(s)

- Spatial awareness and perception(Proprioception - Awareness of body/ body parts in space and in relation to each other)

Parietal Lobe - Cortical Regions

• Primary Somatosensory Cortex (Postcentral Gyrus) – Site involved with processing of tactile and proprioceptive information.

• Somatosensory Association Cortex - Assists with the integration and interpretation of sensations relative to body position and orientation in space. May assist with visuo-motor coordination.

• Primary Gustatory Cortex – Primary site involved with the interpretation of the sensation of Taste.

Primary Somatosensory Cortex/ Postcentral Gyrus

Primary Gustatory Cortex

Somatosensory Association Cortex

Lobes of the Brain – Occipital Lobe

• The Occipital Lobe of the Brain is located deep to the Occipital Bone of the Skull.

• Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Occipital Lobe – Cortical Regions

• Primary Visual Cortex – This is the primary area of the brain responsible for sight -recognition of size, color, light, motion, dimensions, etc.

• Visual Association Area – Interprets information acquired through the primary visual cortex.

Primary Visual Cortex

Visual Association Area

Lobes of the Brain – Temporal Lobe

• The Temporal Lobes are located on the sides of the brain, deep to the Temporal Bones of the skull.

• They play an integral role in the following functions:- Hearing

- Organization/Comprehension of language

- Information Retrieval (Memory and Memory Formation)

Temporal Lobe – Cortical Regions

• Primary Auditory Cortex – Responsible for hearing

• Primary Olfactory Cortex – Interprets the sense of smell once it reaches the cortex via the olfactory bulbs. (Not visible on the superficial cortex)

• Wernicke’s Area – Language comprehension. Located on the Left Temporal Lobe.

- Wernicke’s Aphasia – Language comprehension is inhibited. Words and sentences are not clearly understood, and sentence formation may be inhibited or non-sensical.

Primary Auditory Cortex

Wernike’s Area

Primary Olfactory Cortex (Deep)Conducted from Olfactory Bulb

• Arcuate Fasciculus - A white matter tract that connects Broca’s Area and Wernicke’s Area through the Temporal, Parietal and Frontal Lobes. Allows for coordinated, comprehensible speech. Damage may result in:- Conduction Aphasia - Where auditory comprehension and speech articulation are preserved, but people find it difficult to repeat heard speech.

Click the Region to see its Name

Lobes and Structures of the Brain

B. A.

C.

D. E.

F.

G.

Lobes and Structures of the Brain

B.

A. (groove)

C. (groove)

D. E.

F.

G.

B. Frontal Lobe

G. Parietal Lobe

F. Occipital Lobe

D. Temporal Lobe

A. Central Sulcus

(groove)

E. Transverse Fissure

C. Sylvian/Lateral Fissure

Cortical Regions

A.

B.

C.

D.

E. F.

G.

H.

I.

J.K.

Cortical Regions

A.

B.

C.

D.E. F.

G.

H.

I.

J.K.

A. Primary Motor Cortex/ Precentral Gyrus

B. Broca’s Area

C. Orbitofrontal Cortex

K. Primary Somatosensory Cortex/ Postcentral Gyrus

I. Primary Gustatory Cortex

J. Somatosensory Association Cortex

G. Primary Visual Cortex

H. Visual Association Area

E. Primary Auditory Cortex

F. Wernike’s Area

D. Primary Olfactory Cortex (Deep)

A: Primary Motor Cortex

* This graphic representation of the regions of the Primary Motor Cortex and Primary Sensory Cortex is one example of a HOMUNCULUS:

Q: What do you notice about the proportions depicted in the aforementioned homunculus?

Q: What is meant by depicting these body parts in such outrageous proportions?

A: They are not depicted in the same scale representative of the human body.

A: These outrageous proportions depict the cortical area devoted to each structure.

- Ex: Your hands require many intricate movements and sensations to function properly. This requires a great deal of cortical surface area to control these detailed actions. Your back is quite the opposite, requiring limited cortical area to carry out its actions and functions, or detect sensation.

* Note: Homunculus literally means “little person,” and may refer to one whose body shape is governed by the cortical area devoted to that body region.

Further Investigation

Phineas Gage: Phineas Gage was a railroad worker in the 19th century living in Cavendish, Vermont. One of his jobs was to set off explosive charges in large rock in order to break them into smaller pieces. On one of these instances, the detonation occurred prior to his expectations, resulting in a 42 inch long, 1.2 inch wide, metal rod to be blown right up through his skull and out the top. The rod entered his skull below his left cheek bone and exited after passing through the anterior frontal lobe of his brain.

Remarkably, Gage never lost consciousness, or quickly regained it (there is still some debate), suffered little to no pain, and was awake and alert when he reached a doctor approximately 45 minutes later. He had a normal pulse and normal vision, and following a short period of rest, returned to work several days later. However, he was not unaffected by this accident.

Gage’s personality, reasoning, and capacity to understand and follow social norms had been diminished or destroyed. He illustrated little to no interest in hobbies or other involvements that at one time he cared for greatly. ‘After the accident, Gage became a nasty, vulgar, irresponsible vagrant. His former employer, who regarded him as "the most efficient and capable foreman in their employ previous to his injury," refused to rehire him because he was so different.’

FUNCTIONAL BRAIN SYSTEMS

• The relations between the organizational principles and the structural components of the human brain are illustrated in three functional systems:

the thalamocortical,basal ganglia, and limbic systems

Thalamocortical Systems• Thalamus: Group of nuclei located medial to the basal

ganglia that serves as the major synaptic relay station for the information reaching the cerebral cortex

• the thalamic nuclei can be divided into six groups: anterior, medial, lateral, reticular, intralaminar, and midline nuclei

BASAL GANGLIA• Basal ganglia are a collection of nuclei that have been

grouped together on the basis of their interconnections• play an important role in regulating movement and in

certain disorders of movement eg chorea ,dyskinesia,athetosis,tremors

• include the caudate nucleus, the putamen, the globus pallidus (referred to as the paleostriatum or pallidum), the subthalamic nucleus, and the substantia nigra

• striatum ->caudate nucleus + the putamen together; • corpus striatum -> caudate nucleus +putamen + globus

pallidus; • lentiform nucleus-> putamen + globus pallidus

FUNCTIONAL CIRCUITS OF BASAL GANGLIA

• INPUTS:• The striatum is the major recipient of the inputs to the basal

ganglia. Three major afferent systems are known to terminate in the striatum: the corticostriatal, nigrostriatal, and thalamostriatal afferents.

• Disruption of the input pathways of the basal ganglia has been associated with some movement disorders, such as Parkinson's disease

INTERNAL PROCESSING

• The intrinsic circuitry of the basal ganglia is disrupted by a severe loss of neurons in the striatum in Huntington's disease.

This autosomal-dominant disorder is characterized by progressive chorea and dementia

OUTPUTS

• globus palllidus provides a projection to the ventral lateral and ventral anterior nuclei of the thalamus and to the intralaminar thalamic nuclei, particularly the central median nucleus

• The pars reticulata of the substantia nigra also provides a projection to the ventral anterior and ventral lateral thalamic nuclei.

• the basal ganglia are able to indirectly influence the output of the primary motor cortex through thalamic nuclei.

• Functions of basal ganglia:• important in the control of movement

• recent studies of the connections of the basal ganglia in nonhuman primates also support a role for these structures in cognitive functions.

LIMBIC SYSTEM

• the cingulate and parahippocampal gyri (limbic cortex),

• the hippocampal formation,(dentate gyrus, the hippocampus, and the subicular complex)

• the amygdala,

• the septal area, the hypothalamus, and

• related thalamic and cortical areas.

FUNCTIONS OF LIMBIC SYSTEM

• Integration of olfactory, visceral, somatic impulses• Control of activities necessary for survival of animal• Control of activities necessary survival of species• Emotional behaviour• Retention of recent memory

• In 1937, James Papez postulated, primarily on the basis of anatomical data, that these cortical regions were linked to the hippocampus, mammillary body, and anterior thalamus in a circuit that mediated emotional behavior

neural circuit for emotion as originally proposed by James Papez

• However, over the last 40 years, it has become clear that some limbic structures (for example, the hippocampus) are also involved in other complex brain processes, such as memory

• Other cognitive processes with the hypothalamus and its output pathways that control autonomic, somatic, and endocrine functions

• LIMBIC CORTEX• composed of two general regions, the cingulate gyrus and

the parahippocampal gyrus

• ENTORHINAL CORTEX(Brodmann’s area no 28)

• Receive projections from olfactory bulb

• HIPPOCAMPAL FORMATION• Three distinct zones—the dentate gyrus, the

hippocampus, and the subicular complex—constitute the hippocampal formation, which is located in the floor of the temporal horn of the lateral ventricle

• These zones are composed of adjacent strips of cortical tissue

• On the basis of differences in the cytoarchitecture and connectivity, the hippocampus can be divided into three distinct fields, which have been labeled CA3, CA2, and CA1.

• The major input to the hippocampal formation arises from neurons in layers II and III of the entorhinal cortex

• The major input to the hippocampal formation arises from neurons in layers II and III of the entorhinal cortex

FUNCTIONS OF HIPPOCAMPUS• Retention of short term memory – long term declarative memory

AMYGDALA• Almond• Involved in Central regulation of ANS connection to hypothalamus

• Controls survival fight-or-flight response of ANS• Emotional & visceral responses

AMYGDALA

• Several group of nucleus• B/w inferior horn of lateral ventricle & lentiform nucleus

• Two divisions :-

-dorsomedial

-ventrolateral – Basolateral

- central

• Functional Circuits of limbic systemThe major structures of the limbic system are interconnected with each other and with other components of the nervous system in a variety of ways.. highly processed sensory information from the cingulate, the orbital and temporal cortices, and the amygdala is transmitted to the entorhinal cortex of the parahippocampal gyrus and then to the hippocampal formation. After traversing the intrinsic circuitry of the hippocampal formation, information is projected through the fornix either to the anterior thalamus, which, in turn, projects to the limbic cortex, or to the septal area and the hypothalamus. These latter two regions provide feedback to the hippocampal formation through the fornix. In addition, the mammillary bodies of the hypothalamus project to the anterior thalamus. Finally, the hypothalamus and the septal area project to the brainstem and the spinal cord

• Highly processed sensoryinformation, primarily from the association regions of the prefrontal and temporal cortices, projects to the amygdala. Output from the amygdala is conducted through two main pathways (Fig. 1.2-37). A dorsal route, the stria terminalis, accompanies the caudate nucleus in an arch around the temporal lobe and contains axons that project primarily to the septal area and the hypothalamus. The second major output route, the ventral amygdalofugal pathway, passes below the lenticular nucleus and contains fibers that terminate in a number of regions, including the septal area, the hypothalamus, and the medial dorsal thalamic nucleus. The medial dorsal nucleus, in turn, projects heavily to prefrontal and some temporal cortical regions.

• Both of these pathways reveal how the limbic system is able to integrate the highly processed sensory and cognitive information content of the cerebral cortical circuitry with the hypothalamic pathways that control autonomic and endocrine systems

• the ventral amygdalofugal pathway also projects to the nucleus accumbens (ventral striatum), the area where the head of the caudate nucleus fuses with the putamen (Fig. This region sends efferents to the ventral palladium, an extension of the globus pallidus. This area, in turn, projects to the medial dorsal thalamic nucleus. The pathway indicates that the functions of the basal ganglia extend beyond the regulation of motor activities and shows the necessity of considering the function or dysfunction of particular brain regions in the context of all aspects of their circuitry.

FUNCTIONAL ANATOMY OF BRAIN IN RELATION TO PSYCHIATRIC DISORDER

schizophrenia• Reduced nmda glutamate receptors causing cognitive symptoms

• Responsible for negative symptoms

• Anatomical abnormality of prefrontal cortex

• Mri & pet shows functional difference in brain activity in frontal lobe,hippocampus,temporal lobe

• Pet shows less frontal activity during working memory related to neurocognitive defects

• Latera land third ventricular enlargement • Reduced volumes of cortical gray matter• reduced symmetry in thetemporal,frontal,and occipital

lobes• decrease inthe size the amygdala, the hippocampus,and

the parahippocampal gyrus. • functionallyabnormal hippocampus as indicated by

disturbances in glutamate transmis-sion. D

• Anatomical abnormalitiesin the prefrontal cortex in

schizophrenia• volume shrinkage or neuronal loss in thalamus , in

particular subnuclei

Mood disorders

• The most consistent abnormality observed in the depressive disorders is increased frequency of abnormal hyperintensities in subcortical regions such as periventricular regions, the basal ganglia, and the thalamus

• reduced hippocampal or caudate nucleus volumes• increase in blood flow and neuronal activity in the

thalamus and medial PFC.• decreased anterior brain metabolism, which is generally

more pronounced on the left side

• global reduction of anterior cerebral metabolism, increased glucose metabolism has been observed in several limbic regions, particularly among patients with relatively severe recurrent depression and a family history of mood disorder

ANXIETY DISORDERS• icreasedactivityintheseptohippocampalpathway, which may lead to anxiety,

and the cingulate gyrus, which hasbeen implicated particularly in the pathophysiology of ocd.

altered function in neuro circuit

increased blood flow&metabolism in frontal lobe

compulsive hoarding:compulsive hoarding or pathological

hoarding or disposophobia is the excessive acquisition of possessions, even

if the items are worthless, hazardous, or unsanitary.

damage to rt medial prefrontal cortex cause HOARDING

ADHD GENERAL REDUCTION OF BRAIN VOLUME ,BUT PROPORTIONALLY

GREAT REDUCTION OF LT PREFRONTAL CORTEX

RECENT RESEARCH SHOWS FOLLOWING FOUR CONNECTED FRONTOSTRIATAL REGIONS PLAY A ROLE IN ADHD-lateral prefrontal cortex ,Dorsal anterior cingulate,caudate,Putamen

DELAYED DEVELOPMENT OF FRONTAL CORTEX,TAMPORAL LOBE&FAST MATURITY OF MOTOR CORTEX SEEN

THIS CONTRIBUTES SLOW BEHAVIOURAL CONTROL &ADVANCED MOTOR DEVELOPMENT LEADS TO FIDGETINESS,THAT IS CHARACTERISTIC OF ADHD

PET SHOS LOW PERFUSION AND METABOLISM OF FRONTAL AREA

APPLIED ANATOMY BASAL GAGLIA

• MOVEMENT DISORDER

1- athetosis: lesion of globus pallidus

2- hemiballismus: lesion of subthalamic nuclei

3-chorea: multiple small lesion in putamen

4-parkinsonism disease: destruction of substantia nigra

5 hutingtons disease: loss of cell bodies of GABA secreting neurons in caudate nucleus and putamen

• NEUROPSYCHIATRIC DISORDER• Impairment in cognition• Depression• Personality changes• Poor judgment• Impaired concentration• Social withdrawl • Agitation

APPLIED ANATOMY OF LIMBIC SYSTEM

• Kluver Bucy syndrome

-complete removal of both temporal lobes

-amygdaloid body, hippocampal formation

-docility, lack of emotional responses, increased sexual activity (perverted), visual agnosia

-Amygdaloid body lesion

-Lesion of hippocampi

•Anxiety states-Inappropriate activity of amygdala

-Panic attacks of excessive activity of sympathetic nervous system, subjective feeling of worry

-Treatment – anxiolytic drugs

• Schizophrenia

-anatomical measurements reduced in size

-antipsychotics antagonise action of dopamine

-parkinsonism

-tardive dyskinesia

•Memory disorders-consolidation of new short term memory

-arterial occlusion – infarction – loss of hippocampal function

-transient global amnesia

-head injury –damage to hippocampus – hemorrhage – anterograde amnesia

- B/l hippocampal lesion – major circuit of hippocampus- B/l transaction of fornix – severe amnesia

•Alzheimer’s disease –- loss of cholinergic neurons of substantia innominata

which project to hippocampus

-ass. with degenerative changes in entorhinal cortex, hippocampus, extensive neocortical atrophy

-amnesia for recently occurred events as mechanism for retention of new memory not operating

FUNCTION AL ASSESSMENT OF BRAIN(NEURO-PSYCHOLOGICAL ASSESMENT)

• Neuropsychological Assessment provides an objective evaluation of cognitive and structural functioning

• Areas of neurological assessment:• Abstract reasoning/compensation(e.g. problem solving,

executive functions)• Activities of daily living(e.g toiletting, dressing,feeeding)• Attention• Emotional/psychological distress(depression, impusivity)

• Language skills • Motor• Orientation• Sensation/perception• Visuospatial

Neuropsychological tests• Intelligence• Ammons Quick Test• National Adult Reading Test (NART)• Wechsler Adult Intelligence Scale (WAIS)• Wechsler Intelligence Scale for Children (WISC)• Wechsler Preschool and Primary Scale of Intelligence (W

PPSI)• Wechsler Test of Adult Reading (WTAR)

• Memory• California Verbal Learning Test• Cambridge Prospective Memory Test (CAMPROMPT)• Doors and People• MCI Screen• Memory Assessment Scales (MAS)• Rey Auditory Verbal Learning Test• Rivermead Behavioural Memory Test• Test of Memory and Learning (TOMAL)• Wechsler Memory Scale (WMS)• Test of Memory Malingering (TOMM)

• Language• Boston Diagnostic Aphasia Examination• Boston Naming Test• Comprehensive Aphasia Test (CAT)• Lexical decision task• Multilingual Aphasia Examination

• Executive function• Behavioural Assessment of Dysexecutive Syndrome (BADS)• CogScreen: Aeromedical Edition• Continuous Performance Task (CPT)• Controlled Oral Word Association Test (COWAT)• d2 Test of Attention• Delis-Kaplan Executive Function System (D-KEFS)• Digit Vigilance Test• Figural Fluency Test• Halstead Category Test• Hayling and Brixton tests• Iowa gambling task• Kaplan Baycrest Neurocognitive Assessment (KBNA)• Kaufman Short Neuropsychological Assessment• Paced Auditory Serial Addition Test (PASAT)• Pediatric Attention Disorders Diagnostic Screener (PADDS)• Rey-Osterrieth Complex Figure• Ruff Figural Fluency Test• Stroop task• Test of Variables of Attention (T.O.V.A.)• Tower of London Test• Trail-Making Test (TMT) or Trails A & B• Wisconsin Card Sorting Test (WCST)• Symbol Digit Modalities Test• Test of Everyday Attention (TEA)

• Visuospatial[edit]• Neuropsychological tests of visuospatial function should

cover the areas of visual perception, visual construction and visual integration.[9] Though not their only functions, these tasks are to a large degree carried out by areas of the parietal lobe.[10]

• Clock Test• Hooper Visual Organisation Task (VOT)• Rey-Osterrieth Complex Figure

Batteries assessing multiple neuropsychological functions• There are some test batteries which combine a range of

tests to provide an overview of cognitive skills. • These are usually good early tests to rule out problems in

certain functions and provide an indication of functions which may need to be tested more specifically.

Goals of Neuropsychological Assessment

• Diagnose the presence of cortical damage and localize it if possible

• Facilitate patient care• Identify mild disturbances• Identify unusual brain organization• Identify the cause of disorders• Rehabilitation• Help the patient and their family understand the disorder

PRIMITIVE REFLEXESThese are newborn reflexes disappear or inhibited by Frontal lobe

during normal development,which are not being suppressed in

frontal lobe injury causes frontal release signs.WALKING/STEPPING REFLEXROOTING REFLEXSUCKING REFLEXTONIC NECK REFLEXPALMAR GRASP REFLEXPLANTAR REFLEXGALANT REFLEXSWIMMING REFLEXBABKIN REFLEX

FUNCTIONAL NEUROIMAGING OF BRAIN IN RELATION TO MENTAL IN ILLNESS

Neuroimaging and Mental IllnessStructural

– Computerized Tomography (CT)– Magnetic Resonance Imaging (MRI)

Functional– Positron Emission Tomography (PET)– Single Photon Emission CT (SPECT)– functional MRI (fMRI)– MR spectroscopy– EEG & Event-Related Potentials (ERP)– Magnetoencephalography (MEG)– near infrared spectroscopy (NIRS)

Neuroimaging and Mental IllnessStructural

– Computerized Tomography (CT)– Magnetic Resonance Imaging (MRI)

Functional– Positron Emission Tomography (PET)– Single Photon Emission CT (SPECT)– functional MRI (fMRI)– MR spectroscopy– EEG & Event-Related Potentials (ERP)– Magnetoencephalography (MEG)– near infrared spectroscopy (NIRS)

Functional MRI (fMRI)• Observation of active brain areas at a given time

• Blood-oxygen-level dependent or BOLD fMRI• Increased blood flow releases oxygen to active neurons at a greater rate

than to inactive neurons • Increased blood flow to active areas creates the magnetic signal

variation that can be detected by an MRI

• Comparisons can be made of brain activity • during rest • scripted thoughts• patterned actions• controlled experiences

Advantages of fMRINoninvasively record brain signals without risks of radiation

It can record on a spatial resolution in the region of 3-6 millimeters.

Disadvantages of fMRIBOLD signal is an indirect measure of neural activity

It is susceptible to influence by non-neural changes in the body

BOLD signals are most strongly associated with the input to a given area rather than with the output.

The temporal response of the blood supply is poor relative to the electrical signals that define neuronal communication.

Motor

Workingmemory/Executivefunctions

Speechproduction

Emotions Memory Vision

Motor/sequencing

Audition / speechperception

Attention

Sensory

Assumption in fMRI-BOLD imaging studies is a ”cognitive map”

Depression group

Healthy Controls

Schizophrenia group

fMRIHealthy Controls

Copyright restrictions may apply.

Psychotherapy vs Drug TreatmentIn Depression

Interpersonal psychotherapy

Venlafaxine

Positron Emission Tomography• A PET scan is a radionuclide scan that produces a 3-D image or map of

functional processes such as blood flow, oxygen use and blood sugar (glucose) metabolism.

• Glucose is often combined with a radioactive substance (radiotracer) fluorodeoxyglucose (FDG), that's injected into the patient

• PET tracer emits positrons which annihilate with electrons up to a few millimeters away, causing two gamma photons to be emitted in opposite directions. A PET scanner detects these emissions as "coincident" in time

• Different tissues in your body take up different radionuclides at different rates.

• The number of positrons emitted by an organ or area of tissue indicates the amount of radioactive substance

• Intense color = high uptake = hot spots • Less intense color = low uptake of radioactive substance = cold spots.

PET Radiotracers• Dopamine

• Benzodiazepine• Serotonin• Histamine

• Muscarinic cholinergic• Amyloid

• Protein kinase C • Monoamine oxidase

PET scan

Increased loss of gray matter in adolescence between the ages of 12-16 compared to healthy adolescence. Red—Gray Matter GainBlue—Gray Matter Loss

PET scan of Schizophrenics participating in the Wisconsin card sorting task

PET ScanObsessive Compulsive Disorder

DepressedNot Depressed

PET scans of a 45 year old woman with recurrent depression

pre and post treatment.

PET ScanADHD vs. Normal

White, Red, Orange = higher glucose metabolism

Blue, Green, Purple = lower glucose metabolism

ADHD Normal

Single photon emission computed tomography (SPECT)

• SPECT is very similar to PET

• Uses a radioactive tracer material and detects gamma rays.

• In contrast with PET, the tracer used emits gamma radiation that is measured directly.

• SPECT have lower resolution than a PET scan.

• SPECT scans are significantly less expensive.

SPECT Images

Depressed

Not Depressed

How Radiology Can Aid Psychiatry

• Structural brain changes can be seen on CT

• MRI studies in patients can confirm significant differences in brain volume and structure

• Functional chemical changes can be seen on PET, SPECT and fMRI• altered blood flow and metabolism • PET and SPECT studies have demonstrated treatment

receptor occupancy and treatment progression

• Radiological studies of psychiatric populations add to available knowledge on the biological aspects of psychiatry.

Thank you