Forebrain 3 Flashcards
(139 cards)
1
Q
What does the neocortex do?
A
- Has the idea for a movement
2
Q
What does the direct pathway do as part of motor control?
A
- Through the basal ganglia it facilitates the appropriate pattern of motor activity
- Allowing it to acheive the desired movement
*
3
Q
What happens with the information after the basal ganglia?
A
- Information sent via the thalamus to the supplementary motor area
- This communicates with the motor cortex (M1)
- M1 controls motor neurones via the corticospinal tract
4
Q
What does the cerebellum do in terms of motor control?
A
- Identifies & corrects errors in movement
5
Q
What does the indirect pathway do to movement?
A
- Brings an end to a movement
6
Q
Explain the motor pathway in the brain, form the idea to execution of a movement.
A
- Neocortex –> has idea for a movement
- Direct Pathway via the Basal Ganglia –> facilitates appropriate patterns of motor activity to achieve desired movement
- Information sent via thalamus to SMA
- SMA communicates with M1
- M1 controls motor neurones via corticospinal tract
- Cerebellum –> identifies & correct errors in movement
- Indirect Pathway –> brings an end to the movement
7
Q
What is the thalamus part of?
A
- Diencephalon
8
Q
What 3 pathways synapse in the thalamus on their way to the cerebral cortex?
A
- Basal Ganglia (usually globus pallidus internal segment)
- Dentate Nucleus of Cerebellum
- Somatosensory Pathways (spinothalamic tract & lateral meniscal pathway)
NB: All pathways carrying specific information to the cerebral cortex synapses in the thalamus
NB: Thalamus is a sort of translation centre (translating incoming excitatory signals for cortex)
This information goes to the thalamus to be relayed to the cortex
9
Q
Where is the thalamus found?
A
- Either side of the 3rd Ventricle
10
Q
Which part of the globus pallidus has an outflow to the thalamus?
A
- Internal Segment
NB: Most things that need to go to the thalamus/cortex from the basal ganglia go via the globus pallidus internal segment
11
Q
What is the only information type that goes to the cerebral cortex that is not relayed by the thalamus?
A
- Smell
12
Q
What is important about the connection between the thalamus & cerebral cortex?
A
- Each nucleus of the thalamus –> has reciprical connections with a specific area of cerebral cortex
- Informaton can also be passed between cortical areas via the thalamus
13
Q
What is communication between region of cortex called?
A
- Direct Association Neurones (main way of communication)
NB: They can also communicate with other regions via the thalamus (however this is not the main way)
14
Q
Important point about the thalamus.
A
- Different types of information –> go to different nuclei in the thalamus
15
Q
What is the superior colliculus important for?
A
- Eye Movement
16
Q
What is the inferior colliculus important for?
A
- Auditory Pathway
17
Q
Where is the hypothalamic sulcus found between?
A
Groove between:
- Intraventricular Foramen
- Opening of the Aqueduct
18
Q
What is above & below the hypothalamic sulcus?
A
- Anything Below –> HYPOTHALAMUS
- Anything Above –> THALAMUS (on the side of the 3rd ventricle)
NB: Thalamus is further back than 3rrd ventricle but forms a large part of the 3rd ventricle wall
19
Q
Where is the internal medullary lamina (intramedullary) found and what is it?
A
- Sheet of White Matter
- Found in the middle of the thalamus (which is mostly grey) which divides at the front (fork)
20
Q
Where is the anterior nucleus found?
A
- Between the 2 branches of the internal medullary lamina (front fork)
- Front of the Thalamus
21
Q
Where is the dorsal medial nucleus found?
A
- Nucleus on the medial side of the internal medullary lamina
*
22
Q
Where is the pulvinar nucleus found?
A
- Expanded nucleus at the back
23
Q
What 2 areas does the pulvinar nucleus have lots of connections with?
A
- Parietal Lobe (more)
- Occipital Lobe (less)
NB: Enlarged in primates
24
Q
Where is the intralaminar nuclei?
A
- Found inside the internal medullary lamina
- Group of nuclei found here (middle of thalamus)
25
How many **lateral nuclei** are there?
What are they called?
* 3 nuclei
1. **Ventral-Posterior** Lateral Nucleus (back)
2. **Ventral-Lateral** Lateral Nucleus (side)
3. **Ventral-Anterior** Lateral Nucleus (front - besides anterior nucleus)
NB: Each are important with specific connections with specific places of the brain
26
Which pathway is the **lateral** **geniculate** **nuclei** involved in?
* Visual Pathway
27
Which **pathway** is the **medial** **geniculate** **nuclei** involved in?
* Auditory Pathway
28
Where are the **lateral** & **medial** **geniculate** **nuclei** found?
* These sit at the **bottom** of the **thalamus**
* They look like **'pimples'**
29
Where is the **thalamic** **reticular** **nucleus** found?
What is its **function**?
* Around the **lateral** **sides** of the **thalamus**
* This is **different** from the **rest** of the **thalamus**
* Receives **collaterals** from fibres that come **in** & **out** of the **thalamus**
* Function --\> **Counsciousness**
30
What is the **claustrum** important for?
* It is the seat of **consciousness**
31
What **sensory** **modalities** does the **dorsal column / medial lemniscal pathway** relay?
1. Discriminative Touch
2. Conscious Propioception
3. Vibration Sense
32
What **sensory** **modalities** does the **spinothalamic** **tract** relay?
1. Nociception
2. Temperature
3. Light Touch
33
Where in the brain do **all somatosensory fibres** **relay** before going to the **cerebral** **cortex**?
* Thalamus
NB: **All** somatosensory fibres do this
34
Which **nucleus** do **somatosensory** **fibres** relay through in the **thalamus**?
* Ventral-Posterior Nucleus
35
What is the **main** **somatosensory** **nucleus** of the **thalamus**?
* **Ventral-Posterior Nucleus** of the **Thalamus**
36
What **arrangement** is the **ventral**-**posterior** **nucleus** in?
Roughly how is it organised?
* Somatotopic Arrangement
* **Head** Sensory Information --\> **Medial** Part of VP Nucleus
* **Rest of Body** Sensory Information --\> **Lateral** Part of VP Nucleus
37
What is the **ventral**-**posterior** **nucleus** of the **thalamus** important for?
* Somatosensory relay
* **Connected** to the **somatosensory** **cortex (post-central gyrus)**
38
What **syndrome** can arise from damage to the **somatosensory nuclei in the thalamus**?
* Thalamic Syndrome
39
**Occlusion** in which blood supply can cause **thalamic** **syndrome**?
* Posterior Cerebral Artery (supplies thalamus)
40
Where do the **blood** **supply** to the **thalamus** come from?
* Posterior Cerebral Artery (PCA)
41
How does **damage** to the **thalamus** usually arise?
* Vascular Problem
42
How is the **ventral**-**posterior** **nucleus** specifically supplied?
* Small blood vessels from the PCA
These can be **blocked** --\> causing **variable** **effects** --\> however **somatosensation** is **almost** **_always_** **affected**
43
What are the **effects** of **thalamic** **syndrome**?
* **All** **somatosensory** activity from the **contralateral** **side** --\> is **interpreted** as **painful**
* Will **not** feel other somatosensation
* **Numb but painful feeling**
* This will be **ongoing** (24 hours a day)
NB: Pain is like being immersed in boiling hot water continuously
44
What is a **big** **issue** with **thalamic** **syndrome**?
* Pain is ongoing
* Very painful
* **High rate of suicide** (due to pain)
45
What are the effects of **prefrontal** **lobotomy** on **pain**?
* Patients could **_still_** **feel** **pain**
* However --\> they were **no** **longer** **worried** about the **pain** (thus no longer suicidal)
No prefrontal lobe --\> means you cannot plan for the future --\> therefore you do not worry for the rest of your life
**NB**: Pain is a construct of the cerebral cortex
46
Good diagram of the brain blood supply
47
Describe the **pathway** of the **PCA** and the **supply to the thalamus.**
* **Winds** **around** the **midbrain**
* Gives off **lots** of **small** **branches** at the **base** **of** **the** **brain**
* Some Branches --\> **penetrating central branches** --\> supplying **thalamus**
48
What is the **main** **output** from the **cerebellum**?
* Dentate Nucleus
NB: Helps to coordinate movements via 2 nuclei in the thalamus
49
Which **2 nuclei** are the **destinations** of the **main** **output** from the **cerebellum** (dentate nucleus)?
* **Ventral-Lateral** Nuclei
* **Ventral-Anterior** Nuclei
NB: These then have recipricol connections with the pre-motor & motor cortex
50
What part of the brain activates when planning movements?
* Supplementary Motor Area
* Active Bilaterally (even if the movement is one sided)
51
What are the **2 main motor nuclei** in the **thalamus** which relay **motor** **information** to the **motor** **cortex**?
* Ventral-Anterior Nucleus
* Ventral-Lateral Nucleus
52
What is the **general** **function** of the **corpus** **striatum**?
* **Part** of the **basal** **ganglia**
* Selects **appropriate** **programs** for **producing** **movements** that your **cortex** **desires**
53
What are the **2 main functions** of the **cerebellum**?
1. Coordination of Movement
2. Correction of Errors
54
Where does the **basal** **ganglia** particularly **relay** **information** up to?
Where does it go via?
* Supplementary Motor Area (SMA)
* Thalamus
55
Where does the **optic** **tract** go via to get to **Area V1?**
* Lateral Geniculate Nucleus
56
What are **2 other names** for **area V1**?
* Brodmann Area 17
* Calcarine Cortex
57
Discribe briefly the path from the **retina** to the **brain**.
* **Retinal Ganglia** --\> send information down the optic nerve
* It goes the **lateral geniculate nucleus (LGN)**
* **LGN** --\> has **recipricol** **connection** with **V1** in the **calcirine** **cortex**
58
Outline the **auditory** **pathway** in the brain from the **cochlear** **nuclei**.
1. Fibre from the **Cochlea** --\> synapses onto the **Inferior** **Colliculus**
2. Fibres from here go to the **Medial** **Geniculate** **Nucleus** of the **Thalamus**
3. **Medial Geniculate Nucleus** --\> fibres go to the **Primary Auditory Cortex**
Cochlea --\> Inferior Colliclus --\> Medial Geniculate Nucleus --\> Primary Auditory Cortex
59
Where is the **primary** **auditory** **cortex** found?
* Buried in the **Lateral** **Fissure** on the **Superior** **Surface** of the **Temporal** **Lobe**
60
Where does the fibre from the **cochlea** first synapse?
* Inferior Colliculus
61
Which part of the **thalamus** is involved in the **auditory** **pathway**?
* Medial Geniculate Nucleus
62
Which nucleus in the **thalamus** is involved with **emotions** & **personality**?
* Dorsal Medial Nucleus
63
What is the pathway for emotions? (generally)
* **Amygdala --\> Dorsomedial Nucleus (Thalamus) --\> Prefrontal Cortex**
NB: Recipricol connection always between thalamus & cortex
64
Via what **part** of the **internal** **capsule** do the fibres go to the **prefrontal** **cortex**?
* Anterior Limb of the Internal Capsule
NB: Recipiricol connection
65
What are the effects of the amygdala when its **stimulated** and when its **ablated**?
* **Stimulated** --\> Anger & Fright
* **Ablated (Bilaterally)** --\> Placcidity
66
What is the **intralaminar** **nuclei** important for?
* Consciousness
67
What type of monoamine does the **locus** **ceruleus** send?
* Noradrenaline (NA)
NB: Found at the base of the brain (fibres go everywhere)
68
Where is the **locus** **ceruleus** found?
* Pons
69
What does the **locus** **ceruleus** & **noradrenaline** fibres do?
* **Activates** the **cerebral** **cortex**
70
What **monoamine** does the **nucleus** **basalis** send **all over the neocortex**?
* Cholinergic Fibres
71
What nucleus can the **reticular** **fibres** activate?
* Nucleus Basalis (ACh)
72
What function are the following involved in?
* Locus Ceruleus (pons)
* Reticular Fibres
* Nucleus Basalis
* Hypothalamic Nuclei
* Consciousness (keep you alert)
73
Where are the **reticular** **formation** found? (2 places)
1. **Medial part** of the **Rostral Pons**
2. **Midbrain**
74
Damage to what **3 places** can cause a **profound** **coma** to be induced?
1. Reticular Formation (**medial part of the rostral pons**)
2. Reticular Formation (**midbrain**)
3. **Intralaminer** **Nuclei** in the **Thalamus** (bilaterally)
Damage/distruption to this system --\> means the cerebral cortex is not stimulated/woken up --\> giving rise to a coma
75
Where do fibres from the **intralaminer** **nuclei** go?
* **Cerebral Cortex**
* **Non-specific** (unlike other nuclei in the thalamus)
* **Widespread** **excitatory** **neurones**
* **Collaterals** going all over to **large areas of neocortex**
76
What is the **main** **input** into the **intralaminer** **nuclei**?
Why is this pathway important?
* Information from the **Reticular** **Formation** in the **Brainstem**
* Lots of **Nociceptive** **Inputs** go to the **Reticular** **Formation**
Therefore painful stimuli go to reticular formation --\> then to intralaminer nuclei --\> which then goes to widespread areas of cortex --\> important in consciousness
* Allows you to be **awoken** in **cortex** if there is **pain**
* **Protective function**
77
What **2** **places** do **axon** **collaterals** go to from the **intralaminer** **nuclei**?
Why is this needed?
1. Cerebral Cortex
2. Striatum
Allows the **striatum** & **cortex** to be **prepared & ready** to **organise** **movements** in response to a **nasty** **stimulus**
NB: Cold object on your face whilst you are asleep
78
Other than the **brainstem** **reticular** **formation**, from where else does the **intralaminer** **nuclei** get **inputs** from?
* **Spinothalamic Tract** (nociceptive pathway) - directly
79
What procedure may be able to help patients with damage to these alertness centres restore consciousness?
What does the procedure involve?
* **Deep brain stimulation**
* **Electrodes** placed in the **central** **part** of the **thalamus**
* Stimulate the **intralaminer** **nucleus** in the **thalamus**
NB: Very important nucleus in consciousness
80
Name the **6 structures** which make up the **limbic** **system**
1. Amygdala
2. Hippocampus
3. Thalamus
4. Hypothalamus
5. Basal Ganglia
6. Cingulate Gyrus
81
What is the overall function of the amygdala?
* **Emotion** centre of the brain
82
What is the overall **hippocampus** function?
* Essential role in forming **new memories** about **past** **experiences**
83
Where is the **limbic** **cortex**?
* **Anterior** **part** of the **cingulate gyrus**
* **Continous** with the **parahippocampal** **gyrus** (via isthmus)
* **Ends** at the **uncus** (medial temporal lobe part for smell)
84
Where is the **cingulate** **gyrus** found? (generally)
* Goes around the **corpus** **callosum**
85
What are the **main 2 functions** of the **limbic** **cortex**?
1. Memory
2. Controlling ANS
NB: Complicated functions
NB: When forming **memory** **information** goes from the **_anterior cingulate gyrus_** to the **_parahippocampus_** (centre for memory)
86
Where is the **high** **micturition** **centre**?
* **Anterior** **part** of the **cingulate** **gyrus**
87
What is the high **mictruition** **centre** responsible for?
* Enables **what** & **when** & **where** it is appropriate for you to **empty** your **bladder**
* **Anterior** **part** of the **cingulate** **gyrus**
* It must be functioning on **at least 1 side** of the **brain**
88
What **condition** can affect the **cingulate** **gyrus** area?
* Meningioma
89
What effect does **nocieption** have on the **anterior** **cingulate** **gyrus**?
* It activates the **ANS** **system** (e.g. sympathetic)
90
**Schematic** of the **medial** **side** of the **brain** **hemisphere**.
91
What is the **cingulum**?
* **Bundle** of **axons** connecting the **cingulate** **cortex** with the **entorhinal** **cortex + parahippocampal gyrus**
92
Where is the **entorhinal** **cortex** found?
* **Anterior** **part** of the **parahippocampal** **gyrus**
93
To where does the **entorhinal** **cortex** send axons?
NB: **Entorhinal** **cortex** = anterior part of the parahippocampal gyrus
* Hippocampus
94
What is the **overall** **general** **pathway** of the **limbic** **system**?
Cingulate Gyrus --\> Parahippocampal Gyrus + Entorhinal Cortex --\> Hippocampus
95
What do the **3 red arrows** point to on this scan?
96
What is found in the **inferomedial** **temporal** **lobe**?
* Hippocampus & Adjacent Cortex
97
What is the important function of the **inferomedial** **temporal** lobe?
* Needed for **Episodic** **Memory** formation
NB: New events about past memories (who, what, where etc.)
98
In which **fossa** is the **hippocampus** situated in?
* Middle Cranial Fossa
99
What **pathology** can happen in the **middle** **cranial** **fossa** and what part of the **brain** could this affect?
* **Infection** can **accumulate**
* Can affect **Hippocampus**
100
Where is the **hippocampus** found?
* **Deep** in the **medial temporal lobe**
101
What do you need for **episodic** **memory**?
* **Hippocampus** (medial temporal lobe) on **at least one side**
102
What **condition** do you get from **bilateral ablation** of the **hippocampus** (medial temporal lobe)?
What is this condition?
* Anterograde Amnesia
* **Cannot** put **new** **memories** into your **memory** **stores** --\> thus **cannot** make **long**-**term** **memories** (does not affect short-term memory)
NB: It is necessary on **one** **side** of the brain to form **episodic** **memory**
103
What **condition** can commonly affect the **medial** **temporal** **lobe** in the **middle** **cranial fossa**?
How does it happen?
What is affected?
* Meningitis
* Common
* Lots of **bacteria** found in the **subarachnoid** **space**
* **Subarachnoid** **space** contains **CSF** and is found **all around the brain**
* Bacteria settles down in the **middle** **temporal** **fossa** around **medial** **temporal** **lobe** (hippocampus region)
* This damage causes **inability** to form **episodic memory**
104
What **types** of **neurones** are found in the **hippocampus**?
* Pyramidal Neurones
105
How is the **hippocampus** **shaped**?
What **divisions** is it divided into?
* **Medial** **surface** of the **temporal** **lobe** --\> the **cortex** is **folded in**
* Forms the **hippocampus**
* **Divided** into **CA1**
106
What **2 other structures** are part of the **hippocampus**?
* **Fornix** (white matter from hippocampal formation)
* **Dentate gyrus**
107
How many **layers** are there in the **hippocampus** and what is the **middle** **layer** called?
* **3 layers**
* **Middle** --\> Pyramidal Cell Layer
108
Learn this diagram
109
What does the **septal** **nucleus** do in terms of the **hippocampus**?
* Sends **cholinergic** **neurones** back to the **hippocampus** along the **same** **pathway** through the **fornix**
* **Cholinergic fibres** --\> do **not** carry **specific information** --\> they help **synaptic** **activity** **everywhere**
110
Where is the **mammilary** **body** found?
* Bump on the **bottom** of the **hypothalamus**
111
What are the **2 sources of afferent input** into the **hippocampus** called?
* **Perforant path**
* **Septohippocampal**
112
What do the the **septohippocampal** carry?
* **Cholinergic** **fibres** (from septal nuclei)
* Carries **ACh** (non-specific information) --\> to **improve** & **speed up information** **processing** --\> this **promotes** **synaptic** **activity**
* Comes from the **septal** **nuclei**
**NB**: Septal nuclei afferents go all over the hippocampus
113
What is the **perforant** **pathway**?
* Path from the **entorhinal** **cortex** to the **dentate** **gyrus**
* Carries **specific** **information** about **what** things are going into the **memory** **stores**
* Axons **perforate** the **cortex** --\> **enter dentate gyrus**
* **Mossy** **fibres** then go to **CA3 (hippocampus)**
Entorhinal Cortex --\> Dentate Gyrus --\> Hippocampus
114
What is the path from the **septal** **nuclei** to the **hippocampus**?
How does it help?
* Sends **cholinergic** **fibres** through the **fornix** --\> into **hippocampus**
* **Promotes synaptic activity --\> helps memorisation**
115
What **disease** involves **problems** with the **septal** **nuclei**?
* Alzeihmers
116
What are the **2 possible output** **directions** form the **hippocampal** **formation**?
* **Via fornix**
* **Via Entorhinal Cortex** (back the way they came)
117
Describe the **hippocampal** **output** pathway via **fornix**.
Which **nucleus** of the **thalamus** does it synapse into?
* **Output** from the **hippocampus**
* Runs along the **pathway** to **mammary** **body** (all the way around)
* Synapses into the **anterior** **nucleus** of the **thalamus**
118
Where does **CA1** **output** go?
* Entorhinal Cortex
119
Name the 3 pointed structures.
120
What happens to the **mammilary** **body** in **alcoholics**?
**Why?**
How can this be **stopped** or **_maybe_** **reveresed**?
* Shrivels up & dies
* **Lack** **thymine** in the diet
* Giving **thymine** **supplements**
121
Learn this summary of tracts.
122
What is so important about this **circuit of papez**?
* Necessary on **at least one side** of the **brain** in order to **form a memory**
NB: **Hippocampus** & **medial temporal lobe** are needed on **at least one side** for forming **memory**
123
What happens if there is **bilateral** **damage** to the **circuit of papez**?
* **Loss** of **episodic** **memory**
124
What happened to **patient** **NA**?
* **Fencing foil** --\> whent up his nose straight into **thalamus**
* Destroyed **mammillary** **bodies** (hypothalamus) & **mammalothalamic tract**
* These are part of the **circuit of papez**
* **Bilateral** **damage** --\> meant **lose of ability** to **form episodic memory**
He kept things around him to try and remind of places he had been & had lists around the house of things he needed to remember
There were **no cognitive deficiences**
125
What can cause **bilateral** **damage** to **medial** **temporal** **lobes**?
* **Infections**
* **Accumulate bilaterally** in the **medial cranial fossa**
**NB:** Bilateral stroke can also cause this but this is very unlikely
126
What happened to **patient** **HM**?
* **_Bilateral_** **removal** of **medial** **temporal** **lobes**
* **No** cognitive effects
* Could **not** remember **new** **events** **again (episodic memory)**
127
What is the **syndrome** called when you have **bilateral** **damage** to the **temporal** **lobes**?
* **Kluver-Bucy Syndrome**
* Loss of **anterior** **temporal** **lobe** **bilaterally**
*
128
What are the effects of **Kluver**-**Bucy** **syndrome**?
* **Profound amnesia** (inability to form episodic memory) --\> **anterograde** (new events)
* **Hypersexuality** (amygdala removed)
* **Placidity** (amygdala removed)
* **Taste everything**
* **Visual agnosia** (loss of visual association cortex)
129
How is the **temporal** **lobe** involved in **vision**?
* **Temporal lobe** --\> part of **visual** **association** **cortex**
* Involved in **identifying** **objects** in the **visual** **field** ('what' stream)
**NB**: FFA is also part of the temporal lobe
130
What are the effects of **losing** **vision** **areas** in **temporal** **lobe**?
* **Inability** to **recognise things**
* **Visual agonsia (**if bilateral)
* Mix up a **tree** with a b
131
What causes **Korsakoff's** **syndrome**? (2 things)
* **Mammillary nuclei** degeneration
* **Anterior** **thalamus** degeneration
132
What causes **Korsakoff's syndrome**?
Among who is it common?
* **Loss** of **Vitamin B1 Intake**
* Causes **degeneration** of **mammillary body** & **anterior nucleus**
* **Common** among **alcoholics** & **vitamin deficiency**
133
What are the **effects** of **Korsakoff's** **syndrome**?
1. **Profound** **retrograde** **amnesia** (loss of memmory from before event)
2. **Confabulation**
134
What is the **hypothalamus** **in** **charge** of?
* Hormones!
* **Top** **centre** that **controls** **_ANS_** & **_Hormones_**
135
What are the **hypothalamic** **nuerones** involved in?
* **Neurosecretion** from **Posterior Pituitary Gland**
* **Production** of **Release** **Factors** that **regulate hormone release** from **Anterior Pituitary Gland**
136
What happens in terms of **body** **temperature** if the **hypothalamus** is **damaged**?
* **No control** over **body temperature**
* **Constantly** need to **measure it**
* Go into **cold** & **warm** places to change it
* **Cold-Blooded**
137
Name the **7 things** that the **hypothalamus** **regulates**?
1. **Sleep** & **wakefulness**
2. **Body temperature**
3. **Food intake**
4. **Water intake & loss** (hormones & behaviour)
5. Other aspects of **ANS**
6. **Sex** & **reproduction** (hormones & behaviour)
7. **Direct stress response** (influences blood flow to specific tissues bya cting as 1st step in stimulation of secretion of adrenal stress hormones)
138
Where is **histamine** released from?
What is its affect on **consciousness**?
* **Histaminergic** **neurones** found in the **hypothalamus**
* **Controls sleep/day cycle**
* **More Histamine --\> More Awake**
* **Less** **histamine** is released during **sleep**
139
What is a **common** **side effect** of **anti-histamines?**
Does this **always** happen?
* **Sleepiness**
* Only if it **penetrates** the **blood-brain barrier** (thus affects brain)
