Thalamus and hypothalamus

The thalamus and hypothalamus together form a part of the brain known as the diencephalon, which resides at the centre of the brain. This pattern in one in a series of pattern that fit together to form a life-sized human brain, and also includes details on how to make the optic nerve. I have already published the pattern for the cerebellum/brainstem and the ventricles/corpus collosum.

Note that the thalamus/ hypothamus are shown in green in the image above, with the optic nerve in gold. The blue section is the ventricles.

Difficulty:

Easy - difficult

The main difficulty comes from the fiddlyness of the hypothalamus

You will need:

• A 2.5mm crochet hook
• A 1mm crochet hook
• A 0.8mm crochet hook (optional)
• Anchor creativa fino 4ply cotton in green
• Rico essentials #10 cotton in emerald and gold
• Polyester toy stuffing
• A darning needle for sewing up

For each of the thalami (make 2):
With green 4ply yarn and a 2.5mm crochet hook make a magic loop with 5sc

Round 1: make 2sc in each st (10sts)
Round 2: sc5, make 2sc in the next st, sc2, make 2sc in the following st, sc (12sts)
Round 3: sc6, make 2sc in the next st, sc3, make 2sc in the following st, sc (14sts)
Round 4: sc7, make 2sc in the next st, sc3, make 2sc in the following st, sc2 (16sts)
Round 5: sc9, make 2sc in the next st, sc4, make 2sc in the following st, sc (18sts)
Rounds 6 - 10: (5 rounds) sc in each st
Round 11: sc, sc3tog, sc, sc3tog, sc2, sc3tog, sc, sc3tog, sc (10sts)
Stuff firmly
Round 12: sc2tog 5 times (5sts)
Fasten off

For the centre bit:
With the green 4ply and 2.5mm hook ch6
Round 1: sc in the first chain st you made, then sc in each of the following 5 chain sts to make a loop (6sts)
Fasten off

Sew this between the two lobes to connect them. It should be positioned slightly closer to the magic loop end compared to where you fastened off.

(ignore the optic nerve for the minute-we'll come to that later)

Note that if you intend to make a complete brain, make the ventricles first. After this you should sew the connecting section to one side of the thalamus, before threading it through the hole in the centre of the ventricles and sewing the other end to the other thalamus (see images below)

For the hypothalamus:

With a 1mm crochet hook and emerald #10 yarn ch4
Round 1: sc in the 2nd chain st from hook and the next chain st. Make 3sc in the first chain st you made, then sc in the back of the previous chain st you crocheted into. Make 2sc in the back of the first chain st you crocheted into (8sc)
Round 2: Make 2sc in the first st, sc2, make 3hdc in the next st, sc2, make 2sc in each of the last 2sts (13sts)
Round 3: Slip1, make 3hdc in the next st, sc3, ch1, make 2hdc in the following st, ch1 sc3, make 2hdc in the next st, slip2, make 3hdc in the last st (21sts(including the chain sts))
Round 4: Sc in each st
Round 5: (Note that this is slightly more than 1 round. The number of stitches is the number you should have after the round is complete) Sc7, sc2tog, sc, sc2tog, sc7, sc3tog (17sc)
Round 6: Sc8, ch6, skip the remaining sts of this round
Round 7: Sc6, sc3tog between the next 2sts and following chain st, sc in the next 5 chain sts (12sc)
Round 8: Sc5, sc3tog, sc4 (10sc)
Round 9: make 4hdc in the first st, sc3, sc3tog, sc3 (11sts)
Round 10: Sc2, make 2sc in each of the next 2sts, sc3, sc3tog, sc (11sts)
Round 11: Sc, sc5tog, sc, sc2tog twice (5sts)
Fasten off

Round 5: Ch6, then sc in the 2nd st after the last st you crocheted into on round 4. Sc in the next 7sts

Round 6: Sc in the first 5 chain sts of the last round, then sc3tog between the last chain st and the following 2sts. Sc in the next 6sts (12sc)
Round 7: Sc4, sc3tog, sc5 (10sc)
Round 8: Sc3, sc3tog, sc3, make 4hdc in the last st (11sts)
Round 9: Sc2, sc3tog, sc3, make 2sc in each of the next 2sts, sc (11sts)
Round 10: Sc, sc2tog twice, sc, sc5tog (5sts)
Fasten off

Rejoin yarn to row 4 to one of the sts you haven't crocheted into yet. 

Row 5: Sc in this st. ch1, turn
Rows 6 - 9: (4 rows) Sc in this st. ch1, turn

Row 10: sc in this st
Fasten off

Sew the end you just fastened off to the other st you haven't crocheted into in row 4, then stuff lightly and sew the sides of this bit you just made to the chain sts you made of row 5, as shown below

Sew to the  front of the thalamus (the end closest to where you sewed the connecting part). The cast-on chain should be on the side furthest away from the thalamus, as shown below.

Front-on view

The optic nerve is an optional extra., which you can choose to add if you wish. I am also planning to included this design in a future pattern I publish detailing how to make all of the cranial nerves, so if you're planning to make the whole brain you don't need to worry about making this yet.

For the optic nerve:

With gold #10 yarn and 0.8mm hook make a magic loop with 6sc

Rounds 1 - 2: (2 rounds) sc in each st

Round 3: sc2tog, sc4 (5sc)

Round 4: sc2tog, sc3 (4sc)

Rounds 5 - 8: (4 rounds) sc in each st

Rounds 9 - 10: (2 rounds) slip2, hdc2

Rounds 11 - 15: (5 rounds) sc in each st

---

Fasten off neatly

Repeat as before up to --- 

Round 16: sc3, sc in the 'new' st of the first section you made, sc in the next 2sts (6sc)

Round 17: sc in the first 3sts of the last round, ch1

Round 18: slip the first 2sts of last round, then hdc in the next st and chain st (4sts)

Rounds 19 - 21: (3 rounds) sc in each st

Fasten off

Rejoin yarn to round 16 to the st after the last st you crocheted in before you made the ch1 on round 17

Round 17: Sc in this st and the next 2sts, ch1

Round 18: slip2, hdc2

Rounds 19 - 21: (3 rounds) sc in each st

Fasten off

Sew the ends of this nerve to the outer edges of the thalami as shown below. (The hypothalamus isn't shown in these images but the principal is the same)

That's all for this pattern, I hope you have enjoyed it! If you have any questions about this or any of my other patterns please don't hesitate to get in touch - you can leave a comment below or contact  me via my  Ravelry or  Instagram (Instagram is best if you're hoping for a speedy reply). You can also email me at lhodginscrochet@gmail.com if you prefer :)

As always you are very welcome to sell finished products but please don't re-post this pattern or claim it as your own. Thank you!