Neuroscience

1. Domina Petric, MD

2. We effortlessly detect and classify objects from among
tens of thousands of possibilities (Biederman, 1987).
We do so within a fraction of a second (Potter, 1976;
Thorpe, 1996).
There is tremendous variation in appearance that each
object produces on our eyes.
Our survival depends on our accurate and rapid
extraction of object identity from the patterns of photons
on our retinae.

3. Importance of the dorsal visual stream for:
supporting the ability to guide the eyes or covert
processing resources (spatial attention) toward
objects (Ikkai, 2011; Noudoost 2010; Valyear,
2006)
supporting the ability to shape the hand to
manipulate an object (Goodale, 1994; Murata,
2000)

4. Object recognition is the ability
to assign labels (nouns) to
particular objects, ranging from
precise labels (identification) to
course labels (categorization).

5. The ventral visual stream has been parsed
into distinct visual areas based on:
 anatomical connectivity patterns
 distinctive anatomical structure
 retinotopic mapping (Felleman, Van Essen,
1991)

6. All visual cortical areas share a six-layered structure and
the inputs and outputs to each visual area share
characteristic patterns of connectivity:
 ascending feedforward input is received in layer 4
 ascending feedforward output originates in the upper
layers
 descending feedback originates in the lower layers
 feedback is received in the upper and lower layers of the
lower cortical area (Felleman, Van Essen, 1991)

7. The only known means of rapidly conveying
information through the ventral pathway is via the
spiking activity that travels along axons.
The neuronal representation in a given cortical area is
the spatiotemporal pattern of spikes produced by the
set of pyramidal neurons that project out of that area.

8. STREAM ALSO
PLAYS AN
IMPORTANT
ROLE IN VISUAL
OBJECT
RECOGNITION!
http://www.cs.tau.ac.il/~
wolf/OR/img/street_anno
tated.jpg

9. DiCarlo JJ, Zoccolan D, Rust NC. How
does the brain solve visual object
recognition? Neuron. 2012;73(3):415-
434. doi:10.1016/j.neuron.2012.01.010.

10. It is the activation in memory of a
representation of a stimulus class from an
image projected by an object to the retina.
One three dimensional object can project
an infinity of possible images onto the two
dimensional retina.

11. Biederman I. An Invitation
to Cognitive Science:
Visual cognition. The MIT
Press.

12. Amnesic patients with hippocampal damage exhibit
significant impairments in the discrimination of
simultaneously presented complex spatial scene stimuli.
The hippocampus plays a role in higher-order spatial
perception.
The hippocampus is critical for the representation of
complex conjunctions of features that constitute spatial
scenes.

13. episodic memory (via mechanisms such
as pattern separation and completion)
other areas of cognition (perception,
non-declarative memory)

14. Lee ACH, Yeung L-K, Barense MD.
The hippocampus and visual
perception.Frontiers in Human
Neuroscience. 2012;6:91.
doi:10.3389/fnhum.2012.00091.

15. http://www.memory
lossonline.com/glo
ssary/images/hippo
campus.jpg